Molecular detection of Theileria cervi in equids from México

Equine piroplasmosis is a parasitic illness caused by various protozoa of the Babesia and Theileria genera, which parasitize within red blood cells. The transmission of these pathogens occurs through certain genus of ticks, including Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. In recent times, an increase in the identification of new Theileria species and genotypes has been observed. This is further complicated by the presence of mixed Theileria infections in both mammals and tick vectors, particularly in regions where wildlife and livestock share habitats and vectors. Therefore, the objective of this study is to document the occurrence of Theileria cervi in a non-typical host. A total of 88 horses (Equus caballus) and 10 donkeys (Equus asinus) were sampled in three municipalities in Veracruz, Mexico. Molecular techniques were employed to identify Babesia/Theileria through the amplification of a segment of the 18S-rDNA and hsp70 genes. The phylogenetic reconstruction grouped the obtained sequences into a monophyletic cluster alongside sequences of T. cervi. This work represents the first documented occurrence of T. cervi in equids. These findings have significant implications from an epidemiological point of view. In addition, further studies are needed to determine the distribution and pathogenicity of this species for domestic animals and to develop effective control strategies.