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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Publications at this Location » Publication #309928

Title: Equine Piroplasmosis

item Wise, Lauren
item MEALEY, ROBERT - Washington State University
item Knowles Jr, Donald

Submitted to: Veterinary Clinics of North America
Publication Type: Book / Chapter
Publication Acceptance Date: 10/6/2014
Publication Date: 12/1/2014
Citation: Wise, L.N., Mealey, R.H., Knowles Jr, D.P. 2014. Equine Piroplasmosis. Veterinary Clinics of North America. 30(3):677-93.

Interpretive Summary: Equine piroplasmosis is a disease exotic to the U. S. that has recently reemerged. This book chapter describes update information concerning diagnosis, transmission and treatment.

Technical Abstract: Equine piroplasmosis is an infectious, tick-borne disease caused by the hemoprotozoan parasites Theileria (previously Babesia) equi and Babesia caballi. Piroplasmosis affects all wild and domestic equid species and causes signs related to intravascular hemolysis and associated systemic illness. Infection with either parasite can lead to a similar clinical syndrome yet T. equi and B. caballi are distinct in terms of disease severity, life cycle, infection dynamics, and persistence in the horse and drug susceptibility. While most horses recover from the initial phase of the disease, infection can be fatal, more often with T. equi. Horses that survive acute disease inevitably become inapparent carriers and exhibit no clinical signs of infection yet can serve as reservoirs for transmission to naïve horses. The carriers represent the largest challenge in diagnosis, eradication and control measures. The parasites and their natural tick vectors are endemic to most countries with tropical and subtropical climates yet the United States and Canada, as well as a small number of other nations, are considered “free” or non-endemic. Goals of disease control vary tremendously between endemic and non-endemic nations and as demonstrated by the “silent” re-emergence of T. equi in 2009 in Texas, endeavors to understand and control transmission especially in areas that wish to remain non-endemic must continue.