Parasiticides: perspectives and prospects

Abstract

For over 50 years, anthelmintics, insecticides and acaricides have played a central role in the treatment and control of ruminant parasites, but over the same time-frame, their effectiveness has gradually diminished through the emergence of resistance. Currently, in parallel with initiatives to reduce on-farm use of antibiotics, the routine use of anthelmintics and ectoparasiticides is actively discouraged by several organisations and individuals. For these reasons, there is little incentive for the animal health industry to discover and develop new products for farm animals. While the removal of parasites in clinical disease must inevitably rest on effective therapeutics, longer term control of parasitism can be facilitated through complementary practices that enhance host resistance and resilience and reduce parasite challenge. When parasiticides are used, preservation and maintenance of refugia are key to reducing selection pressure for resistance and mitigating any untoward side-effects in the environment. Adoption of such approaches requires adaptability, more attention to detail and extra effort by farmers. Veterinarians can play an important role in encouraging the adoption of proven diagnostic and monitoring technologies and providing advice to farmers as they transition away from parasiticide-dependence.