Prevalence of Equine Piroplasmosis Among Horses in Lithuania

Abstract

Background: Equine piroplasmosis (EP), a tick-borne disease caused by Theileria equi and Babesia caballi, poses a significant health concern for equines worldwide (1, 2). In Lithuania, no previous data have been published regarding the prevalence or diagnostic testing for these pathogens. Given the growing concern over tick populations and climate change, it is critical to assess the current epidemiological status of EP within the country (1). Aim(s): This study aimed to determine the prevalence of T. equi and B. caballi in Lithuanian horses using both serological and molecular diagnostic methods, and to identify potential risk factors associated with the infection. Methods: A total of 152 serum samples and 83 whole blood samples were collected from clinically healthy horses across twelve municipalities in Lithuania. The sampled horses varied in age, sex, and breed. Competitive enzyme-linked immunosorbent assay (cELISA) was used to detect specific antibodies, while polymerase chain reaction (PCR) targeting the 18S rRNA gene was employed to detect parasite DNA. Results: Piroplasm-specific IgG antibodies were detected in 7.89 ± 4.4% of serum samples. PCR revealed T. equi or B. caballi DNA in 27.7 ± 9.5% of blood samples. Antibodies were found in horses from four municipalities, while PCR confirmed infections in horses from six out of seven tested municipalities. The highest seroprevalence was found in Palanga district (46.2%), and the highest PCR prevalence in Trakai district (60.0%). A statistically significant association was observed between infection rates and horse breed, as well as the municipality of residence (p<0.05). Conclusion This research represents the first documentation of the prevalence of Theileria equi and Babesia caballi within the equine population of Lithuania, employing both serological and molecular methodologies. The results highlight the importance of ongoing surveillance using both serological and molecular methods. Given the influence of environmental factors on vector populations, broader nationwide monitoring is recommended to protect equine health.