دانشگاه رازی

   Abstract Background and Objective: Anaplasmosis is one of the important tick-borne diseases of small ruminants and can cause clinical and economic losses in livestock herds. Considering the importance of this disease and the role of ticks in the transmission of Anaplasma agents, the present study was conducted to investigate infection with the genus Anaplasma and to identify Anaplasma ovis and Anaplasma marginale in sheep and goats in Kermanshah Province, Iran, and to evaluate the association of infection with selected demographic, clinical, and geographic factors. Materials and Methods: In this cross-sectional study, 400 small ruminants, including 304 sheep and 96 goats, from different areas of Kermanshah Province were examined in 2025. Blood samples were collected from each animal, and DNA was extracted. Detection of the genus Anaplasma was performed using PCR targeting the msp4 gene, and positive samples were further examined using species-specific PCR for A. ovis and A. marginale. In addition, 800 ticks collected from the animals were morphologically identified at the genus and species levels. Associations between infection status and the investigated variables were evaluated using appropriate statistical tests, with a significance level of 0.05. Results: Of the 400 animals examined, 298 (74.5%) were positive for Anaplasma. Species-specific analysis showed that 286 animals (71.5%) were positive for A. ovis and 20 (5.0%) for A. marginale, with concurrent infection by both species detected in 8 animals. The prevalence of infection was 76.0% in goats and 74.0% in sheep, and no statistically significant association was observed with animal species, sex, age, or abortion history. A statistically significant difference in infection prevalence was observed among the different counties (P=0.014). Among the 800 ticks identified, the genera Rhipicephalus (67.4%), Hyalomma (26.9%), Haemaphysalis (4.1%), and Dermacentor (1.6%) were identified. Conclusion: The high molecular prevalence of Anaplasma infection among small ruminants in Kermanshah Province and the detection of both A. ovis and A. marginale indicate a considerable presence of these agents in the studied population. The significant geographic variation in infection prevalence highlights the importance of regional and environmental factors in the distribution pattern of Anaplasma infection and may be considered in surveillance and control programs for anaplasmosis in small ruminants. Keywords: Anaplasma, Anaplasma ovis, Anaplasma marginale, sheep, goats, PCR, ticks, Kermanshah