ants and Dicrocoeliasis

Dicrocoeliosis is a helminthosis caused by the small liver fluke Dicrocoelium spp. (Trematoda, Dicrocoeliidae) parasitizing in the bile ducts and gall bladder of ruminants as well as many other animal species including humans. In the biological life cycle of Dicrocoelium, land snails are first intermediate hosts and ants are second intermediate hosts. Sporocysts and cercaria, which are larval stages, live in the hepatopancreas of land snails and metacercaria, which is also the larval stage, lives in the abdomen and brain of ants. Land snails, which are the first intermediate host of this parasite in Turkey, include Helicopsis derbentina, Helicopsis protea, Helicopsis krynickii, Cernuella virgata, Trochoidea pyramidata, Cochicella acuta, Monacha carthusiana, Helicella candicans, Helix aspersa, Helix lucorum, and Chondrus tournefortianus. Dicrocoeliosis is widespread in ruminants and affects their liver, which can lead to weight loss and reduced milk production. The number of reports on dicrocoeliosis is increasing due to the expansion of dry habitats and parasites becoming resistant to antihelminthic drugs. This study provides information on the epidemiology and control methods of Dicrocoelium.

Topics: Animals; Ants; Dicrocoeliasis; Dicrocoelium; Helix, Snails; Host-Parasite Interactions; Humans; Turkey

The transmission, control and the relationship between Dicrocoelium dendriticum and its definitive (sheep and cattle) and intermediate (molluscs and ants) hosts under natural and experimental conditions are described. Eleven species of molluscs and four of ants were found infected with larval D. dendriticum in León province, north-west Spain. Infected ants were observed between April and November and in tetania at 7.5-26.9 degrees C. The highest shedding of eggs by sheep and cattle was detected in winter. Two treatments applied in November and January were the most effective. In experimentally infected molluscs, the parasite was not visible under the stereomicroscope, at least until 50 days post-infection (p.i.). The prepatent period in experimentally infected lambs was 49-79 days p.i. The number of eggs per gram increased with the days p.i. and the parasite burden. The aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, leukocyte and neutrophil values of infected lambs increased, but those of lymphocytes decreased. Using the enzyme-linked immunosorbert assay technique, the IgG antibody response to excretory-secretory and somatic antigens of D. dendriticum was positive from day 30 p.i., although the maximum antibody levels were observed on day 60 p.i. The number of worms per lamb ranged between 30 and 2063. Cholangitis and cholangiectasia of the septal bile and hepatic ducts were observed. The best enzymatic systems for adult and larval D. dendriticum characterization were lactate dehydrogenase, glucose phosphate isomerase and phosphoglucomutase. Genetic variability of adult D. dendriticum was high using the random amplified polymorphic DNA technique.

Topics: Animals; Anthelmintics; Antigens, Helminth; Ants; Cricetinae; Dicrocoeliasis; Dicrocoelium; Disease Vectors; Genes, Helminth; Genetic Variation; Immunoenzyme Techniques; Larva; Mollusca; Sheep Diseases; Sheep, Domestic; Spain

The expansion of parasite distributions outside of their native host and geographical ranges has occurred repeatedly over evolutionary time. Contemporary examples include emerging infectious diseases (EIDs), many of which pose threats to human, domestic animal, and wildlife populations. Theory predicts that parasites with complex life cycles will be rare as EIDs due to constraints imposed by host specialization at each life-cycle stage. In contrast to predictions of this theory, we report 2 new intermediate hosts in the 3-host life cycle of the liver fluke Dicrocoelium dendriticum in Cypress Hills Provincial Park, Alberta, Canada. Results of sequence analysis of the cytochrome oxidase 1 (cox1) mitochondrial gene identified the terrestrial snail Oreohelix subrudis and the ant Formica aserva as first and second intermediate hosts, respectively, in the region. Neither of these intermediate hosts, nor their suite of domestic and wild mammalian grazers used in the life cycle, occurs within the native range of D. dendriticum in Europe. Our results from host surveys show that the prevalence of D. dendriticum in samples of O. subrudis varied between 4% and 10%, whereas mean metacercariae intensity in F. aserva varied between 33 and 41 (n = 163, mean ± SD = 38 ± 35). These results are the first to describe the complete life cycle of emerging lancet fluke in western North America. The process of multi-level ecological fitting, in which the lancet fluke possesses pre-existing traits to utilize host resources, rather than host species, at each life-cycle stage provides a mechanism for the establishment of this complex life cycle in a novel habitat and in novel hosts.

Topics: Alberta; Animals; Ants; Communicable Diseases, Emerging; Dicrocoeliasis; Dicrocoelium; DNA Barcoding, Taxonomic; DNA, Helminth; Ecosystem; Life Cycle Stages; Sequence Analysis, DNA; Snails

There is a need for improved methods for the study of the impacts of climatic and livestock management change on the epidemiology of production-limiting helminth parasitic diseases. In this study we report the application of molecular methods to describe the natural history of the small lancet fluke, Dicrocoelium dendriticum on Machair pastures on the Inner Hebridean Isle of Coll. Our results build upon those of the only previous historic field study of D. dendriticum in the British Isles that had been undertaken on the same study site. We demonstrate the value of combining conventional parasitological methods with PCR amplification of a mitochondrial DNA fragment for the detection of D. dendriticum in ants and snails, and PCR amplification of ITS2 and 28S ribosomal DNA fragments to support the species identity of the intermediate hosts, to improving understanding of the epidemiology of D. dendriticum. We report the presence of D. dendriticum infection in cattle, sheep and rabbits grazing on Machair pastures. D. dendriticum infection was identified in a high percentage of the snails, identified as Cochlicella acuta and Cernuella virgata, and in a high percentage of Formica fusca and Myrmica ruginoides ants that were collected from, or clinging to, the tops of flowers. We have identified the involvement of different intermediate host species and higher prevalences of snail and ant infection than previously reported, in part reflecting differences between the sensitivity and specificity of morphological and molecular speciation methods. Overall, our results highlight the complex life history of dicrocoeliosis and illustrate the parasite's generalist host strategy that confers potential to exploit new niches created by climatic change or grazing management for habitat conservation.

Topics: Animals; Ants; Cattle; Dicrocoeliasis; Dicrocoelium; Disease Reservoirs; DNA, Helminth; DNA, Mitochondrial; DNA, Ribosomal Spacer; Feces; Hebrides; Polymerase Chain Reaction; Rabbits; Sensitivity and Specificity; Sequence Analysis, DNA; Sheep; Snails

The lancet fluke, Dicrocoelium dendriticum, is perhaps the best-known example of parasite manipulation of host behavior, which is manifested by a radically changed behavior that leaves infected ants attached to vegetation at times when transmission to an herbivore host is optimal. Despite the publicity surrounding this parasite, curiously little is known about factors inducing and maintaining behavioral changes in its ant intermediate host. This study examined the importance of 3 environmental factors on the clinging behavior of red wood ants, Formica polyctena , infected with D. dendriticum . This behavior, hypothesized to involve cramping of the mandibular muscles in a state of tetany, was observed in naturally infected F. polyctena under controlled temperature, light, and humidity conditions. We found that low temperature significantly stimulated and maintained tetany in infected ants while light, humidity, ant size, and infection intensity had no influence on this behavior. Under none of the experimental conditions did uninfected ants attach to vegetation, demonstrating that tetany was induced by D. dendriticum . Temperature likely has a direct impact on the initiation of clinging behavior, but it may also serve as a simple but reliable indicator of the encounter rate between infected ants and ruminant definitive hosts. In addition, temperature-sensitive behavior manipulation may protect infected ants from exposure to temperatures in the upper thermal range of the host.

Topics: Animals; Ants; Behavior, Animal; Circadian Rhythm; Dicrocoeliasis; Dicrocoelium; Humidity; Insect Vectors; Light; Logistic Models; Metacercariae; Temperature

Topics: Adult; Animals; Ants; Dicrocoeliasis; Dicrocoelium; Feces; Food Parasitology; Humans; Iran; Male; Middle Aged; Parasite Egg Count

Topics: Adult; Animals; Ants; Cattle; Dicrocoeliasis; Dicrocoelium; Feces; Female; Humans; Parasite Egg Count; Sheep

An epidemiological study on dicrocoeliosis caused by Dicrocoelium dendriticum was carried out on sheep, molluscs and ants in the mountains of León province (NW Spain) between 1987-1991. The results concerning the intermediate hosts and a review of some aspects of dicrocoeliosis are summarized. Mollusc collection for the helminthological study was random throughout the study area at fortnightly intervals. Twenty-nine Gastropoda species were identified. D. dendriticum infection was only detected in 2.98%, of the 2084 Helicella itala examined and in 1.06% of 852 H. corderoi. The highest infection prevalence was detected in H. itala in September and in H. corderoi in February. Daughter sporocysts with well-developed cercariae predominated in spring and autumn. Infection prevalence increased with mollusc age and size. Ants were collected from anthills or plants to which they were attached. The behaviour of ants in tetania was followed. Twenty-one Formicidae species were identified, but only the following harboured D. dendriticum: Formica cunicularia (1158 examined specimens, 0.69% infection prevalence, 2-56 metacercariae per ant); F. sanguinea (234, 1.28%, 2-63); F. nigricans (1770, 4.97%, 1-186); F. rufibarbis (288, 6.59%, 2-107). In a flat area close to León town, 95.39% of the 2085 F. rufibarbis specimens collected in tetania contained metacercariae (1-240) in the abdomen. These were used for parasite characterization by isoelectric focusing and to infect lambs and hamsters. Only one brainworm per ant was found.

Topics: Animals; Ants; Cricetinae; Dicrocoeliasis; Dicrocoelium; Isoelectric Focusing; Isoenzymes; Prevalence; Seasons; Sheep; Sheep Diseases; Snails; Spain

The relationship between egg elimination and parasitic burden was studied in two groups of 12 lambs experimentally infected with 1000 and 3000 Dicrocoelium dendriticum metacercariae, respectively. Half the animals in each group were slaughtered 2 months post-infection (p.i.) and the other half 6 months p.i. In order to detect and follow elimination of D. dendriticum eggs by the lambs, faeces samples collection started one and a half months p.i. and continued fortnightly until the end of the experiment. Egg elimination was first detected between days 49 and 79 p.i. (mean = 59 +/- 1.6 SE). Mean eggs per gram (epg) was higher in the lambs infected with 3000 metacercariae (347.2 +/- 42.4 epg) than in those infected with 1000 (194.8 +/- 14.4), although no significant differences were detected between both groups using the Student 't' test. Egg elimination was higher in the faeces samples taken in the afternoon (mean = 357.8 +/- 47.6 epg) than in those from the morning (mean = 215.7 +/- 21.3). The percentage of metacercariae which became established as worms was higher in the animals dosed with 1000 metacercariae (21.6%) than in those infected with 3000 (16.3%). The number of worms recovered on necropsy of each animal varied between 30 and 2063 (mean = 346.6 +/- 80.5) and their length between 2.6 and 7.1 mm (mean = 5.2 +/- 0.1). The mean number of parasites for lambs infected with 3000 metacercariae (489.3 +/- 163.1) was higher than that obtained from those dosed with 1000 (215.7 +/- 41.4), although more worms were collected in some cases from the lambs infected with the latter dose than the former. In general there was an increase in the number of epg eliminated as days p.i. and parasitic burden increased. A positive relationship was observed via the correlation coefficient between the number of epg eliminated by each of the lambs throughout the experiment and that of worms recovered. This relationship was more intense on considering only the number of epg eliminated between days 120 and 180 p.i.

Topics: Albendazole; Animals; Anthelmintics; Ants; Dicrocoeliasis; Dicrocoelium; Feces; Gallbladder; Liver; Male; Parasite Egg Count; Sheep; Sheep Diseases

Epizootiological questions were studied on a permanent pasture of a farm situated in one of the dicrocoeliasis areas in the GDR during the 1986 grazing season. Helicella obvia snails and Formica fusca ants were found to be first and second intermediate hosts respectively. A total of 1,121 snails and 70 ants were dissected. The infestation rate with Dicrocoelium dendriticum stages in snails decreased in summer after the high spring peak and increased again in autumn. Paralysed ants were found only at temperatures below 20 degrees C. Parthenogenetic stages in snails were identified morphologically according to the structure of cercariae; the metacercariae isolated from the ants' body cavity were determined in animal experiments.

Topics: Animals; Ants; Dicrocoeliasis; Dicrocoelium; Disease Vectors; Germany, East; Seasons; Snails

Topics: Ants; Dicrocoeliasis; Dicrocoelium; Humans; Insect Bites and Stings; Insect Vectors

Infection experiments showed that the African ant Camponotus compressiscapus can serve as a second intermediate host of Dicrocoelium hospes. Most of the cercariae penetrated the crop-wall and encysted in the hemocoel, whereas one or more larvae invaded the ant's central nervous system. These larvae cause behavioral changes, which increase their chance of being ingested by final hosts. Experimental infections of definitive hosts were obtained in golden hamsters, Meriones unguiculatus, guinea-pigs, and sheep.

Topics: Animals; Ants; Behavior, Animal; Central Nervous System; Cricetinae; Dicrocoeliasis; Dicrocoelium; Gerbillinae; Larva; Mesocricetus; Mice; Rabbits; Rats; Sheep

In the district of Frankfurt/Oder of the German Democratic Republic, faecal examinations of 143 sheep stocks revealed a 31.3 percent infection with Dicrocoelium dendriticum. In different territories of the district, the intensity of the infection with Dicrocoelium dendriticum varied remarkably. Detailed investigations demonstrated, that the parasite was limited to pastures with Brownearth soil. Routine examinations revealed the fact, that the egg-output of Dicrocoelium dendritcum was very variable during the pasture season. During the whole time of the examinations, the authors found eggs in the faeces of sheep belonging to Dicrocoelium dendriticun. In the German Democratic Republic, this helminth species is not restricted to hills with limestones. It occurs also in lowlands with small amounts of lime like the Brown-earth zones of the district Frankfurt/Oder.

Topics: Animals; Ants; Calcium; Dicrocoeliasis; Dicrocoelium; Female; Gallbladder Diseases; Germany, East; Humans; Intestinal Diseases, Parasitic; Liver Diseases, Parasitic; Male; Parasite Egg Count; Sheep; Sheep Diseases; Snails; Soil

Topics: Animals; Ants; Dicrocoeliasis; Mollusca; USSR

Topics: Animals; Ants; Dicrocoeliasis; Insect Vectors; Uzbekistan

Topics: Animals; Ants; Dicrocoeliasis; Disease Reservoirs; Kazakhstan; Snails

Topics: Age Factors; Animals; Ants; Dicrocoeliasis; Disease Vectors; Seasons; Sheep; Sheep Diseases; Snails; Turkey

Topics: Animals; Ants; Arachnida; Cattle; Cattle Diseases; Chickens; Dicrocoeliasis; Disease Vectors; Ecology; Insecticides; Mollusca; Sheep; Sheep Diseases

Topics: Animals; Ants; Austria; Dicrocoeliasis; Dicrocoelium; Disease Reservoirs; Snails

Topics: Animals; Ants; Biological Phenomena; Dicrocoeliasis; Dicrocoelium; Physiological Phenomena

Topics: Animals; Ants; Biology; Cysts; Dicrocoeliasis; Dicrocoeliidae; Dicrocoelium; Gastropoda; Trematoda

Topics: Animals; Ants; Dicrocoeliasis; Dicrocoeliidae; Dicrocoelium; Gastropoda; Snails; Trematoda