Gastrointestinal Parasites In Horses Research Articles

Evaluation of the Efficacy of Oral Paste Formulations of Ivermectin against Gastrointestinal Parasites in Horses

The anthelmintic efficacy of oral paste formulations of ivermectin against gastrointestinal parasites in horses was evaluated, using fifteen active racehorses in which nematodes had been detected in their gastrointestinal tracts by fecal examination. A single dose of ivermectin was given orally to twelve horses of the treatment groups at a dosage rate of 200 μg/kg in order to obtain and identify gastrointestinal parasites in their feces for 3 days after treatment. Small strongyles, strongyles, and Parascaris equorum were found passed in feces up to post-treatment day (PTD) 2, but they were no longer observed on PTD 3. Horse bot fly Gasterophilus spp. larvae were found on PTD 2 and 3. The percentages of small strongyles found on PTD 1 were 75-100% (88% on average), and the rest were found (12% on average) on PTD 2. The nematodes were 16 species from 7 genera, of which 11 species were identified as small strongyles. In the fecal examination conducted on PTD 14, all horses of the treatment groups showed negative for nematode eggs. No abnormalities were observed in general clinical signs of the treated horses for 14 days after treatment. Three non-treated horses of the control groups still showed positive for nematode eggs on PTD 14. These results confirm that when ivermectin was given orally to horses at a dosage rate of 200 μg/kg, small strongyles, strongyles, and P. equorum, were excreted in feces up to PTD 2, and Gasterophilus spp. larvae on and after PTD 2, demonstrating the potent anthelmintic efficacy of ivermectin against these parasites.

Occurrence of gastrointestinal parasites in horses in metropolitan Perth, Western Australia.

To assess the occurrence of gastrointestinal parasites in horses in Perth. To apply polymerase chain reaction (PCR) for the identification of some species of encysted larval cyathostomes. Between February and September of 2000, the gastrointestinal tracts of 29 horses submitted to a local knackery and Murdoch University Veterinary hospital in Perth were examined post mortem for the presence of gastrointestinal parasites. The gastrointestinal tract was divided into six sections, which were screened for the presence of parasites such as Gasterophilus sp, Anoplocephala sp and Parascaris equorum. Samples of contents were taken for worm counts. Cyathostomes were found in 28 of the 29 horses. Eighteen species of gastrointestinal helminths were identified. Twelve of these were cyathostomes, with the four most common species being Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus and Cylicostephanus goldi. The large strongyle, Triodontophorus serratus, was found in three of the horses but species of Strongylus were not found. In contrast to a study conducted on horses from this region in 1985, cyathostomes were the most common gastrointestinal parasites found. The four most common cyathostome species found in the present study correlated well with findings of studies in other locations. The high number of cyathostomes may be due to the increase in resistance to anthelmintics among the species, and to improper anthelmintic use. The apparent reduction in number of large strongyles may be due to the widespread use of ivermectin, which is very effective against these parasites, and also possibly because some larvae may not have been detected.

Oxibendazole: critical anthelmintic trials in equids.

The efficacy of oxibendazole against gastrointestinal parasites of horses was evaluated by the critical test method. Naturally infected ponies of various ages were given single oral doses of 5, 10, or 15 mg-kg of bodyweight. The drug was highly effective against adult large strongylids (Strongylus vulgaris, S edentatus, S equins), adult small strongylids (especially species of the genera Cylicostephanus, Cylicocyclus, Cyaathostomum, and Triodontophorus), and adult and larval stages of the large pinworm, Oxyuris equi. There was no apparent dose-related differences in efficacy. Oxibendazole was less effective against fourth-stage small strongylid larvae than it was against adults. The drug was inactive against stomach bots (Gasterophilus spp), tapeworms (Anoplocephala magna and A perfoliata), lungworms (Dictyocaulus arnfieldi), abdominal worms )Setaria equina), and mature or immature nematodes in locations other than the lumen of the gastrointestinal tract.