The effect of oral ivermectin on immature ascarids in foals

Orally administered ivermectin^awas 100% effective against experimentally induced 11-day-old infections of Parascaris equorum (L₃) in 2 trials. In 4 additional trials there was 98% efficacy of ivermectin treatment against induced 28-day-old infections of P. equorum (L₄). In 2 trials with natural infections of ascarids, invermectin paste had 93% efficacy against immature P. equorum and 100% efficacy against the adult. One of the latter 2 trials also emphasized the potential problem of reinfection.