ciguatoxins and Ciguatera-Poisoning

Ciguatera is a major circumtropical poisoning caused by the consumption of marine fish and invertebrates contaminated with ciguatoxins (CTXs): neurotoxins produced by endemic and benthic dinoflagellates which are biotransformed in the fish food-web. We provide a history of ciguatera research conducted over the past 70 years on ciguatoxins from the Pacific Ocean (P-CTXs) and Caribbean Sea (C-CTXs) and describe their main chemical, biochemical, and toxicological properties. Currently, there is no official method for the extraction and quantification of ciguatoxins, regardless their origin, mainly due to limited CTX-certified reference materials. In this review, the extraction and purification procedures of C-CTXs are investigated, considering specific objectives such as isolating reference materials, analysing fish toxin profiles, or ensuring food safety control. Certain in vitro assays may provide sufficient sensitivity to detect C-CTXs at sub-ppb levels in fish, but they do not allow for individual identification of CTXs. Recent advances in analysis using liquid chromatography coupled with low- or high-resolution mass spectrometry provide new opportunities to identify known C-CTXs, to gain structural insights into new analogues, and to quantify C-CTXs. Together, these methods reveal that ciguatera arises from a multiplicity of CTXs, although one major form (C-CTX-1) seems to dominate. However, questions arise regarding the abundance and instability of certain C-CTXs, which are further complicated by the wide array of CTX-producing dinoflagellates and fish vectors. Further research is needed to assess the toxic potential of the new C-CTX and their role in ciguatera fish poisoning. With the identification of C-CTXs in the coastal USA and Eastern Atlantic Ocean, the investigation of ciguatera fish poisoning is now a truly global effort.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Fishes; Public Health

Ciguatera Poisoning (CP) is a seafood poisoning highly prevalent in French Polynesia. This illness results from the consumption of seafood contaminated with ciguatoxins (CTXs) produced by Gambierdiscus, a benthic dinoflagellate. Ciguatera significantly degrades the health and economic well-being of local communities largely dependent on reef fisheries for their subsistence. French Polynesia has been the site of rich and active CP research since the 1960's. The environmental, toxicological, and epidemiological data obtained in the frame of large-scale field surveys and a country-wide CP case reporting program conducted over the past three decades in the five island groups of French Polynesia are reviewed. Results show toxin production in Gambierdiscus in the natural environment may vary considerably at a temporal and spatial scale, and that several locales clearly represent Gambierdiscus spp. "biodiversity hotspots". Current data also suggest the "hot" species G. polynesiensis could be the primary source of CTXs in local ciguateric biotopes, pending formal confirmation. The prevalence of ciguatoxic fish and the CTX levels observed in several locales were remarkably high, with herbivores and omnivores often as toxic as carnivores. Results also confirm the strong local influence of Gambierdiscus spp. on the CTX toxin profiles characterized across multiple food web components including in CP-prone marine invertebrates. The statistics, obtained in the frame of a long-term epidemiological surveillance program established in 2007, point towards an apparent decline in the number of CP cases in French Polynesia as a whole; however, incidence rates remain dangerously high in some islands. Several of the challenges and opportunities, most notably those linked to the strong cultural ramifications of CP among local communities, that need to be considered to define effective risk management strategies are addressed.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Food Chain; Humans; Polynesia

The first ciguatera fish poisoning (CFP) in Portugal dates from 2008 when 11 people reported CFP symptoms after consuming a 30 kg amberjack caught around the Selvagens Islands (Madeira Archipelago). Since then, 49 human poisonings have been reported. The emergence of a new threat challenged scientists and regulators, as methods for toxic microalgae analyses and ciguatoxin (CTX) detection were not implemented. To minimise the risk of ciguatera, the Madeira Archipelago authorities interdicted fisheries in Selvagens Islands and banned the capture of amberjacks weighing more than 10 kg in the entire region of Madeira Archipelago. The accurate identification and quantification of the benthic toxin-producing algae species spreading to new areas require efforts in terms of both microscopy and molecular techniques. Two ciguatera-causing dinoflagellates,

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ecosystem; Fishes; Humans; Portugal; Retrospective Studies

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Fishes; Foodborne Diseases; Humans

Currently, digital technologies influence information dissemination in all business sectors, with great emphasis put on exploitation strategies. Public administrations often use information systems and establish open data repositories, primarily supporting their operation but also serving as data providers, facilitating decision-making. As such, risk analysis in the public health sector, including food safety authorities, often relies on digital technologies and open data sources. Global food safety challenges include marine biotoxins (MBs), being contaminants whose mitigation largely depends on risk analysis. Ciguatera Fish Poisoning (CFP), in particular, is a MB-related seafood intoxication attributed to the consumption of fish species that are prone to accumulate ciguatoxins. Historically, CFP occurred endemically in tropical/subtropical areas, but has gradually emerged in temperate regions, including European waters, necessitating official policy adoption to manage the potential risks. Researchers and policy-makers highlight scientific data inadequacy, under-reporting of outbreaks and information source fragmentation as major obstacles in developing CFP mitigation strategies. Although digital technologies and open data sources provide exploitable scientific information for MB risk analysis, their utilization in counteracting CFP-related hazards has not been addressed to date. This work thus attempts to answer the question, "What is the current extent of digital technologies' and open data sources' utilization within risk analysis tasks in the MBs field, particularly on CFP?", by conducting a systematic literature review of the available scientific and grey literature. Results indicate that the use of digital technologies and open data sources in CFP is not negligible. However, certain gaps are identified regarding discrepancies in terminology, source fragmentation and a redundancy and downplay of social media utilization, in turn constituting a future research agenda for this under-researched topic.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Digital Technology; Disease Outbreaks; Fishes; Humans; Information Storage and Retrieval; Marine Toxins; Risk Assessment; Seafood

Ciguatera poisoning is one of the most prevalent types of fish poisoning, but it is often underreported, leading many health practitioners to be unfamiliar in correctly identifying and treating this toxicity.. We present a case of ciguatera toxicity encountered in an emergency department in a Midwest community hospital setting. A 56-year-old woman presented to the ED with symptoms of perioral numbness, generalized pruritis, and hot/cold temperature reversal. Through careful history taking it was determined that the patient had recently returned from vacationing in the Caribbean and had been consuming meals containing various types of fish. A clinical diagnosis of ciguatera toxicity was made, and the patient was treated supportively. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This topic is important in the realm of emergency medicine because it presents a known toxicologic pathogen in an unsuspecting geographic location. This case highlights the importance of maintaining broad differentials and considering a patient's travel and exposure history to make the clinical diagnosis of ciguatoxin as well as the importance of preventative management to avoid recurrence of symptoms. We review the etiology of this fascinating toxin as well as the clinical implications in the diagnosis and management of this toxicity.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Female; Humans; Middle Aged; Travel

Ciguatera fish poisoning (CFP) is one of the most devastating food-borne illnesses caused by fish consumption. Ciguatoxins (CTXs) are potent neurotoxins synthesized by the benthic microalgae Gambierdiscus spp. and Fukuyoa spp. that are transmitted to fish by grazing and predation. Despite the high incidence of CFP, affecting an estimated number of 50,000 persons per year in tropical and subtropical latitudes, the factors underlying CTXs occurrence are still not well understood. Toxin transfer and dynamics in fish and food-webs are complex. Feeding habits and metabolic pathways determine the toxin profile and toxicity of fish, and migratory species may transport and spread the hazard. Furthermore, CTX effect on fish may be a limiting factor for fish recruitment and toxin prevalence. Recently, new occurrences of Gambierdiscus spp. in temperate areas have been concomitant with the detection of toxic fish and CFP incidents in non-endemic areas. CFP cases in Europe have led to implementation of monitoring programs and fisheries restrictions with considerable impact on local economies. More than 400 species of fish can be vectors of CTXs, and most of them are high-valued commercial species. Thus, the risk uncertainty and the spread of Gambierdiscus have serious consequences for fisheries and food safety. Here, we present a critical review of CTXs impacts on fish, fisheries, and humans, based on the current knowledge on CFP incidence and CTXs prevalence in microalgae and fish.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Europe; Fisheries; Fishes; Food Contamination; Food Safety; Humans

Ciguatera fish poisoning (CFP) is currently the most common marine biotoxin food poisoning worldwide, associated with human consumption of circumtropical fish and marine invertebrates that are contaminated with ciguatoxins. Ciguatoxins are very potent sodium-channel activator neurotoxins, that pose risks to human health at very low concentrations (>0.01 ng per g of fish flesh in the case of the most potent Pacific ciguatoxin). Symptoms of CFP are nonspecific and intoxication in humans is often misdiagnosed. Presently, there is no medically approved treatment of ciguatera. Therefore, to mitigate the risks of CFP, reliable detection of ciguatoxins prior to consumption of fish tissue is acutely needed, which requires application of highly sensitive and quantitative analytical tests. During the last century a number of methods have been developed to identify and quantify the concentration of ciguatoxins, including in vivo animal assays, cell-based assays, receptor binding assays, antibody-based immunoassays, electrochemical methods, and analytical techniques based on coupling of liquid chromatography with mass spectrometry. Development of these methods, their various advantages and limitations, as well as future challenges are discussed in this review.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes; Food Contamination; Humans

Ciguatera fish poisoning (CFP), the most prevalent seafood poisoning worldwide, is caused by the consumption of tropical and subtropical fish contaminated with potent neurotoxins called ciguatoxins (CTXs). Ciguatera is a complex clinical syndrome in which peripheral neurological signs predominate in the acute phase of the intoxication but also persist or reoccur long afterward. Their recognition is of particular importance in establishing the diagnosis, which is clinically-based and can be a challenge for physicians unfamiliar with CFP. To date, no specific treatment exists. Physiopathologically, the primary targets of CTXs are well identified, as are the secondary events that may contribute to CFP symptomatology. This review describes the clinical features, focusing on the sensory disturbances, and then reports on the neuronal targets and effects of CTXs, as well as the neurophysiological and histological studies that have contributed to existing knowledge of CFP neuropathophysiology at the molecular, neurocellular and nerve levels.

Topics: Action Potentials; Animals; Ciguatera Poisoning; Ciguatoxins; Diagnostic Errors; Humans; Nervous System Diseases; Prevalence

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Europe; Fishes; Food Analysis; Limit of Detection; Seafood; Tandem Mass Spectrometry

Historical records of ciguatera in Mexico date back to 1862. This review, including references and epidemiological reports, documents 464 cases during 25 events from 1984 to 2013: 240 (51.72%) in Baja California Sur, 163 (35.12%) in Quintana Roo, 45 (9.69%) in Yucatan, and 16 (3.44%) cases of Mexican tourists intoxicated in Cuba. Carnivorous fish, such as snapper (

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes; Foodborne Diseases; Humans; Mexico; Seafood

Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world. It causes substantial human health, social, and economic impacts. The illness produces a complex array of gastrointestinal, neurological and neuropsychological, and cardiovascular symptoms, which may last days, weeks, or months. This paper is a general review of CFP including the human health effects of exposure to ciguatoxins (CTXs), diagnosis, human pathophysiology of CFP, treatment, detection of CTXs in fish, epidemiology of the illness, global dimensions, prevention, future directions, and recommendations for clinicians and patients. It updates and expands upon the previous review of CFP published by Friedman et al. (2008) and addresses new insights and relevant emerging global themes such as climate and environmental change, international market issues, and socioeconomic impacts of CFP. It also provides a proposed universal case definition for CFP designed to account for the variability in symptom presentation across different geographic regions. Information that is important but unchanged since the previous review has been reiterated. This article is intended for a broad audience, including resource and fishery managers, commercial and recreational fishers, public health officials, medical professionals, and other interested parties.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fishes; Humans; Public Health; Seafood

Moray eels (

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Eating; Eels; Food Contamination; Humans; Risk

Ciguatoxins (CTX) and brevetoxins (BTX) are polycyclic ethereal compounds biosynthesized by the worldwide distributed planktonic and epibenthic dinoflagellates of

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Humans; Ligands; Marine Toxins; Oxocins; Potassium Channels, Voltage-Gated

In the coastal countries of East Asia and Southeast Asia, ciguatera should be common because of the extensive tropical and subtropical coral reefs along the coasts and in the neighboring seas with ciguatoxic fishes. An extensive search of journal databases, the Internet and the government websites was performed to identify all reports of ciguatera from the regions. Based on the official data and large published case series, the incidence of ciguatera was higher in the coastal cities (Hong Kong, Foshan, Zhongshan) of southern China than in Japan (Okinawa Prefecture). In Singapore, ciguatera appeared to be almost unknown. In other countries, only isolated cases or small case series were reported, but under-reporting was assumed to be common. Ciguatera may cause severe acute illness and prolonged neurological symptoms. Ciguatera represents an important public health issue for endemic regions, with significant socio-economic impact. Coordinated strategies to improve risk assessment, risk management and risk communication are required. The systematic collection of accurate data on the incidence and epidemiology of ciguatera should enable better assessment and management of its risk. Much more work needs to be done to define the size threshold for important coral reef fish species from different regions, above which the risk of ciguatera significantly increases.

Topics: Animals; Asia, Eastern; Asia, Southeastern; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Humans; Incidence; Risk Assessment; Risk Management

To determine the ciguatoxic potential of brown-marbled grouper (Epinephelus fuscoguttatus) in relation to fish size and geographical origin, this review systematically analyzed: 1) reports of large ciguatera outbreaks and outbreaks with description of the fish size; 2) Pacific ciguatoxin (P-CTX) profiles and levels and mouse bioassay results in fish samples from ciguatera incidents; 3) P-CTX profiles and levels and risk of toxicity in relation to fish size and origin; 4) regulatory measures restricting fish trade and fish size preference of the consumers. P-CTX levels in flesh and size dependency of toxicity indicate that the risk of ciguatera after eating E. fuscoguttatus varies with its geographical origin. For a large-sized grouper, it is necessary to establish legal size limits and control measures to protect public health and prevent overfishing. More risk assessment studies are required for E. fuscoguttatus to determine the size threshold above which the risk of ciguatera significantly increases.

Topics: Animals; Body Size; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Geography; Humans; Indian Ocean; Pacific Ocean; Perciformes; Risk Assessment

Brown marbled grouper (Epinephelus fuscoguttatus) is an apex predator from coral reefs of the Indo-Pacific region. All five published case series of ciguatera after consumption of brown marbled grouper were reviewed to characterize the types, severity and chronicity of ciguatera symptoms associated with its consumption. Three of these case series were from large outbreaks affecting over 100-200 subjects who had eaten this reef fish served at banquets. Affected subjects generally developed a combination of gastrointestinal, neurological and, less commonly, cardiovascular symptoms. Gastrointestinal symptoms occurred early and generally subsided in 1-2 days. Some neurological symptoms (e.g., paresthesia of four limbs) could last for weeks or months. Sinus bradycardia and hypotension occurred early, but could be severe and prolonged, necessitating the timely use of intravenous fluids, atropine and dopamine. Other cardiovascular and neurological features included atrial ectopics, ventricular ectopics, dyspnea, chest tightness, PR interval >0.2 s, ST segment changes, polymyositis and coma. Concomitant alcohol consumption was associated with a much higher risk of developing bradycardia, hypotension and altered skin sensation. The public should realize that consumption of the high-risk fish (especially the ciguatoxin-rich parts and together with alcohol use) and repeated ciguatoxin exposures will result in more severe and chronic illness.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Foodborne Diseases; Humans; Perciformes

In the present review, the main objective was to describe the epidemiology and clinical features of ciguatera fish poisoning in Hong Kong. From 1989 to 2008, the annual incidence of ciguatera varied between 3.3 and 64.9 (median 10.2) per million people. The groupers have replaced the snappers as the most important cause of ciguatera. Pacific-ciguatoxins (CTX) are most commonly present in reef fish samples implicated in ciguatera outbreaks. In affected subjects, the gastrointestinal symptoms often subside within days, whereas the neurological symptoms can persist for weeks or even months. Bradycardia and hypotension, which can be life-threatening, are common. Treatment of ciguatera is primarily supportive and symptomatic. Intravenous mannitol (1 g/kg) has also been suggested. To prevent ciguatera outbreaks, the public should be educated to avoid eating large coral reef fishes, especially the CTX-rich parts. A Code of Practice on Import and Sale of Live Marine Fish for Human Consumption for Prevention and Control of Ciguatera Fish Poisoning was introduced from 2004 to 2013. The Food Safety Ordinance with a tracing mechanism came into full effect in February 2012. The Government would be able to trace the sources of the fishes more effectively and take prompt action when dealing with ciguatera incidents.

Topics: Administration, Intravenous; Animals; Atropine; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Dopamine; Fishes; Hong Kong; Humans; Incidence; Mannitol; Seafood

Humphead wrasse (Cheilinus undulatus) is an apex predator from coral reefs of the Indo-Pacific region. A food surveillance project using a validated mouse bioassay revealed the presence of ciguatoxins in significantly greater amounts in its flesh than in groupers and other coral reef fishes commonly available in Hong Kong wholesale market. Humphead wrasse has long been known to cause ciguatera, but there was a lack of clinical reports. A 45-year-old woman developed ciguatera after eating humphead wrasse. She required ICU care and infusions of intravenous fluids and dopamine for management of severe hypotension. All 5 published case series are also reviewed to characterise the types, severity and chronicity of ciguatera symptoms after its consumption. In addition to the gastrointestinal, neurological and other features that were typical of ciguatera, some subjects developed sinus bradycardia, hypotension, shock, neuropsychiatric features (e.g. mental exhaustion, depression, insomnia and memory loss), other central nervous system symptoms (e.g. coma, convulsions and ataxia) and myocardial ischaemia. Other subjects still experienced residual symptoms 6 months later; these were mainly neurological or neuropsychiatric complaints and skin pruritus. To prevent ciguatera, the public should avoid eating humphead wrasse and other large coral reef fishes. They should realise that consumption of the high-risk fish may result in more severe and chronic illness, including life-threatening complications and neuropsychiatric features.

Topics: Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Female; Foodborne Diseases; Humans; Middle Aged; Perciformes

Ciguatera fish poisoning (CFP) is an illness caused by eating tropical coral fish contaminated with ciguatoxins (CTXs). The clinical management of patients with CFP is generally supportive and symptomatic in nature as no antidote exists. Of the many drugs prescribed, several have been claimed to be efficient in small, uncontrolled studies, but the outcomes of treatments with these medicines are often contradictory. In New Caledonia, traditional remedies are commonly employed in the treatment of CFP and of the 90 plant species catalogued as useful in CFP, the most popular herbal remedy by far is a decoction prepared from the leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae). Other important plants used in the treatment of CFP include Euphorbia hirta L. (Euphorbiaceae) and Vitex L. sp. (Lamiaceae). This review focuses on the evidence for efficacy of these species and pharmacological studies which support their use. Other plants used in CFP and the conventional treatment of CFP are also discussed briefly.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Humans; Molecular Structure; New Caledonia; Phytotherapy; Plant Extracts; Plants, Medicinal; Vanuatu

Ciguatera fish poisoning is a seafood-borne illness caused by consumption of fish that have accumulated lipid-soluble ciguatoxins. In the United States, ciguatera is responsible for the highest reported incidence of food-borne illness outbreaks attributed to finfish, and it is reported to hold this distinction globally. Ciguatoxins traverse the marine food web from primary producers, Gambierdiscus spp., to commonly consumed fish in tropical and subtropical regions of the world. Ciguatoxins comprise 12 known congeners among Caribbean and tropical Atlantic fish and 29 reported congeners among Pacific fish. Expanding trade in fisheries from ciguatera-endemic regions contributes to wider distribution and increasing frequency of disease among seafood consumers in non-endemic regions. Ciguatoxins produce a complex array of gastrointestinal, neurological and cardiological symptoms. Treatment options are very limited and supportive in nature. Information derived from the study of ciguatera outbreaks has improved clinical recognition, confirmation, and timely treatment. Such studies are equally important for the differentiation of ciguatoxin profiles in fish from one region to the next, the determination of toxicity thresholds in humans, and the formulation of safety limits. Analytical information from case and outbreak investigations was used to derive Pacific and Caribbean ciguatoxin threshold contamination rates for adverse effects in seafood consumers. To these threshold estimates 10-fold safety factors were applied to address individual human risk factors; uncertainty in the amount of fish consumed; and analytical accuracy. The studies may serve as the basis for industry and consumer advisory levels of 0.10ppb C-CTX-1 equivalent toxicity in fish from the tropical Atlantic, Gulf of Mexico, Caribbean, and 0.01ppb P-CTX-1 equivalent toxicity in fish from Pacific regions.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Consumer Product Safety; Dinoflagellida; Disease Outbreaks; Dose-Response Relationship, Drug; Environmental Monitoring; Fishes, Poisonous; Food Chain; Humans; Industry; Preventive Medicine; Risk Assessment; Seafood

Ciguatera fish poisoning (CFP) occurs mainly when humans ingest finfish contaminated with ciguatoxins (CTXs). The complexity and variability of such toxins have made it difficult to develop reliable methods to routinely monitor CFP with specificity and sensitivity. This review aims to describe the methodologies available for CTX detection, including those based on the toxicological, biochemical, chemical, and pharmaceutical properties of CTXs. Selecting any of these methodological approaches for routine monitoring of ciguatera may be dependent upon the applicability of the method. However, identifying a reference validation method for CTXs is a critical and urgent issue, and is dependent upon the availability of certified CTX standards and the coordinated action of laboratories. Reports of CFP cases in European hospitals have been described in several countries, and are mostly due to travel to CFP endemic areas. Additionally, the recent detection of the CTX-producing tropical genus Gambierdiscus in the eastern Atlantic Ocean of the northern hemisphere and in the Mediterranean Sea, as well as the confirmation of CFP in the Canary Islands and possibly in Madeira, constitute other reasons to study the onset of CFP in Europe [1]. The question of the possible contribution of climate change to the distribution of toxin-producing microalgae and ciguateric fish is raised. The impact of ciguatera onset on European Union (EU) policies will be discussed with respect to EU regulations on marine toxins in seafood. Critical analysis and availability of methodologies for CTX determination is required for a rapid response to suspected CFP cases and to conduct sound CFP risk analysis.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Climate Change; Dinoflagellida; Disease Outbreaks; Environmental Monitoring; Epidemiological Monitoring; Europe; Fishes; Food Contamination; Food Inspection; Health Communication; Humans; Internationality; Phytoplankton; Risk Assessment; Seafood

Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world, and it causes substantial physical and functional impact. It produces a myriad of gastrointestinal, neurologic and/or cardiovascular symptoms which last days to weeks, or even months. Although there are reports of symptom amelioration with some interventions (e.g. IV mannitol), the appropriate treatment for CFP remains unclear to many physicians. We review the literature on the treatments for CFP, including randomized controlled studies and anecdotal reports. The article is intended to clarify treatment options, and provide information about management and prevention of CFP, for emergency room physicians, poison control information providers, other health care providers, and patients.

Topics: Ciguatera Poisoning; Ciguatoxins; Humans

Ciguatera is a global disease caused by the consumption of certain warm-water fish that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera arising from the consumption of ciguateric fish include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from an Australian perspective, especially the laboratory-based research into the problem that was initiated by the late "Bob" Endean at the University of Queensland.

Topics: Animals; Australia; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Dinoflagellida; Humans; Sodium Channels

Ciguatera is a seafood intoxication that results from ingestion of reef fish contaminated with ciguatoxins at levels orally toxic for humans. Precursors of those toxins, gambiertoxins, are produced by benthic dinoflagellates (genus Gambierdiscus), and then accumulated and biotransformed by herbivorous and carnivorous fishes into ciguatoxins, more toxic for humans. In the absence of specific treatment, that disease remains a health problem with otherwise adverse socio-economic impacts. Thus a cost-effective means of detecting ciguatoxins in fish has long been searched for. Many assays have been developed, including in vivo, in vitro, chemical or immunochemical approaches. This review focuses on some biological methods, from the well-standardised mouse assay to the specific radio-labelled ligand binding assay that is performed on rat brain synaptosomes. In addition to the mouse, the chick and the mongoose were still recently used, in particular for preliminary tests before ciguatoxin extraction from fish, since assays in these animals can directly assay the whole flesh. In contrast, various other in vivo methods, such as the kitten, mosquito and diptera larvae assays, were abandoned despite their interesting results. Finally, the mouse neuroblastoma and rat brain synaptosome assays, carried out in vitro as alternative approaches to animal-using assays, are highly sensitive and much more specific than the in vivo methods to detect ciguatoxins.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Models, Animal; Fishes; Humans; Larva; Mice; Rats; Seafood

The Pacific coast of Central and North America has long been and still is impacted by the flourishing of microalgal populations known as Harmful Algal Blooms (HABs). The organisms that have caused recent HABs episodes in the region are among others, Gymnodinium catenatum, Pyrodinium bahamense var. compressum, and recently Cochlodinium cf. catenatum. In spite of the accumulated effects on the human health, the economic activities and the environment, scarce information is available on the subject. The augmented use of coastal zones for human activities is also paralleled by increased awareness of global climate changes. Thus, it is not an easy task to discriminate anthropogenic or natural phenomena, or both, as the major driving forces. The long-term data sets available for limited regions, as well as some sporadic observations during notorious blooms, allowed us to discriminate major changes in the biodiversity and biogeography of HAB organisms. Main changes refer to number of events, covered area, duration and frequency, number of blooming species and appearance of not previously reported harmful taxa. The variables more clearly related to these dynamic phenomena, seems to be sea surface temperature and wind force, but it is not yet possible to weight their contributions. The participation of rain is not fully evaluated to date. The collaborative communication among small-budget monitoring operations in the region allowed to "pass the voice" about peaking concentrations of HAB organisms, diminishing the risk of poisoning.

Topics: Animals; Central America; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ecosystem; Environmental Monitoring; Epidemiological Monitoring; Eutrophication; Humans; Marine Toxins; North America; Pacific Ocean; Saxitoxin; Tropical Climate

Ciguatera is an important form of human poisoning caused by the consumption of seafood. The disease is characterised by gastrointestinal, neurological and cardiovascular disturbances. In cases of severe toxicity, paralysis, coma and death may occur. There is no immunity, and the toxins are cumulative. Symptoms may persist for months or years, or recur periodically. The epidemiology of ciguatera is complex and of central importance to the management and future use of marine resources. Ciguatera is an important medical entity in tropical and subtropical Pacific and Indian Ocean regions, and in the tropical Caribbean. As reef fish are increasingly exported to other areas, it has become a world health problem. The disease is under-reported and often misdiagnosed. Lipid-soluble, polyether toxins known as ciguatoxins accumulated in the muscles of certain subtropical and tropical marine finfish cause ciguatera. Ciguatoxins arise from biotransformation in the fish of less polar ciguatoxins (gambiertoxins) produced by Gambierdiscus toxicus, a marine dinoflagellate that lives on macroalgae, usually attached to dead coral. The toxins and their metabolites are concentrated in the food chain when carnivorous fish prey on smaller herbivorous fish. Humans are exposed at the end of the food chain. More than 400 species of fish can be vectors of ciguatoxins, but generally only a relatively small number of species are regularly incriminated in ciguatera. Ciguateric fish look, taste and smell normal, and detection of toxins in fish remains a problem. More than 20 precursor gambiertoxins and ciguatoxins have been identified in G. toxicus and in herbivorous and carnivorous fish. The toxins become more polar as they undergo oxidative metabolism and pass up the food chain. The main Pacific ciguatoxin (P-CTX-1) causes ciguatera at levels=0.1 microg/kg in the flesh of carnivorous fish. The main Caribbean ciguatoxin (C-CTX-1) is less polar and 10-fold less toxic than P-CTX-1. Ciguatoxins activate sodium ion (Na ) channels, causing cell membrane excitability and instability. Worldwide coral bleaching is now well documented, and there is a strong association between global warming and the bleaching and death of coral. This, together with natural environmental factors such as earthquakes and hurricanes, and man-made factors such as tourism, dock construction, sewage and eutrophication, may create more favourable environments for G. toxicus. While low levels of G. toxicus are found th

Topics: Acute Disease; Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Cnidaria; Demography; Dinoflagellida; Disease Outbreaks; Fishes, Poisonous; Foodborne Diseases; Humans; Incidence; Indian Ocean Islands; Muscles; Pacific States; Prevalence; Risk Factors; Socioeconomic Factors

Ciguatera is a toxin-related disease caused by ingestion of a variety of toxic fish living in tropical or subtropical areas. This article aims to look at the epidemiology of the disease, from both the descriptive and analytical points of view, and to discuss them in relation to environmental aspects and socioeconomic impact.

Topics: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Asia; Australia; Caribbean Region; Child; Child, Preschool; Ciguatera Poisoning; Ciguatoxins; Cohort Studies; Female; Florida; Foodborne Diseases; Hawaii; Humans; Incidence; Indian Ocean Islands; Infant; Male; Middle Aged; Pacific Islands; Sex Factors; Socioeconomic Factors

1. Ciguatera is a disease caused by sodium channel activator toxins and results from the consumption of warm water fish contaminated by the ciguatoxin class of polyether toxins. 2. Other toxins, including okadaic acid and maitotoxin, have no proven role in causing human illness associated with ciguatera. 3. Ciguatera often affects only a discrete region of a reef, with flare-ups of ciguatera being both temporally and spatially unpredictable. 4. The ciguatoxins likely arise through the biotransformation and acid-catalysed spiroisomerisation of gambiertoxin-4A produced by Gambierdiscus toxicus and it is unlikely that other toxic benthic dinoflagellates are involved. 5. Events leading to a ciguatera outbreak are initiated by environmental and genetic factors that favour the proliferation of gambiertoxins, with an apparent role for anthropomorphic effects; however, the precise factors involved are yet to be determined. 6. The gambiertoxins and/or ciguatoxins are transferred from the benthos to herbivorous species (fish, invertebrates etc) and then to carnivorous fish via marine food chains. 7. Factors influencing the concentration of ciguatoxins that accumulate in fish include the rate of dietary intake, the efficiency of assimilation, the degree and nature of any toxin biotransformation, the rate of depuration, and the rate of growth of fish.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Fishes, Poisonous; Foodborne Diseases; Marine Toxins

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes, Poisonous; Humans; New Caledonia; Poisoning

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes; Food Analysis; Hawaii; Humans; Mannitol

Ciguatera poisoning has long been recognized as a serious problem in the tropical and subtropical regions of the world. Due to international and interstate commerce and tourist travel the phenomenon is spreading to other parts of the globe. Various species of fish (surgeonfish, snapper, grouper, barracuda, jack, amberjack among others) have been implicated in this type of poisoning. These fish accumulate toxins in their flesh and viscera through the consumption of smaller fish that have been previously contaminated by feeding on toxic dinoflagellates. The most probable source of ciguatera is thought to be the benthic microorganism, Gambierdiscus toxicus, which produces both CTX and MTX, but other species of dinoflagellates such as Prorocentrum lima may also contribute with secondary toxins associated with the disease. Potentially ciguatoxic dinoflagellates have been isolated, cultured under laboratory conditions and dinoflagellate growth requirements as well as some factors affecting toxin production have been determined. Also, data from their ecological environment have been accumulated in an attempt to reveal a relationship with the epidemiology of ciguatera outbreaks. Several bioassays have been employed to determine the ciguatoxicity of fish. Cats have been used due to their sensitivity, but regurgitation has made dosage information difficult to obtain. Mongooses have also been used but they often carry parasitic and other type of diseases which complicate the bioassay. Mice have been used more commonly; they offer a more reliable model, can be easily housed, readily are dosed in several ways, and manifest diverse symptoms similar to human intoxications; but the amount of toxic extract needed, time consumed, complicated extraction techniques, and instrumentation involved limit the use of this assay commercially. Other bioassays have been explored including the brine shrimp, chicken, mosquito, crayfish nerve cord, guinea pig ileum, guinea pig atrium, and other histological preparations. All require elaborate time-consuming procedures, are not reproducible, lack specificity, and are semiquantitative at best. The techniques that appear to represent the major advance in identifying and detecting ciguatoxic fish are immunochemical methods: radioimmunoassay (RIA), competitive enzyme immunoassay (EIA), and enzyme-linked immunosorbent assay (ELISA). Of these, the enzyme immunoassay stick test is the simplest, fastest, most specific, more sensitive, and does n

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Fishes; Foodborne Diseases; Global Health; Humans

Topics: Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Female; Fishes, Poisonous; Foodborne Diseases; Humans; Male; Marine Toxins; Paresthesia

The known and theoretical pharmacology of poisons involved in toxic marine ingestions has assisted in the development of specific therapeutics for these afflictions. The clinical manifestations of several toxic marine ingestions have suggested toxins/cogeners that may be involved in the poisoning process, providing direction for the development of diagnostic laboratory tests, including those for cyclic ethers. Future investigations should involve utilization of acetaminophen and indomethacin for chronic ciguatera fish poisoning, and the evaluation of the role of polycyclic ethers in the temperature sensation reversal phenomenon of both ciguatera and neurotropic shellfish poisoning.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes, Poisonous; Hallucinogens; Humans; Marine Toxins; Neurotoxins; Sea Cucumbers; Shellfish; Tetrodotoxin

Ciguatera fish poisoning arises from consumption of any of the 400 species of tropical marine reef fish containing polyether toxins. No laboratory method is available for clinical diagnosis of acute ciguatera poisoning. The objective of this pilot study was to ascertain the potential usefulness of a bioassay to detect ciguatoxins in humans suspected of acute intoxication. We analyzed plasma of healthy volunteers (asymptomatic negative controls), participants with gastrointestinal (GI) illness but without recent fish consumption (symptomatic negative controls), and participants with GI illness who had recently consumedfish.. Blood samples, questionnaires, and consent forms were collected from 11 symptomatic negative controls and 86 patients that visited emergency rooms in southern Puerto Rico over a 1-year period. Patients had consumed fish within 24 hour prior to the symptoms. Plasma samples were analyzed by a neuroblastoma cell bioassay that detects seafood toxins active at the sodium voltage-gated channel in a dose-dependent fashion. Concentrations were expressed in terms of brevetoxin-1 equivalents (ng PbTx-1 equiv/mL).. The mean plasma concentration of 14 asymptomatic negative controls was 39.4 ng PbTx-1 equiv/mL (range 2-74). Of 86 potential ciguatoxic patients who reported fish consumption, 43 had values within the range of normal volunteers, and 9 had concentrations in the nondiagnostic range (73.9-100 ng). Thirty-four patients (40%) had concentrations 3 standard deviations above asymptomatic negative controls (>100 ng PbTx-1 equiv/mL). They had a mean concentration of 1,074 +/- 244.5 ng PbTx-1 equiv/mL (range 101-7,056ng).. Preliminary findings of elevated PbTx-1 equivalents in 40% of the patients with both ciguatera symptomatology and fish consumption in a geographical area where ciguatera is common suggest that the neuroblastoma bioassay may be a potential diagnostic tool for acute ciguatera intoxication.

Topics: Acute Disease; Adolescent; Adult; Aged; Aged, 80 and over; Animals; Biological Assay; Child; Child, Preschool; Ciguatera Poisoning; Ciguatoxins; Dose-Response Relationship, Drug; Female; Foodborne Diseases; Gastrointestinal Diseases; Humans; Infant; Male; Marine Toxins; Middle Aged; Neurotoxins; Oxocins; Pilot Projects; Puerto Rico; Tropical Climate

Convergent and scalable synthesis of the ABCDE-ring fragment of Caribbean ciguatoxin C-CTX-1, the major causative toxin for ciguatera poisoning in the Caribbean Sea and the Northeast Atlantic areas, is described in detail. The key features of the synthesis include an iterative use of 2,2,6,6-tetramethyl piperidine 1-oxyl (TEMPO)/PhI(OAc)

Topics: Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Humans

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Humans; Marine Toxins; Tandem Mass Spectrometry

The dinoflagellates Gambierdiscus and Fukuyoa can produce Ciguatoxins (CTXs) and Maitotoxins (MTXs) that lead to ciguatera poisoning (CP). The CP hotspots, however, do not directly relate to the occurrence of the ciguatoxic Gambierdiscus and Fukuyoa. Species-wide investigations often showed no association between CTX level and the molecular identity of the dinoflagellates. In the Pacific region, Kiribati is known as a CP hotspot, while Malaysia has only three CP outbreaks reported thus far. Although ciguatoxic strains of Gambierdiscus were isolated from both Kiribati and Malaysia, no solid evidence on the contribution of ciguatoxic strains to the incidence of CP outbreak was recorded. The present study aims to investigate the regional differences in CP risks through region-specific toxicological assessment of Gambierdiscus and Fukuyoa. A total of 19 strains of Gambierdiscus and a strain of Fukuyoa were analyzed by cytotoxicity assay of the neuro-2a cell line, hemolytic assay of fish erythrocytes, and high-resolution mass spectrometry. Gambierdiscus from both Kiribati and Malaysia showed detectable ciguatoxicity; however, the Kiribati strains were more hemolytic. Putative 44-methylgambierone was identified as part of the contributors to the hemolytic activity, and other unknown hydrophilic toxins produced can be potentially linked to higher CP incidence in Kiribati.

Topics: Animals; Cell Line; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Malaysia

Ciguatera is a common marine, toxin-borne illness caused by the consumption of fish that contain toxins that activate voltage-sensitive sodium channels. The clinical manifestations of ciguatera are typically self-limited, but chronic symptoms may occur in a minority of patients. This report describes a case of ciguatera poisoning with chronic symptoms, including pruritus and paresthesias. A 40-y-old man was diagnosed with ciguatera poisoning after consuming amberjack while vacationing in the US Virgin Islands. His initial symptoms, including diarrhea, cold allodynia, and extremity paresthesias, evolved into chronic, fluctuating paresthesias and pruritus that became worse after the consumption of alcohol, fish, nuts, and chocolate. After a comprehensive neurologic evaluation failed to reveal another cause for his symptoms, he was diagnosed with chronic ciguatera poisoning. His neuropathic symptoms were treated with duloxetine and pregabalin, and he was counseled to avoid foods that triggered his symptoms. Chronic ciguatera is a clinical diagnosis. Signs and symptoms of chronic ciguatera can include fatigue, myalgias, headache, and pruritus. The pathophysiology of chronic ciguatera is incompletely understood but may involve genetic factors or immune dysregulation. Treatment involves supportive care and avoidance of foods and environmental conditions that may exacerbate symptoms.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Diarrhea; Male; Marine Toxins; Paresthesia

Ciguatera Poisoning is an emerging risk in the east Atlantic Ocean. Despite characterization efforts, the complete profile of ciguatoxin chemical species in these waters is still unknown. These efforts have been complicated by a lack of reference materials and scarcity of fish contaminated with high levels of ciguatoxins. Development and application of analytical methods with enhanced selectivity and sensitivity is essential for ciguatoxin characterization. Here, we developed an analytical characterization approach using capillary liquid chromatography coupled to high resolution mass spectrometry applied to reference materials obtained from ciguatoxin contaminated fish. Capillary LC coupled mass spectrometry resulted in increased sensitivity leading to the confirmation of C-CTX1 as the principal ciguatoxin present in these samples. We also detected and structurally characterized minor C-CTXs analogues consisting of C-CTX3/4, hydroxy-, didehydro-, and methoxy- metabolites.

Topics: Animals; Atlantic Ocean; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Mass Spectrometry

Ciguatera poisoning (CP) is a severe seafood-borne disease, caused by the consumption of reef fish contaminated with Caribbean ciguatoxins (C-CTXs) in the Caribbean and tropical Atlantic. However, C-CTXs have not been identified from their presumed algal source, so the relationship to the CTXs in fish causing illness remains unknown. This has hindered the development of detection methods, diagnostics, monitoring programs, and limited fundamental knowledge on the environmental factors that regulate C-CTX production. In this study, in vitro and chemical techniques were applied to unambiguously identify a novel C-CTX analogue, C-CTX5, from Gambierdiscus silvae and Gambierdiscus caribaeus strains from the Caribbean. Metabolism in vitro by fish liver microsomes converted algal C-CTX5 into C-CTX1/2, the dominant CTX in ciguatoxic fish from the Caribbean. Furthermore, C-CTX5 from G. silvae was confirmed to have voltage-gated sodium-channel-specific activity. This finding is crucial for risk assessment, understanding the fate of C-CTXs in food webs, and is a prerequisite for development of effective analytical methods and monitoring programs. The identification of an algal precursor produced by two Gambierdiscus species is a major breakthrough for ciguatera research that will foster major advances in this important seafood safety issue.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Fishes

Ciguatoxins (CTXs) are marine neurotoxins that cause ciguatera poisoning (CP), mainly through the consumption of fish. The distribution of CTXs in fish is known to be unequal. Studies have shown that viscera accumulate more toxins than muscle, but little has been conducted on toxicity distribution in the flesh, which is the main edible part of fish, and the caudal muscle is also most commonly targeted for the monitoring of CTXs in the Canary Islands. At present, whether this sample is representative of the toxicity of an individual is undisclosed. This study aims to assess the distribution of CTXs in fish, considering different muscle samples, the liver, and gonads. To this end, tissues from four amberjacks (Seriola spp.) and four dusky groupers (Epinephelus marginatus), over 16.5 kg and captured in the Canary Islands, were analyzed by neuroblastoma-2a cell-based assay. Flesh samples were collected from the extraocular region (EM), head (HM), and different areas from the fillet (A-D). In the amberjack, the EM was the most toxic muscle (1.510 CTX1B Eq·g

Topics: Animals; Bass; Ciguatera Poisoning; Ciguatoxins; Fishes; Liver; Seafood

Tropical epibenthic dinoflagellate communities produce a plethora of bioactive secondary metabolites, including the toxins ciguatoxins (CTXs) and potentially gambierones, that can contaminate fishes, leading to ciguatera poisoning (CP) when consumed by humans. Many studies have assessed the cellular toxicity of causative dinoflagellate species to better understand the dynamics of CP outbreaks. However, few studies have explored extracellular toxin pools which may also enter the food web, including through alternative and unanticipated routes of exposure. Additionally, the extracellular exhibition of toxins would suggest an ecological function and may prove important to the ecology of the CP-associated dinoflagellate species. In this study, semi-purified extracts obtained from the media of a

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Humans; Mice; Toxins, Biological

Ciguatera fish poisoning (CFP) is a foodborne illness affecting > 50,000 people worldwide annually. It is caused by eating marine invertebrates and fish that have accumulated ciguatoxins (CTXs). Recently, the risk of CFP to human health, the local economy, and fishery resources have increased; therefore, detection methods are urgently needed. Functional assays for detecting ciguatoxins in fish include receptor binding (RBA) and neuroblastoma cell-based assay (N2a assay), which can detect all CTX congeners. In this study, we made these assays easier to use. For RBA, an assay was developed using a novel near-infrared fluorescent ligand, PREX710-BTX, to save valuable CTXs. In the N2a assay, a 1-day assay was developed with the same detection performance as the conventional 2-day assay. Additionally, in these assays, we used calibrated CTX standards from the Pacific determined by quantitative NMR for the first time to compare the relative potency of congeners, which differed significantly among previous studies. In the RBA, there was almost no difference in the binding affinity among congeners, showing that the differences in side chains, stereochemistry, and backbone structure of CTXs did not affect the binding affinity. However, this result did not correlate with the toxic equivalency factors (TEFs) based on acute toxicity in mice. In contrast, the N2a assay showed a good correlation with TEFs based on acute toxicity in mice, except for CTX3C. These findings, obtained with calibrated toxin standards, provide important insights into evaluating the total toxicity of CTXs using functional assays.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes; Humans; Mice; Neuroblastoma; Protein Binding

An outbreak of food poisoning of unknown origin was notified to Central Queensland Public Health Unit on 9 December 2021. The bulk carrier sailing from Higashiharima, Japan to Gladstone, Australia reported an incident of sudden illness, with 19 out of 20 sailors on board reporting a combination of gastrointestinal and neurological symptoms. Central Queensland Public Health Unit started the outbreak investigation as per Queensland Health public health management guidelines. All 20 of the sailors consumed a self-caught barracuda and squid, prepared by the ship's cook, the day before. Unconsumed samples of the fish and squid were sent for testing. The affected sailors were triaged on arrival and were provided with medical care as required. The barracuda sample contained ciguatoxins (CTXs; P-CTX-1, P-CTX-2, P-CTX-3) with a total count of 3.40 ug/kg confirming the diagnosis. We propose the usage of the combination of gastrointestinal symptoms and paraesthesia in the light of a recent intoxication event for early detection of ciguatera poisoning (CP) in the eastern seaboard of Australia.

Topics: Animals; Australia; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Early Diagnosis; Humans

The growing concern about ciguatera fish poisoning (CF) due to the expansion of the microorganisms producing ciguatoxins (CTXs) increased the need to develop a reliable and fast method for ciguatoxin detection to guarantee food safety. Cytotoxicity assay on the N2a cells sensitized with ouabain (O) and veratridine (V) is routinely used in ciguatoxin detection; however, this method has not been standardized yet. This study demonstrated the low availability of sodium channels in the N2a cells, the great O/V damage to the cells and the cell detachment when the cell viability is evaluated by the classical cytotoxicity assay and confirmed the absence of toxic effects caused by CTXs alone when using the methods that do not require medium removal such as lactate dehydrogenase (LDH) and Alamar blue assays. Different cell lines were evaluated as alternatives, such as human neuroblastoma, which was not suitable for the CTX detection due to the greater sensitivity to O/V and low availability of sodium channels. However, the HEK293 Nav cell line expressing the α1.6 subunit of sodium channels was sensitive to the ciguatoxin without the sensitization with O/V due to its expression of sodium channels. In the case of sensitizing the cells with O/V, it was possible to detect the presence of the ciguatoxin by the classical cytotoxicity MTT method at concentrations as low as 0.0001 nM CTX3C, providing an alternative cell line for the detection of compounds that act on the sodium channels.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; HEK293 Cells; Humans; Mice; Neuroblastoma; Sodium Channels

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ecosystem; Gas Chromatography-Mass Spectrometry; Tandem Mass Spectrometry; Zebrafish

Topics: Animals; Bass; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Ecosystem; Fisheries; Fishes; Hawaii; Tandem Mass Spectrometry

Ciguatoxins (CTXs) which are produced by dinoflagellates of the genus Gambierdiscus and Fukuyoa and share a ladder-shaped polyether structure, are causative compounds of one of the most frequent foodborne illness disease known as ciguatera fish poisoning (CFP). CFP was initially found in tropical and subtropical areas but nowadays the dinoflagellates producers of ciguatoxins had spread to European coasts. Therefore, this raises the need of establishing toxicity equivalency factors for the different compounds that can contribute to ciguatera fish poisoning, since biological methods have been replaced by analytical techniques. Thus, in this work, the effects of six compounds causative of ciguatera, on their main target, the human voltage-gated sodium channels have been analyzed for the first time. The results presented here led to the conclusion that the order of potency was CTX1B, CTX3B, CTX4A, gambierol, gambierone and MTX3. Furthermore, the data indicate that the activation voltage of sodium channels is more sensitive to detect ciguatoxins than their effect on the peak sodium current amplitude.

Topics: Cell Line; Ciguatera Poisoning; Ciguatoxins; Humans; Kinetics; Toxicity Tests; Voltage-Gated Sodium Channels

Topics: Animals; Bass; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Mice; Tandem Mass Spectrometry

Topics: Animals; Bass; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Fishes; Polynesia; Seafood

Ciguatoxins are marine compounds that share a ladder-shaped polyether structure produced by dinoflagellates of the genus Gambierdiscus and Fukuyoa, and include maitotoxins (MTX1 and MTX3), ciguatoxins (CTX3C) and analogues (gambierone), components of one of the most frequent human foodborne illness diseases known as ciguatera fish poisoning. This disease was previously found primarily in tropical and subtropical areas but nowadays, the dinoflagellates producers of ciguatoxins had spread to European coasts. One decade ago, the European Food Safety Authority has raised the need to complete the toxicological available data for the ciguatoxin group of compounds. Thus, in this work, the in vivo effects of ciguatoxin-related compounds have been investigated using internationally adopted guidelines for the testing of chemicals. Intraperitoneal acute toxicity was tested for maitotoxin 1 at doses between 200 and 3200 ng/kg and the acute oral toxicity of Pacific Ciguatoxin CTX3C at 330 and 1050 ng/kg and maitotoxin 1 at 800 ng/kg were also evaluated showing not effects on mice survival after a 96 h observation period. Therefore, for the following experiments the oral subchronic doses were between 172 and 1760 ng/kg for gambierone, 10 and 102 ng/kg for Pacific Ciguatoxin CTX3C, 550 and 1760 ng/kg for maitotoxin 3 and 800, 2560 and 5000 ng/kg for maitotoxin 1. The results presented here raise the need to reevaluate the in vivo activity of these agents. Although the intraperitoneal lethal dose of maitotoxin 1 is assumed to be 50 ng/kg, without chemical purity identifications and description of the bioassay procedures, in this work, an intraperitoneal lethal dose of 1107 ng/kg was obtained. Therefore, the data presented here highlight the need to use a common procedure and certified reference material to clearly establish the levels of these environmental contaminants in food.

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Humans; Mice

Ciguatera poisoning is a global health concern caused by the consumption of seafood containing ciguatoxins (CTXs). Detection of CTXs poses significant analytical challenges due to their low abundance even in highly toxic fish, the diverse and in-part unclarified structures of many CTX congeners, and the lack of reference standards. Selective detection of CTXs requires methods such as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) or high-resolution MS (LC-HRMS). While HRMS data can provide greatly improved resolution, it is typically less sensitive than targeted LC-MS/MS and does not reliably comply with the FDA guidance level of 0.1 µg/kg CTXs in fish tissue that was established for Caribbean CTX-1 (C-CTX-1). In this study, we provide a new chemical derivatization approach employing a fast and simple one-pot derivatization with Girard's reagent T (GRT) that tags the C-56-ketone intermediate of the two equilibrating C-56 epimers of C-CTX-1 with a quaternary ammonium moiety. This derivatization improved the LC-MS/MS and LC-HRMS responses to C-CTX-1 by approximately 40- and 17-fold on average, respectively. These improvements in sensitivity to the GRT-derivative of C-CTX-1 are attributable to: the improved ionization efficiency caused by insertion of a quaternary ammonium ion; the absence of adduct-ions and water-loss peaks for the GRT derivative in the mass spectrometer, and; the prevention of on-column epimerization (at C-56 of C-CTX-1) by GRT derivatization, leading to much better chromatographic peak shapes. This C-CTX-1-GRT derivatization strategy mitigates many of the shortcomings of current LC-MS analyses for C-CTX-1 by improving instrument sensitivity, while at the same time adding selectivity due to the reactivity of GRT with ketones and aldehydes.

Topics: Amination; Ammonium Compounds; Animals; Caribbean Region; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Tandem Mass Spectrometry

Ciguatera poisoning (CP) is one of the most common causes worldwide of marine poisoning associated with fish consumption from tropical areas. Its incidence is underreported. CP cases seem to increase with grouped cases reported during summer. Exposure to ciguatoxins, toxins responsible for CP with sodium-channel agonistic, voltage-gated potassium channel blocking, cholinergic, and adrenergic activities, may result in a large spectrum of manifestations. We aimed to describe the clinical characteristics, management, and outcome of CP in Martinique, French West Indies. We conducted an observational retrospective single-center study during six years (October 2012 to September 2018) including all CP patients managed by the prehospital medical services, admitted to the university hospital emergency department, or declared to the regional health agency. A total of 149 CP patients (81 females/63 males; median age, 46 years (interquartile range, 34-61)) were included. Acute features consisted in general (91%; mainly, myalgia pruritus, and asthenia), gastrointestinal (90%; mainly diarrhea, abdominal pain, and nausea), neurological (72%; mainly, paresthesia, dysgeusia, and impairment of hot/cold feeling), and cardiovascular manifestations (22%; bradycardia, hypotension, and heart conduction disorders). Management was supportive. No patient died but symptoms persisted in 40% of the 77 patients with follow-up at day 15. CP was mainly attributed to the ingestion of trevallies (59%), snappers (13%), and king mackerels (8%) with collective contaminations (71%). Unusual fish (tuna, salmon, and spider conchs) were suspected in rare cases. Ingestion of trevallies was associated with significantly higher persistent symptoms (odds ratio, 3.00; 95% confidence interval, (1.20-8.00);

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Female; Fishes; Humans; Male; Martinique; Retrospective Studies; West Indies

Gambierdiscus spp. is mainly responsible for the ciguatera fish poisoning (CFP) around the world. The gambiertoxin produced by Gambierdiscus can be passed through the food chain to form ciguatoxins (CTXs) that cause ciguatoxins poisoning. However, the toxic effects of Gambierdiscus on fish through the food chain and related mechanism remains unclear. In this study, the toxicity of Gambierdiscus caribaeus on the marine medaka (Oryzias melastigma) was investigated, where the simulated food chain toxic algae-food organism-fish (G. caribaeus-Artemia metanauplii-O. melastigma) was set. The results showed that direct or indirect exposure through the food chain of G. caribaeus could affect the swimming behaviour of O. melastigma, manifested as decreased swimming performance and spontaneous abnormal swimming behaviours. Histological observation showed that direct or indirect exposure of G. caribaeus caused different degrees of pathological damage to the gills, intestine and liver tissues of O. melastigma. Transcriptome sequencing and RT-qPCR demonstrated that G. caribaeus exposure could trigger a series of physiological and biochemical responses, mainly reflected in energy metabolism, reproductive system, neural activity, immune stress and drug metabolism in marine medaka. Our finding may provide novel insight into the toxicity of Gambierdiscus on fish.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Oryzias

Ciguatera fish poisoning (CFP) is recognized as the most frequent seafood poisoning due to the consumption of fish containing the principal toxins, ciguatoxins (CTXs). In Japan, CFP events have been reported annually from Okinawa and Amami Islands, locating subtropical regions. In addition, there have been reported several outbreaks due to consumption of the fish caught from the Pacific coast of the Mainland and they were often caused by the matured spotted knifejaw, Oplegnathus punctatus. As part of our research on CFP in Japan, we investigated CTXs analysis by LC-MS/MS on 176 individuals of O. punctatus (weight: 100-6,350 g, standard length: 13-60 cm) from the coast of the Mainland (Honshu, Shikoku, and Kyushu), Amami, Okinawa, and Ogasawara (Bonin) Islands. CTXs were detected from only two specimens collected from Okinawa. Total CTXs levels of the two specimens were at 0.014 and 0.040 μg/kg, respectively, exceeding FDA guidance level at 0.01 μg CTX1B equivalent/kg. However, they might be little risk of CFP because consuming over 1.5 kg of flesh is needed to develop intoxication. The toxins consisted of CTX1B analogs including CTX1B, 52-epi-54-deoxyCTX1B, CTX4A, and CTX4B, and no CTX3C analogs, supporting the finding that ciguatoxic fishes in Okinawan Waters containing only CTX1B analogs.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Japan; Tandem Mass Spectrometry

Topics: Cell Size; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Humans; Oxocins

Dinoflagellates of the genera Gambierdiscus and Fukuyoa are able to produce potent neurotoxins like ciguatoxins (CTXs), which, after biooxidation in fish, are responsible for ciguatera intoxication. An isolate of G. australes from the Canary Islands, that revealed the presence of CTX-like compounds by immunosensing tools, was studied by immunocytochemistry to localize intracellular CTX-like compounds, using 8H4 monoclonal antibody that specifically recognizes the right wing of CTX1B and CTX3C analogues. Confocal microscopy observations of immunostained whole cells revealed a strong positive reaction on cell surface and all along the cell outline, while no reaction was detected inside the cells, probably because the antibody was not able to pass through thecal plates. Cell sections showed a positive antibody staining not only on thecal plates, but also inside cytoplasm, with numerous small dots and larger tubule-like reticulate structures. Small fluorescent dots were detected also on the nuclear surface. These observations indicate that CTX-like compounds are present in G. australes cytoplasm, and then are, at least in part, released to cover the cell surface.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Microscopy, Confocal; Spain

The benthic dinoflagellate genus

Topics: Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ethers; Humans; Toxins, Biological

Ciguatera poisoning is mainly caused by the consumption of reef fish that have accumulated ciguatoxins (CTXs) produced by the benthic dinoflagellates

Topics: China; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Dinoflagellida; Species Specificity

Ciguatera poisoning (CP) is one of the most abundant seafood poisonings in the world. CP frequently occurred in the tropical and subtropical Indo-Pacific Ocean and the Caribbean Sea. In Japan, CP cases have been reported annually, from the subtropical regions, including Okinawa Prefecture and Amami Islands, Kagoshima Prefecture. The principal toxins, named ciguatoxins (CTXs), are bio-synthesized by benthic dinoflagellate of genera Gambierdiscus and Fukuyoa. They are bio-transferred herbivorous animals to carnivorous fishes via the food chain.The Ogasawara Islands comprise more than 30 islands, Mukojima Islands, Chichijima (Bonin) Islands, Hahajima Islands, Iwo Islands, Nishinoshima, Minamitorishima, and Okinotorishima, which locate in the tropical to subtropical regions. The Mukojima Islands, Chichijima Islands, and Hahajima Islands locate approximately the same latitude as Okinawa. The distance from Tokyo is approximately 1,000 km for Chichijima, 1,700 km for Okinotorishima (the southernmost tip of Japan), and 1,900 km for Minamitorishima (the easternmost tip of Japan). These islands exist in a wide range of waters, latitudes from 20°25' to 27°44' North and longitudes from 136°04' to 153° 59' East. We collected 65 specimens of a grouper, Variola louti, the most frequent species implicated in CP in Japan, from the waters around the Chichijima, Mukojima, and Hahajima islands. The fish flesh specimens were analyzed CTXs using the liquid chromatography-tandem mass spectrometer (LC-MS/MS). While the peak whose retention time is almost identical to that of CTX1B was detected in all specimens on our routine protocol, no 52-epi-54-deoxyCTX1B nor 54-deoxyCTX1B was detected. The peak retention time was quite different from that of CTX1B when re-analyzing by changing the analytical column. Thus, the CTXs in the specimens in the waters of these islands seemed to be undetectable levels.

Topics: Animals; Bass; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Islands; Japan; Smallpox; Tandem Mass Spectrometry

Modeling ciguatoxin (CTX) trophic transfer in marine food webs has significant implications for the management of ciguatera poisoning, a circumtropical disease caused by human consumption of CTX-contaminated seafood. Current models associated with CP risk rely on modeling abundance/presence of CTX-producing epi-benthic dinoflagellates, e.g.,

Topics: Animals; Bioaccumulation; Ciguatera Poisoning; Ciguatoxins; Perciformes; Risk Assessment; Tissue Distribution

Benthic dinoflagellates of the genus Gambierdiscus produce ciguatoxins, compounds that when metabolized in fish and consumed by humans cause ciguatera poisoning (CP). This syndrome, which is widespread in tropical and subtropical regions, has recently been reported also in subtropical-temperate latitudes such as the Canary Islands where CP events have been regularly detected since 2004. This study examined the effect of temperature on the growth of Gambierdiscus isolated from Canary waters: G. australes, G. caribaeus, G. carolinianus, G. excentricus, and G. silvae. From the temperature vs. growth curves, the maximum growth (µ

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Spain; Temperature

The proliferation of harmful microalgae endangers aquatic ecosystems and can have serious economic implications on a global level. Harmful microalgae and their associated toxins also pose a threat to human health since they can cause seafood-borne diseases such as ciguatera. Implementation of DNA-based molecular methods together with appropriate detection strategies in monitoring programs can support the efforts for effective prevention of potential outbreaks. A PCR-lateral flow assay (PCR-LFA) in dipstick format was developed in this work for the detection of two Gambierdiscus species, G. australes and G. excentricus, which are known to produce highly potent neurotoxins known as ciguatoxins and have been associated with ciguatera outbreaks. Duplex PCR amplification of genomic DNA from strains of these species utilizing species-specific ssDNA tailed primers and a common primer containing the binding sequence of scCro DNA binding protein resulted in the generation of hybrid ssDNA-dsDNA amplicons. These were captured on the dipsticks via hybridization with complementary probes and detected with a scCro/carbon nanoparticle (scCro/CNPs) conjugate. The two different test zones on the dipsticks allowed the discrimination of the two species and the assay exhibited high sensitivity, 6.3 pg/μL of genomic DNA from both G. australes and G. excentricus. The specificity of the approach was also demonstrated using genomic DNA from non-target Gambierdiscus species and other microalgae genera which did not produce any signals. The possibility to use cells directly for amplification instead of purified genomic DNA suggested the compatibility of the approach with field sample testing. Future work is required to further explore the potential use of the strategy for on-site analysis and its applicability to other toxic species.

Topics: Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ecosystem; Nucleic Acids

Ciguatera fish poisoning is caused by the consumption of fish contaminated with ciguatoxins (CTXs). The most distressing symptoms are cutaneous sensory disturbances, including cold dysesthesia and itch. CTXs are neurotoxins known to activate voltage-gated sodium channels, but no specific treatment exists. Peptidergic neurons have been critically involved in ciguatera fish poisoning sensory disturbances. Protease-activated receptor-2 (PAR2) is an itch- and pain-related G protein‒coupled receptor whose activation leads to a calcium-dependent neuropeptide release. In this study, we studied the role of voltage-gated sodium channels, PAR2, and the PAR2 agonist cathepsin S in the cytosolic calcium increase and subsequent release of the neuropeptide substance P elicited by Pacific CTX-2 (P-CTX-2) in rat sensory neurons and human epidermal keratinocytes. In sensory neurons, the P-CTX-2‒evoked calcium response was driven by voltage-gated sodium channels and PAR2-dependent mechanisms. In keratinocytes, P-CTX-2 also induced voltage-gated sodium channels and PAR2-dependent marked calcium response. In the cocultured cells, P-CTX-2 significantly increased cathepsin S activity, and cathepsin S and PAR2 antagonists almost abolished P-CTX-2‒elicited substance P release. Keratinocytes synergistically favored the induced substance P release. Our results demonstrate that the sensory effects of CTXs involve the cathepsin S-PAR2 pathway and are potentiated by their direct action on nonexcitable keratinocytes through the same pathway.

Topics: Animals; Calcium; Cathepsins; Ciguatera Poisoning; Ciguatoxins; Coculture Techniques; Cytosol; Disease Models, Animal; Epidermis; Humans; Intravital Microscopy; Keratinocytes; Paresthesia; Primary Cell Culture; Pruritus; Rats; Receptor, PAR-2; Sensory Receptor Cells; Single-Cell Analysis; Substance P

Ciguatera fish poisoning (CFP), one of the most frequently occurring seafood poisonings due to marine finfish consumption, mainly affects the tropical and subtropical Indo-Pacific region and the Caribbean Sea. The principal class of toxins, ciguatoxins (CTXs) from the Pacific, includes more than 20 derivatives and are classified into two groups, CTX1B and CTX3C congeners, based on their skeletal structures. As part of risk management of CFP by the Japanese government, the import of certain species of fish into Japan is prohibited. Additionally, local governments recommend rejecting certain fish species caught in Japan. In this study, we used LC-MS/MS to analyze CTXs from 18 fish specimens belonging to 7 species that had been brought to a wholesale market but were disapproved for sale because of their potential danger of CFP. CTXs were detected in four specimens of Lutjanus bohar and one specimen of Variola louti. It was estimated that the two most poisonous specimens (no. 5: 0.348 μg/kg, no. 8: 0.362 μg/kg) had a toxicity of 0.05 MU/g. Consumption of 200 g of flesh from these fish could cause CFP. Thus, the guidance of the local government to disallow the sale of these fish species in the market contributed to the prevention of CFP.Only CTX1B congeners were detected in L. bohar (specimen no. 5), which had no record of the area where it captured from. It is presumed that the origin of specimen no. 5 was the same as that of the Okinawan L. bohar because the CTX compositions were similar. In two specimens (nos. 6 and 8) from Wakayama, both CTX1B and CTX3C congeners were detected. This is the first report to reveal the CTX profile in fish collected off the Honshu island in Japan.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Japan; Tandem Mass Spectrometry

Synthesis of the JKLMN-ring fragment of Caribbean ciguatoxin C-CTX-1, the causative toxin of ciguatera fish poisoning in the Caribbean Sea and the Northeast Atlantic areas, is described in detail. Key to the synthesis are a [2,3]-sigmatropic rearrangement to construct a seven-membered α-hydroxy

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Ethers; Fishes

Ciguatera fish poisoning (CFP) poses a serious threat to both public health and the use of aquatic resources from the various warm-water regions of the world. Hence, a process for the efficient determination of the relevant toxins is required.. We sought to develop and validate the first LC-MS/MS method to quantify the major toxins prevalent in fish from the Pacific Ocean.. Toxins were extracted from fish flesh (2 g) using a methanol-water mixture (9:1, v/v). The extract was heated at 80°C, and low-polarity lipids were eliminated using hexane, initially from the basic solution and later from the acidic solution. The cleanup was performed using solid-phase extraction, Florisil, silica, reversed-phase C18, and primary secondary amine columns. A validation study was conducted by spiking fish flesh with two representative toxins having different skeletal structures and polarities and was calibrated by NMR (qNMR) spectroscopy.. The validation parameters for the ciguatera toxins CTX1B and CTX3C at spiked levels of 0.1 µg/kg were as follows: repeatabilities of 2.3-3.5% and 3.2-5.3%; intermediate precisions of 6.3-9.8% and 6.0-7.4%; recoveries of 80-107% and 95-120%, respectively. The lowest detection levels were 0.004 µg/kg for CTX1B, 0.005 µg/kg for 51-hydroxyCTX3C, and 0.009 µg/kg for CTX3C.. The described method practically clears the international action level of 0.01 µg/kg CTX1B equivalents set by the U.S. Food and Drug Administration and the European Food Safety Authority and satisfies the global standards set by Codex and AOAC INTERNATIONAL.. A validation study for an LC-MS/MS method for ciguatoxin detection was completed for the first time using calibrated toxin standards.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Tandem Mass Spectrometry

Topics: Animals; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Tandem Mass Spectrometry

Ciguatera poisoning has caused illnesses in New Zealand through the consumption of contaminated reef fish imported from Pacific Islands. In May 2020 five people became ill and one was hospitalised following the consumption of Fiji Kawakawa (camouflage grouper; Epinephelus polyphekadion). The fish was purchased in New Zealand but imported from Fiji. The meal remnants were analysed for ciguatoxins, the causative compounds of ciguatera poisoning, and showed the presence of the three main toxic fish metabolites. Other fish tested from the same shipment did not contain detectable levels of ciguatoxins, indicating they were likely not toxic.

Topics: Adult; Animals; Bass; Ciguatera Poisoning; Ciguatoxins; Fiji; Humans; Male; Middle Aged; New Zealand; Seafood; Young Adult

Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including

Topics: Animals; Cell Line, Tumor; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Environmental Monitoring; Mice; Salinity; Seasons; United States Virgin Islands; Weather

Ciguatoxins (CTX) are potent marine neurotoxins, which can bioaccumulate in seafood, causing a severe and prevalent human illness known as ciguatera poisoning (CP). Despite the worldwide impact of ciguatera, effective disease management is hindered by a lack of knowledge regarding the movement and biotransformation of CTX congeners in marine food webs, particularly in the Caribbean and Western Atlantic. In this study we investigated the hepatic biotransformation of C-CTX across several fish and mammalian species through a series of in vitro metabolism assays focused on phase I (CYP P450; functionalization) and phase II (UGT; conjugation) reactions. Using liquid chromatography high-resolution mass spectrometry to explore potential C-CTX metabolites, we observed two glucuronide products of C-CTX-1/-2 and provided additional evidence from high-resolution tandem mass spectrometry to support their identification. Chemical reduction experiments confirmed that the metabolites were comprised of four distinct glucuronide products with the sugar attached at two separate sites on C-CTX-1/-2 and excluded the C-56 hydroxyl group as the conjugation site. Glucuronidation is a novel biotransformation pathway not yet reported for CTX or other related polyether phycotoxins, yet its occurrence across all fish species tested suggests that it could be a prevalent and important detoxification mechanism in marine organisms. The absence of glucuronidation observed in this study for both rat and human microsomes suggests that alternate biotransformation pathways may be dominant in higher vertebrates.

Topics: Animals; Biotransformation; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Fishes; Food Chain; Glucuronides; Humans; Microsomes, Liver; Rats, Wistar; Seafood

Ciguatera fish poisoning (CFP) and neurotoxic shellfish poisoning syndromes are induced by the consumption of seafood contaminated by ciguatoxins and brevetoxins. Both toxins cause sensory symptoms such as paresthesia, cold dysesthesia and painful disorders. An intense pruritus, which may become chronic, occurs also in CFP. No curative treatment is available and the pathophysiology is not fully elucidated. Here we conducted single-cell calcium video-imaging experiments in sensory neurons from newborn rats to study in vitro the ability of Pacific-ciguatoxin-2 (P-CTX-2) and brevetoxin-1 (PbTx-1) to sensitize receptors and ion channels, (i.e., to increase the percentage of responding cells and/or the response amplitude to their pharmacological agonists). In addition, we studied the neurotrophin release in sensory neurons co-cultured with keratinocytes after exposure to P-CTX-2. Our results show that P-CTX-2 induced the sensitization of TRPA1, TRPV4, PAR2, MrgprC, MrgprA and TTX-r NaV channels in sensory neurons. P-CTX-2 increased the release of nerve growth factor and brain-derived neurotrophic factor in the co-culture supernatant, suggesting that those neurotrophins could contribute to the sensitization of the aforementioned receptors and channels. Our results suggest the potential role of sensitization of sensory receptors/ion channels in the induction or persistence of sensory disturbances in CFP syndrome.

Topics: Animals; Animals, Newborn; Aquatic Organisms; Ciguatera Poisoning; Ciguatoxins; Marine Toxins; Models, Animal; Oxocins; Pacific Ocean; Pain; Pruritus; Rats; Rats, Wistar; Sensory Receptor Cells

Local population frequently consumes moray eels and dusky groupers from the Canary Islands. These species are top predators and the interactions between them include predation but also, in some cases, collaborative hunting. These fish are well known to cause ciguatera (CFP) outbreaks in several marine areas such as Japan, Hawaii, French Polynesia and Caribe. Groupers have been involved in CFP events in the Canary Islands, however, moray eels have not yet been well studied in this regard. The present research seeks to describe the finding of a black moray in the stomach of a positive dusky grouper during its necropsy, and to clarify the implication of groupers and moray eels in the food webs, accumulating CTXs in the Canarian environment. The study also updates statistics on the presence of toxic groupers in this archipelago. For these purposes, 248 grouper samples from the CFP official control in the Canary Islands (2018-2019) were analysed and 36 moray eels (5 species) were collected under the EuroCigua project and one was obtained during a dusky grouper necropsy. All samples were analysed with the Neuro-2a cell-based assay (CBA) to evidence CTX-like toxicity. Regarding the necropsied grouper and the moray eel found in its stomach content, the LCMS/MS method allowed the identification and quantification of CCTX1 in both fish at similar levels while none of the P-CTXs for which standards were available were detected. Among groupers, 25.4 % displayed CTX-like toxicity with differences between islands. For moray eels 38.9 % showed toxicity, involving 4 species. Black moray exhibited a high proportion of positives (9/12) and a positive correlation was found between CTX-like toxicity quantification and the black moray weight. Regarding the grouper, and the moray eel found in its stomach, the LCMS/MS method allowed the identification and quantification of C-CTX1 in both fish at similar levels. This found suggests a trophic interaction between these species and their role in maintaining CTXs in the Canary waters where local population commonly demand those species for consumption. The island of El Hierro stands out above all the other Canary Islands with the concerning percentage of positive grouper samples and the high CTX toxicity levels obtained in moray eel specimens analysed in this marine area. This is the first report of CTX-like toxicity in flesh of moray eels fished in the Canary archipelago and the confirmation of the presence of C-CTX1 by LCMS/MS in

Topics: Animals; Cell Line, Tumor; Cell Survival; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Eels; Environmental Monitoring; Food Chain; Food Contamination; Gastrointestinal Contents; Muscles; Seafood; Spain; Water Pollutants, Chemical

Few studies have been carried out on benthic dinoflagellates along the Florida Keys, and little is known about their distribution or toxicity in Florida Bay. Here, the distribution and abundance of benthic dinoflagellates was explored in northern and eastern Florida Bay and along the bay and ocean sides of the Florida Keys. Isolates were brought into culture and their toxicity was tested with oyster larvae bioassays. Seven genera were detected, including Prorocentrum, Coolia, Ostreopsis, Amphidinium, Gambierdiscus, Fukuyoa (all included potentially toxic species) and Sinophysis. In general, distribution increased with water temperature and nutrient availability, especially that of phosphate. This study documented the first record of Coolia santacroce in the Florida Keys. Potential toxic effects of Gambierdiscus caribaeus, the abundance of which exceeded 1000 cells g

Topics: Animals; Atlantic Ocean; Bays; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Florida; Temperature

Gambierdiscus spp. can produce the polyketide compound, ciguatoxin (CTX), and are hence responsible for ciguatera fish poisoning (CFP). Studying the molecular mechanism that regulates CTX production is crucial for understanding the environmental trigger of CTX as well as for better informing fishery management. Commonly, polyketide synthases are important for polyketide synthesis; however, no gene has been confirmatively assigned to CTX production. Here, suppression subtractive hybridization (SSH) and transcriptome sequencing (RNA-Seq) were used to compare a CTX-producing strain with a non-CTX-producing strain. Using both methods, a total of 52 polyketide synthase (PKS) genes were identified to be up-regulated in the CTX-producing G. balechii, including transcripts encoding single-domain PKSs as well as transcripts encoding multi-domain PKSs. Using reverse transcription quantitative PCR, the expression of these genes in the CTX-producing strain and in nitrogen-limited cultures of the strain was further documented. These data suggest that PKSs are likely involved in polyketide synthesis and potentially in CTX synthesis in this dinoflagellate species. Our study provides the candidate biomarkers for the detection of CTXs or CFP in waters or any other organisms as well as a valuable genomic resource for the research on Gambierdiscus and other dinoflagellates.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Polyketide Synthases; Transcriptome

In the last decade, several outbreaks of ciguatera fish poisoning (CFP) have been reported in the Canary Islands (central northeast Atlantic Ocean), confirming ciguatera as an emerging alimentary risk in this region. Five

Topics: Animals; Atlantic Ocean; Bioaccumulation; Cell Line, Tumor; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Dose-Response Relationship, Drug; Erythrocytes; Fishes; Food Chain; Humans; Spain; Water Pollutants, Chemical

Ciguatera fish poisoning is a frequently reported non-bacterial food-borne illness related to the consumption of seafood contaminated with ciguatoxins, and possibly maitotoxins. These toxins are synthesized by marine dinoflagellate species of Gambierdiscus and Fukuyoa genera, and their abundance is a matter of great concern due to their adverse effects to aquatic life and human health. The present study aims to assess the sensitivity of rat cardiomyoblast H9c2(2-1) cells to Gambierdiscus toxic compounds using concentration- and time-dependent sulforhodamine B (SRB) colorimetric assays. Low concentrations of Gambierdiscus extracts (corresponding to 1.3-2.3 cells mL

Topics: Animals; Biological Assay; Cell Culture Techniques; Cell Line; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Dose-Response Relationship, Drug; Environmental Monitoring; Inhibitory Concentration 50; Myoblasts, Cardiac; Plankton; Rats; Sensitivity and Specificity; Time Factors; Water Pollutants, Chemical

Ciguatera poisoning (CP) is a common seafood intoxication mainly caused by the consumption of fish contaminated by ciguatoxins. Recent studies showed that Caribbean ciguatoxin-1 (C-CTX1) is the main toxin causing CP through fish caught in the Northeast Atlantic, e.g., Canary Islands (Spain) and Madeira (Portugal). The use of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) combined with neuroblastoma cell assay (N2a) allowed the initial confirmation of the presence of C-CTX1 in contaminated fish samples from the abovementioned areas, nevertheless the lack of commercially available reference materials for these particular ciguatoxin (CTX) analogues has been a major limitation to progress research. The EuroCigua project allowed the preparation of C-CTX1 laboratory reference material (LRM) from fish species (

Topics: Animals; Atlantic Ocean; Biological Monitoring; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Food Contamination; Portugal; Seafood; Tandem Mass Spectrometry; Water Pollutants, Chemical

Ciguatera poisoning (CP), arising from ciguatoxins produced by toxic dinoflagellate Gambierdiscus, is one of the most common food-borne diseases in the South Pacific. Climate change as well as its related events have been hypothesized to a higher abundance and wider presence of toxic dinoflagellates, hence a higher risk of the disease. Yet existing studies assessing the relationship between climate factors and CP are limited or based on old data. In this study, we used prewhitened cross-correlation analysis and auto-regressive integrated moving-average (ARIMA) modeling to develop predictive models of monthly CP incidence in Cook Islands and French Polynesia, two ciguatera-endemic regions in the South Pacific, utilizing the latest epidemiological data. Results reveal the significant time-lagged associations between the monthly CP incidence rate and several indicators relating to sea surface temperature (SST). In particular, SST anomaly is proven to be a strong positive predictor of an increased ciguatera incidence for both countries. If these time-lags can be supported by more investigations, it will allow health authorities to take appropriate actions, to limit or avoid an epidemic risk, especially on high-risk climate scenarios.

Topics: Ciguatera Poisoning; Ciguatoxins; Climate Change; Dinoflagellida; Incidence; Seawater; Temperature

Gambierdiscus and Fukuyoa are genera of toxic dinoflagellates which were mainly considered as endemic to marine intertropical areas, and that are well known as producers of ciguatoxins (CTXs) and maitotoxins (MTXs). Ciguatera poisoning (CP) is a human poisoning occurring after the consumption of fish or more rarely, shellfish containing CTXs. The presence of these microalgae in a coastal area is an indication of potential risk of CP. This study assesses the risk of CP in the Balearic Islands (Western Mediterranean Sea) according to the distribution of both microalgae genera, and the presence of CTX-like and MTX-like toxicity in microalgal cultures as determined by neuro-2a cell based-assay (neuro-2a CBA). Genetic identification of forty-three cultured microalgal strains isolated from 2016 to 2019 revealed that all of them belong to the species G. australes and F. paulensis. Both species were widely distributed in Formentera, Majorca and Minorca. Additionally, all strains of G. australes and two of F. paulensis exhibited signals of CTX-like toxicity ranging respectively between 1 and 380 and 8-16 fg CTX1B equivalents (equiv.) • cell

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Mediterranean Sea; Spain

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Climate Change; Disease Outbreaks; Fishes; Food Contamination; Humans; Incidence; Microalgae; Polynesia; Seaweed; Tandem Mass Spectrometry; Temperature

Topics: Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Hydrogen-Ion Concentration; Nitrates; Nitrogen; Phosphorus; Urea

Ciguatera fish poisoning (CFP) is an illness contracted through the ingestion of seafood containing ciguatoxins. It is prevalent in tropical regions worldwide, including in Australia. Ciguatoxins are produced by some species of Gambierdiscus. Therefore, screening of Gambierdiscus species identification through quantitative PCR (qPCR), along with the determination of species toxicity, can be useful in monitoring potential ciguatera risk in these regions. In Australia, CFP is prevalent in tropical Queensland and increasingly in sub-tropical regions of Australia, but has a report rate of approximately 10%. Yet the identity, distribution and abundance of ciguatoxin producing Gambierdiscus spp. is largely unknown. In this study, we developed a rapid qPCR assay to quantify the presence and abundance of Gambierdiscus lapillus, a likely ciguatoxic species first described from Australia. We assessed the specificity and efficiency of the qPCR assay. The assay was tested on 25 environmental samples from the Heron Island reef in the southern Great Barrier Reef, a ciguatera endemic region, to determine the presence and patchiness of this species across samples from Chnoospora sp., Padina sp. and Sargassum sp. macroalgal hosts.

Topics: Australia; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Dinoflagellida; DNA, Protozoan; Endemic Diseases; Genes, rRNA; Humans; Phylogeny; Real-Time Polymerase Chain Reaction

The increased emergence of Ciguatera Fish Poisoning in the Canary Islands and Madeira demanded the development of confirmatory methods by liquid chromatography coupled to tandem mass spectrometry to characterize the risk. Efforts were particularly focused on the optimization of sample pretreatment, especially in the sample cleanup step, to efficiently remove matrix interferences as a critical factor to consider in mass spectrometry detection. Two different LC-MS/MS approaches have been used for confirmation purposes, the first one using the sodium adduct as precursor and product ion to allow an increased sensitivity in the detection, whereas additional fragments were also monitored for further confirmation. The optimized conditions above mentioned allowed the confirmation of Caribbean Ciguatoxin-1 as the main responsible for the samples analyzed from these geographical areas, while the presence of a new hydroxyl metabolite of C-CTX1 was also confirmed in one sample analyzed in this study.

Topics: Animals; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Limit of Detection; Seafood; Solid Phase Extraction; Spain; Tandem Mass Spectrometry

The two most toxic Gambierdiscus species identified from the Caribbean are G. excentricus and G. silvae. These species are the primary causes of ciguatera fish poisoning and likely contribute disproportionately to the toxicity of marine food webs. While Gambierdiscus species are difficult to distinguish using light or scanning electron microscopy, reliable species-specific molecular identification methods have been developed and used successfully to identify a number of other Gambierdiscus species. Corresponding species-specific assays are not yet available for G. excentricus and G. silvae, which imposes limitations on species identification and related ecological studies. The following note describes species-specific polymerase chain reaction assays for G. excentricus and G. silvae that can be used for these purposes.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Phylogeny; Polymerase Chain Reaction

This research identifies factors associated with the contamination by ciguatoxins (CTXs) in a population of fish and proposes a predictive score of the presence of CTX-like toxicity in amberjack samples from the official control program of ciguatera in the Canary Islands of the Directorate-General (DG) Fisheries (Canary Government). Out of the 970 samples of fish studied, 177 (18.2%) samples showed CTX-like toxicity. The fish were classified according to the species, amberjack (Seriola dumerili and S. rivoliana) (n = 793), dusky grouper (Epinephelus marginatus) (n = 145) and wahoo (Acanthocybium solandri) (n = 32). The data were separated by species category and statistically examined, resulting in 137 (17.3%) amberjack and 39 (26.9%) grouper samples showing CTX-like toxicity; regarding wahoo species, only 1 toxic sample (3.1%) was found. According to fishing location the contamination rates suggested grouping the islands in four clusters; namely: {El Hierro: HI; La Gomera: LG; La Palma: LP}, {Gran Canaria: GC; Tenerife: TF}, {Fuerteventura: FU} and {Lanzarote: LZ}. For the amberjack species, the multivariate logistic regression showed the factors that maintained independent association with the outcome, which were the warm season (OR = 3.617; 95% CI = 1.249-10.474), the weight (per kg, 1.102; 95% CI = 1.069-1.136) and the island of fish catching. A prediction score was obtained for the probability of contamination by CTX in amberjack fish samples. The area under de curve (AUC) obtained using the validation data was 0.747 (95% CI = 0.662-0.833). Regarding grouper species, the island of fishing was the only factor that showed significant differences associated with the presence of CTX-like toxicity. We provide herein data for a better management and prediction of ciguatera in the Canary Islands, suggesting a review of the minimum limits of fish weight established by the Canary Government for the control program.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fish Diseases; Fishes; Islands; Seafood; Spain

Topics: Animals; Cell Line, Tumor; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Mice; Perciformes; Tandem Mass Spectrometry

Dinoflagellates belonging to the genus

Topics: Atlantic Ocean; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Phylogeography; Spain; Tropical Climate

Ciguatoxins (CTXs) are lipid-soluble polyether compounds produced by dinoflagellates from the genus Gambierdiscus spp. typically found in tropical and subtropical zones. This endemic area is however rapidly expanding due to environmental perturbations, and both toxic Gambierdiscus spp. and ciguatoxic fishes have been recently identified in the North Atlantic Ocean (Madeira and Canary islands) and Mediterranean Sea. Ciguatoxins bind to Voltage Gated Sodium Channels on the membranes of sensory neurons, causing Ciguatera Fish Poisoning (CFP) in humans, a disease characterized by a complex array of gastrointestinal, neurological, neuropsychological, and cardiovascular symptoms. Although CFP is the most frequently reported non bacterial food-borne poisoning worldwide, there is still no simple and quick way of detecting CTXs in contaminated samples. In the prospect to engineer rapid and easy-to-use CTXs live cells-based tests, we have studied the effects of CTXs on the yeast Saccharomyces cerevisiae, a unicellular model which displays a remarkable conservation of cellular signalling pathways with higher eukaryotes. Taking advantage of this high level of conservation, yeast strains have been genetically modified to encode specific transcriptional reporters responding to CTXs exposure. These yeast strains were further exposed to different concentrations of either purified CTX or micro-algal extracts containing CTXs. Our data establish that CTXs are not cytotoxic to yeast cells even at concentrations as high as 1μM, and cause an increase in the level of free intracellular calcium in yeast cells. Concomitantly, a dose-dependent activation of the calcineurin signalling pathway is observed, as assessed by measuring the activity of specific transcriptional reporters in the engineered yeast strains. These findings offer promising prospects regarding the potential development of a yeast cells-based test that could supplement or, in some instances, replace current methods for the routine detection of CTXs in seafood products.

Topics: Animals; Calcineurin; Ciguatera Poisoning; Ciguatoxins; Humans; Mediterranean Sea; Saccharomyces cerevisiae; Spain

This retrospective case study analysed the incidence and symptoms of ciguatera fish poisoning (ciguatera) in Guadeloupe (French West Indies) between 2013 and 2016. Cases attending the emergency departments of the two public hospitals and the reports received by the regional health authority in charge of monitoring (ARS) were compiled. Two hundred and thirty-four cases of poisoning were observed, with a mean annual incidence of 1.47/10,000 (95% CI): 1.29-1.66), i.e 5 times higher than the previously reported incidence (1996-2006). The main species described as being responsible for poisoning were fish from the Carangidae family (n = 47) (jack), followed by fish from the Lutjanidae family (n = 27) (snapper), Serranidae family (n = 15) (grouper), Sphyraenidae family (n = 12) (barracuda), and Mullidae family (n = 12) (goatfish). One case of lionfish ciguatera was observed. 93.9% of patients experienced gastrointestinal symptoms, 76.0% presented neurological signs (mainly paresthesia, dysesthesia and pruritus) and 40.3% presented cardiovascular symptoms (bradycardia and/or hypotension). A high frequency (61.4%) of hypothermia (body temperature <36.5 °C) was observed. This study reports for the first time the relatively high frequency of cardiac symptoms and low body temperature. The monitoring of ciguatera poisoning throughout the Caribbean region must be improved, notably after reef disturbance due to Irma and Maria major cyclones.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Fishes; Guadeloupe; Humans; Incidence; Perciformes; Retrospective Studies; Seafood; West Indies

Ciguatera fish poisoning (CFP) caused by the consumption of fish that have accumulated ciguatoxins (CTXs) affects more than 50000 people annually. The spread of CFP causes enormous damage to public health, fishery resources, and the economies of tropical and subtropical endemic regions. The difficulty in avoiding CFP arises from the lack of sensitive and reliable analytical methods for the detection and quantification of CTXs in contaminated fish, along with the normal appearance, smell, and taste of fish contaminated with the causative toxins. Thus, an accurate, sensitive, routine, and portable detection method for CTXs is urgently required. We have successfully developed a highly sensitive fluorescent sandwich ELISA, which can detect, differentiate, and quantify four major CTX congeners (CTX1B, CTX3C, 51-hydroxyCTX3C, and 54-deoxyCTX1B) with a detection limit of less than 1 pg/mL. The ELISA protocol, using one microtiter plate coated with two mAbs (10C9 and 3G8), and ALP-linked 8H4, can detect any of the four CTX congeners in a single operation. CTX1B spiked into fish at the FDA guidance level of 0.01 ppb CTX1B equivalent toxicity in fish from Pacific regions was also proven to be reliably detected by this ELISA. Furthermore, the efficiency of extraction/purification procedures and the matrix effect of contaminants in fish were evaluated in detail, since pretreatment and matrix effects are critical for ELISA analysis.

Topics: Animals; Antibodies, Monoclonal; Ciguatera Poisoning; Ciguatoxins; Enzyme-Linked Immunosorbent Assay; Fishes; Humans; Limit of Detection; Seafood

Lionfish, native to reef ecosystems of the tropical and sub-tropical Indo-Pacific, were introduced to Florida waters in the 1980s, and have spread rapidly throughout the northwestern Atlantic, Caribbean Sea and the Gulf of Mexico. These invasive, carnivorous fish significantly reduce other fish and benthic invertebrate biomass, fish recruitment, and species richness in reef ecosystems. Fisheries resource managers have proposed the establishment of a commercial fishery to reduce lionfish populations and mitigate adverse effects on reef communities. The potential for a commercial fishery for lionfish is the primary reason to identify locations where lionfish accumulate sufficient amounts of ciguatoxin (CTX) to cause ciguatera fish poisoning (CFP), the leading cause of non-bacterial seafood poisoning associated with fish consumption. To address this issue, an initial geographic assessment of CTX toxicity in lionfish from the Caribbean and Gulf of Mexico was conducted. Lionfish samples (n = 293) were collected by spearfishing from 13 locations (74 sampling sites) around the Caribbean and Gulf of Mexico between 2012 and 2015. The highest frequencies of lionfish containing measurable CTX occurred in areas known to be high-risk regions for CFP in the central to eastern Caribbean (e.g., 53% British Virgin Islands and 5% Florida Keys). Though measurable CTX was found in some locations, the majority of the samples (99.3%) contained CTX concentrations below the United States Food and Drug Administration guidance level of 0.1 ppb Caribbean ciguatoxin-1 (C-CTX-1) equivalents (eq.). Only 0.7% of lionfish tested contained more than 0.1 ppb C-CTX-1 eq. As of 2018, there has been one suspected case of CFP from eating lionfish. Given this finding, current risk reduction techniques used to manage CTX accumulating fish are discussed.

Topics: Animals; Caribbean Region; Cell Line; Cell Proliferation; Ciguatera Poisoning; Ciguatoxins; Fisheries; Gulf of Mexico; Humans; Introduced Species; Perciformes; Phylogeography

Species in the epi-benthic dinoflagellate genus Gambierdiscus produce ciguatoxins (CTXs) and maitotoxins (MTXs), which are among the most potent marine toxins known. Consumption of fish contaminated with sufficient quantities of CTXs causes Ciguatera Fish Poisoning (CFP), the largest cause of non-bacterial food poisoning worldwide. Maitotoxins, which can be found in the digestive system of fish, could also contribute to CFP if such tissues are consumed. Recently, an increasing number of Gambierdiscus species have been identified; yet, little is known about the variation in toxicity among Gambierdiscus strains or species. This study is the first assessment of relative CTX- and MTX-toxicity of Gambierdiscus species from areas as widespread as the North-Eastern Atlantic Ocean, Pacific Ocean and the Mediterranean Sea. A total of 13 strains were screened: (i) seven Pacific strains of G. australes, G. balechii, G. caribaeus, G. carpenteri, G. pacificus, G. scabrosus and one strain of an undetermined species (Gambierdiscus sp. Viet Nam), (ii) five strains from the North-Eastern Atlantic Ocean (two G. australes, a single G. excentricus and two G. silvae strains), and (iii) one G. carolinianus strain from the Mediterranean Sea. Cell pellets of Gambierdiscus were extracted with methanol and the crude extracts partitioned into a CTX-containing dichloromethane fraction and a MTX-containing aqueous methanol fraction. CTX-toxicity was estimated using the neuro-2a cytoxicity assay, and MTX-toxicity via a human erythrocyte lysis assay. Different species were grouped into different ratios of CTX- and MTX-toxicity, however, the ratio was not related to the geographical origin of species (Atlantic, Mediterranean, Pacific). All strains showed MTX-toxicity, ranging from 1.5 to 86pg MTX equivalents (eq) cell

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Erythrocytes; Marine Toxins; Oxocins; Phylogeny

Topics: Calcium; Cell Line, Tumor; Cell Proliferation; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Food Contamination; Humans; Neurons; Ouabain; Veratridine

Severe food poisoning events after the consumption of sharks have been reported since the 1940s; however, there has been no clear understanding of their cause. Herein, we report for the first time the presence of ciguatoxins (CTXs) in sharks. The identification by mass spectrometry of CTXs, including two new analogues, in a bull shark (Carcharhinus leucas) that was consumed by humans, causing the poisoning and death of 11 people in Madagascar in 2013 is described. Typical neurotoxic ciguatera symptoms were recorded in patients, and toxicological assays on extracts of the shark demonstrated CTX-like activity. These results confirm this episode as a ciguatera poisoning event and expand the range of pelagic fish species that are involved in ciguatera in the Indian Ocean. Additionally, gambieric acid D, a molecule originally described in CTX-producing microalgae, was identified for the first time in fish. This finding can contribute to a better understanding of trophic relations within food webs. The present work confirms that consumption of sharks from the Indian Ocean should be considered a ciguatera risk, and actions should be taken to evaluate its magnitude and risk in order to manage shark fisheries.

Topics: Animals; Biological Assay; Cell Line; Cell Survival; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Humans; Indian Ocean; Madagascar; Mass Spectrometry; Mice; Public Health Surveillance; Seafood; Sharks

Ciguatoxins (CTXs) are marine toxins that cause ciguatera fish poisoning, a debilitating disease dominated by sensory and neurological disturbances that include cold allodynia and various painful symptoms as well as long-lasting pruritus. Although CTXs are known as the most potent mammalian sodium channel activator toxins, the etiology of many of its neurosensory symptoms remains unresolved. We recently described that local application of 1 nM Pacific Ciguatoxin-1 (P-CTX-1) into the skin of human subjects induces a long-lasting, painful axon reflex flare and that CTXs are particularly effective in releasing calcitonin-gene related peptide (CGRP) from nerve terminals. In this study, we used mouse and rat skin preparations and enzyme-linked immunosorbent assays (ELISA) to study the molecular mechanism by which P-CTX-1 induces CGRP release. We show that P-CTX-1 induces CGRP release more effectively in mouse as compared to rat skin, exhibiting EC

Topics: Animals; Calcitonin Gene-Related Peptide; Calcium; Ciguatera Poisoning; Ciguatoxins; Enzyme-Linked Immunosorbent Assay; Humans; Hyperalgesia; Lidocaine; Male; Marine Toxins; Membrane Potentials; Mice; Mice, Transgenic; NAV1.1 Voltage-Gated Sodium Channel; NAV1.7 Voltage-Gated Sodium Channel; NAV1.9 Voltage-Gated Sodium Channel; Rats; Receptors, Calcitonin Gene-Related Peptide; Tetrodotoxin

This study confirms the presence of the toxigenic benthic dinoflagellates Gambierdiscus belizeanus and Ostreopsis spp. in the central Red Sea. To our knowledge, this is also the first report of these taxa in coastal waters of Saudi Arabia, indicating the potential occurrence of ciguatera fish poisoning (CFP) in that region. During field investigations carried out in 2012 and 2013, a total of 100 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast and examined for the presence of Gambierdiscus and Ostreopsis, two toxigenic dinoflagellate genera commonly observed in coral reef communities around the world. Both Gambierdiscus and Ostreopsis spp. were observed at low densities (<200 cells g

Topics: Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Geography; Indian Ocean; Salinity; Seaweed; Sequence Analysis, DNA

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Magnetic Resonance Spectroscopy; Pacific Ocean; Protons; Reference Standards; Tandem Mass Spectrometry

Between 2014 and 2016, five cases of ciguatera fish poisoning (CFP), involving twenty four individuals, were linked to Spanish Mackerel (

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Humans; New South Wales; Risk Management

Ciguatera fish poisoning (CFP) is a common human food poisoning caused by consumption of ciguatoxin (CTX)-contaminated fish affecting over 50,000 people worldwide each year. CTXs are classified depending on their origin from the Pacific (P-CTXs), Indian Ocean (I-CTXs), and Caribbean (C-CTXs). P-CTX-1 is the most toxic CTX known and the major source of CFP causing an array of neurological symptoms. Neurological symptoms in some CFP patients last for several months or years; however, the underlying electrophysiological properties of acute exposure to CTXs remain unknown. Here, we used CTX purified from ciguatera fish sourced in the Pacific Ocean (P-CTX-1). Delta and theta electroencephalography (EEG) activity was reduced remarkably in 2 h and returned to normal in 6 h after a single exposure. However, second exposure to P-CTX-1 induced not only a further reduction in EEG activities but also a 2-week delay in returning to baseline EEG values. Ciguatoxicity was detected in the brain hours after the first and second exposure by mouse neuroblastoma assay. The spontaneous firing rate of single motor cortex neuron was reduced significantly measured by single-unit recording with high spatial resolution. Expression profile study of neurotransmitters using targeted profiling approach based on liquid chromatography-tandem mass spectrometry revealed an imbalance between excitatory and inhibitory neurotransmitters in the motor cortex. Our study provides a possible link between the brain oscillations and neurotransmitter release after acute exposure to P-CTX-1. Identification of EEG signatures and major metabolic pathways affected by P-CTX-1 provides new insight into potential biomarker development and therapeutic interventions.

Topics: Animals; Chromatography, High Pressure Liquid; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Electroencephalography; Fishes; Male; Metabolic Networks and Pathways; Mice, Inbred C57BL; Motor Cortex; Neurotransmitter Agents

Gambierdiscus is a genus of benthic dinoflagellates found worldwide. Some species produce neurotoxins (maitotoxins and ciguatoxins) that bioaccumulate and cause ciguatera fish poisoning (CFP), a potentially fatal food-borne illness that is common worldwide in tropical regions. The investigation of toxigenic species of Gambierdiscus in CFP endemic regions in Australia is necessary as a first step to determine which species of Gambierdiscus are related to CFP cases occurring in this region. In this study, we characterized five strains of Gambierdiscus collected from Heron Island, Australia, a region in which ciguatera is endemic. Clonal cultures were assessed using (i) light microscopy; (ii) scanning electron microscopy; (iii) DNA sequencing based on the nuclear encoded ribosomal 18S and D8-D10 28S regions; (iv) toxicity via mouse bioassay; and (v) toxin profile as determined by Liquid Chromatography-Mass Spectrometry. Both the morphological and phylogenetic data indicated that these strains represent a new species of Gambierdiscus, G. lapillus sp. nov. (plate formula Po, 3', 0a, 7″, 6c, 7-8s, 5‴, 0p, 2″″ and distinctive by size and hatchet-shaped 2' plate). Culture extracts were found to be toxic using the mouse bioassay. Using chemical analysis, it was determined that they did not contain maitotoxin (MTX1) or known algal-derived ciguatoxin analogs (CTX3B, 3C, CTX4A, 4B), but that they contained putative MTX3, and likely other unknown compounds.

Topics: Animals; Australia; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Marine Toxins; Oxocins; Phylogeny; Sequence Analysis, DNA

Ciguatoxins are the major toxins responsible for ciguatera fish poisoning, a disease dominated by muco-cutaneous sensory disorders including paresthesiae, cold dysesthesia and pruritus. While the ciguatoxins are well known to target voltage-gated sodium channels (VGSCs), the ensuing molecular mechanisms underlying these sensory disorders remain poorly understood. In this study, we propose a primary sensory neuron-keratinocyte co-culture as an appropriate model to study the neuro-cutaneous effects of ciguatoxins. Using this model, we show for the first time that nanomolar concentrations of Pacific ciguatoxin-2 (P-CTX-2) induced a VGSC-dependent release of substance P (SP) and calcitonin gene-related peptide (CGRP). As these neuropeptides are known mediators of pain and itch sensations, the ciguatoxin-induced sensory disturbances in ciguatera fish poisoning may involve the release of these neuropeptides. We further determined time- and P-CTX-2 concentration-dependence of the release of SP and CGRP from the co-culture model. Moreover, we highlighted the influence of extracellular calcium on the release of neuropeptides elicited by P-CTX-2. These findings underline the usefulness of this novel in vitro model for studying the cellular and molecular mechanisms of the neuro-cutaneous effects of ciguatoxins, which may assist with identifying potential therapeutics for ciguatera fish poisoning.

Topics: Animals; Calcitonin Gene-Related Peptide; Calcium; Ciguatera Poisoning; Ciguatoxins; Coculture Techniques; Humans; Immunohistochemistry; Keratinocytes; Models, Biological; Neuropeptides; Rats; Sensory Receptor Cells

Ciguatera fish poisoning is an illness suffered by > 50,000 people yearly after consumption of fish containing ciguatoxins (CTXs). One of the current methodologies to detect ciguatoxins in fish is a radiolabeled receptor binding assay (RBA(R)). However, the license requirements and regulations pertaining to radioisotope utilization can limit the applicability of the RBA(R) in certain labs. A fluorescence based receptor binding assay (RBA(F)) was developed to provide an alternative method of screening fish samples for CTXs in facilities not certified to use radioisotopes. The new assay is based on competition binding between CTXs and fluorescently labeled brevetoxin-2 (BODIPY®-PbTx-2) for voltage-gated sodium channel receptors at site 5 instead of a radiolabeled brevetoxin. Responses were linear in fish tissues spiked from 0.1 to 1.0 ppb with Pacific ciguatoxin-3C (P-CTX-3C) with a detection limit of 0.075 ppb. Carribean ciguatoxins were confirmed in Caribbean fish by LC-MS/MS analysis of the regional biomarker (C-CTX-1). Fish (N = 61) of six different species were screened using the RBA(F). Results for corresponding samples analyzed using the neuroblastoma cell-based assay (CBA-N2a) correlated well (R2 = 0.71) with those of the RBA(F), given the low levels of CTX present in positive fish. Data analyses also showed the resulting toxicity levels of P-CTX-3C equivalents determined by CBA-N2a were consistently lower than the RBA(F) affinities expressed as % binding equivalents, indicating that a given amount of toxin bound to the site 5 receptors translates into corresponding lower cytotoxicity. Consequently, the RBA(F), which takes approximately two hours to perform, provides a generous estimate relative to the widely used CBA-N2a which requires 2.5 days to complete. Other RBA(F) advantages include the long-term (> 5 years) stability of the BODIPY®-PbTx-2 and having similar results as the commonly used RBA(R). The RBA(F) is cost-effective, allows high sample throughput, and is well-suited for routine CTX monitoring programs.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Fishes; Protein Binding; Rats; Rats, Sprague-Dawley; Synaptosomes; Tandem Mass Spectrometry

Ciguatera fish poisoning is common in tropical and sub-tropical areas and larger fish (> 10 kg) are more susceptible to toxin accumulation with age. Although the coastal climate of northern New South Wales is considered sub-tropical, prior to 2014 there has only been 1 documented outbreak of ciguatera fish poisoning from fish caught in the region. During February and March 2014, 2 outbreaks of ciguatera fish poisoning involved 4 and 9 individuals, respectively, both following consumption of Spanish mackerel from northern New South Wales coastal waters (Evans Head and Scotts Head). Affected individuals suffered a combination of gastrointestinal and neurological symptoms requiring hospital treatment. At least 1 individual was symptomatic up to 7 months later. Liquid chromatography-tandem mass spectrometry detected the compound Pacific ciguatoxin-1B at levels up to 1.0 µg kg(-1) in fish tissue from both outbreaks. During April 2015, another outbreak of ciguatera fish poisoning was reported in 4 individuals. The fish implicated in the outbreak was caught further south than the 2014 outbreaks (South West Rocks). Fish tissue was unavailable for analysis; however, symptoms were consistent with ciguatera fish poisoning. To our knowledge, these cases are the southernmost confirmed sources of ciguatera fish poisoning in Australia. Educational outreach to the fishing community, in particular recreational fishers was undertaken after the Evans Head outbreak. This highlighted the outbreak, species of fish involved and the range of symptoms associated with ciguatera fish poisoning. Further assessment of the potential for ciguatoxins to occur in previously unaffected locations need to be considered in terms of food safety.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fish Products; Humans; New South Wales; Perciformes; Tandem Mass Spectrometry; Time Factors

Ciguatoxins (CTXs) produced by benthic Gambierdiscus dinoflagellates, readily biotransform and bioaccumulate in food chains ultimately bioconcentrating in high-order, carnivorous marine species. Certain shark species, often feeding at, or near the top of the food-chain have the ability to bioaccumulate a suite of toxins, from both anthropogenic and algal sources. As such, these apex predators are likely sinks for CTXs. This assumption, in conjunction with anecdotal knowledge of poisoning incidents, several non-specific feeding trials whereby various terrestrial animals were fed suspect fish flesh, and a single incident in Madagascar in 1994, have resulted in the widespread acceptance that sharks may accumulate CTXs. This prompted a study to investigate original claims within the literature, as well as investigate CTX bioaccumulation in the muscle and liver of 22 individual sharks from nine species, across four locations along the east coast of Australia. Utilizing an updated ciguatoxin extraction method with HPLC-MS/MS, we were unable to detect P-CTX-1, P-CTX-2 or P-CTX-3, the three primary CTX congeners, in muscle or liver samples. We propose four theories to address this finding: (1) to date, methods have been optimized for teleost species and may not be appropriate for elasmobranchs, or the CTXs may be below the limit of detection; (2) CTX may be biotransformed into elasmobranch-specific congeners as a result of unique metabolic properties; (3) 22 individuals may be an inadequate sample size given the rare occurrence of high-order ciguatoxic organisms and potential for CTX depuration; and (4) the ephemeral nature and inconsistent toxin profiles of Gambierdiscus blooms may have undermined our classifications of certain areas as CTX hotspots. These results, in combination with the lack of clarity within the literature, suggest that ciguatoxin bioaccumulation in sharks remains elusive, and warrants further investigation to determine the dynamics of toxin production, accumulation and transformation throughout the entire food-web.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Sharks

In November 2012, 23 cases of ciguatera with typical combinations of gastrointestinal and neurological symptoms occurred in Germany after consumption of imported tropical fish (Lutjanus spp.). A questionnaire was used to gather information on the disease course and fish consumption. All patients suffered from pathognomonic cold allodynia. Aside from two severe courses of illness, all other cases showed symptoms of moderate intensity. During a three-year follow-up, seven patients reported prolonged paresthesia for more than one year. Two of them reported further neuropathies over almost three years. This is the first time that long-term persistence of symptoms has been documented in detail. Outbreak cases were allocated to eight clusters in seven German cities. A further cluster was prevented by the successful recall of ciguatoxic fish. Three clusters were confirmed by the detection of ciguatoxin in samples of suspicious and recalled fish. An extrapolation on the basis of ciguatoxic samples revealed twenty prevented cases of ciguatera. Further officially unknown cases should be assumed. During the outbreak investigations, inadvertently falsely labelled fish species and fishing capture areas on import and retail level documents were observed. The ascertainment of cases and the outbreak investigations proved to be difficult due to inconsistent case reports to poisons centers, local health and veterinary authorities. In Germany, many physicians are unaware of the disease pattern of ciguatera and the risks caused by tropical fish. The occurrence of further outbreaks during the following years emphasizes the increasing significance of ciguatera in Germany.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Cluster Analysis; Comorbidity; Disease Outbreaks; Female; Fishes; Gastrointestinal Diseases; Germany; Humans; Incidence; Male; Nervous System Diseases; Population Surveillance; Risk Factors

Ciguatera fish poisoning (CFP) is the most common cause of seafood-toxin poisoning in the world and is most prevalent in tropical and subtropical areas. It causes gastroenteritis but also myriad neurological and cardiovascular symptoms. We present a cluster of CFP that occurred in Wellington Hospital, New Zealand. It resulted in three patients with life threatening cardiotoxicity and a fourth case with severe gastro-intestinal symptoms. The epidemiology, clinical manifestations, diagnosis, treatment and public health issues are discussed.

Topics: Adult; Aged; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Diuretics, Osmotic; Female; Gastroenteritis; Humans; Male; Mannitol; Middle Aged; New Zealand; Public Health

Ciguatera Fish Poisoning (CFP) is a non-bacterial seafood poisoning well characterized in the remote archipelagos of French Polynesia, yet poorly documented in the Society archipelago, most notably on Moorea, the second most populated island in French Polynesia, which counts a high proportion of fishermen fishing on a regular basis. To address this knowledge gap, a holistic study of the ciguatera issue was conducted on Moorea. First, ciguatera risk was analysed in terms of incidence rate, fish species most commonly involved and risk stratification in Moorea lagoon based on 2007-2013 epidemiological data. A mean incidence rate of 8 cases per 10,000 inhabitants for the study period and an average under-reporting rate of 54% were found. Taking into account hospitalization and medication fees, and loss of productive days, the health-related costs due to CFP were estimated to be USD $1613 and $749 for each reported and unreported case, respectively, with an overall cost of USD $241,847 for the study period. Comparison of the present status of CFP on Moorea with a risk map established in the late 1970's showed that the spatial distribution of the risk has stayed relatively stable in time, with the north shore of the island remaining the most prone to ciguatera. Evaluation of the current knowledge on CFP among different populations groups, i.e. fishermen, residents and visitors, was also conducted through direct and indirect interviews. About half of the fishermen interviewed were actually able to identify risky fishing areas. While, overall, the CFP risk perception in the fishing community of Moorea seemed accurate, although not scientifically complete, it was sufficient for the safe practice of their fishing activities. This may be due in part to adaptive responses adopted by 36% of the fishermen interviewed, such as the avoidance of either high-risk fishing sites or toxic species. At the residents and visitors' level, the study points out a striking lack of awareness of the CFP issue among visitors, as compared to local residents. Indeed, less than 25% of Moorea visitors vs. an average of 98% in residents were aware of CFP or of its presence on the island. Interestingly, evaluation of the fish consumption preferences showed that 70% of visitors do not consume lagoon fish during their stay, not for fear of CFP, but mainly due to the lack of availability of these species in recreational facilities or because they have nutritional preference for pelagic fish. Th

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fisheries; Fishes; Health Care Costs; Health Knowledge, Attitudes, Practice; Humans; Incidence; Islands; Polynesia; Risk Assessment; Seafood

Lionfish (Pterois spp.) are invasive species that have recently spread throughout the Caribbean. Lionfish are available for purchase in local markets for human consumption in several islands of the region. We examined the prevalence of ciguatoxins (CTXs) in lionfish from the French Antilles, a ciguatera-endemic region. The neuroblastoma-2a (N2a) cell assay was used to assess composite cytotoxicity in 120 fish samples collected from the surrounding waters of Guadeloupe (n = 60), Saint Barthélemy Islands (n = 55) and Saint Martin (n = 5). Twenty-seven of these samples exhibited CTX-like activity by the N2a assay. Ciguatoxin (CTX) was confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple samples that presented highest composite toxicity levels by N2a. Those fish found to contain CTXs were all from Saint Barthélemy. Lionfish from Guadeloupe and Saint Martin did not exhibit toxin activity, although the sample size from Saint Martin was insufficient to draw any conclusions as to the incidence of CTXs. In this study, we provide information about the potential hazard of ciguatera associated with the consumption of lionfish from known endemic areas. We also demonstrate the utility of the cell-based assay combined with LC-MS/MS to assess activity and to provide structural confirmation of CTXs respectively.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Food Contamination; Guadeloupe; Humans; Incidence; Marine Toxins; Perciformes; Prevalence; West Indies

Ciguatera fish poisoning (CFP) is a syndrome caused by the ingestion of fish contaminated with Ciguatoxins (CTXs). These phycotoxins are produced mainly by dinoflagellates that belong to the genus Gambierdiscus that are transformed in more toxic forms in predatory fish guts, and are more present in the Indo-Pacific and Caribbean areas. It is estimated that CFP causes per year more than 10,000 intoxications worldwide. With the rise of water temperature and anthropogenic intervention, it is important to study the prevalence of CFP in more temperate waters. Through inter- and subtidal sampling, 22 species of organisms were collected, in Madeira and Azores archipelagos and in the northwestern Moroccan coast, during September of 2012 and June and July of 2013. A total of 94 samples of 22 different species of bivalves, gastropods, echinoderms and crustaceans where analyzed by Ultra Performance Liquid Chromatography-Mass Spectometry-Ion Trap-Time of Flight (UPLC-MS-IT-TOF) and Ultra Performance Chromatography- Mass Spectrometry (UPLC-MS). Our main aim was to detect new vectors and ascertain if there were some geographical differences. We detected for the first time putative CTXs in echinoderms, in two starfish species-M. glacialis and O. ophidianus. We detected differences regarding uptake values by organisms and geographical location. Toxin amounts were significant, showing the importance and the need for continuity of these studies to gain more knowledge about the prevalence of these toxins, in order to better access human health risk. In addition, we suggest monitoring of these toxins should be extended to other vectors, starfish being a good alternative for protecting and accessing human health risk.

Topics: Animals; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Dose-Response Relationship, Drug; Food Contamination; Mass Spectrometry; Prevalence; Starfish

From 2010 to 2012, 35 ciguatera fish poisoning (CFP) events involving 87 individuals who consumed locally-caught fish were reported in Guadeloupe (French West Indies). For 12 of these events, the presence of ciguatoxins (CTXs) was indicated in meal remnants and in uncooked fish by the mouse bioassay (MBA). Caribbean ciguatoxins (C-CTXs) were confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Using a cell-based assay (CBA), and the only available standard Pacific ciguatoxin-1 (P-CTX-1), the lowest toxins level detected in fish samples causing CFP was 0.022 µg P-CTX-1 equivalent (eq.)·kg(-1) fish. Epidemiological and consumption data were compiled for most of the individuals afflicted, and complete data for establishing the lowest observable adverse effects level (LOAEL) were obtained from 8 CFP events involving 21 individuals. Based on toxin intakes, the LOAEL was estimated at 4.2 ng P-CTX-1 eq./individual corresponding to 48. 4 pg P-CTX-1 eq.kg(-1) body weight (bw). Although based on limited data, these results are consistent with the conclusions of the European Food Safety Authority (EFSA) opinion which indicates that a level of 0.01 µg P-CTX-1 eq.kg(-1) fish, regardless of source, should not exert effects in sensitive individuals when consuming a single meal. The calculated LOAEL is also consistent with the U.S. Food and Drug Administration guidance levels for CTXs (0.1 µg C-CTX-1 eq.kg(-1) and 0.01 µg P-CTX-1 eq.kg(-1) fish).

Topics: Animals; Cell Line, Tumor; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Dose-Response Relationship, Drug; Fishes; Guadeloupe; Humans; Male; Mice; Seafood; Toxicity Tests

Ciguatera fish poisoning is a debilitating human neuro-intoxication caused by consumption of tropical marine organisms, contaminated with bioaccumulated ciguatoxins (CTXs). The growing number of cases coupled with the high toxicity of CTXs makes their reliable detection and quantification of paramount importance. Three commonly occurring ciguatoxins, P-CTX-1, 2 and 3 from five different ciguatoxic Spanish mackerel (Scomberomorus commerson), were used to assess the effectiveness of different extraction techniques: homogenization (high powered blending vs. ultrasonication); C-18 column sizes (500 mg vs. 900 mg); and a novel HILIC SPE cleanup. Despite minor differences, blending and sonication proved equally effective. Larger 900 mg columns offered a greater extraction efficiency, increasing detected P-CTX-1 by 37% (P < 0.001). The newly adapted cleanup was highly effective at reducing co-eluting phospholipids thereby reducing matrix effects and increasing detectable CTXs by HPLC-MS/MS. Silica cleanup extraction efficiencies were also compared between the highly effective and validated ciguatoxin rapid extraction method (CREM) and current best practice extraction method employed by Queensland Health (QH). Overall, the QH protocol proved more effective, especially when paired with the newly adapted cleanup, as this increased the amount of extracted P-CTX-1 by 46% (P < 0.01), P-CTX-2 by 10% and P-CTX-3 by 71% (P = 0.001). This study suggests the QH protocol utilizing a 900 mg C-18 column and newly adapted HILIC SPE cleanup was most effective at extracting P-CTX-1, -2, -3. Specifically P-CTX-1, the primary ciguatoxin congener of concern due to its extremely high potency and an ability to cause CFP at 0.1 μg/kg following consumption of carnivorous fish flesh. Despite being more time intensive (an additional 85 min per batch of 12 samples), this will be especially effective for assessing lower toxin burdens, which may be near the limit of detection.

Topics: Animals; Aquatic Organisms; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Environmental Monitoring; Humans; Limit of Detection; Perciformes; Reproducibility of Results; Silicon Dioxide; Solid Phase Extraction; Tandem Mass Spectrometry

Accumulation of ciguatoxins (CTXs) in tropical reef fish tissues during their life is responsible of the most prevalent human seafood intoxication in the South Pacific called Ciguatera Fish Poisoning (CFP). It has been assumed for a long time that CTXs are transferred and accumulated along the trophic food chain, and consequently that smaller individuals within a given fish species are safer to eat than larger ones. However, the relationship between toxicity and fish size has been studied for a limited number of species only and the conclusions are often contradictory. The toxicity of 856 fishes from 59 different species sampled in six islands in French Polynesia between 2003 and 2011 was assessed by Receptor Binding Assay. Among them, 45 species × island and 32 families × island for which the number of individuals was ≥6 allowed testing the relationship between toxicity and size. Except for six specimens of Lutjanus bohar caught in Fakarava (P < 0.01; R(2) = 0.854), the 44 remaining species × island showed no significant increase of CTXs concentration with fish total length (TL). Moreover, the proportion of toxic individuals decreased significantly for Epinephelus polyphekadion from Fakarava (n = 24; P < 0.05) and Kyphosus cinerascens from Raivavae (n = 29; P < 0.05), while no significant variation was detected for the other 43 species × island. At the family level, only three positive and three negative relationships between size and CTXs concentration were observed among the 32 family × island analyzed. No relationship between the proportion of toxic fish within a family and the relative total length of individuals were observed. The lack of relationship between toxicity and size observed for most of the species and families from the six islands suggests that fish size cannot be used as an efficient predictor of fish toxicity in French Polynesia. These results highlight the need for improving our knowledge about metabolic processes which may play a role in CTXs bio-accumulation and depuration among the different trophic levels of fishes.

Topics: Animals; Body Size; Ciguatera Poisoning; Ciguatoxins; Fishes; Humans; Poisons; Polynesia; Species Specificity

The present study used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate retrospectively ciguatoxin (CTX)-positive samples as determined by mouse bioassay (MBA) in the past 10 years in Hong Kong. The results showed that Pacific CTXs (P-CTX-1, -2 and -3) were the most commonly observed toxins found in the samples, indicating Pacific Ocean areas as the most important origin of ciguatera fish poisoning. Clinical diagnosis from ciguatera patients also revealed the predominance of neurological illnesses in most cases, supporting intoxication of Pacific origin. This study demonstrated the ability of laboratory analysis to identify and quantify Pacific CTXs in suspected fish samples, so as to support the clinical diagnosis of ciguatera. Comparative analysis (Student's t-test and Spearman's rank correlation analysis) on the two CTX detection methods showed approximate linearity for overall P-CTXs (P-CTX-1, -2 and -3)/P-CTX-1 alone as derived by LC-MS/MS and total toxicity levels (P-CTX-1 equivalent) as determined by MBA. The LC-MS/MS method coupled with the rapid extraction method could allow the detection of trace amount of CTXs at levels below the clinically relevant limit, 0.1 ppb P-CTX-1 in fish flesh. For practical application, the adoption of a two-tiered approach for testing, chemical analysis by LC-MS/MS for toxic fish screening, coupled with biological assay by MBA for final toxicity confirmation, was proposed for first-line screening of CTX in potentially contaminated fish samples in the market, with an aim to minimizing the use of laboratory mice and at the same time providing reasonably effective means for routine analysis.

Topics: Animals; Biological Assay; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Fishes; Hong Kong; Humans; Mass Spectrometry; Mice; Retrospective Studies

Ciguatera fish poisoning (CFP) is a foodborne illness caused by fish containing ciguatoxin (CTX). The toxin is produced by the microalgae Gambierdiscus spp. which are then eaten by reef fish; humans contract the illness when eating either fish that have eaten the algae, or carnivorous fish that have eaten those fish. CTX is an odorless, tasteless, and colorless neurotoxin that blocks voltage-sensitive Na(+) channels and accumulates in many tissues of the fish, especially the viscera. The illness is typically mild to moderate in severity with gastrointestinal (diarrhea, cramping, nausea, vomiting) and neurological (paraesthesias, cold allodynia, fatigue, pruritis) manifestations. Rarely, the disease can be more severe with significant neuropathic or cardiac effects such as bradycardia and hypotension. Endemic to Hawai'i and islands throughout the Caribbean and Pacific, CFP incidence rates range from several to thousands of cases per 100,000 per year. Since fishing is important for local food supply, exportation, and recreation throughout the Pacific, CFP is medically and economically significant in these areas. We present a case of CFP from Hawai'i to illustrate the disease, demonstrating that the diagnosis is primarily clinical, with confirmatory tests from fish samples available in some cases. Treatment is supportive and symptomatic with no disease specific remedy. The prognosis for most cases is good with a short duration of self-limited symptoms, but for some cases neurological sequelae can become chronic. With no effective treatment, education on which species of reef fish and which body parts to avoid eating is essential in the prevention of CFP.

Topics: Ciguatera Poisoning; Ciguatoxins; Hawaii; Humans; Male; Middle Aged; Pacific Islands

Ciguatoxins (CTXs) cause long-term disturbance of cerebral functions. The primary mechanism of neurotoxicity is related to their interaction with voltage-gated sodium channels. However, until now, the neurological targets for CTXs in the brain of intact animals have not been described. In our study, 1 day following oral exposure to 0.26 ng/g of Pacific ciguatoxin 1 (P-CTX-1), we performed in vivo electrophysiological recordings in the rat anterior cingulate cortex (ACC) and identified the increase in spontaneous firings and enhanced responses to visceral noxious stimulation. Local field recordings characterized the P-CTX-1-induced synaptic potentiation and blockage of the induction of electrical stimulation-induced long-term potentiation in the medial thalamus (MT)-ACC pathway. Furthermore, intracerebroventricular administration of P-CTX-1 at doses of 1.0, 5.0, and 10 nM produced a dose-dependent increase in ACC neuronal firings and MT-ACC synaptic transmission. Further studies showed upregulated Na(+) channel expression in astrocytes under pathological conditions. We hypothesized that the astrocytes might have been activated in the ciguatera poisoning in vivo. Increases in glial fibrillary acid protein expression were detected in reactive astrocytes in the rat ACC. The activation of astroglia was further indicated by activation of the gap junction protein connexin 43 and upregulation of excitatory amino acid transporter 2 expression suggesting that glutamate was normally rapidly cleared from the synaptic cleft during acute ciguatera poisoning. However, neurotoxicity and reactive astrogliosis were not detected in the ACC after 7 days of P-CTX-1 exposure. The present results are the first characterization of P-CTX-1-invoked brain cortex neuronal excitotoxicity in vivo and supported the theme that neuron and astroglia signals might play roles in acute ciguatera poisoning.

Topics: Action Potentials; Administration, Oral; Animals; Astrocytes; Body Weight; Ciguatera Poisoning; Ciguatoxins; Connexin 43; Convalescence; Dose-Response Relationship, Drug; Electric Stimulation; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Transporter 2; Gliosis; Gyrus Cinguli; Injections, Intraperitoneal; Injections, Intraventricular; Long-Term Potentiation; Male; Microdialysis; Neurons; Random Allocation; Rats; Rats, Sprague-Dawley; Synaptic Transmission; Thalamus; Voltage-Gated Sodium Channels

Ciguatera results when ciguatoxin-contaminated coral reef fish from tropical or subtropical waters are consumed. The clinical features that present in affected persons are mainly gastrointestinal, neurological, general, and much less commonly, cardiovascular. We report the case of a 50-year-old man who developed the characteristic combination of acute gastrointestinal and neurological symptoms after the consumption of an unidentified coral reef fish head. In addition to those symptoms, he developed dizziness, severe bradycardia (46 bpm) and prolonged hypotension, which required the administration of intravenous atropine and over three days of intravenous fluid replacement with dopamine infusion. Patients with ciguatera can develop severe bradycardia and prolonged hypotension. Physicians should recognise the possible cardiovascular complications of ciguatera and promptly initiate treatment with intravenous atropine, intravenous fluid replacement and inotropic therapy if such complications are observed.

Topics: Animals; Bradycardia; Ciguatera Poisoning; Ciguatoxins; Fishes; Humans; Hypotension; Male; Middle Aged

Ciguatera and scombroid fish poisonings are common causes of fish-related foodborne illness in the United States; however, existing surveillance systems underestimate the overall human health impact.. This study aimed to describe existing data on ciguatera and scombroid fish poisonings from outbreak and poison control center reports and to estimate the overall number of ciguatera and scombroid fish-poisoning illnesses, hospitalizations, and deaths in the United States.. We analyzed outbreak data from the Foodborne Disease Outbreak Surveillance Systems (FDOSS) from 2000 to 2007 and poison control center call data from the National Poison Data System (NPDS) from 2005 to 2009 for reports of ciguatera and scombroid fish poisonings. Using a statistical model with many inputs, we adjusted the outbreak data for undercounting due to underreporting and underdiagnosis to generate estimates. Underreporting and underdiagnosis multipliers were derived from the poison control call data and the published literature.. Annually, an average of 15 ciguatera and 28 scombroid fish-poisoning outbreaks, involving a total of 60 and 108 ill persons, respectively, were reported to FDOSS (2000-2007). NPDS reported an average of 173 exposure calls for ciguatoxin and 200 exposure calls for scombroid fish poisoning annually (2005-2009). After adjusting for undercounting, we estimated 15,910 (90% credible interval [CrI] 4140-37,408) ciguatera fish-poisoning illnesses annually, resulting in 343 (90% CrI 69-851) hospitalizations and three deaths (90% CrI 1-7). We estimated 35,142 (90% CrI: 10,496-78,128) scombroid fish-poisoning illnesses, resulting in 162 (90% CrI 0-558) hospitalizations and 0 deaths.. Ciguatera and scombroid fish poisonings affect more Americans than reported in surveillance systems. Although additional data can improve these assessments, the estimated number of illnesses caused by seafood intoxication illuminates this public health problem. Efforts, including education, can reduce ciguatera and scombroid fish poisonings.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fishes; Foodborne Diseases; Hospitalization; Humans; Marine Toxins; Public Health Surveillance; Seafood; United States

Invasive Indo-Pacific lionfish (Pterois volitans) have rapidly expanded in the Western Atlantic over the past decade and have had a significant negative impact on reef fish biodiversity, habitat, and community structure, with lionfish out-competing native predators for resources. In an effort to reduce this population explosion, lionfish have been promoted for human consumption in the greater Caribbean region. This study examined whether the geographical expansion of the lionfish into a known ciguatera-endemic region can pose a human health threat for ciguatera fish poisoning (CFP). More than 180 lionfish were collected from waters surrounding the US Virgin Islands throughout 2010 and 2011. Ciguatoxin testing included an in vitro neuroblastoma cytotoxicity assay for composite toxicity assessment of sodium-channel toxins combined with confirmatory liquid chromatography tandem mass spectrometry. A 12% prevalence rate of ciguatoxic lionfish exceeding the FDA guidance level of 0.1 µg/kg C-CTX-1 equivalents was identified in fish from the U.S. Virgin Islands, highlighting a potential consumption risk in this region. This study presents the first evidence that the invasive lionfish, pose a direct human health risk for CFP and highlights the need for awareness and research on this food safety hazard in known endemic areas.

Topics: Animals; Atlantic Ocean; Biodiversity; Caribbean Region; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Ecosystem; Fishes; Food Safety; Humans; Indicators and Reagents; Marine Biology; Marine Toxins; Meat; Neuroblastoma; Predatory Behavior; Seafood; Sodium Channel Blockers; Tandem Mass Spectrometry; Toxicity Tests; United States Virgin Islands

Ciguatoxins (CTXs) responsible for ciguatera fish poisoning (CFP) in Amami Islands, Kagoshima, Japan in 2008 were determined by LC-MS/MS analysis. Ciguatoxin-1B (CTX1B), 54-deoxyCTX1B, and 52-epi-54-deoxyCTX1B were detected in Variola louti and Lutjanus monostigma. The toxin profile distinctly differed from that of a CFP-related fish from Miyazaki, which mainly contained ciguatoxin-3C type toxins. Toxin profiles were species-specific, as observed in fish from Okinawa. The LC-MS/MS and mouse bioassay (MBA) methods produced comparable data, though 54-deoxyCTX1B was not taken into consideration owing to the lack of toxicity data. To improve assessment, toxicity data for this compound are needed. A reef fish caught on the same occasion and judged nontoxic by MBA (<0.025 MU/g) was found to contain low levels of CTX, indicating a potential risk for CFP.

Topics: Animals; Biological Assay; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Fish Products; Food Contamination; Japan; Mice; Molecular Conformation; Tandem Mass Spectrometry; Toxicity Tests

Ciguatera fish poisoning (CFP), a disease caused by consuming fish that have accumulated ciguatoxins (CTXs) in their tissue, is regarded as the most prevalent form of intoxication in French Polynesia. Recently, the Australes, one of the least affected archipelago until the early 1980s, has shown a dramatic increase in its incidence rates in 2009 with unusual CFP cases. In the present work, potential health hazards associated with the proliferation of various marine phytoplankton species and the consumption of fish and marine invertebrates highly popular among local population were assessed in three Australes islands: Raivavae, Rurutu and Rapa. Extracts from the marine dinoflagellates Gambierdiscus, Ostreospis and mat-forming cyanobacteria as well as fish, giant clams and sea urchin samples were examined for the presence of CTXs and palytoxin (PLTX) by using the neuroblastoma cell-based assay (CBA-N2a). Cytotoxic responses observed with both standards (Pacific CTX-3C and PLTX) and targeted marine products indicate that CBA-N2a is a robust screening tool, with high sensitivity and good repeatability and reproducibility. In Rurutu and Raivavae islands, our main findings concern the presence of CTX-like compounds in giant clams and sea urchins, suggesting a second bio-accumulation route for CFP toxins in the ciguatera food chain. In Rapa, the potential CFP risk from Gambierdiscus bloom and fish was confirmed for the first time, with levels of CTXs found above the consumer advisory level of 0.01 ng Pacific CTX-1B g(-1) of flesh in three fish samples. However, despite the presence of trace level of PLTX in Ostreopsis natural assemblages of Rapa, no sign of PLTX accumulation is yet observed in tested fish samples. Because this multi-toxinic context is likely to emerge in most French Polynesian islands, CBA-N2a shows great potential for future applications in the algal- and toxin-based field monitoring programmes currently on hand locally.

Topics: Cell Line, Tumor; Ciguatera Poisoning; Ciguatoxins; Humans; Neuroblastoma; Polynesia; Reproducibility of Results; Seafood

Ciguatera fish poisoning is a seafood intoxication commonly afflicting island communities in the Pacific. These populations, which are strongly dependent on fish resources, have developed over centuries various strategies to decrease the risk of intoxication, including the use of folk tests to detect ciguateric fish. This study aims to evaluate the effectiveness of two folk tests commonly used in Raivavae Island (Australes, French Polynesia): the rigor mortis test (RMT) and the bleeding test (BT). A total of 107 fish were collected in Raivavae Lagoon, among which 80 were tested by five testers using the RMT versus 107 tested by four testers using BT. First, the performance between testers was compared. Second, the efficiency of these tests was compared with toxicity data obtained via the receptor binding assay (RBA) by assessing various parameter's values such as sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV). Comparisons of outcomes between folk tests and RBA analyses were considered: tests used separately or in a parallel versus the series approach by each tester. The overall efficiency of the RMT and BT tests was also evaluated when the judgments of all testers were "pooled". The results demonstrate that efficiencies varied between testers with one showing the best scores in detecting toxic fish: 55% with RMT and 69.2% with BT. BT gave the best results in detecting toxic fish as compared with RMT, giving also better agreement between testers. If high NPV and Se values were to be privileged, the data also suggest that the best way to limit cases of intoxication would be to use RMT and BT tests in a parallel approach. The use of traditional knowledge and a good knowledge of risky versus healthy fishing areas may help reduce the risk of intoxication among communities where ciguatera fish poisoning is highly prevalent.

Topics: Animals; Cell Line, Tumor; Ciguatera Poisoning; Ciguatoxins; Humans; Observer Variation; Polynesia

Ciguatoxins are sodium channel activator toxins responsible for ciguatera fish poisoning. In this study, we determined the toxicokinetic parameters of the Pacific ciguatoxin P-CTX-1 in rats after an intravenous (iv) dose of 0.13 ng P-CTX-1 per g of body weight. The ciguatoxin activity was assessed over time in blood using the sensitive functional Neuro2a assay. The data were analyzed with a two-compartmental model. After exposure, the ciguatoxin activity exhibited a rapid (alpha half-life of 6 min) and extensive distribution into tissues (apparent steady state volume of distribution of 7.8 L). Ciguatoxin elimination from blood was slower with a beta half-life estimated at 35.5 h. The toxicokinetic parameters determined from this study were compared to data previously obtained after oral and intraperitoneal exposure of rats to 0.26 ng P-CTX-1 per g of body weight. Maximal bioavailability was determined by the area under the concentration curve, and was used to calculate the absolute P-CTX-1 bioavailabilities for oral and intraperitoneal routes of exposures of 39% and 75%, respectively.

Topics: Administration, Oral; Animals; Area Under Curve; Biological Availability; Cell Line, Tumor; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Half-Life; Injections, Intraperitoneal; Injections, Intravenous; Male; Mice; Neuroblastoma; Rats; Rats, Sprague-Dawley; Sodium Channels

The ouabain/veratridine-dependent neuroblastoma (neuro-2a) cell-based assay (CBA) was applied for the determination of the presence of ciguatoxin (CTX)-like compounds in ciguatera-suspected fish samples caught in the Canary Islands. In order to avoid matrix interferences the maximal concentration of wet weight fish tissue exposed to the neuro-2a cells was set at 20 mg tissue equivalent (TE) ml(-1) according to the sample preparation procedure applied. In the present study, the limit of quantification (LOQ) of CTX1B equivalents in fish extract was set at the limit of detection (LOD), being defined as the concentration of CTX1B equivalents inhibiting 20% cell viability (IC(20)). The LOQ was estimated as 0.0096 ng CTX1B eq.g TE(-1) with 23-31% variability between experiments. These values were deemed sufficient even though quantification given at the IC(50) (the concentration of CTX1B equivalents inhibiting 50% cell viability) is more accurate with a variability of 17-19% between experiments. Among the 13 fish samples tested, four fish samples were toxic to the neuro-2a cells with estimations of the content in CTX1B g(-1) of TE ranging from 0.058 (± 0.012) to 6.23 (± 0.713) ng CTX1B eq.g TE(-1). The high sensitivity and specificity of the assay for CTX1B confirmed its suitability as a screening tool of CTX-like compounds in fish extracts at levels that may cause ciguatera fish poisoning. Species identification of fish samples by DNA sequence analysis was conducted in order to confirm tentatively the identity of ciguatera risk species and it revealed some evidence of inadvertent misidentification. Results presented in this study are a contribution to the standardisation of the neuro-2a CBA and to the risk analysis for ciguatera in the Canary Islands.

Topics: Animals; Base Sequence; Cell Line, Tumor; Ciguatera Poisoning; Ciguatoxins; DNA Primers; Fishes; Humans; Inhibitory Concentration 50; Limit of Detection; Neuroblastoma; Spain

Ciguatera fish poisoning (CFP) is a form of food poisoning caused by the ingestion of a variety of reef fish that have accumulated trace amounts of ciguatoxins produced by dinoflagellates of the genus Gambierdiscus through the food chain. CFP affects more than 50,000 people each year. The extremely low level of the causative neurotoxins, ciguatoxins, in fish has hampered the preparation of antibodies for detecting the toxins. In this paper, we describe a thiol strategy for synthesizing a keyhole limpet hemocyanin (KLH)-conjugate (20) of the ABCDE-ring fragment of the Pacific ciguatoxins, CTX1B (1) and 54-deoxyCTX1B (4). We succeeded in producing a monoclonal antibody (3G8) against the left wings of these ciguatoxins by immunizing mice with the hapten-KLH conjugate (20) as the synthetic antigen. The most promising mAb, 3G8, does not cross-react with other related marine toxins. Sandwich enzyme-linked immunosorbent assay (ELISA) utilizing 3G8 and the previously prepared monoclonal antibody (8H4) enabled us to detect 1 specifically at less than 0.28 ng/mL.

Topics: Adjuvants, Immunologic; Animals; Antibodies, Monoclonal; Antibody Affinity; Ciguatera Poisoning; Ciguatoxins; Cross Reactions; Dinoflagellida; Enzyme-Linked Immunosorbent Assay; Fishes; Food Contamination; Food Inspection; Haptens; Hemocyanins; Limit of Detection; Seafood

Senescent leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae) are traditionally used in the Pacific region to treat Ciguatera Fish Poisoning. This plant contains rosmarinic acid that is known for its multiple biological activities. In the present study, H. foertherianum aqueous extract, rosmarinic acid and its derivatives were evaluated for their capacity to reduce the effect of ciguatoxins.. Aqueous extract of H. foertherianum leaves was prepared and studied for its effects against a Pacific ciguatoxin (P-CTX-1B) in the neuroblastoma cell assay and the receptor binding assay. Rosmarinic acid and six derivatives were also evaluated by means of these bioassays. For this purpose, we have developed an improved synthetic route for caffeic acid 3,4-dihydroxy-phenethyl ester (CADPE).. Both the aqueous extract of H. foertherianum leaves and rosmarinic acid showed inhibitory activities against a Pacific ciguatoxin in the above bioassays. Among all the molecules that were evaluated, rosmarinic acid was the most active compound.. These results confirm further the potential of H. foertherianum in the treatment of Ciguatera Fish Poisoning.

Topics: Animals; Cell Line, Tumor; Ciguatera Poisoning; Ciguatoxins; Cinnamates; Depsides; Heliotropium; Medicine, Traditional; Mice; Neuroblastoma; Pacific Islands; Phytotherapy; Plant Extracts; Plant Leaves; Rosmarinic Acid

Ciguatera fish poisoning is a travel-related illness characterized by a combination of gastrointestinal and neurological symptoms in persons who eat ciguatoxic seafood in endemic areas.. In 2009, an outbreak of the disease on a refrigerator vessel in the port of Hamburg was investigated. The ship's crew fell ill after they ate fish from a catch in the Caribbean 2 weeks earlier. All 15 sailors on board were examined by port medical officers. Samples of blood and stool specimens were taken from symptomatic sailors. The frozen fish was secured for the prevention of further disease spreading and additional diagnostic tests.. All but one sailor ate the fish. The intoxication resulted in gastrointestinal or neurological symptoms in all 14 sailors who consumed the fish and persisted in varying degrees in 93% of sailors over at least 14 days. No fatality occurred, but two seamen were "unfit for duty" on the ship due to severity of symptoms. The diagnosis was supported by the fact that all seafarers who consumed the same reef fish, experienced typical signs, symptoms, and time course consistent with ciguatera fish poisoning. The fish from the catch in the Caribbean was identified as Caranx sexfasciatus (Bigeye Trevally) and Cephalopholis miniata (Red Grouper). An experimental assay later confirmed presence of the ciguatoxin in the fish.. Sailors are an occupational group at risk for ciguatera fish poisoning due to potentially unsafe food sources during international travel. Even if no fatality occurred, the disease affected marine operations due to high attack rates and chronicity of symptoms. Medical doctors must be aware that ciguatera fish poisoning is a risk for seafarers traveling in tropical and subtropical areas. Stocking of food in affected ports from safe sources, adequate training of ship cooks, and informing sailors about the risk of fishing are needed to prevent disease occurrence in seafarers in international trade and traffic.

Topics: Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Foodborne Diseases; Germany; Humans; Male; Middle Aged; Naval Medicine; Ships; Travel

Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are large ladder-like polycyclic ethers. We report a highly stereoselective 6-exo radical cyclization/ring-closing olefin metathesis sequence to construct the syn/trans-fused polyether system. The new method was applied to the practical synthesis of ciguatoxin CTX3C.

Topics: Ciguatera Poisoning; Ciguatoxins; Cyclization; Models, Molecular; Molecular Structure; Seafood; Stereoisomerism; Structure-Activity Relationship; Sulfoxides; Vinyl Compounds

Ciguatoxins are voltage-gated selective algal toxins responsible for ciguatera fish poisoning. In this study we evaluate the toxicokinetics of one of the most common ciguatoxins found in the Pacific, the P-CTX-1, in rat after an oral or intraperitoneal (ip) dose of 0.26 μg/kg body weight. We report levels of ciguatoxin activity assessed over time in blood, urine and feces, and at 4 days in liver, muscle and brain, using the functional in vitro N2A cytotoxicity assay. Following exposure, the ciguatoxin activity exhibited a rapid systemic absorption that was followed by a bi-exponential decline, and data best fit a two-compartment model analysis. Maximum blood concentrations were reached at 1.97 and 0.43 h after the oral and ip dose, respectively. Ciguatoxin elimination from blood was slow with terminal half lives (t(½)β) estimated at 82 h for oral and 112 h for ip dosing. Ciguatoxin activity remained in liver, muscle and brain 96 h after ip and oral administration. While smaller amounts appeared in the urine, the main excretion route was feces, with peak rates reaching > 10 pg P-CTX-1 equivalents/h in both routes of administration. Assay guided fractionation showed the presence in the feces and liver of peaks of activity corresponding to the P-CTX-1 and to other less polar metabolites. In conclusion, biologically active ciguatoxins are detectable in blood, liver, muscle and brain, and continued to be excreted in urine and feces 4 days following exposure. Blood, as well as urine and feces may be useful matrices for low-invasive testing methods for ciguatera clinical cases.

Topics: Administration, Oral; Animals; Ciguatera Poisoning; Ciguatoxins; Eels; Injections, Intraperitoneal; Male; Pharmacokinetics; Rats; Rats, Sprague-Dawley; Tissue Distribution

Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n=41], 8% [n=13] and 68% [n=117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g(-1)). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n=3-19) were toxic. Toxicity varied within species and among locations by up to 10000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g(-1) threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n=6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Coral Reefs; Environmental Monitoring; Epidemiological Monitoring; Fishes; Humans; Liver; Micronesia; Muscles; Poisons

To find out the reason of three ciguatera fish poisoning cases in Xiamen in 2005 and identify the fish species.. The grouper implicated in food poisoning and seven other coral reef fishes collected from market were tested by mice bioassay and ciguatoxin-test kit. The mtDNA was extracted from toxic grouper meat, and Cty b gene segment was amplified and the PCR products were sequenced. The sequences were compared with those in the GenBank.. The result turned out to be positive by the ciguatoxin-test kit, while the toxicity of the toxic grouper implicated in food poisoning was 0.11 mouse unit (MU)/g by mice bioassay. A 475 bp segments of Cty b gene was amplified by PCR and the sequence was 99% homologous with Epinephelus fuscoguttatus (GenBank: AY950695).No ciguatoxin in six grouper species collected from market was detected.. All three food poisoning cases were caused by consumption of ciguatoxin-carrying groupers.

Topics: Animals; China; Ciguatera Poisoning; Ciguatoxins; Foodborne Diseases; Humans; Male; Mice; Mice, Inbred Strains; Perciformes; Toxicity Tests

Okinawa being located in the subtropical region has the highest incidence of ciguatera in Japan. Officially, 33 outbreaks involving 103 patients have been reported between 1997 and 2006. The implicated species were Variola louti, Lutjanus bohar, Lutjanus monostigma, Epinephelus fuscoguttatus, unidentified Lutjanus sp., Plectropomus areolatus, Oplegnathus punctatus, Epinephelus polyphekadion, Caranx ignobilis and moray eel. Toxicities of the leftover meals, as determined by mouse bioassays, ranged from 0.025 to 0.8 MU/g or above (equivalent to 0.175-5.6 ngCTX1B/g). We collected 612 specimens of fish belonging to L. monostigma, L. bohar, Lutjanus argentimaculatus, Lutjanus russellii, V. louti, Variola albimarginata, and E. fuscoguttatus from the coasts around Okinawa and examined the toxicity of the flesh by the mouse bioassay. The rate of toxic fish was as follows: L. monostigma: 32.3%, L. bohar: 11.9%, V. louti: 14.3%, E. fuscoguttatus: 20.8%. Only one out of 36 samples of V. albimarginata and two of 74 samples of L. russellii were found toxic. None of the 35 samples of L. argentimaculatus was toxic. Nor the L. bohar samples weighing less than 4 kg were toxic. In all toxic samples, CTX1B was detected by LC/MS analysis but CTX3C and 51-hydroxyCTX3C were not.

Topics: Animals; Biological Assay; Chromatography, Liquid; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fishes; Humans; Incidence; Japan; Mass Spectrometry; Mice; Solid Phase Extraction; Species Specificity

The growth and toxin production in a clonal strain of Gambierdiscus polynesiensis, TB-92, was examined in batch culture conditions. The mean growth rate at exponential phase was (0.13+/-0.03)division day(-1). Regardless of the age of cultures, all mice injected with dichloromethanolic and methanolic extracts showed symptoms specific to ciguatoxin (CTX) and maitotoxin (MTX) bioactivity, respectively. The highest total toxicity assessed in TB-92 cultures was 10.4 x 10(-4) mouse unit cell(-1). The toxin production pattern reveals an enhanced cellular toxin content with the age of the culture. CTX- and MTX-like compounds each accounted for approx. 50% of the total toxicity of TB-92 cultures, except in aged cells where CTXs were dominant. The high ciguatoxic activity of TB-92 was further confirmed in dichloromethanolic extracts by means of the receptor-binding assay. The highest CTX level monitored at late stationary phase was (11.9+/-0.4)pg P-CTX-3C equiv cell(-1). Further HPLC and LC-MS analysis revealed the presence of five CTXs congeners in lipid-soluble extracts, i.e. CTX-3C, -3B, -4A, -4B and M-seco-CTX-3C, and of new CTX congeners. Toxin composition comparison between two G. polynesiensis strains suggests that the toxin profile is a stable characteristic in this species. G. polynesiensis clones also proved inherently more toxic than other Gambierdiscus species isolated from other geographical areas.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Mice

Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are potent neurotoxic polycyclic ethers. We report herein the total synthesis of a 10-membered F-ring analogue of 51-hydroxyCTX3C, which constitutes the first example of an F-ring modified ciguatoxin that exhibits potent cytotoxicity as well as mouse acute toxicity.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Injections, Intraperitoneal; Mice; Molecular Conformation

Dinoflagellates in the genus Gambierdiscus produce toxins that bioaccumulate in tropical and sub-tropical fishes causing ciguatera fish poisoning (CFP). Little is known about the diversity and distribution of Gambierdiscus species, the degree to which individual species vary in toxicity, and the role each plays in causing CFP. This paper presents the first global distribution of Gambierdiscus species. Phylogenetic analyses of the existing isolates indicate that five species are endemic to the Atlantic (including the Caribbean/West Indies and Gulf of Mexico), five are endemic to the tropical Pacific, and that two species, Gambierdiscus carpenteri and Gambierdiscus caribaeus are globally distributed. The differences in Gambierdiscus species composition in the Atlantic and Pacific correlated with structural differences in the ciguatoxins reported from Atlantic and Pacific fish. This correlation supports the hypothesis that Gambierdiscus species in each region produce different toxin suites. A literature survey indicated a >100-fold variation in toxicity among species compared with a 2 to 9-fold within species variation due to changing growth conditions. These observations suggest that CFP events are driven more by inherent differences in species toxicity than by environmental modulation. How variations in species toxicity may affect the development of an early warning system for CFP is discussed.

Topics: Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Phylogeny; Species Specificity

Ciguatera fish poisoning (CFP) is endemic in certain tropical and subtropical regions of the world. CFP had not been described on the West Africa Coast until a 2004 outbreak in the Canary Islands. In 2008-2009, two additional outbreaks of ciguatera occurred. Individuals afflicted had consumed lesser amberjack (Seriola rivoliana) captured from nearby waters. Caribbean ciguatoxin-1 (C-CTX-1) was confirmed in fish samples by LC-MS/MS. Ciguatoxic fish in this region may pose a new health risk for the seafood consumer.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fishes; Humans; Risk Assessment; Seafood; Spain

The synthetic ciguatoxin CTX3C has been shown to activate tetrodotoxin (TTX)-sensitive sodium channels (Na(v)1.2, Na(v)1.4, and Na(v)1.5) by accelerating activation kinetics and shifting the activation curve toward hyperpolarization (Yamaoka, K., Inoue, M., Miyahara, H., Miyazaki, K., and Hirama, M. (2004) Br. J. Pharmacol. 142, 879-889). In this study, we further explored the effects of CTX3C on the TTX-resistant sodium channel Na(v)1.8. TTX-resistant channels have been shown to be involved in transducing pain and related sensations (Akopian, A. N., Sivilotti, L., and Wood, J. N. (1996) Nature 379, 257-262). Thus, we hypothesized that ciguatoxin-induced activation of the Na(v)1.8 current would account for the neurological symptoms of ciguatera poisoning. We found that 0.1 mum CTX3C preferentially affected the activation process of the Na(v)1.8 channel compared with those of the Na(v)1.2 and Na(v)1.4 channels. Importantly, without stimulation, 0.1 mum CTX3C induced a large leakage current (I (L)). The conductance of the I (L) calculated relative to the maximum conductance (G (max)) was 10 times larger than that of Na(v)1.2 or Na(v)1.4. To determine the molecular domain of Na(v)1.8 responsible for conferring higher sensitivity to CTX3C, we made two chimeric constructs from Na(v)1.4 and Na(v)1.8. Chimeras containing the N-terminal half of Na(v)1.8 exhibited a large response similar to wild-type Na(v)1.8, indicating that the region conferring high sensitivity to ciguatoxin action is located in the D1 or D2 domains.

Topics: Animals; Base Sequence; Cell Line; Ciguatera Poisoning; Ciguatoxins; Gene Expression; Humans; Molecular Sequence Data; Muscle Proteins; NAV1.4 Voltage-Gated Sodium Channel; NAV1.8 Voltage-Gated Sodium Channel; Nerve Tissue Proteins; Peptide Mapping; Protein Structure, Tertiary; Rats; Recombinant Fusion Proteins; Sodium Channels

Ciguatera is a global food poisoning caused by the consumption of fish that have accumulated sodium channel activator toxins, ciguatoxins. At present, most diagnosed cases of ciguatera are treated with symptomatic and supportive remedies, and no specific therapy has been devised. Here we report that ciguatoxin CTX3C can be effectively neutralized in vitro and in vivo by simultaneous use of two anti-ciguatoxin monoclonal antibodies, providing the first rational approach toward directly preventing and treating ciguatera.

Topics: Animals; Antibodies, Monoclonal; Cell Line, Tumor; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Lethal Dose 50; Male; Mice; Neutralization Tests

Ciguatera fish poisoning (CFP) is an intertropical ichthyosarcotoxism that manifests in complex assortment of symptoms in humans. Ciguatoxins (CTXs), issued from Gambierdicus spp., are causative agents of this intoxication. We have recently demonstrated that a Pacific CTX (P-CTX-1B) strongly modulated iNOS expression, leading to overproduction of nitric oxide (NO) in RAW 264.7 murine macrophage cells. NO produced in large amounts is involved in a wide range of pathophysiological processes. Many traditional remedies are commonly used in the Pacific against CFP. In this context, bioassay-guided screening was carried out to study NO inhibiting capacity of 28 selected plant extracts.. We prepared aqueous extracts of plants used in New Caledonia in the treatment of CFP and screened their NO inhibitory activity in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages.. Among 28 plants tested, Euphorbia hirta (Euphorbiaceae), Syzygium malaccense (Myrtaceae), Schinus terebenthifolius (Anacardiaceae), Punica granatum (Punicaceae), Cerbera manghas (Apocynaceae), Vitex trifolia (Labiateae) and Ximenia americana (Olacaceae) showed inhibitory activity, validating their use as traditional remedies in CFP, and the potential for use in the treatment of conditions accompanied by NO overproduction.. These plants are promising candidates for further screening of their active compounds through activity-guided fractionation.

Topics: Animals; Cell Line; Ciguatera Poisoning; Ciguatoxins; Humans; Lipopolysaccharides; Macrophages; Magnoliopsida; Medicine, Traditional; Mice; Nitric Oxide; Plant Extracts; Plants, Medicinal

Florisil solid-phase extraction (SPE) cartridges were used for purifying ciguatoxin (CTX)-contaminated coral fish extracts, with the aim of removing extracted lipid but retaining optimal level of CTXs in the purified fractions. The CTX-containing fraction (target fraction) in fish ether extract was isolated and purified by eluting through a commercially available Florisil cartridge with hexane-acetone-methanol solvent mixtures of increasing polarity (hexane-acetone (4:1, v/v) < acetone-methanol (7:3, v/v) < 100% methanol). Application of Florisil SPE using acetone-methanol (7:3, v/v) condition facilitated the separation of 4.2 +/- 0.4 mg (mean +/- standard error of the mean (SEM)) of purified target fraction from 20 mg ether extract with good retention of CTXs. The mouse bioassay was used to demonstrate that the average CTX recovery of the target fraction from CTX-spiked samples was 75.8% +/- 3.3%, which was significantly increased by 96.7% +/- 15% when compared with CTX recovery from ether extracts (44.8% +/- 5.2%) without performing SPE purification. Over 70% of non-target lipids were removed in which no CTX toxicity was found. Moreover, the target fractions of both CTX-spiked and naturally CTX-contaminated samples gave more prominent toxic responses of hypothermia and/or induced more rapid death of the mice. The use of acetone-methanol (7:3, v/v) condition in the elution could significantly improve overall recovery of CTXs, while minimizing the possible interferences of lipid matrix from co-extractants on mice.

Topics: Animals; Biological Assay; China; Ciguatera Poisoning; Ciguatoxins; Fishes; Food Contamination; Humans; Hypothermia; Lethal Dose 50; Marine Toxins; Mice; Poisons; Solid Phase Extraction; Tissue Extracts

Food poisoning due to ingestion of an unknown red grouper occurred in southern Taiwan. To identify the species of toxic red grouper implicated in food poisoning, a 475-bp sequence of the cytochrome b gene from six species of fresh red grouper meat was amplified by using a pair of primers (L14735/H15149). This fragment could be amplified when fish meat was treated with different heating processes. After sequencing, it was found that no variation in sequences was detected among individuals within each species. The species of toxic red grouper meat implicated in food poisoning was judged to be Lutjanus bohar based on sequence analysis. In addition, restriction enzyme analysis with HaeIII rapidly distinguished these six species of red grouper and the two samples implicated in food poisoning. No toxicity of viscera in 18 specimens of six red grouper species was detected, but two food poisoning samples were found to be toxic. This study indicated that DNA sequence and restriction enzyme analysis are powerful methods for identifying potentially toxic red grouper species as L. bohar.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Consumer Product Safety; Cytochrome b Group; DNA Primers; Food Contamination; Food Microbiology; Perciformes; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Seafood; Sequence Analysis, DNA; Species Specificity; Taiwan

The applicability of a new enzyme-linked immunoassay (ELISA) for detecting ciguatoxin (CTX) in fish tissue was evaluated by testing three fish species commonly implicated in ciguatera fish poisoning in Hawaii. A total of 164 individual almaco jack (Seriola rivoliana) and greater amberjack (S. dumerili) and a total of 175 individuals of the blue-spotted grouper (Cephalopholis argus) were caught at various locations in the Hawaiian Islands. Muscle tissue from each individual was assessed for the presence of CTX using two methods: a semi-quantitative ELISA that was recently developed for detecting picogram levels of CTX in fish extract and a neuroblastoma (NB) cell assay commonly used to screen for marine toxins in fish. Results of the tests were highly correlated, with the ELISA indicating the presence of CTX in 9.4% of all fish samples, and the NB assay indicating toxicity in 6.8% of the fish samples. We conclude that the ELISA produces reliable and accurate results that are consistent with those provided by the accepted NB assay and that the ELISA has potential for future applications in screening fish populations for CTX.

Topics: Animals; Biological Assay; Cell Survival; Ciguatera Poisoning; Ciguatoxins; Environmental Monitoring; Enzyme-Linked Immunosorbent Assay; Food Contamination; Mice; Muscle, Skeletal; Neuroblastoma; Perciformes; Reproducibility of Results; Seafood; Tumor Cells, Cultured

A sandwich enzyme-linked immunosorbent assay was developed to detect ciguatoxin (CTX) in fish tissue. The assay utilizes two antibodies, chicken immunoglobulin Y specific to the ABCD domain of CTX and a mouse monoclonal immunoglobulin G-horseradish peroxidase conjugate specific to the JKLM domain of CTX. The sensitivity, working range, cross reactivity, accuracy, precision, and reproducibility were examined.

Topics: Animals; Antibodies, Monoclonal; Biological Assay; Chickens; Ciguatera Poisoning; Ciguatoxins; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Immunoglobulins; Mice; Neuroblastoma; Poisons; Predictive Value of Tests; Reproducibility of Results; Seafood; Tumor Cells, Cultured

Topics: Animals; Canada; Chile; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Ethanol; Female; Fishes; Gait Disorders, Neurologic; Humans; Paris; Recurrence; Seafood; Sodium Channel Blockers; Travel; Young Adult

Ciguatoxins and brevetoxins are neurotoxic cyclic polyether compounds produced by dinoflagellates, which are responsible for ciguatera and neurotoxic shellfish poisoning (NSP) respectively. Recently, brevenal, a natural compound was found to specifically inhibit brevetoxin action and to have a beneficial effect in NSP. Considering that brevetoxin and ciguatoxin specifically activate voltage-sensitive Na+ channels through the same binding site, brevenal has therefore a good potential for the treatment of ciguatera. Pacific ciguatoxin-1B (P-CTX-1B) activates voltage-sensitive Na+ channels and promotes an increase in neurotransmitter release believed to underpin the symptoms associated with ciguatera. However, the mechanism through which slow Na+ influx promotes neurosecretion is not fully understood. In the present study, we used chromaffin cells as a model to reconstitute the sequence of events culminating in ciguatoxin-evoked neurosecretion. We show that P-CTX-1B induces a tetrodotoxin-sensitive rise in intracellular Na+, closely followed by an increase in cytosolic Ca2+ responsible for promoting SNARE-dependent catecholamine secretion. Our results reveal that brevenal and beta-naphtoyl-brevetoxin prevent P-CTX-1B secretagogue activity without affecting nicotine or barium-induced catecholamine secretion. Brevenal is therefore a potent inhibitor of ciguatoxin-induced neurotoxic effect and a potential treatment for ciguatera.

Topics: Animals; Antidotes; Calcium; Catecholamines; Cattle; Chromaffin Cells; Ciguatera Poisoning; Ciguatoxins; Neurosecretion; Sodium; Sodium Channels; Thiopental

To review the clinical features and laboratory investigations of ciguatera patients in Hong Kong between 2004 and 2007 in order to show the timely sampling of implicated fish from ciguatera victims and application of validated mouse bioassay for confirming suspected clinical cases of ciguatera.. Diagnosis of the ciguatera victims was based on history of coral fish consumption and clinical presentations stated in official guidelines for clinical diagnosis of ciguatera fish poisoning in Hong Kong. Food remnants of coral fish samples were collected swiftly from ciguatera victims between 2004 and 2007 for ciguatoxins (CTXs) analysis.. Major clinical symptoms in ciguatera patients included gastrointestinal and neurological effects including limb numbness and diarrhoea, which developed at 0.5 to 15 hours after consumption of fish. In most cases, neurological symptoms were more common than gastrointestinal symptoms. A broad range of attack rate (10%-100%) was observed in each ciguatera outbreak. Validated mouse bioassay on ether extracts of the food remnant samples confirmed that all were CTXs-positive (<0.5 - 4.3 MU/20 mg ether extract) and directly linked to the corresponding ciguatera cases.. Consistency between clinical and laboratory analysis for ciguatera poisoning illustrates the application of laboratory mouse bioassay in a timely fashion for confirming ciguatera poisoning cases and implementing effective public health measures. With further improvement in laboratory techniques, features of ciguatera fish poisoning cases can be better defined. Further studies are needed to determine the risk of each class of CTXs (Pacific-, Indian- and Caribbean-CTXs) in Hong Kong.

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Fishes; Gastrointestinal Diseases; Hong Kong; Humans; Mice; Nervous System Diseases; Prevalence; Public Health; Risk Factors; Time Factors

In this study, we pharmacologically characterized gambierol, a marine polycyclic ether toxin which is produced by the dinoflagellate Gambierdiscus toxicus. Besides several other polycyclic ether toxins like ciguatoxins, this scarcely studied toxin is one of the compounds that may be responsible for ciguatera fish poisoning (CFP). Unfortunately, the biological target(s) that underlies CFP is still partly unknown. Today, ciguatoxins are described to specifically activate voltage-gated sodium channels by interacting with their receptor site 5. But some dispute about the role of gambierol in the CFP story shows up: some describe voltage-gated sodium channels as the target, while others pinpoint voltage-gated potassium channels as targets. Since gambierol was never tested on isolated ion channels before, it was subjected in this work to extensive screening on a panel of 17 ion channels: nine cloned voltage-gated ion channels (mammalian Na(v)1.1-Na(v)1.8 and insect Para) and eight cloned voltage-gated potassium channels (mammalian K(v)1.1-K(v)1.6, hERG and insect ShakerIR) expressed in Xenopus laevis oocytes using two-electrode voltage-clamp technique. All tested sodium channel subtypes are insensitive to gambierol concentrations up to 10 microM. In contrast, K(v)1.2 is the most sensitive voltage-gated potassium channel subtype with almost full block (>97%) and an half maximal inhibitory concentration (IC(50)) of 34.5 nM. To the best of our knowledge, this is the first study where the selectivity of gambierol is tested on isolated voltage-gated ion channels. Therefore, these results lead to a better understanding of gambierol and its possible role in CFP and they may also be useful in the development of more effective treatments.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Dose-Response Relationship, Drug; Oocytes; Potassium Channel Blockers; Potassium Channels, Voltage-Gated; Sodium Channels; Xenopus laevis

This study examined 328 CFS sera in a study with 17 CCFP, 8 Gulf War Veterans (GWV), 24 Prostate Cancer (PC), and 52 normal sera in the modified Membrane Immunobead Assay (MIA) procedure for CTX. Three hundred and twenty-eight CFS patients' sera were examined by the modified MIA with purified MAb-CTX and 91.2% gave a titre > or =1:40. 76% of the 17 CCFP sera samples and 100% of the 8 GWV sera samples also had a titre > or =1:40. 92.3% of 52 normal sera showed titres of 1:20 or less, while 4 gave titres of > or =1:40. In addition, 41 sera were examined for Anti-Cardiolipin (aCL) by a commercial ELISA procedure with 87.8% demonstrating IgM, IgM+IgA, or IgM+IgG aCL antibodies. These results showed mostly the IgM aCL antibody alone in the sera samples. In addition, 41 serum samples were examined for aCL, with 37 showing positive for aCL, representing 90.2% positive for the three disease categories examined: CFS, CCFP and GWV. Examination for antiMitochondrial-M2 autoantibody (aM-M2) in 28 patients (CFS (18), CCFP (5), and GWV (5)) was negative for aM-M2. Inhibition analysis with antigens, CTX, CFS "Acute Phase Lipids", commercial Cardiolipin (CL) and 1,2-Dipalmitoyl-sn-Glycero-3-[Phospho-L-Serine] (PS) and antibodies, MAb-CTX and aCL from patients' serum show that the phospholipids in CL and CTX are antigenically indistinguishable with antibodies MAb-CTX and CFS-aCL. Preliminary chemical analyses have shown the lipids to be phospholipids associated with CL of the mitochondria. We designate this "Acute Phase Lipid" comparable to "Acute Phase Proteins" (C-reactive protein (CRP) and Serum Amyloid A (SAA)) in inflammatory conditions.

Topics: Acute-Phase Reaction; Antibodies, Anticardiolipin; Antibodies, Monoclonal; C-Reactive Protein; Cardiolipins; Chronic Disease; Ciguatera Poisoning; Ciguatoxins; Enzyme-Linked Immunosorbent Assay; Fatigue Syndrome, Chronic; Gulf War; Humans; Marine Toxins; Mitochondria; Phospholipids; Reference Standards; Serum Amyloid A Protein

Ciguatoxins (CTX) are polyether neurotoxins that target voltage-gated sodium channels and are responsible for ciguatera, the most common fish-borne food poisoning in humans. This study characterizes the global transcriptional response of mouse liver to a symptomatic dose (0.26 ng/g) of the highly potent Pacific ciguatoxin-1 (P-CTX-1). At 1 h post-exposure 2.4% of features on a 44K whole genome array were differentially expressed (p < or = 0.0001), increasing to 5.2% at 4 h and decreasing to 1.4% by 24 h post-CTX exposure. Data were filtered (/fold change/ > or = 1.5 and p < or = 0.0001 in at least one time point) and a trend set of 1550 genes were used for further analysis. Early gene expression was likely influenced prominently by an acute 4 degrees C decline in core body temperature by 1 h, which resolved by 8 h following exposure. An initial downregulation of 32 different solute carriers, many involved in sodium transport, was observed. Differential gene expression in pathways involving eicosanoid biosynthesis and cholesterol homeostasis was also noted. Cytochrome P450s (Cyps) were of particular interest due to their role in xenobiotic metabolism. Twenty-seven genes, mostly members of Cyp2 and Cyp4 families, showed significant changes in expression. Many Cyps underwent an initial downregulation at 1 h but were quickly and strongly upregulated at 4 and 24 h post-exposure. In addition to Cyps, increases in several glutathione S-transferases were observed, an indication that both phase I and phase II metabolic reactions are involved in the hepatic response to CTX in mice.

Topics: Animals; Body Temperature; Body Temperature Regulation; Ciguatera Poisoning; Ciguatoxins; Cytochrome P-450 Enzyme System; Down-Regulation; Genomics; Glutathione Transferase; Liver; Metabolic Detoxication, Phase I; Metabolic Detoxication, Phase II; Mice; Oligonucleotide Array Sequence Analysis; Poisons; RNA, Messenger; Transcription, Genetic

Topics: Adult; Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Female; Humans; Hysteria; Nephropidae; Psychophysiologic Disorders

Ciguatera diagnosis relies on clinical observations associated with a recent consumption of fish. Although needed, direct confirmation of exposure in subjects showing ciguatera disease symptoms is currently unavailable. We previously reported that ciguatoxins were measurable in the blood of mice exposed to extracts of Pacific ciguatoxins isolated from Gambierdiscus polynesiensis, and of Indian Ocean or Caribbean Sea ciguatoxins, isolated from fish. Although highly efficient for extracting spiked purified Caribbean-CTX-1, the methanolic extraction method previously described is found here to yield only 6% recovery of spiked Pacific-CTX-1 (P-CTX-1). We report in this short communication a substantially modified method for ciguatoxin extraction from both dried and fresh blood. With this method, toxin measurement is directly accomplished in acetonitrile deproteinated whole fresh blood or phosphate buffer solution (PBS) eluted dried blood using the N2A cell-based assay. Spike studies using increasing concentrations of purified ciguatoxins reveal linear (r2 above 0.87 for all toxins) and overall efficient toxin recoveries (62%, 96%, and 96% from fresh blood and 75%, 90%, and 74% from dried blood, for C-CTX-1, P-CTX-3C, and P-CTX-1, respectively). Comparative blood matrix analysis for P-CTX-1 recovery shows increased recovery of ciguatoxin activity from whole fresh blood than from dried blood, greater by 20% in P-CTX-1 spiked mice blood and by over 85% in P-CTX-1 exposed mouse blood. In conclusion, both Caribbean and Pacific ciguatoxins can be readily extracted from blood using this modified method; however, in the case of P-CTX-1 we find that fresh blood is optimal.

Topics: Animals; Cell Line, Tumor; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Female; Fishes; Fractional Precipitation; Mice; Mice, Inbred ICR; Sensitivity and Specificity

Ciguatera Fish Poisoning (CFP) is a tropical syndrome well known in remote archipelagos where the population is still dependent on fish resources. In order to assess the ciguatera risk in two islands of French Polynesia, Tubuai (Australes) and Nuku Hiva (Marquesas), a study was carried out on both Gambierdiscus populations as well as on various fish species using the receptor-binding assay (RBA) to detect and quantify ciguatoxins. Relationship between RBA data and size or weight of fish was evaluated, and when only few individuals for a particular species were available the trophic level was used to help comparisons between studied areas. According to epidemiological data, toxic versus safe areas were explored and compared in both islands. In Tubuai Island, Gambierdiscus cells were surprisingly absent in the north area, considered as a toxic area, but almost 94% of fishes were classified as RBA+. In contrast, the south area, supposed to be safe, was evolving to be a risky area because of the presence of Gambierdiscus cells and 74% of fishes being RBA+. In Nuku Hiva Island, Gambierdiscus cells were present in the toxic areas, Anaho, Taiohae and Taipivei, with two toxic blooms in Anaho Bay, but none in Terre Déserte, the fishing area of this island. With RBA data, fishes were analyzed to be RBA+ at a high percentage in Anaho and Taiohae, higher than in Taipivei and Terre Déserte areas. In general, our findings were congruent with epidemiological data and the knowledge of local people only for risky fish species.

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Environmental Monitoring; Eukaryota; Food Contamination; Inhibitory Concentration 50; Plant Extracts; Polynesia; Rats; Risk Assessment; Risk Factors; Sodium Channel Blockers; Sodium Channels; Synaptosomes

Ciguatera fish poisoning and neurotoxic shellfish poisoning are distinct clinical entities characterized by gastrointestinal and neurological disturbances, following the consumption of certain reef fish and shellfish containing toxic polyether compounds sporadically present in certain toxic marine dinoflagellates. The biotransformation and bioaccumulation of gambierol and brevetoxin, and their congeners, are believed to be involved in the pathogenesis of these "food-chain diseases", for which no effective treatments are available. Here, we describe for the first time the potent effect of gambierol and brevetoxin on TRPV1 channels, a key player in thermal and pain sensation. Our findings may lead to promising new therapeutic interventions.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Ethers, Cyclic; Humans; Marine Toxins; Oxocins; Patch-Clamp Techniques; Polycyclic Compounds; Shellfish; TRPV Cation Channels; Xenopus laevis

Ciguatoxins (CTX) are a suite of cyclic polyether toxins produced by the marine dinoflagellate Gambierdiscus sp., are potent activators of voltage-gated sodium channels and a leading cause of human poisoning from food fish. This report characterizes the genomic and proteomic response in whole blood of adult male mice exposed i.p. to 264 ng/kg of the Pacific congener of CTX (P-CTX-1) at 1, 4 and 24h. Whole genome microarray expression data were filtered by tightness of fit between replicates, fold change (1.8) and p-value (10(-5)), resulting in 183 annotated genes used for trending analysis, K-means clustering and ontology classification. Genes involved with cytokine signaling, proteasome complex and ribosomal function were dominant. qPCR performed on 19 genes of interest had a correlation of 0.95 to array results by Pearson's correlation coefficient. Serum protein analysis showed small but significant changes in 6 of 60 proteins assayed: Ccl2, Ccl12, CD40, IL-10, leptin and M-CSF. In large part, the gene expression was consistent with a Th2 immune response with interesting similarities to expression seen in asthmatic models.

Topics: Animals; Antibody Formation; Blood Proteins; Ciguatera Poisoning; Ciguatoxins; Cluster Analysis; Disease Models, Animal; Gene Expression Profiling; Immunoassay; Male; Mice; Mice, Inbred C57BL; Oligonucleotide Array Sequence Analysis; Proteomics; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; RNA; Th2 Cells; Time Factors; Transcription, Genetic

Ciguatera toxin is a marine neurotoxin produced by microorganisms that becomes concentrated in predatory fish. Toxicity in humans results from the ingestion of contaminated fish harvested in tropical waters. Clinical manifestations of illness include the rapid onset of gastrointestinal symptoms and neurological abnormalities. Because of the rapid onset of symptoms and the potential for case clusters from a common source ingestion of contaminated fish, there is the potential that ciguatera poisoning may initially mimic illnesses caused by antipersonnel biological and chemical agents. We present data on an active duty soldier who presented to sick call for evaluation of new onset paresthesias and was diagnosed with ciguatera toxin poisoning. We also present a review of ciguatera poisoning literature with emphasis on the distinguishing features between ciguatoxin and other neurotoxins of military significance.

Topics: Adult; Ciguatera Poisoning; Ciguatoxins; Delivery of Health Care; Diagnosis, Differential; Follow-Up Studies; Humans; Immunoassay; Male; Military Medicine; Military Personnel

Gambierol, a representative of the marine ladder toxin family, consists of eight ether rings, 18 stereocenters, and two challenging pyranyl rings having methyl groups that are in a 1,3-diaxial orientation to one another. Herein we describe the generation of gambierol's A-C and F-H ring systems and demonstrate the versatility of the glycosyl anhydride, enol ether-olefin RCM strategy to fused polycyclic ethers. This work has both enabled us to generate sufficient quantities of the gambierol precursors and has enabled us to better understand the chemical transformations that were key to these efforts. Fundamental work included efforts to C-glycosides and C-ketosides, Claisen rearrangements, and enol ether-olefin RCM reactions.

Topics: Ciguatera Poisoning; Ciguatoxins; Cyclization; Epoxy Compounds; Ethers; Ethers, Cyclic; Glycosides; Indicators and Reagents; Magnetic Resonance Spectroscopy; Marine Toxins; Polycyclic Compounds

[reaction: see text] A convergent synthesis of the right-hand half of ciguatoxin (the HIJKLM ring system) has been achieved with complete stereocontrol in the introduction of the stereocenters on the eight-membered I ring. Key steps are Sonogashira coupling, dicobalt complexation, intramolecular conjugate addition, and hydrogenation of an endo-olefin to provide the 39-alpha-methyl group.

Topics: Ciguatera Poisoning; Ciguatoxins; Cyclization; Hydrogenation; Molecular Biology; Molecular Structure

The monoclonal antibody to ciguatoxin (CTX) produced from a hybridoma cell line was assayed for the detection of four congeners of CTX: Pacific ciguatoxin-1 (P-CTX-1), Pacific ciguatoxin-2 (P-CTX-2), Pacific ciguatoxin-3 (P-CTX-3), and Caribbean ciguatoxin-1 (C-CTX-1) and related marine toxins, including domoic acid, palytoxin, and okadaic acid, using a modified enzyme-linked immunosorbent assay (ELISA). Lower detection limits were assessed and linearity was statistically established (P<0.05) for P-CTX-1, P-CTX-2, and P-CTX-3 and C-CTX-1 at concentrations ranging from 0 to 5.00 ng, while the other marine toxins showed statistically insignificant cross-reactivities at similar concentrations. Thus, the monoclonal antibody to CTX is able to specifically detect various CTX congeners at levels comparable to those naturally occurring in ciguatoxic fish.

Topics: Acrylamides; Antibodies, Monoclonal; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Cnidarian Venoms; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Kainic Acid; Okadaic Acid; Pacific Ocean; Seafood

Topics: Animals; Body Temperature; Body Weight; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Dose-Response Relationship, Drug; Hong Kong; Humans; Mice

Ciguatera toxin causes a range of gastrointestinal, cardiovascular and neurological symptoms that occur within 1-6 h of ingesting fish with the toxin and can last for days, months or years. It is a well-recognized problem in the tropics. Avon Health Protection Team investigated food poisoning on a ship at Avonmouth, which was thought by the crew to be related to a white snapper fish from the Caribbean. The symptoms were initially thought to be scombroid fish poisoning but were consistent with ciguatera fish poisoning. Cases of fish poisoning from fish imported from the Caribbean and Pacific or travellers returning from tropical countries may be ciguatera fish poisoning, but mistakenly diagnosed as scombroid fish poisoning.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Humans; Risk Assessment; Risk Factors; Seafood; Ships; Surveys and Questionnaires; Travel; Tropical Climate; United Kingdom

Ciguatera is a human food poisoning caused by consumption of tropical and subtropical fish that have, through their diet, accumulated ciguatoxins in their tissues. This study used laboratory mice to investigate the potential to apply blood collection cards to biomonitor ciguatoxin exposure. Quantitation by the neuroblastoma cytotoxicity assay of Caribbean ciguatoxin (C-CTX-1) spiked into mice blood was made with good precision and recovery. The blood collected from mice exposed to a sublethal dose of Caribbean ciguatoxic extract (0.59 ng/g C-CTX-1 equivalents) was analyzed and found to contain detectable toxin levels at least 12 h post-exposure. Calculated concentration varied from 0.25 ng/ml at 30 min post-exposure to 0.12 ng/ml at 12 h. A dose response mice exposure revealed a linear dose-dependent increase of ciguatoxin activity in mice blood, with more polar ciguatoxin congeners contributing to 89% of the total toxicity. Finally, the toxin measurement in mice blood exposed to toxic extracts from the Indian Ocean or from the Pacific Ocean showed that the blood collection card method could be extended to each of the three known ciguatoxin families (C-CTX, I-CTX and P-CTX). The low matrix effect of extracted dried-blood samples (used at 1:10 or 1:20 dilution) and the high sensitivity of the neuroblastoma assay (limit of detection 0.006 ng/ml C-CTX-1), determined that the blood collection card method is suitable to monitor ciguatoxin at sublethal doses in mice and opens the potential to be a useful procedure for fish screening, environmental risk assessment or clinical diagnosis of ciguatera fish poisoning in humans or marine mammals.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dose-Response Relationship, Drug; Environmental Exposure; Gas Chromatography-Mass Spectrometry; Mice; Models, Animal; Neuroblastoma; Pacific States; Risk Assessment; Time Factors

In Florida (USA), numerous cases of human ciguatera fish poisoning, as well as neurotoxic shellfish poisoning following consumption of local seafood products, have been reported. By using in parallel, the sodium channel receptor binding assay (RBA), and the ouabain/veratridine-dependent cytotoxicity assay (N2A assay), we established criteria to identify, detect, and quantify ciguatoxins in fish extracts, with a brevetoxin as internal standard. Results showed that the Caribbean ciguatoxin C-CTX-1 exhibited an 8-fold higher potency in the RBA than brevetoxins and, a 440 and 2300-fold higher potency in the N2A assay than PbTx-1 and PbTx-3, respectively. Moreover, a sensitivity comparison between assays revealed that the N2A assay was more sensitive (12-fold) for ciguatoxin analysis, whereas the RBA was more sensitive (3-24-fold) for brevetoxins analysis. Based on the relative potency between toxins and the opposite sensitivity of both assays we have used the RBA and the N2A assay to screen great barracuda (Sphyraena barracuda) collected from the Florida Keys for ciguatoxins and brevetoxins. Fish extract analysis showed a sodium channel-dependent activity consistent with the presence of ciguatoxins, and not brevetoxins. Among 40 barracudas analyzed, 60% contained ciguatoxin levels in their liver measurable by the N2A assay with the most toxic fish containing 2.1ppb C-CTX-1 equivalents.

Topics: Animals; Biological Assay; Cells, Cultured; Ciguatera Poisoning; Ciguatoxins; Fishes; Florida; Food Contamination; Humans; Lethal Dose 50; Marine Toxins; Ouabain; Oxocins; Protein Binding; Seawater; Sensitivity and Specificity; Sodium Channels; Veratridine

After a twelve-year struggle, the total synthesis of ciguatoxin CTX3C has been achieved. Annually, more than 20,000 people worldwide suffer from ciguatera seafood poisoning. The extremely small amounts of the causative neurotoxin, ciguatoxin, in fish hampered the isolation, structural elucidation, detailed biological study, and preparation of anti-ciguatoxin antibodies for detecting these toxins. The large (3 nanometers long) and complicated molecular structure of ciguatoxins hindered chemists from completing a total synthesis. The chemical synthesis of CTX3C, determination of the absolute configuration, and synthesis-based preparation of the monoclonal antibodies as well as the effect of synthetic CTX3C on voltage-sensitive sodium channels are outlined.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Immunoassay; Models, Molecular; Molecular Conformation

Ciguatera fish poisoning (CFP) has been a significant and increasing public health problem in Hong Kong since 1980s. With growing demand for imported live coral fishes, the number of people who suffered from this disease has also been increasing. An outbreak of CFP in 2004 was the second most prominent in record as compared with the most significant one that occurred in 1998. In 2004, out of a total of 823 reported food poisoning outbreaks involving 3159 persons, 65 incidents (7.9%) affecting 247 people (7.8%) were attributed to CFP. Validated mouse bioassay analysis of surveillance samples revealed that seven samples (13%) were confirmed to be contaminated with ciguatoxins (CTXs). Typical symptoms of CTXs were found in mice injected with 20mg of fish extracts. The causative fishes included Cheilinus undulatus, Epinephelus coioides, Plectropomus areolatus, and Plectropomus leopardus. Most of these CTX-positive samples analyzed had only trace amounts of CTXs in their extract, except a C. undulatus sample which contained a mice lethal dose (2.5MU/20mg ether extract). This fish species was also the major origin of coral fish that caused clusters of CFP in the last quarter of 2004. Cigua-Check analysis of 20 flesh grains from seven CTX-positive fishes, previously confirmed as CTX-positive samples by mouse bioassay, showed that 50% of flesh grains were CTX contaminated.

Topics: Animals; Biological Assay; Body Weight; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Female; Fishes; Food Contamination; Hong Kong; Humans; Meat; Mice; Mice, Inbred ICR

We report an outbreak of ciguatoxin poisoning after barracuda fish ingestion in southern Taiwan. Three members of a family developed nausea, vomiting, watery diarrhea, and myalgias about 1 hour after eating three to ten eggs of a barracuda fish. Numbness of the lips and extremities followed the gastrointestinal symptoms about 2 hours after ingestion. Other manifestations included hyperthermia, hypotension, bradycardia, and hyperreflexia. Bradycardia persisted for several days, and one patient required a continuous infusion of intravenous atropine totaling 40 mg over 2 days. Further follow-up of the patients disclosed improvement of neurologic sequelae and bradycardia, but sensory abnormalities resolved several months later. In conclusion, ciguatoxin poisoning causes mainly gastrointestinal and neurologic effects of variable severity. In two patients with ciguatoxin poisoning after barracuda fish egg ingestion, persistent bradycardia required prolonged atropine infusion.

Topics: Aged; Animals; Bradycardia; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Disease Outbreaks; Female; Fishes; Food Contamination; Humans; Male; Middle Aged; Seafood; Taiwan

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Humans; Perciformes; Seafood; Spain

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Fishes; Humans

Analyses of ciguatoxicity in the great barracuda Sphyraena barracuda and quantity of toxic benthic dinoflagellates on coastal reefs (correlated with the number of cases of human ciguatera intoxications in Puerto Rico) were used to construct a model formulated on data obtained during the period of 1985-1988. The validity of the proposed model has been questioned by recent data obtained during the period of 1990-2000. Barracuda ciguatoxicity no longer showed a prominent seasonality while the fraction of randomly caught barracuda that were ciguatoxic significantly increased during this period. These two changes, accompanied by the discovery that ciguatoxic fish contained a variety of multiple toxins, appear to be correlated with the steadily increasing periods of elevated sea surface temperatures in this region.

Topics: Animals; Caribbean Region; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Eutrophication; Fishes, Poisonous; Humans; Perciformes; Seasons; Seawater; Tropical Climate

Clinical reports and descriptions of chronic fatigue syndrome (CFS) and chronic ciguatera fish poisoning (CCFP) show great similarities in clinical symptomology. These similarities in the literature suggested the exploration of lipids in sera of CFS, CCFP, and other diseases with the membrane immunobead assay (MIA), which is typically used for screening ciguateric ocean fish. Sera from patients with other diseases, including hepatitis B, cancer, and diabetes, were included to assess the degree of specificity involved. Sera were treated with acetone in a ratio of 1 part serum to 4 parts acetone. The suspension was centrifuged, and the acetone layer was evaporated. The residue was weighed and redissolved in 1.0 mL methanol and tested by the MIA, undiluted and titered to 1:160. The undiluted acetone fraction of the 37 normal showed +/- activity to +activity with 16 no titer, 15 with 1:5 titer and two with 1:10 titer, and four with > or =1:40 titers. One hundred fifteen CFS sera showed 1 with 1+ and 114 with 2+ activity in the undiluted samples, 1 with 1:10 titer, 3 with 1:20 titer, 31 with 1:40 titer, 50 with 1:80 titer, and 30 with 160 titer. Thus 95.6% of the samples had > or =1:40 titer. Eight hepatitis B sera samples had > or =1:40 titers. Four CCFP samples had > or =1:40 titers. Three of 16 cancer samples had 1:40 titer. These data are summarized in Fig. 1. As shown in Table 1, a significant increase (P<0.001) in the chronic phase lipids (CPLs) was shown relative to the normal group. A preliminary chemical study in C18 octadecylsilyl columns showed all fractions (100% chloroform, 9:1 chloroform : methanol, 1:1 chloroform : methanol, and 100% methanol) to contain lipids reactive to MAb-CTX with different intensities. Prostaglandins were shown in 100% methanol fraction. Competitive MIA with crude fish ciguatoxin and CFS with synthetic JKLM ciguatoxin epitope suggested similarities in structure with ciguatoxin. This was compatible with the neuroblastoma assay demonstrated in the C(18) column fractions 9:1 and 1:1, chloroform : methanol solvents.

Topics: Acute Disease; Animals; Antibodies, Monoclonal; Cell Line, Tumor; Cell Survival; Chronic Disease; Ciguatera Poisoning; Ciguatoxins; Epitopes; Fatigue Syndrome, Chronic; Female; Hepatitis B; Humans; Lipids; Male; Mice; Neoplasms; Neuroblastoma

Ciguatera is a common seafood poisoning in Western Atlantic and French West Indies. Ciguatera fish poisoning in the Caribbean is a public health problem. A toxicological study was carried out on 178 Caribbean fish specimens (26 species) captured off Guadeloupe and Saint Barthelemy between 1993 and 1999. The mouse bioassay and the chick feeding test were used to control fish edibility. Ciguatoxins presence was assumed when symptomatology was typical of ciguatera in mouse and chick. Fishes were classified in three groups: non toxic fish (edible), low toxic fish (not edible) and toxic fish (not edible). 75% of fishes were non toxic. Toxic fish specimens belonged to four families of high trophic level carnivores: Carangidae, Lutjanidae, Serranidae et Sphyraenidae. Percentages of toxic fishes to humans reached 55% for Caranx latus and 33% for Caranx bartholomaei and Caranx lugubris. Only a significant correlation between weight and toxicity was only found for C. latus and snappers. Small carnivorous groupers (Serranidae) were also toxic. Atoxic fish species were (a) pelagic fish (Coryphaena hippurus, Auxis thazard and Euthynnus pelamis), (b) invertebrates feeders (Malacanthus plumieri, Balistes vetula), (c) small high-risk fish or (d) fish of edible benthic fish families. Liver of four fishes (Mycteroperca venenosa, Caranx bartholomaei, Seriola rivoliana, Gymnothorax funebris) contained ciguatoxins at a significant level although their flesh was safe. This study confirms the usefulness of mouse and chick bioassays for sanitary control of fish.

Topics: Animals; Biological Assay; Chickens; Ciguatera Poisoning; Ciguatoxins; Fishes, Poisonous; Guadeloupe; Humans; Liver; Mice; Public Health

Ciguatera poisoning appears after ingestion of contaminated fish from tropical coral reefs. Due to the diversity of clinical symptoms and the absence of a specific test in humans, the diagnosis is often difficult.. A retrospective study of 10 patients consulting for a clinical and epidemiological picture compatible with ciguatera poisoning after a trip to tropical countries between 1993 and 2000.. Most infections but one were acquired in the Caribbean area and there were 8 females. Clinical manifestations started within the first 24 hours after fish ingestion. Chief symptoms were diarrhea and nausea, followed by neurological symptoms, mainly limbs paresthesias that persisted for several weeks.. The severity of clinical symptoms was variable and not related to age or initial symptoms. Ciguatera poisoning has to be considered in the diagnosis of acute gastroenteritis affecting travellers to tropical areas.

Topics: Adolescent; Adult; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Diarrhea; Female; Humans; Male; Middle Aged; Retrospective Studies; Spain; Travel

A barracuda implicated in ciguatera fish poisoning in Guadeloupe was estimated to have an overall flesh toxicity of 15 MUg/g using mouse bioassay. A lipid soluble extract was separated into two toxic fractions, FrA and FrB, on a LH20 Sephadex column eluted with dichloromethane/methanol (1:1). When intraperitoneal injected into mice, FrA provoked symptoms characteristic of slow-acting ciguatoxins, whereas FrB produced symptoms indicative of fast-acting toxins (FAT). High performance liquid chromatography/mass spectrometry/radio-ligand binding (HPLC/MS/RLB) analysis confirmed the two fractions were distinct, because only a weak overlap of some compounds was observed. HPLC/MS/RLB analysis revealed C-CTX-1 as the potent toxin present in FrA, and two coeluting active compounds at m/z 809.43 and 857.42 in FrB, all displaying the characteristic pattern of ion formation for hydroxy-polyethers. Other C-CTX congeners and putative hydroxy-polyether-like compounds were detected in both fractions, however, the RLB found them inactive. C-CTX-1 accounted for > 90% of total toxicity in this barracuda and was confirmed to be a competitive inhibitor of brevetoxin binding to voltage-sensitive sodium channels (VSSCs) with a potency two-times lower than P-CTX-1. However, FAT active on VSSCs and < 900 Da were suspected to contribute to the overall toxicity.

Topics: Animals; Biological Assay; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Humans; Male; Marine Toxins; Mass Spectrometry; Mice; Muscle, Skeletal; Perciformes; Radioligand Assay; Toxicity Tests

Gambierol was isolated from Gambierdiscus toxicus, which causes ciguatera fish poisoning. The acute toxicological effects induced in mice by synthesized gambierol were studied. The lethal doses were about 80 microg/kg by i.p. and i.v., and 150 microg/kg by p.o. The main injury by this toxin was observed in the lung, and secondary in the heart, resulting in systemic congestion. Another toxic effect was seen in the stomach, inducing hypersecretion and ulceration. With survival from the severe stage during the initial 3 h, recovery was favorable, especially after 4 days. Additional effects were not evident during 1-week post-administration observation.

Topics: Administration, Oral; Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Disease Models, Animal; Ethers, Cyclic; Injections, Intraperitoneal; Injections, Intravenous; Lethal Dose 50; Lung; Male; Mice; Mice, Inbred ICR; Myocardium; Polycyclic Compounds; Stomach

A benthic toxic dinoflagellate identified as Prorocentrum lima (Syn. Exuviaella lima), and designated as strain PRL-1, was isolated from the coast of El Pardito (Coyote) Island in Baja California Sur, Mexico, after a fisherman poisoning incident involving consumption of liver from Lutjanus colorado, and Mycteroperca prionura fish. Purification and culturing was done in ES-Si medium, under 12:12 light/dark cycle (4 x 20 W cool-white fluorescent lamps), at 22 degrees C and constant stirring during 28 days. Whole cells were toxic to Artemia franciscana and its methanolic extract to mouse and to the marine yeast Debaryomyces hansenii. Chromatographic analysis (TLC and HPLC-MS) of such extract indicated an unusual proportion (1:2) okadaic acid (OA) and dinophysistoxin-1 (DTX-1). Estimated total toxin content by mouse bioassay (based on OA toxicity) was 19 pg/cell, a value significantly higher than that found by HPLC-MS (about 5.2 pg/cell, taking into account OA and DTX-1 only), suggesting that additional toxic components of unidentified nature are detected with the bioassay. This is the first report of a successful isolation and culturing of a toxic dinoflagellate from the Gulf of California, Mexico.

Topics: Animals; Chromatography, Thin Layer; Ciguatera Poisoning; Ciguatoxins; Diarrhea; Dinoflagellida; Foodborne Diseases; Mexico; Mice; Okadaic Acid; Pyrans; Risk Assessment; Shellfish

A grey snapper (Lutjanus griseus), a grouper (Serranidae) and a black jack (Caranx lugubris) were implicated in three different ciguatera poisonings in Guadeloupe, French West Indies. A mouse bioassay indicated toxicity for each specimens: 0.5-1, > or = 1 and > 1 MUg g(-1), respectively. After purification by gel filtration chromatography, the samples were analysed by high-performance liquid chromatography coupled to mass spectrometry (LC-MS). The toxin profiles differ from one fish to another. C-CTX-1 was detected at 0.24, 0.90 and 13.8 ng g(-1) flesh in the snapper, grouper and jack, respectively. It contributed only to part of the whole toxicity determined by the mouse bioassay. Other toxins identified were C-CTX-2 (a C-CTX-1 epimer), three additional isomers of C-CTX-1 or-2, and five ciguatoxin congeners (C-CTX-1127, C-CTX-1143 and its isomer C-CTX-1143a, and C-CTX-1157 and its isomer C-CTX-1157b). Putative hydroxy-polyether-like compounds were also detected in the flesh of the grouper with [M+ + H]+ ions at m/z 851.51, 857.50, 875.51, 875.49 and 895.54 Da. Some of these compounds have the same mass range as some known dinoflagellate toxins. In conclusion, this study confirms the usefulness of LC-MS analysis to determine the ciguatoxins levels and the toxin profile in fish flesh hazardous to humans.

Topics: Adult; Animals; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Female; Fishes; Guadeloupe; Humans; Male; Mass Spectrometry; Mice; Middle Aged

[structure: see text] Ciguatoxin CTX3C is a representative congener of ciguatoxins, which are known to be the principal causative agents of ciguatera seafood poisoning. The structure of CTX3C spans more than 3 nm and is characterized by 13 ether rings. In this paper, an improved total synthesis of CTX3C is reported. Alteration of the protective group from benzyl ether to 2-naphthylmethyl (NAP) ether drastically increases the yield for final global deprotection and has provided a sufficient amount of sample for further biological studies.

Topics: Ciguatera Poisoning; Ciguatoxins; Molecular Structure

Advances in synthetic strategies and analytical technology are allowing ever more natural product molecules to be synthesized. In his Perspective, Markó briefly reviews the history of this field and highlights the synthesis of ciguatoxin by Hirama et al. This marine toxin belongs to the ciguatera family of neurotoxins, which poison some 20,000 people every year. The elegant and highly convergent strategy developed by the authors will be helpful in the development of antibodies to ciguatoxin for the detection of contaminated seafood.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Molecular Structure; Seafood; Vitamin B 12

Topics: Animals; Antitoxins; Ciguatera Poisoning; Ciguatoxins; Fishes; Foodborne Diseases; Humans

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fish Products; Foodborne Diseases; History, 16th Century; History, 17th Century; History, 18th Century; History, 20th Century; History, 21st Century; Humans; Tropical Climate

The development of a simplified and modified procedure for the assessment of ciguatoxin (CTX) and related polyethers from ciguateric contaminated fish tissues is presented in this study. The previous method, stick-enzyme immunoassay (S-EIA) used an organic correction fluid-coated bamboo paddle stick for the solid phase; this new procedure, membrane immunobead assay (MIA), uses a plastic stick with a synthetic membrane laminated onto one end. The membrane is hydrophobic and serves as the solid-phase receptor for the binding of methanol-extracted CTX or its related polyether lipids from fish tissues. Detection of the bound polyether toxin(s) on the membrane is carried out with colored polystyrene beads coated with monoclonal antibody to CTX (MAb-CTX). Intensity of the color on the membrane is proportional to the amount of toxic polyethers on the membrane. The MIA is compared with previous procedures developed for CTX detection (S-EIA and solid-phase immunobead assay, SPIA) using State of Hawaii Department of Health (DOH) implicated ciguateric fishes, and reef fishes from Hawaii and Kwajalein. The data presented show good correlation between the three test systems, especially with ciguatera implicated fish and toxic, routinely assessed fishes in the mouse toxicity (MT) bioassay. Variations between MT results and those of the S-EIA, SPIA, and MIA of routine fishes are generally attributable to diverse toxins present in the fish species examined. The MIA is a simple, rapid, sensitive, and specific detection method for CTX and its related polyethers, with no reported false negative results. The test is useful for field and personal use and can be adapted to the laboratory for large-scale screening of potentially ciguateric fishes.

Topics: Animals; Antibodies, Monoclonal; Ciguatera Poisoning; Ciguatoxins; Fishes; Immunoassay; Marine Toxins; Membranes, Artificial

Ciguatera fish poisoning is the most common form of toxin-related food poisoning in the United States. Originating from dinoflagellates living on coral reefs, it is spread up the food and affects humans who ingest the ciguatoxic fish. Ciguatera is primarily endemic in tropical regions of the world. It is a self-limiting disease that presents with characteristic gastrointestinal, neurological, and cardiovascular symptoms. Recent advances in testing procedures and symptom recognition has improved ciguatoxin identification and clinical management. However, there is still a need for better diagnostic, preventive, and reporting protocols to more accurately study and understand this diverse and temporarily debilitating clinical syndrome.

Topics: Ciguatera Poisoning; Ciguatoxins; Heart; Humans; Poisoning

We report a retrospective study of the clinical signs and symptoms associated with a point-source outbreak of fish poisoning that occurred with a fish captured from the Arafura Sea, northern Australia. Twenty cases (16 Aboriginal and 4 non-Aboriginal) characteristic of ciguatera, including 4 inpatients and 16 outpatients from the Gove Hospital, were identified based on the pattern of clinical symptoms and signs after ingestion of a large coral cod from a known ciguatera-prone coral reef. In the absence of a serologic test for the victim, laboratory analysis of a 230-g sample of the coral cod (Cephalopolis miniatus), using both mouse bioassay and HPLC/mass spectometry, showed that Pacific ciguatoxin-1 was the principal toxin involved. Intravenous mannitol was administered to one patient without clear benefit. Risk factors for ciguatera poisoning are ingestion of larger portions of reef fish from ciguatera-prone areas. Despite apparent local awareness of the distribution and etiology of the disease, large common-source outbreaks of ciguatera still occur.

Topics: Adult; Animals; Australia; Chromatography, High Pressure Liquid; Ciguatera Poisoning; Ciguatoxins; Disease Outbreaks; Female; Fishes; Foodborne Diseases; Humans; Male; Mass Spectrometry; Mice; Retrospective Studies

Topics: Ciguatera Poisoning; Ciguatoxins; Glucose; Magnetic Resonance Spectroscopy; Stereoisomerism

Serranidae and Labridae fish caught in 1993 at Alijos Rocks, 300 miles off East Magdalena Bay, Southern Baja California, caused severe illness of a fishing boat crew. The described symptoms resembled those of ciguatera. The presence of ciguatera-like toxins was confirmed on extracts from these fish using the mouse bioassay procedure, showing activities between 220 to 390 mouse units (M.U.). The founding of ciguatoxin at Alijos Rocks 24 degrees 57' N, 115 degrees 45' W) extends to the northeast its geographical distribution in the Pacific and locates the outbreak near the continental coastline.

Topics: Adult; Animals; Bass; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Humans; Mexico; Mice; Pacific Islands; Poisoning; Seafood

Ciguatera fish poisoning is an important public health problem wherever humans consume tropical and subtropical fish. It accounts for over half of fish-related poisonings in the United States but is uncommonly diagnosed and underreported. Produced by dinoflagellates, ciguatoxin accumulates up the food chain in herbivorous and carnivorous fishes. Cnidaria jellyfish and related invertebrates) have not previously been associated with direct ciguatera intoxication in humans. We report the first case of ciguatera fish poisoning associated with cnidarian ingestion. A 12-year-old Tongan female presented to our Emergency Department with mid-abdominal pain, nausea, change in mental status, and new-onset movement disorder after ingestion of jellyfish imported from American Samoa. Clinical diagnosis was confirmed by strongly positive serum identification of ciguatoxin and related polyether toxins (including okadaic acid) with a rapid extraction method (REM) and highly reliable solid-phase immunobead assay (S-PIA) performed by the Food Toxicology Research Group, University of Arizona. Ciguatera pathophysiology, clinical presentation, differential diagnosis (including consideration of palytoxin poisoning), and treatment are briefly reviewed. We emphasize the growing incidence of ciguatera fish poisoning outside "high-risk" areas. In regions with immigrant populations, privately imported exotic fish may be toxin vectors. Marine species other than carnivorous fish are now suspect in human ciguatera intoxication. Reliable tests can aid in premarket fish testing, diagnosis, and follow-up of ciguatera fish poisoning. The global prevalence of marine toxins demands fishermen, consumers, and physicians maintain a high index of suspicion for ciguatera fish poisoning.

Topics: Animals; Child; Ciguatera Poisoning; Ciguatoxins; Diagnosis, Differential; Emergency Treatment; Female; Foodborne Diseases; Humans

This study is an individual case report of an imported cultured salmon which may have caused ciguatera. The individual's documented clinical symptoms, along with our immunological tests and bioassays (hemolytic, mouse toxicity and guinea-pig atrial assays) of the salmon extracts, strongly suggest that the salmon may have contained a ciguatoxin-like toxin (or toxins). The unique ability of the toxin(s) to block the sodium channel of the guinea-pig atrium, however, distinguishes it from ciguatoxin-1 isolated from moray eel liver.

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Female; Fisheries; Foodborne Diseases; Guinea Pigs; Hemolytic Plaque Technique; Humans; Mice; Salmon

Mannitol (1 g/kg i.v.) is currently the treatment of choice for acute ciguatera, but confirmation of this treatment's apparent efficacy awaits further experimental or controlled clinical evidence. In mice, mannitol (1 g/kg i.v.) administered before or after i.p. ciguatoxin did not influence the signs of intoxication or the time to death. The effects of oral ciguatoxin differed from those following i.p. ciguatoxin, but again i.v. mannitol provided no detectable benefit. Development of hypothermia was rapid in mice receiving i.p. or oral ciguatoxin and was unaffected by i.v. mannitol. A sublethal i.p. dose of ciguatoxin initially retarded (day 0-4) but then accelerated (day 4-12) the growth of mice. Mannitol (i.v.) had no influence on these effects of ciguatoxin on the growth of mice. Ciguatoxin inhibited responses of isolated diaphragms to nerve stimulation (ED50 = 9 x 10(-11) M), while directly stimulated diaphragms were inhibited by five-fold higher concentrations. Mannitol (50 mM) added to the organ bath did not influence the ciguatoxin-induced inhibition of diaphragm responses to nerve stimulation in vitro. Responses of isolated diaphragm to nerve stimulation were normal in preparations removed from ciguatoxin-treated mice displaying pronounced dyspnoea (gasping). However, responses to nerve stimulation were reduced in preparations removed from mice immediately following death from ciguatoxin. Mannitol (i.v.) partially protected the phrenic nerve-diaphragm from this effect of ciguatoxin in vivo. We conclude that the lethal effects of ciguatoxin in mice probably stem from a central action, and suggest that species differences may account for the absence of any marked beneficial effect of i.v. mannitol in the mouse model for ciguatera in humans.

Topics: Animals; Body Weight; Ciguatera Poisoning; Ciguatoxins; Diaphragm; Disease Models, Animal; Female; Hypothermia; Lethal Dose 50; Male; Mannitol; Mice; Muscle Contraction; Phrenic Nerve

Epidemiologic characterization of ciguatera fish poisoning has been limited by lack of laboratory confirmation, absence of prospective follow-up, and incomplete analysis of age-related factors. A 1985 outbreak on the island of Kauai in the state of Hawaii that involved 15 persons of various ages was investigated to determine factors associated with disease severity. The presence of ciguatoxin was detected in leftover portions of the implicated fish by enzyme immunoassay. All cases were medically and epidemiologically investigated and followed prospectively. Ten of the 15 cases demonstrated bradycardia; seven were hospitalized, including two requiring placement in intensive care. Bradycardia was associated with increasing age and body weight (P < 0.01 and < 0.05, respectively) as well as the amount of toxic fish consumed (P < 0.01). Duration of illness ranged from two to 132 days. Increasing duration of illness was correlated with both increasing age and weight (rs = 0.64 and rs = 0.72, respectively, both P < 0.01) and was independent of amount and components of toxic fish consumed. The correlation between increasing age and weight with duration and severity of symptoms may be explained by prior subclinical toxin exposure and is consistent with the observation that repeated ciguatoxin exposures are associated with more severe illness. The association between amount of toxic fish consumed and bradycardia is consistent with an increased dose of ciguatoxin. The findings of this outbreak investigation support previously unconfirmed observations.

Topics: Adolescent; Adult; Age Factors; Aged; Animals; Body Weight; Bradycardia; Child; Child, Preschool; Ciguatera Poisoning; Ciguatoxins; Cohort Studies; Disease Outbreaks; Eating; Female; Fishes; Food Analysis; Foodborne Diseases; Hawaii; Humans; Immunoenzyme Techniques; Male; Middle Aged; Prospective Studies; Time Factors

A patient is presented who developed an acute gastrointestinal and neurologic syndrome progressing to coma after ingestion of a fish soup made in Rhode Island. Laboratory studies confirmed the clinical diagnosis of ciguatera poisoning. Physicians should be aware of the diagnostic features of this disease even in non-endemic areas.

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Coma; Fishes; Guinea Pigs; Humans; Male; Mice; Middle Aged; Rhode Island

A survey for the assessment of the ciguatera problem has been determined in Puako, South Kohala, on the Island of Hawaii. This is in the area of persistent ciguateric outbreaks during the months of January through March, caused by a specific species of fish (Cheilinus rhodochrous, red rose wrasse, or po'ou). Analyses of algae, Gambierdiscus toxicus, and various species of fish, including herbivores and carnivores, gave positive indications of Puako as a potential ciguateric area. Algae associated with Gambierdiscus toxicus blooms and the dinoflagellate itself were found in transects A and D. Transects A and D showed 291 G. toxicus per gram of Tolycarpidia glomurata and 9 G. toxicus per gram of Turbinaria sp. with epiphytic Jania sp., respectively. No G. toxicus was found in transects B and C. This may be attributed to the low salinity from intrusion of freshwater in this vicinity. Examinations of the fish, kole, manini, Hawaiian kole, roi, and po'ou by the solid-phase immunoassay showed 89% of fish in the borderline and positive categories from all transects. Extracts of viscera and flesh showed high levels of toxicity in mouse (13 of 23 deaths), particularly in the viscera (gut) of both herbivores and carnivores. The guinea pig atrial analysis generally showed a few ciguatoxin-like, but most were nonciguateric type responses. The data presented in this Puako survey showed evidence of toxic fish associated with ciguatoxin-like and most probably other toxins, either polyethers or non-polyethers as yet unidentified.

Topics: Animals; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Data Collection; Dinoflagellida; Disease Outbreaks; Eukaryota; Female; Fishes; Foodborne Diseases; Guinea Pigs; Hawaii; Humans; Male; Mice

The major impediment to the thorough study of Ciguatera in human populations has been the lack of definitive diagnostic ability. However, recently an ELISA test was developed which can diagnose Ciguatera qualitatively and quantitatively in human fluids, as well as in contaminated fish tissue. This study proposes to evaluate this new ELISA test in human subjects with the clinical diagnoses of acute and chronic Ciguatera Poisoning. The contaminated fish from exposed subjects, and the blood and urine of exposed and controls, will be examined using the new ELISA. The ELISA performance will be compared to traditional bioassays for the fish testing. In addition, a distinct diagnostic profile will be developed using serial questionnaires, physical examinations, and nerve conduction tests. Ultimately this ELISA test can be used not only in establishing the correct diagnosis of Ciguatera Poisoning, but also in the treatment and clinical prognosis, and in epidemiologic studies of Ciguatera Poisoning in human populations. We hope that this protocol will serve as a model for the study of the effects of other marine toxins on human populations.

Topics: Adult; Animals; Body Fluids; Ciguatera Poisoning; Ciguatoxins; Enzyme-Linked Immunosorbent Assay; Female; Fishes; Humans; Male; Vomiting

An epidemiological study on ciguatera fish poisoning in the French West Indies on St-Barthelemy, St-Martin and Anguilla was conducted in the years 1985-1986-1987 and 1991-1992. A study on the toxicity of coral fish was realized. The toxicity of 700 fish belonging to 57 species was evaluated by bio-assays. 430 mosquito-bio-assays were performed on individual fish (flesh or liver) and 19 on pools (flesh or liver; with 4 to 24 fish). A second group was evaluated on liver by the chick feeding-test (33 individual and 64 on pools with 2 to 24 fish). The results showed that many species are involved in the toxic food chain. At least 25% may have a high level of toxicity, 32.5% are intermediate and 10% are doubtful. Major results concern: (1) high risk species (Caranx bartholomaei, C. lugubris, Lutjanus apodus, L. jocu, Gymnothorax funebris, G. moringa, Mycteroperca venenosa, M. tigris, Epinephelus morio, Sphyraena barracuda); (2) intermediate species (Caranx latus, C. ruber, Lutjanus buccanella); (3) low risk species (Balistes vetula, Haemulon album, Priacantus arenatus, Alphestes afer). Occasionally other species or new species are involved Etelis oculatus, Lutjanus analis, Pristipomoides macrophtalmus, Rhomboplites aurorubens, Haemulon album, Scarus vetula.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Biological Assay; Chickens; Ciguatera Poisoning; Ciguatoxins; Culicidae; Fishes; Food Analysis; Humans; West Indies

A case of a severe episode of ciguatera poisoning in a mother during the second trimester is presented. The mother experienced an increase of fetal movements one hour after the poisonous meal. She endured multisystemic symptoms typical of ciguatera for eight weeks. The presence of ciguatoxin in the fish was confirmed by immunoassay and two bioassays. The newborn at term was normal with adequate respiratory and neurological reflexes. The child developed normally in his first 10 months. This is in contrast with another report of a mother exposed to ciguatoxin at term who delivered an infant suffering from facial palsy and possible myotonia of the hands. Dose and gestational timing may explain these observed differences.

Topics: Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Female; Fishes; Foodborne Diseases; Humans; Infant, Newborn; Molecular Structure; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy Trimester, Second

Acute poisoning induced by ciguatoxin or ciguatoxin-4c in male ICR mice was examined by light and electron microscopy. Target organs were the heart, medulla of adrenal glands, autonomic nerves and penis. There were no significant differences between the toxicity of ciguatoxin and ciguatoxin-4c. Either i.p. injection or oral administration (0.7 micrograms/kg) resulted in marked swelling and focal necrosis of cardiac muscle cells and effusion into the interstitial space of the heart. Degeneration of cells in the medulla of the adrenal glands was also observed. Continuous erection of the penis was observed in about 15% of the mice suffering from ciguatoxicosis. Although severe diarrhea was brought about by the administration of these phycotoxins, no morphological alterations were seen in the mucosa and muscle layers of the small intestine except in autonomic nerve fibers and synapses. Atropine suppressed the symptoms of diarrhea but had no effect on the injury to the cardiac muscle. Reserpine aggravated the clinical signs and pathological findings. Guanethidine and 5-hydroxy dopamine as well as those undergoing bilateral adrenalectomy had no significant effects on the ciguatoxicosis.

Topics: Adrenal Medulla; Adrenalectomy; Animals; Autonomic Nervous System; Cell Membrane Permeability; Ciguatera Poisoning; Ciguatoxins; Fishes, Poisonous; Foodborne Diseases; Male; Mice; Mice, Inbred ICR; Microscopy; Microscopy, Electron; Myocardium; Penis

A near fatal case of ciguatera-related intoxication following consumption of smoked Decapterus macrosoma is documented. In addition to some of the hallmark symptoms of ciguatera poisoning, the patient exhibited acute respiratory distress and severe muscle spasms. Laboratory results showed large elevations in a number of blood enzymes, indicative of muscle damage. The responsible agent was extracted from corresponding fish samples and identified as palytoxin.

Topics: Acrylamides; Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Cnidarian Venoms; Fishes; Foodborne Diseases; Humans; Male; Marine Toxins; Meat; Muscle Contraction; Seizures

Ciguatera is a type of food poisoning associated with the consumption of contaminated marine fish. We report two cases in which painful ejaculation in an affected male and dyspareunia in an unaffected female following her partner's ejaculation suggest the sexual transfer of the responsible agent, ciguatoxin (CTX). Immunoassay of semen samples for CTX were not diagnostic, but the sensitivity and timing of the test employed may have precluded detection of small quantities of the toxin. We conclude that CTX may be present in the semen of men affected with ciguatera toxicity and be capable of producing symptomatology in both males and females during sexual intercourse.

Topics: Ciguatera Poisoning; Ciguatoxins; Dyspareunia; Ejaculation; Female; Foodborne Diseases; Humans; Male; Marine Toxins; Oligospermia; Pain; Penile Diseases; Semen; Sexually Transmitted Diseases

Topics: Adult; Animals; Ciguatera Poisoning; Ciguatoxins; Female; Fishes; Foodborne Diseases; Humans; Immunoassay; Male; Marine Toxins; Middle Aged; Vermont

Chick poisoning induced by oral administration of toxic fish tissues or extracts gave rise to internal hypersalivation, decrease in weight and acute motor ataxia. Detoxification was low and repeated administration therefore led to toxin accumulation. Response of the chicken to liver feeding was roughly quantitative; so liver, which is the most potential toxic tissue, may be used for a preventive screening test in ciguatera-endemic areas.

Topics: Animals; Biological Assay; Chickens; Ciguatera Poisoning; Ciguatoxins; Fishes; Foodborne Diseases; Liver; Marine Toxins

Preliminary immunologic studies of ciguatera poisoning were performed with serum samples from patients and extracts from both toxic and nontoxic fish. Counterimmunoelectrophoresis disclosed precipitin lines with toxic fish extracts and effectively discriminated between samples established as toxic or nontoxic on the basis of human toxic reactions and by an in vivo mouse bioassay. However, it is not currently possible to conclude that affected individuals had specific antibody to ciguatoxin, since putative immune and nonimmune serum samples gave equally clear precipitin reactions with toxic extracts.

Topics: Animals; Antibodies; Ciguatera Poisoning; Ciguatoxins; Counterimmunoelectrophoresis; Fishes, Poisonous; Humans; Marine Toxins; Mice; Precipitin Tests

Topics: Animals; Antitoxins; Biological Assay; Ciguatera Poisoning; Ciguatoxins; Dinoflagellida; Fishes, Poisonous; Foodborne Diseases; Hawaii; Humans; Marine Toxins; Radioimmunoassay; Rhodophyta

Topics: Animals; Ciguatera Poisoning; Ciguatoxins; Fishes; Humans; Male; Marine Toxins; Middle Aged; United Kingdom