Investigative studies on Babesia caballi and Theileria equi piroplasms within the horse population in Lithuania

Equine piroplasmosis is a globally distributed, tick-borne disease affecting horses, donkeys, and other equids, caused by the protozoan parasites Theileria equi and Babesia caballi. While infected animals often show few signs—like fever, jaundice, pale mucous membranes, or decreased performance – some can be asymptomatic, complicating detection and control. The epidemiology and prevalence of this disease in Lithuania remain largely unreported. To bridge this gap, a study collected 152 serum samples and 83 whole blood samples from clinically healthy horses, varying in age, sex, and breed, across 13 municipalities in Lithuania. The study employed two diagnostic methods: Enzyme-Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR). ELISA, which may not effectively identify early-stage infections or differentiate between active and prior infections, indicated that 7,24% ± 4,2% of serum samples tested positive for Theileria equi, while one sample tested positive for Babesia caballi. PCR, known for its heightened sensitivity and specificity, especially in detecting low parasite levels and identifying pathogens even in chronic stages, determined that 27,7% ± 9,5% of the blood samples tested positive for piroplasms. Statistical analysis indicated a significant relationship between Theileria equi infection and the municipality where horses were kept, though factors like age, sex, and breed showed no significant correlation when tested with ELISA. Further PCR analysis, which included DNA primers specific to piroplasms, found a statistically significant association between breed and infection rate. Additionally, PCR results highlighted a significant correlation between piroplasm infection and the municipality of residence, while no notable correlation was observed with age or sex. Although sample size was limited by available resources, this research confirms the presence of Theileria equi and Babesia caballi in Lithuania’s equine population. As climate change progresses, it is anticipated that the prevalence of these pathogens may rise, underscoring the need for ongoing surveillance and management in affected regions. It is essential to consider appropriate prevention measures and the implementation of an EP surveillance program to reduce and control infection.