Equine piroplasmids

Abstract

Equine piroplasmosis (EP), caused by the tick-borne protozoan parasites Theileria equi or Babesia caballi, is an infectious disease that affects equids worldwide. The disease is of global economic importance due to morbidity, mortality, costs associated with treatment, diagnosis, and impact on the international movement of horses for commerce and competition. Infected horses remain lifelong carriers of T. equi or B. caballi, although horses appear able to occasionally eliminate B. caballi infection. Persistently infected equids are a continuous source for transmission of the protozoal pathogens by tick vectors or iatrogenic transfer. The presence of ticks capable of transmitting these pathogens on all continents increases the need for global surveillance to prevent EP dissemination. This chapter presents life cycle differences between T. equi and B. caballi, the world distribution of competent tick vectors, efficacy of drug treatment to eliminate persistent infection, acaricide treatments to lower tick burden, and improvement of diagnostic assays to prevent dissemination of protozoan parasite strains throughout the world.