Prevalence and Identification of Infectious Abortion Pathogens in Sheep Flocks of North Khorasan, Iran

Abortion has been identified as a primary factor contributing to reproductive losses in small ruminant flocks worldwide. Infection with the agents including Toxoplasma gondii, Campylobacter spp., Chlamydia abortus, and Coxiella burnetii frequently occurs worldwide. In Iran and its neighboring countries, Brucella melitensis has been identified as the predominant cause of abortion. It has been demonstrated that other abortifacient agents, such as C. abortus and C. burnetii, are prevalent among sheep flocks as well. The present study sought to investigate the presence of the most common abortifacient pathogens in sheep in North Khorasan, Iran. The samples were obtained from 133 aborted sheep fetuses. Subsequently, the presence of pathogens was assessed through the implementation of ELISA, conventional PCR, and bacteriological examination. The identified pathogens encompassed Escherichia coli, B. melitensis, Salmonella spp., C. burnetii, Campylobacter spp., Leptospira spp., Listeria monocytogenes, Toxoplasma gondii, Border disease virus, and Blue Tongue virus. The utilization of bacteriological culture techniques resulted in the isolation of E. coli (9%) and B. melitensis (12%). The following pathogens were identified in fetal serology: C. burnetii (2.5%), T. gondii (12%), B. duncani (3%), and B. abortus (9%). B. melitensis (12%), Salmonella (8.5%), Campylobacter spp. (1.7%), Leptospira spp. (2.5%), Chlamydia abortus (25.6%), C. burnetii (14.5%), and T. gondii (6.8%) were detected by PCR. C. abortus was the most prevalent pathogen detected by PCR (25.6%). The present results demonstrated that the studied sheep flocks are infected with the most significant abortifacient pathogens, thereby underscoring the necessity for further investigations to identify abortion causes based on different geographical regions using simple and sensitive methods. The prevalence of ovine abortion is influenced by epidemiological and risk factors, which necessitate further investigation.