Molecular detection of Coxiella burnetii in vaginal and rectal swab samples of small ruminants from Kermanshah Province, western Iran.

Abstract

BACKGROUND AND PURPOSE: Coxiella burnetii is a zoonotic bacterial pathogen that causes Q fever in humans and coxiellosis in livestock. It represents a significant public health concern and leads to considerable economic losses in the livestock industry. This study aims to determine the rate of environmental shedding of Coxiella burnetii in small ruminant herds in Kermanshah Province, western Iran. MATERIALS AND METHODS: A total of 302 sheep and goats from six districts in Kermanshah Province were included in this study. Vaginal and rectal swab samples were collected and tested for Coxiella burnetii by targeting IS1111 gene using TaqMan real-time PCR. RESULTS: Out of 302 small ruminants sampled from 55 herds, the overall molecular prevalence of Coxiella burnetii shedding was 1.65% (5/302; 95% CI: 0.54%-3.86%). The herd-level shedding prevalence was 5.45% (3/55; 95% CI: 1.88%-14.66%). Among the 209 sheep sampled, five tested positive, corresponding to a prevalence of 2.39% (95% CI: 0.78%-5.56%). None of the 93 goats tested positive. A significantly higher infection rate was observed in animals without a history of abortion compared to those with a history of abortion (13.6% vs. 0.8%, p = 0.0041). No significant associations were found between infection status and livestock type (sheep or goat), gender, or age. CONCLUSION: The low shedding rate of C. burnetii in animals with a history of abortion suggests other pathogens may contribute to reproductive losses. Multi-pathogen surveillance, including Brucella melitensis, Chlamydia abortus, and longitudinal sampling are recommended to enhance detection accuracy and elucidate the causes of abortion in livestock.