molecular and histopathological detection of listeria infection in aborted fetuses of small ruminants in east azerbaijan province, iran

Listeria is a group of rod-shaped bacteria in the listeriaceae family, consisting of 21 species. abortion caused by listeriosis in sheep results in a significant economic loss, with increased weaning rates and production costs. this includes increased slaughtering and additional costs for food, labor, and veterinary care. therefore, this study was performed in east azerbaijan province, iran, to investigate listeria infection in the aborted fetuses of sheep and goat flocks through the conventional pcr assay and histopathological evaluation. a total of 62 aborted fetuses of ewes and does were evaluated in east azerbaijan province, from 42 villages (nine cities with different geographical locations) during october to february 2024. at first, the dna extraction was performed from abomasal content of all fetus samples. then, the pcr assay was performed with specific primer pairs to detect the presence of listeria genus. the formalin-fixed tissue samples were used for histopathological examination. the present pcr results showed that 41.93% of the samples were positive for listeria infection, which is a notable infection rate. histopathological studies revealed infiltration of inflammatory cells and marked focal necrosis the liver, kidney, and spleen associated with mild meningoencephalitis and severe hyperemia in the brain samples. this significant detection rate presents that listeria may be a major and notable factor to abortion in small ruminants in this provincethe present findings show a remarkable prevalence of listeria infection in sheep and goat flocks in east azerbaijan province, iran. of note, management and prevention of flocks are very important to avoid this infection. the main preventive measures include sanitation, food control and early detection systems.