Investigation of selected bacterial agents causing sheep abortion in the Van Province by RT-PCR and histopathological methods

Abortion causes significant economic losses in the sheep industry. Determination of the aetiology is important in dealing with abortions. The present study was aimed to identify selected important bacterial pathogens in the abortion cases of sheep. A total of 113 samples (105 aborted sheep foetuses, 4 placentas, and 4 vaginal swab samples) from 85 different sheep flocks were examined by real-time PCR (RT-PCR) regarding Chlamydia (C.) spp., C. abortus, Brucella (B.) spp., B. melitensis, Salmonella (S.) spp., S. Abortusovis, Coxiella (C.) burnetii, Listeria (L.) spp., L. monocytogenes, and Campylobacter spp. All cases that were found to be positive for bacterial agents by RT-PCR, were examined pathologically. Tissue samples of foetuses that were found to be positive for B. melitensis and L. monocytogenes by RT-PCR were also investigated immunohistochemically. A total of 35 (30.9%) samples were found to be positive by RT-PCR, with 15 (42.8%), 9 (25.7%), 5 (14.2%), 4 (11.4%), 1 (2.8%), and 1 (2.8%) of them being identified as C. abortus, B. melitensis, S. Abortusovis, C. burnetii, L. monocytogenes and Campylobacter spp., respectively. The presence of the antigen was confirmed also immunohistochemically in the cases with B. melitensis and L. monocytogenes. As a consequence, C. abortus was found to cause the highest rate of sheep abortion cases, which should be taken into account when implementing control measures in epidemiological investigations.