Investigation of Listeria Infection in the Aborted Fetuses of Small Ruminants in East Azerbaijan Province, Northwest Iran.

INTRODUCTION: Listeriosis, an important food-borne zoonotic disease, is caused by the member of Listeriaceae family. The aim of the present study was to detect the presence of Listeria infection in aborted fetuses and serum samples from adults with a recent history of abortion using serological, molecular, and pathological methods in East Azerbaijan Province. MATERIALS & METHODS: A total of 62 aborted fetuses and 288 vaginal swabs were collected from sheep and goat flocks across nine cities. For molecular analyses, conventional polymerase chain reaction (PCR) was employed to detect the Listeria genome after extracting DNA from the abomasal contents of examined aborted fetuses. Histopathological examinations were also conducted on formalin-fixed tissue samples from the aborted fetuses. RESULTS: In microbiological study, the organism was isolated in 1.24% of abomasal contents, 2.43% of vaginal swaps, and 3.72% of the fetus's brain. Molecular analyses showed that Listeria infection was present in 41.93% (95% CI, 0.41%, 0.12%) of the aborted fetuses. Pathological examinations revealed white foci in the liver, lung, and myocardium, accompanied by severe hyperemia in the brain. In addition, microscopic studies indicated remarkable necrotic and inflammatory responses in the tissue sections, particularly in the brain (encephalitis), lung (pneumonia), liver (hepatitis), and heart (myocarditis). CONCLUSION: In conclusion, the detection of Listeria infection in aborted fetuses at a much higher infection rate indicates that this infection plays a notable role in abortion among sheep and goats in East Azerbaijan. More importantly, it remains a major zoonotic diseases worldwide. Therefore, effective public health management strategies are crucial for its prevention and control.