Investigation of Babesia ovis in sheep using serological and molecular methods in the Di̇yarbakir region

Babesiosis caused by Babesia ovis is a seasonal disease widely prevalent among sheep in various geographical regions of Turkiye, particularly in areas dominated by the tick species Rhipicephalus bursa, leading to high mortality rates along with symptoms such as fever, anemia, jaundice, and hemoglobinuria. Numerous epidemiological studies have been conducted in Turkiye to determine the prevalence of B. ovis using microscopic, serological, and molecular methods. However, in previous studies, the combined detection of B. ovis through both molecular and serological methods has not been utilized in the same study. In this study, the aim was to provide current and comprehensive data on the epidemiology of B. ovis in sheep in the Diyarbakır region by using a combination of nested PCR and indirect ELISA. Blood samples were collected from 414 sheep in 12 randomly selected farms in the Bağlar, Bismil, Çermik, Çınar and Sur districts of Diyarbakır province between April and July 2023. Information regarding the age, location of sampling, and date of collection for each sampled sheep was recorded according to the relevant protocol. For molecular prevalence, the presence of B. ovis DNA in the samples was amplified using nested PCR targeting the 18S ribosomal RNA (rRNA) gene, and positivity was detected in 8 out of 414 sheep (1.9%). To determine seroprevalence, the B. ovis-SA1 (BoSA1) immunoreactive protein, known to be abundant in the cytoplasm of infected erythrocytes, was used. Among the 414 serum samples examined using iELISA, 248 (59.9%) were found to be positive for anti-B. ovis antibodies. All samples that were positive by nested PCR were also positive by iELISA, and the difference in positivity rates between the two tests was statistically significant (p<0.05). In conclusion, this study revealed a high seroprevalence of B. ovis in sheep in Diyarbakır province, while molecular prevalence was found to be low. This difference may be attributed to the prolonged presence of anti-B. ovis antibodies in the serum even in the absence of B. ovis in sheep, and it may also be related to the uncontrolled use of imidocarb dipropionate, commonly used for babesiosis treatment during active tick periods. The importance of using both molecular and serological methods together in evaluating the prevalence of B. ovis in sheep populations has been once again demonstrated by this study.