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Investigating Viral Causes of Abortions: A Comprehensive Molecular and Pathological Study on Small Ruminants in East
Monireh Khordadmehr1,2, Hassan Sadri3,2, Jafar Shirazi4,2
1Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran.
Objective:
Abortion emerges as a primary concern for small ruminant breeders, leading to substantial economic losses for livestock farmers. The most important factor contributing to abortion in sheep and goats is the presence of infectious agents. The bluetongue virus (BTV), border disease virus (BDV), peste des petits ruminants virus (PPRV), Akabane virus (AKAV) and pox virus are notable viruses responsible for inducing abortion in small ruminants globally.
Methods:
This study focused on the prevalence of viral agents in aborted foetuses and adult sheep and goats with a recent abortion history in East Azerbaijan province, Northwest Iran. For this purpose, a comprehensive evaluation was performed in the nine cities of East Azerbaijan province, Iran. A total of 62 aborted foetuses and 373 blood samples were collected from 43 sheep and goat flocks. The conventional and nested PCR methods were employed for BTV, BDV, PPRV, pox virus and AKAV detection after extracting viral DNA/RNA and cDNA synthesis from the buffy coat (adults) and foetal spleen tissue samples. The formalin-fixed tissue samples from the aborted foetuses were examined histopathologically.
Results:
Molecular findings revealed that viral infection was present in 7.77% (29 out of 373) of the blood samples and 35.48% (22 out of 62) of the aborted foetuses. Among the blood samples, 1.34%, 2.41% and 4.29% were positive for BTV, BDV and PPR, respectively. No pox virus or AKAV samples tested positive in the adults. In the samples from aborted foetuses, the positivity rates were 12.90%, 25.80%, 9.67%, 1.61% and 0% for BTV, BDV, PPRV, pox virus and AKAV, respectively. Histopathological studies revealed extensive inflammatory reactions associated with severe hyperaemia and haemorrhagic lesions in the tissue sections, particularly in the brain, heart, intestine and spleen, which were more notable in the PCR-positive samples for BTV.
Conclusion:
In conclusion, the detection of viral agents in both aborted foetuses and blood samples indicates that viral infections play notable roles in the abortion of sheep and goats in East Azerbaijan. Therefore, effective management and vaccination strategies are crucial for preventing and controlling the disease in this region.
