moxidectin and Helminthiasis--Animal

Research in anthelmintic pharmacology faces a grim future. The parent field of veterinary parasitology has seemingly been devalued by governments, universities and the animal industry in general. Primarily due to the success of the macrocyclic lactone anthelmintics in cattle, problems caused by helminth infections are widely perceived to be unimportant. The market for anthelmintics in other host species that are plagued by resistance, such as sheep and horses, is thought to be too small to sustain a discovery program in the animal health pharmaceutical industry. These attitudes are both alarming and foolish. The recent history of resistance to antibiotics provides more than adequate warning that complacency about the continued efficacy of any class of drugs for the chemotherapy of an infectious disease is folly. Parasitology remains a dominant feature of veterinary medicine and of the animal health industry. Investment into research on the basic and clinical pharmacology of anthelmintics is essential to ensure chemotherapeutic control of these organisms into the 21st century. In this article, we propose a set of questions that should receive priority for research funding in order to bring this field into the modern era. While the specific questions are open for revision, we believe that organized support of a prioritized list of research objectives could stimulate a renaissance in research in veterinary helminthology. To accept the status quo is to surrender.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Anti-Infective Agents; ATP Binding Cassette Transporter, Subfamily B; Biological Availability; Caenorhabditis elegans; Cattle; Cattle Diseases; Depsipeptides; Diketopiperazines; Drug Resistance; Helminthiasis, Animal; Helminths; Ivermectin; Macrolides; Nitro Compounds; Peptides, Cyclic; Piperazines; Sheep; Sheep Diseases; Thiazoles

The avermectins and, to a lesser extent, the milbemycins, have revolutionized antiparasitic and antipest control over the last decade. Both avermectins and milbemycins have macrocyclic lactone structures that are superimposable, they are produced by the same genus of soil dwelling organisms, they have the same mode of action, they exert this action against the same nematode/acarine/insect spectrum of targets, and they show the same mechanism-based toxicity in mammals. Reports suggesting that milbemycins have a different mode of action from avermectins with implications that there will be no mutual resistance to the groups have been shown to be false. Contributing to the belief that there were differences in mode of action between the two groups are the vague definitions of resistance presently in use which rely on the ability of the parasite to survive treatment at the manufacturer's recommended use level. More appropriately, drug resistance should be defined as 'a change in gene frequency of a population, produced by drug selection, which renders the minimal, effective dosage previously used to kill a defined portion (e.g. 95%) of the population no longer equally effective'. This type of definition would allow us to detect changes in susceptibility of a population earlier and is essential when comparing different chemicals to determine if there is mutual resistance to them. It is concluded that much effort has been expended by pharmaceutical, government, and academic scientists searching for broad-spectrum second generation avermectin and milbemycin products, but none has exceeded the original avermectin in any fundamental way. The newer avermectin and milbemycin compounds that have appeared claim niches in the market place based on emphasis of certain narrow parts of the overall spectrum. Consequently, there are no second generation avermectins and milbemycins at present and all newer compounds from this mode of action class are viewed as siblings of the first generation.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Antiprotozoal Agents; Dog Diseases; Dogs; Helminthiasis; Helminthiasis, Animal; Ivermectin; Macrolides; Molecular Structure; Parasitic Diseases; Parasitic Diseases, Animal; Sheep; Sheep Diseases; Structure-Activity Relationship

The milbemycins are the only novel broad spectrum anthelmintic chemicals to reach the market place in the last 10 years. Many new systems for delivery and strategies for rational use have, however, been introduced. Boluses which are retained by virtue of specific gravity and by variable geometry are now available. They contain benzimidazoles, morantel, ivermectin and levamisole. Their release mechanisms involve preferential corrosion of a retaining metal core, constant diffusion from a laminated ethylene acetate sandwich, and a hydrostatic pump driven by osmotic pressure. Some are biodegradable. Experimental delivery systems have been developed incorporating ear implants and liposomes. The anthelmintic efficacy of some drugs has been potentiated by the synergistic action of metabolic inhibitors and these combinations hold promise for the future. Much new information is now available on those factors which affect anthelmintic efficacy such as concurrent administration with food and the presence of the target parasites themselves. This knowledge provides a sound basis for the rational use of anthelmintic drugs.

Topics: Alginates; Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Drug Combinations; Drug Delivery Systems; Helminthiasis; Helminthiasis, Animal; Ivermectin; Liposomes; Macrolides; Morantel; Pharmaceutical Vehicles

To compare larvicidal regimens of fenbendazole and moxidectin for reduction and suppression of cyathostomin fecal egg counts (FEC) in a transient herd of embryo transfer-recipient mares.. Randomized, complete block, clinical trial.. 120 mares from 21 states, residing on 1 farm.. An initial fecal sample was collected from each mare; mares with an FEC ≥ 200 eggs/g were assigned to treatment groups. Eighty-two horses received fenbendazole (10.0 mg/kg [4.5 mg/lb], PO, q 24 h for 5 days) or moxidectin (0.4 mg/kg [0.18 mg/lb], PO, once); FEC data were analyzed 14, 45, and 90 days after treatment.. Mean FEC reduction was 99.9% for moxidectin-treated mares and 41.9% for fenbendazole-treated mares 14 days after treatment. By 45 days, mean FEC of fenbendazole-treated mares exceeded pretreatment counts; however, FECs of moxidectin-treated mares remained suppressed below pretreatment values for the duration of the 90-day study. Fecal egg counts were significantly different between groups at 14, 45, and 90 days after treatment.. Failure of the 5-day regimen of fenbendazole to adequately reduce or suppress FEC suggested inadequate adulticidal and larvicidal effects. In contrast, a single dose of moxidectin effectively reduced and suppressed FEC for an extended period. Given the diverse geographic origins of study mares, these results are likely representative of cyathostomin-infected mares in much of the United States, confirming previous findings indicating that fenbendazole resistance in cyathostomins is widespread and that moxidectin remains an effective treatment for control of these important parasites.

Topics: Animals; Anthelmintics; Embryo Transfer; Feces; Female; Fenbendazole; Helminthiasis, Animal; Horse Diseases; Horses; Macrolides; Parasite Egg Count; Pregnancy

Two dosages of moxidectin oral gel were evaluated and compared to a therapeutic dose of ivermectin oral paste in the control of a spectrum of gastrointestinal parasites of ponies naturally infected in southern Louisiana or Mississippi. Thirty-two mixed-breed ponies ranging in age from one to 21 years were used in this controlled test. Eight weeks prior to the experiment, ponies grazing on contaminated pasture were moved to a paddock and fed a pelleted ration, thus reducing or eliminating the potential for additional infection and ensuring the existence of a population of encysted larvae. Ponies were then allocated to replicates of four animals based on values of fecal strongyle egg counts and percent strongyle larvae composition determined from Baermann sedimentations of fecal cultures. Members of replicates were allocated to one of four treatment groups: moxidectin oral gel administered at 300 micrograms kg-1 body weight, moxidectin oral gel at 400 micrograms kg-1, the oral gel vehicle as negative control, and ivermectin oral paste at 200 micrograms kg-1. Prior to treatment, ponies were confined in pairs to covered concrete runs by treatment group. Two weeks following treatment, necropsy examinations of all animals were performed. Parasites were recovered from the lumen of the stomach, the intestinal tract, the cranial mesenteric artery and its major branches, the peritoneal body wall and from pepsin digests of mucosal scrapings taken from the cecum and large colon. Encysted cyathostome larval burdens were also compared using mural transillumination of segments of the large colon for visualization of the encysted forms. Control ponies were not uniformly infected with the spectrum of parasites; however, moxidectin, at either dosage, compared favorably with ivermectin in the control of the adults of Strongylus vulgaris, Strongylus edentatus, Triodontophorus spp., Oesophagodontus robustus, Trichostrongylus axei, Oxyuris equi, Parascaris equorum, Habronema muscae, as well as both the adult and larval Cyathostominae recovered from the lumen. Moxidectin also appears as efficacious as ivermectin against migrating large strongyle larvae at the two weeks post-treatment evaluation. Moxidectin demonstrated a trend towards greater efficacy against encysted cyathostome larvae than a therapeutic dosage of ivermectin, but this difference was not statistically significant. Moxidectin was less effective than ivermectin against Gasterophilus intestinalis and was equally i

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Dose-Response Relationship, Drug; Female; Gels; Helminthiasis; Helminthiasis, Animal; Horse Diseases; Horses; Ivermectin; Macrolides; Male; Nematode Infections; Ointments; Strongyle Infections, Equine; Strongylus

Moxidectin was tested as an oral gel formulation during a controlled test performed to evaluate dosages against equine gastrointestinal parasites. Four groups of ten ponies were used. Ponies ranged from 1 to 20 years of age and were naturally infected in southern Louisiana or Mississippi. Fecal exams and fecal cultures were performed on all ponies to determine the strongyle egg counts and the percent distributions of large and small strongyles. Following these determinations, ponies were allocated to replicates of four ponies to provide an even distribution of strongyle infection, age, weight and gender. Members of each replicate were then randomly assigned to one of four treatment groups. The doses tested were 300, 400 and 500 micrograms kg-1 body weight. The oral gel vehicle alone served as control. Treatments were administered behind the tongue and the ponies were observed continuously for 4 h for any adverse reactions; thereafter, ponies were observed at least twice daily. Necropsy examinations were performed 14 days post-treatment for the recovery and identification of any parasites present. Moxidectin, at all doses tested, was 100% efficacious against adults of Strongylus vulgaris, Strongylus edentatus, Triodontophorus spp. and 22 species of small strongyles. Moxidectin was also 100% efficacious against larvae of Strongylus edentatus and Oxyuris equi, greater than 94% efficacious against Strongylus vulgaris larvae and Oxyuris equi adults at 14 days post-treatment. Moxidectin proved highly efficacious against luminal small strongyle larvae (> 99.9% against L4 and > 92% against L3) and moxidectin demonstrated some efficacy against encysted small strongyle larvae as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Dose-Response Relationship, Drug; Equidae; Female; Gastrointestinal Diseases; Gels; Helminthiasis; Helminthiasis, Animal; Macrolides; Male; Oxyuriasis; Strongylida Infections; Strongylus

Endoparasites are considered a major health problem of South American camelids as shown in a recent survey among German and Austrian camelid owners. Although prophylactic and therapeutic measures such as application of anthelmintics are commonly used, treatment efficacy is usually not assessed. Owners have expressed significant concerns regarding the effect of antiparasitic therapy, so this study aimed to evaluate the outcome of anthelmintic treatment in German alpaca herds with different drugs.. Overall, 617 samples from 538 clinically healthy alpacas > 1 year-old from 27 farms (n = 11-157 animals/herd) were examined. The most common parasites detected by flotation were Eimeria spp. (75.1%) followed by strongylids (55.0%), Nematodirus spp. (19.3%), cestodes (3.1%) and Trichuris (2.7%). After initial coproscopical examination by flotation and strongylid egg quantification by the McMaster technique, positive animals excreting at least 150 eggs per gram of faeces were included in a faecal egg count reduction test (FECRT) using fenbendazole (n = 71 samples), moxidectin (n = 71) or monepantel (n = 66). Pre-treatment larval cultures (n = 23 positive pooled farm samples) revealed Haemonchus (87% of the farms), Cooperia (43.5%), Trichostrongylus (21.7%), Ostertagia (13.0%), Nematodirus and Oesophagostomum (4.3% each). Fenbendazole treatment reduced egg excretion by 45%, moxidectin by 91% and monepantel by 96%. On the farm level, 13/18 farms that used fenbendazole, 6/6 farms that used moxidectin and 2/5 farms that used monepantel had individual FECR values < 90% (fenbendazole) or < 95% (moxidectin, monepantel). Haemonchus and Cooperia were overrepresented on the farms with reduced treatment efficacy.. Gastrointestinal strongylids are common in German alpacas and fenbendazole in particular was not sufficiently effective to reduce strongylid egg excretion. Although the FECRT could not unambiguously determine anthelmintic resistance in the present study, the finding that small ruminant strongylids, especially Haemonchus, are common in alpacas indicates that determination of effective anthelmintic doses, monitoring of efficacy and adapted (selective) treatment regimens must be implemented as part of sustainable deworming practices in this species in accordance with recommendations for ruminants.

Topics: Aminoacetonitrile; Animals; Anthelmintics; Camelids, New World; Feces; Female; Fenbendazole; Haemonchus; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Macrolides; Male; Parasite Egg Count; Strongylida; Strongylida Infections

The effect of maize grain supplementation on the resilience and resistance of browsing Criollo goat kids against gastrointestinal nematodes was evaluated. Five-month-old kids (n = 42), raised worm-free, were allocated to five groups: infected + not supplemented (I-NS; n = 10), infected + maize supplement at 108 g/d (I-S108; n = 8), maize supplement at 1% of body weight (BW) (I-S1%; n = 8), maize supplement at 1.5% BW (I-S1.5%; n = 8), or infected + supplemented (maize supplement 1.5% BW) + moxidectin (0.2 mg/kg BW subcutaneously every 28 d) (T-S1.5%; n = 8). Kids browsed daily (7 h) in a tropical forest for 112 days during the rainy season. Kids were weighed weekly to adjust supplementary feeding. Hematocrit (Ht), hemoglobin (Hb), and eggs per gram of feces were determined fortnightly. On day 112, five goat kids were slaughtered per group to determine worm burdens. Kids of the I-S1.5% group showed similar body-weight change, Ht and Hb, compared to kids without gastrointestinal nematodes (T-S1.5%), as well as lower eggs per gram of feces and Trichostrongylus colubriformis worm burden compared to the I-NS group (P > 0.05). Thus, among the supplement levels tested, increasing maize supplementation at 1.5% BW of kids was the best strategy to improve their resilience and resistance against natural gastrointestinal nematode infections under the conditions of forage from the tropical forest.

Topics: Anemia; Animal Feed; Animals; Anthelmintics; Disease Resistance; Female; Food, Fortified; Forests; Gastrointestinal Diseases; Goat Diseases; Goats; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Larva; Macrolides; Male; Mexico; Nematode Infections; Parasite Egg Count; Random Allocation; Seasons; Trichostrongylosis; Zea mays

Whilst anthelminthic resistance of small strongyles is well documented, anthelmintic failures against infections with Oxyuris equi have scarcely been published so far. We describe two cases of equine oxyurosis and the anthelminthic failure of macrocyclic lactones (moxidectin, ivermectin) resulting in persistent O. equi infections with continuous egg shedding. The horses were kept in two different herds in the federal state of Hessia, Germany. Herd A kept two geldings: an 8-year-old Welsh-Cob-Mix and a 7-year-old Haflinger. Herd B was composed of four animals: 2 Connemara-mares, 31 and 19 years old, one 18-year-old Connemara-gelding and a 27-year-old Norwegian Fjord mare. All animals had a case history of various anthelmintic treatments with macrocyclic lactones (moxidectin and ivermectin alternating irregulary) in 2010 and 2011, nonetheless, they continued to shed O. equi nematodes and eggs. Animals were treated anew with moxidectin by members of the institute and were continuously monitored on a daily base by adhesive tape samples. Follow-up examinations for the reappearance of eggs were performed for 30 days in Herd A and 57 days in Herd B. In total, recurrence of O. equi egg shedding was detected in three out of six horses within 1-4 weeks after treatment. In both herds accompanying horses sharing the same stable and paddock remained negative for detection of O. equi-eggs or worms throughout the whole observation period. This is the first report in Europe showing inefficacy of commercial ivermectin compounds and furthermore the first report at all documenting ineffectiveness of moxidectin compounds in the treatment of O. equi-infections in horses indicating a possible development of resistance or confirming an existing incomplete oxyuricidal efficacy.

Topics: Animals; Anthelmintics; Feces; Female; Germany; Helminthiasis, Animal; Horse Diseases; Horses; Ivermectin; Macrolides; Male; Mebendazole; Nematoda; Treatment Failure

The aim of the present paper was to assess benefit of strategic anthelmintic treatments on milk production in six commercial dairy sheep farms, located in southern Italy, whose animals were naturally infected with gastrointestinal strongyles. On each farm, two similar groups were formed, one untreated control group and one treated group. In all the treated groups, the strategic anthelmintic schemes were based on: (i) only one treatment with moxidectin in the periparturient period (February, Farm No. 6), or; (ii) two treatments, i.e. the first with moxidectin performed in the periparturient period (February, Farms Nos. 1, 2, 3 and 4) or in the postparturient period (April, Farm No. 5), and the second with netobimin at the mid/end of lactation (June, Farms Nos. 1, 2, 3, 4 and 5). Faecal egg count reduction (FECR) tests were performed on each farm in order to asses the anthelmintic efficacy of the drugs used. In addition, milk yield measurements for each animal fortnightly in each farm for the lactation period were performed. In terms of FECR, both moxidectin and netobimin were effective in all the 6 studied farms. Regarding milk production, overall in the 6 study farms the mean daily milk productions of the treated groups were higher than those of the control group. However, there were important differences between the 6 farms, i.e. the increase of milk production in the treated groups versus the control groups was as follows: +18.9% (Farm 1), +30.4% (Farm 2), +4.0% (Farm 3), +37.0% (Farm 4), +5.5% (Farm 5) and +40.8% (Farm 6). The results of the study showed that the economic efficacy of an anthelmintic treatment is not a cause-effect issue, but is a multifactorial issue which depends upon the quali-quantitative parasitological status of the animals, the pathogenesis of the species of parasites, the virulence of the strains of parasites, the local epidemiology, the timing of treatment, the breed of animal in terms of genetics and production types, nutrient supply.

Topics: Animals; Anthelmintics; Comorbidity; Dairying; Drug Evaluation; Female; Guanidines; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Italy; Lactation; Macrolides; Parasite Egg Count; Pregnancy; Pregnancy Complications, Infectious; Puerperal Disorders; Sheep; Sheep Diseases; Strongylida Infections

Controlled trials with a common protocol were conducted in Idaho, Illinois and Tennessee to evaluate anthelmintic effectiveness of Quest Gel (QG; 2% moxidectin) against lumenal parasites in horses. Candidate horses were required to have naturally acquired nematode infections, as confirmed by presence of strongylid eggs in feces. At each site, 24 equids were blocked on the basis of pretreatment strongyle fecal egg counts (EPG) and randomly assigned to treatments within blocks. Within each block of two animals, one received QG on Day 0 at a dosage of 0.4 mg moxidectin/kg b.w. and one was an untreated control. Body weights measured the day before treatment served as the basis for calculating treatment doses. Horses assigned to treatment with QG received the prescribed dose administered orally with the commercially packaged Sure Dial syringe. Horses were necropsied 12-14 days after treatment, and lumenal parasites and digesta were harvested separately from each of five organs, including the stomach, small intestine, cecum, ventral colon and dorsal colon. Parasites from stomachs and small intestines were identified to genus, species and stage. Micro- (i.e., < 1.5 cm) and macroparasites (i.e., > 1.5 cm) in aliquots from the cecum, ventral colon and dorsal colon were examined in aliquots of approximately 200 parasites until at least 600 parasites had been identified to genus, species and stage or until all parasites in the 5% aliquot were examined, whichever occurred first. Data were combined across sites and analyzed by mixed model analysis of variance to assess the fixed effect of treatment and random effects of site and block within site. Because QG does not contain a cestocide, efficacy of QG against tapeworms was not significant (P > 0.05). Based on geometric means, however, efficacy of QG was greater than 90% (P < 0.05) against 38 species and developmental stages of cyathostomes, strongyles, bots, larval pinworms and ascarids encountered in at least 6 of 36 control horses in the combined data set. None of the horses treated with moxidectin exhibited evidence of adverse effects. Study results demonstrate QG, administered to horses with naturally acquired endoparasite infections at a dosage of 0.4 mg moxidectin/kg b.w., was highly effective against a broad range of equine parasitic infections.

Topics: Analysis of Variance; Animals; Anthelmintics; Dose-Response Relationship, Drug; Feces; Female; Helminthiasis, Animal; Horse Diseases; Horses; Macrolides; Male; Organ Specificity; Parasite Egg Count; Random Allocation; Treatment Outcome

The effectiveness, safety and production-enhancing benefit (improved weight gains) of moxidectin long-acting injection given subcutaneously in the ear at the rates of 0.75, 1.0 and 1.5mg/kg bw were evaluated in three studies under common protocol. The only adverse reaction to treatment was a mild (<2 tablespoons in volume), and for the most part transient (<28 days for the treatment rate of 1.0mg/kg bw) injection site swelling as noted in a minority of the animals (12.2% of the animals treated at the rate of 1.0mg/kg bw). Regardless of study site, post-treatment interval or dose rate, average daily gains were improved over control cattle by approximately 33%. Reductions in strongyle EPG counts relative to controls were > or = 90% for all dose rates of moxidectin for a post-treatment period of 42 days (Wisconsin), 84 days (Arkansas) and 140 days (Louisiana). In Arkansas and Louisiana, the majority (>80%) of post-treatment strongyle eggs, as determined by coproculture, were Cooperia spp. As determined by sequential necropsies, periods of continuous, post-treatment protection (> or = 90% efficacy in at least two out of three studies) for moxidectin long-acting injection given at the rate of 1.0 mg/kg bw were 90 days (adult Haemonchus spp.), 120 days (Dictyocaulus viviparus and adult Ostertagia and Oesophagostomum) and 150 days (Ostertagia spp. EL4).

Topics: Animals; Anthelmintics; Cattle; Cattle Diseases; Dose-Response Relationship, Drug; Feces; Helminthiasis, Animal; Helminths; Injections, Subcutaneous; Macrolides; Parasite Egg Count; Random Allocation; Strongylus; Treatment Outcome; Weight Gain

Anthelmintic products form the basis of helminth control practices on horse stud farms at present. Regular evaluation of the efficacy of these products is advisable, as it will provide information on the worm egg reappearance period and the resistance status in the worm population. The aim of this study was to evaluate the efficacy of doramectin, pyrantel pamoate, ivermectin and moxidectin on a Thoroughbred stud farm in the Western Cape Province, South Africa. The study also compared the anthelmintic efficacy of two moxidectin formulations administered at their recommended dosages (an injectable, at 0.2 mg/kg, not registered for horses, and an oral gel at 0.4 mg/kg, registered for horses). Two mixed-sex groups of 30 yearlings and 40 weaners were tested in 2001 and 2002, respectively, divided into 3 and 4 groups of equal size. In 2001, moxidectin was one of 3 drugs administered orally and at a dose rate of 0.4 mg/kg. In 2002, pyrantel pamoate and ivermectin were orally administered at 19 and 0.2 mg/kg. Moxidectin and doramectin (the latter not registered for horses) were administered by intramuscular injection at a dose of 0.2 mg/kg, the dosage registered for other host species. The faecal egg count reduction test was used to determine the anthelmintic efficacies in both years. Each animal acted as its own control and the arithmetic mean faecal egg count and lower 95% confidence limit was calculated for each of the groups. A 100% reduction in the faecal egg counts and a 100% lower 95% confidence limit was recorded for moxidectin (0.4 mg/kg) in 2001. In 2002, a 99% and 96% reduction was recorded for pyrantel pamoate and ivermectin, respectively. In the same year doramectin and moxidectin (both injectable and given at 0.2 mg/kg) did not have any effect on worm egg counts. Of the 4 drugs tested in 2002, only pyrantel pamoate recorded lower 95% confidence limits above 90%.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Dose-Response Relationship, Drug; Feces; Female; Fenbendazole; Helminthiasis, Animal; Horse Diseases; Horses; Injections, Intramuscular; Ivermectin; Macrolides; Male; Parasite Egg Count; Pyrantel Pamoate; Random Allocation; Treatment Outcome

The helminth burdens and biodiversity of 9 randomly selected donkeys (Equus asinus) were examined after necropsy. Prior to necropsy, 8 of the animals were subjected to 1 of 3 management interventions (monthly fecal removal, prewinter moxidectin treatment, and a combination of both treatments) or a control for a 16-mo period. The remaining animal was killed earlier in the study. Quantitative samples were collected from the gastrointestinal tract for helminth recovery. The intestinal walls were examined with transmural illumination and thereafter digested with a HCl-peptic method for identification of the mucosal larval stages of cyathostomes. In this study, 37 helminth species belonging to the Ascarididae, Atractidae, Dictyocaulidae. Habronematidae, Onchocercidae, Oxyuridae, Strongylidae, and Trichostrongylidae, 1 cestode species of the Anoplocephalidae, and 1 trematode species in the Paramphistomatidae were recovered. In addition, 1 species of oestrid fly of the Gasterophilidae was identified. The results obtained in the present study support the application of several intervention methods to reduce the helminth burdens in donkeys.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cecum; Colon; Equidae; Female; Helminthiasis, Animal; Helminths; Intestinal Diseases, Parasitic; Larva; Macrolides; Male; Mucous Membrane; Parasite Egg Count; South Africa

The aim of the study was to determine the effect of alternative management interventions on levels of nematodes and the condition of working donkeys in South Africa. Twenty-four adult donkeys (Equus asinus) within an area of 200km radius were randomly allocated to eight paddocks. Two replicates each of three management interventions together with a control group were tested in a 16-month study. The interventions included monthly removal of feces from paddocks where the donkeys grazed, a pre-winter moxidectin treatment, and a combination of a pre-winter moxidectin treatment and monthly fecal removal. The influence of the different interventions on the nematode fecal egg counts, animal live weights, body condition scores and general blood chemistry were compared. In addition, herbage samples were collected from the pastures in each paddock to determine the number of third-stage larvae (L(3)) per kg dry matter. At the end of the study worm recoveries and counts were performed on eight of the animals following euthanasia. The cyathostomes represented the largest portion of the helminth species composition in both the fecal egg counts and larval cultures. Monthly fecal removal alone did not significantly reduce the L(3) on pasture and consideration of more frequent removal is discussed. Pre-winter moxidectin treatment resulted in a 100% reduction in fecal egg counts, an average egg reappearance period of 42-55 days, a reduced average egg count for up to 8 months, and reduced total helminth burdens in all the treated donkeys. It also resulted in improved live weights, hemoglobin concentration, packed cell volumes and to some extent body condition score of the donkeys.

Topics: Animal Husbandry; Animals; Anthelmintics; Anti-Bacterial Agents; Body Weight; Equidae; Feces; Female; Helminthiasis, Animal; Larva; Macrolides; Male; Parasite Egg Count; Random Allocation; Seasons; South Africa; Treatment Outcome

Faeces voided by 1-year old cattle at 3-70 days after treatment with a pour-on formulation of moxidectin had no detectable effects on development or survival of the common dung beetle Onthophagus taurus. In contrast, faeces voided by cattle treated with a pour-on formulation of eprinomectin were associated with high juvenile mortality during the first 1-2 weeks after treatment. Increased mortality also occurred among newly emerged beetles fed on faeces collected 3 days after eprinomectin treatment and there was evidence of suppressed brood production among those that survived. This effect was still apparent even after insects fed for a further 10 days on the faeces of untreated cattle. A model simulating the effects of drug residues on dung beetle populations suggests that in the absence of immigration a single treatment of eprinomectin is capable of reducing beetle activity in the next generation by 25-35%. Effects are likely to be greatest when treatment coincides with emergence of a new generation of beetles.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Australia; Cattle; Cattle Diseases; Coleoptera; Drug Residues; Feces; Female; Helminthiasis, Animal; Ivermectin; Macrolides; Models, Biological; Time Factors

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Feces; Female; Fenbendazole; Helminthiasis; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Ivermectin; Macrolides; Parasite Egg Count; Pregnancy; Puerperal Infection; Sheep; Sheep Diseases; Time Factors