pathogens Review Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny Sharon Tirosh-Levy 1,* , Yuval Gottlieb 1, Lindsay M. Fry 2,3, Donald P. Knowles 2 and Amir Steinman 1 1 Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 7610001, Israel;
[email protected] (Y.G.);
[email protected] (A.S.) 2 Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA;
[email protected] (L.M.F.);
[email protected] (D.P.K.) 3 Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, Pullman, WA 99164, USA * Correspondence:
[email protected] Received: 7 September 2020; Accepted: 4 November 2020; Published: 8 November 2020 Abstract: Equine piroplasmosis (EP), caused by the hemoparasites Theileria equi, Theileria haneyi, and Babesia caballi, is an important tick-borne disease of equines that is prevalent in most parts of the world. Infection may affect animal welfare and has economic impacts related to limitations in horse transport between endemic and non-endemic regions, reduced performance of sport horses and treatment costs. Here, we analyzed the epidemiological, serological, and molecular diagnostic data published in the last 20 years, and all DNA sequences submitted to GenBank database, to describe the current global prevalence of these parasites. We demonstrate that EP is endemic in most parts of the world, and that it is spreading into more temperate climates. We emphasize the importance of using DNA sequencing and genotyping to monitor the spread of parasites, and point to the necessity of further studies to improve genotypic characterization of newly recognized parasite species and strains, and their linkage to virulence.