Molecular and Serological Detection of Piroplasms in Horses from Nigeria

Abstract

Equine piroplasmosis, an economically important disease of equids caused by the hemoprotozoan parasites <i>Theileria equi</i>, <i>T. haneyi</i>, and <i>Babesia caballi</i>, has a worldwide distribution. These parasites are transmitted by ixodid ticks. To improve the detection of horses in Nigeria exposed to piroplasm parasites, 72 horses with variable clinical signs of piroplasmosis were sampled from Northwest and Northcentral Nigeria and tested by nPCR and cELISA. Blood and serum samples were collected from each horse via jugular venesection. Individually, nPCR or cELISA failed to identify all horses exposed to piroplasms. A combination of species-specific nPCR and the OIE-approved <i>T. equi</i> and <i>B. caballi</i> cELISAs enhanced the detection of horses exposed to parasites. The results also demonstrated horses showing abnormal hematology were positive for only <i>T. equi,</i> except for one sample that was coinfected with <i>T. equi</i> and <i>T. haneyi</i>. We also identified ticks collected from some of the horses, with <i>Rhipicephalus evertsi evertsi</i> being the most prevalent. This study shows that a larger proportion of horses in the sample set were exposed to <i>T. equi</i> than <i>B. caballi</i> or <i>T. haneyi</i>. Additionally, ticks that have been previously reported as potential vectors for these parasites were found to have infested sampled horses. Further studies are needed to investigate which tick species are competent vectors for <i>Theileria</i> spp. and <i>Babesia caballi</i> in Nigeria.