Conference in 22nd Annual Congress for ESVCP&ACCP

June 26^th, 2020

Camino E., Dorrego-Rodriguez A., Gago-Munoz P., de Juan L., Dominguez L. and Cruz F.

Background: Equine piroplasmosis (EP), caused by the haemoparasites Theileria
equi and Babesia caballi, is an infectious tick-borne disease with a great economic
importance to the equine industry. Acute infection often causes pyrexia, lethargy,
anaemia and jaundice in horses. If the acute phase is overcome, horses may
become asymptomatic carriers with low levels of parasitaemia and detectable
antibody levels in their bloodstream, a status that limits their movement to EP-free countries. Several studies have described haematological abnormalities in horses with acute EP infection, but little is known with regards to the EP chronic, carrier stage.
Objective: The goal of this study was to describe the presence of haematological
changes between horses in Spain with three different status: no EP infection
(healthy horses), EP acute form and EP asymptomatic carrier.
Methods: A total of 531 horses in Spain were investigated in this study and were
divided into three groups: 284 EP healthy horses with negative cELISAs and
multiplex PCR, 60 horses with acute EP (showing EP clinical signs and confirmed by PCR) and 187 EP asymptomatic carriers (with positive cELISAs and PCR).
Haematological parameters [red blood cell count (RBC), packed cell volume (PCV),
haemoglobin concentration (HGB), white blood cell count (WBC) and platelet count] were determined in EDTA blood by using an automatic counter system (URIT 2900 Vet Plus, Urit Medical Electronics, China). Results for each parameter in the three groups studied were compared using a Kruskal-Wallis test.
Results: In comparison with healthy and EP carrier horses, those with EP acute
infection showed a significant decrease (p<0.001) of the RBC, PCV, Hgb and
platelet count values. However, WBC followed a different pattern: both EP acute
(p<0.001) and EP carrier horses (p<0.001) presented significantly higher WBC
compared to healthy horses, suggesting that higher WBC were maintained in EP
carriers after the acute infection was overcome.
Conclusion: This study confirmed that EP acute infection causes anaemia and
thrombocytopenia which resolve in EP carriers; interestingly, WBC count could be a useful marker to differentiate chronic EP (carrier) horses from healthy horses

	Servicio de Vigilancia Sanitaria Equina (SEVISEQ). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).