Molecular Detection and Prevalence of Equine Piroplasmosis and Other Blood Parasites in Equids of Western Aegean Türkiye

Equine piroplasmosis (EP), caused by <i>Theileria equi</i> and <i>Babesia caballi</i>, is a tick-borne disease posing significant threats to equine health and the horse industry worldwide. Other vector-borne blood parasites, including <i>Anaplasma phagocytophilum</i>, <i>Trypanosoma</i> spp., and <i>Leishmania</i> spp., can also infect horses; however, their prevalence remains poorly characterized in Türkiye. This study aimed to determine the molecular prevalence of <i>T. equi</i>, <i>B. caballi</i>, <i>A. phagocytophilum</i>, <i>Trypanosoma</i> spp., and <i>Leishmania</i> spp. in equids from the Western Aegean Region of Türkiye. Blood samples were collected from 388 clinically healthy equines across İzmir, Aydın, Denizli, and Muğla provinces. Species-specific PCR assays were performed, and <i>T. equi</i> and <i>B. caballi</i> were detected in 24.74% (96/388) and 12.89% (50/388) of samples, respectively, with co-infections in 3.09%. <i>T. equi</i> and <i>B. caballi</i> infections were detected in horses from all four sampled provinces-Aydın, İzmir, Denizli, and Muğla-except for <i>B. caballi</i>, which was not found in any samples from Muğla. No samples tested positive for <i>A. phagocytophilum</i>, <i>Trypanosoma</i> spp., or <i>Leishmania</i> spp. Prevalence significantly varied by province, breed, age, and sex (<i>p</i> < 0.05). This study demonstrates the considerable prevalence of <i>T. equi</i> and <i>B. caballi</i> in Western Türkiye, underlining the need for routine screening and vector control programs. The absence of other parasites suggests limited circulation; however, continued surveillance remains crucial to safeguard equine health and prevent disease spread.