Veterinary MedicineVeterinary ParasitologyZoologyParasitologyVeterinary Parasitic DiseasesWildlife ParasitologyHelminth InfectionsParasitic Disease PreventionParasitic Diseases Of WildlifeParasitic ZoonosesDrug Efficacy TestingOvine Parasitic InfectionsParasitic Egg Recovery
Ivermectin was injected IM into 12 yearling Shetland ponies. The following reactions in percentages of parasites recovered from ponies given 200 microgram/kg or 300 microgram/kg, as compared with the parasitic population in those given the vehicle at 1 week after injection, were as follows: Otobius megnini nymphs--no reduction; Gasterophilus intestinalis--100% and 99.9%; G nasalis--100% and 99.9%; Parascaris equorum adults--100% and 96%; Strongylus vulgaris adults--100% and 100%; S edentatus adults--100% and 100%; cyathostome adults of the genera Gyalocephalus, Cylicocyclus, Cyathostomum, Cylicostephanus, and Poteriostomum--99.9% and 100%; 4th-stage larvae--97.3% and 96.8%; Oesophagodontus robustus adults--100% and 100%; Triodontophorus spp--adults--100% and 100%, 4th-stage larvae--95.1% and 100%; and Oxyuris equi adult males--66.7% and 77.7%, adult females--96.5% and 100%, and 4th-stage larvae--94.1% and 96.9%. Other parasites encountered were too few in number to estimate drug efficacy.