“…The prophylactic use of anthelmintics without a parasitological diagnosis before treatment is garnering increasing controversy due to growing levels of drug resistance (5,14,32,36). The factors that contribute to anthelmintic resistance include high frequency of treatments, overuse of drugs belonging to the same chemical group, underdosing, absence of weight monitoring, and "prophylactic" mass treatments (12,13,20,26,27,31,32,35). Benzimidazole (BZ) resistance in cyathostomin populations is now highly prevalent and reported worldwide (2,8,16,22,23).…”