Anthelmintic resistance to monepantel in Haemonchus contortus

Abstract

Resistance to anthelmintics is reported in several locations around the world, not only for the parasites of humans, but also to the parasites of veterinary importance. H. contortus, the most important parasite for small ruminants reared in tropical conditions, can develop resistance to anthelmintics used for their control. Resistance is caused by increased frequency of favorable genes to survival in helminth population, hampering the clinical veterinary treatment for this disease. The haemonchosis causes losses related to animal welfare and also to economics, due to the decrease in animal productivity. It is considered that the resistance is established when a previously effective drug becomes unable to eliminate the parasitic population exposed at the recommended therapeutic dose. Thereby, this project aims to induce resistance to the current most effective anthelmintic used in sheep industry: The monepantel, in order to obtain a resistant parasite isolated of H. contortus. The establishment and monitoring of resistance will be evaluated by parasitological tests, including FECRT (Feces egg count reduction test), EPG (Eggs per gram), LDT (Larval development test) and MALDT (Micro-agar LDT).