Anthelmintic Resistance in Gastrointestinal Nematodes of Ru-minants

Abstract

Gastrointestinal nematode (GIN) infections remain one of the most prevalent and important issue affecting ruminants worldwide. Until date, the majority of GIN control has relied on the administra-tion of chemical anthelmintic medications on a regular basis, in recent years, the problem of anthel-mintic resistance has reached new heights where it can no longer be ignored as a major issue in the control of parasites of livestock. Anthelmintics are generally used at farmers' discretion, with no restrictions to access to commercially available drugs and without any assistance from veterinarians. Thus, inadequate use of anthelmintics is not rare, animals are often treated excessively, interfering with production, accelerating selection of resistant parasites, and posing significant problems for the ruminant industry. The unusually high frequency of multi-drug resistance (MDR) in sheep and goat nematodes threatens the sustainability of small-ruminant enterprises in several parts of the world. Although resistance in horses and cattle nematodes has not yet reached the levels reported in small ruminants, data shows that resistance issues, particularly MDR worms, are rising in these hosts. Both innovative non-chemical parasite control methods and molecular tests capable of detecting resistant worms are urgently needed. Keywords: Anthelmintics; Multidrug resistance; Gastrointestinal nematodes; Ruminants; Preva-lence