ClinQuiz: Equine parasites, answer 2A
2) A — Correct.
Parascaris equorum populations apparently resistant to macrocyclic lactones have been increasingly identified in recent years.6 This finding is of particular concern because P. equorum is the most important pathogenic parasite in juvenile horses. Left unchecked, ascarid infections in foals can lead to poor growth, colic, intestinal impaction, and death.6 This foal could be treated with either a benzimidazole or pyrimidine anthelmintic with efficacy against P. equorum. 6 However, because populations of P. equorum that are resistant to both macrocyclic lactones and pyrantel have been reported,7,8 confirmation of efficacy post-treatment is critical.