Controlled trials of fenbendazole and febantel in ponies with parascaris equorum infections

Abstract

The activity of fenbendazole and febantel was evaluated in 12 pony foals whichwere inoculated with 2600 P. equorum eggs. The foals were not maintained free of parasites before or after inoculation. Once patent for P. equorum, the foals were randomly assigned to groups and treated one time intraorally with either 0.5 ml corn syrup/kg of body weight (controls; n=4), 10 mg fenbendazole/kg (n=4), or 6 mg febantel/kg (n=4). Foals were necropsied and examined for parasites 10 days after treatment. Fenbendazole and febantel were highly effective against adult and immature P. equorum. Grosslesions attributed to P. equorum were evident in all foals. P. equorum were not foundin any of the fenbendazole-or febantel-treated foals. The mean number of adult and immature P. equorum found in the controls was 66.8 (15–166) and 65.0 (21–147), respectively. Strongyle infections were insufficient for efficacy evaluations to be done. Neither anthelmintic was effective against mature Drasehia megastoma, mature Habronema majus, immature H. muscae, Gasterophilus intestinalis or late 4th-stage larvae of Strongylus vulgaris. Adverse side effects due to treatment were not observed.