Resistance of companion animal parasites to antiparasitic drugs.

Resistance to chemotherapy continues to limit the ability to cure infectious diseases and cancer. Resistance to antiparasitic drugs is affecting control of many pathogens in human and veterinary medicine. In veterinary medicine, particular attention has been focused on resistance to parasites of livestock, including helminths, ectoparasites and protozoa, as an effect of intensive treatment regimens that promote economic sustainability of production systems. Less attention has been given to drug resistance in parasites of companion animals. We provide a comprehensive review of current knowledge of drug resistance in ectoparasites, helminths and protozoa of importance in dogs and cats to establish a baseline assessment of the field and provide recommendations for research priorities and therapeutic alternatives.