Prevalence of Coxiella burnetii in unpasteurized dairy products in west of Iran

Q fever is a zoonotic disease caused by Coxiella burnetii. This study investigated the prevalence of C. burnetii in traditional dairy products, specifically yogurt and cheese, in Lorestan Province. A total of 100 samples of traditional yogurt and unpasteurized cheese were collected from various regions. To analyze the genome of C. burnetii, DNA was purified and molecular detection was performed using nested PCR with primers specific to the IS1111 transposon gene. The results revealed a prevalence of 13.3 % (95 % CI: 6.9 %–24.16 %) in yogurt samples and 12.5 % (95 % CI: 5.46 %–26.11 %) in cheese samples. Additionally, a significant seasonal variation in contamination levels was observed, with a p-value of less than 0.05. However, no significant correlation was found between geographical location and the degree of contamination. These findings suggest that the contamination of dairy products with C. burnetii is likely due to the bacterium's ‘spore-like’ form and the lack of pasteurization in the traditional production of yogurt and cheese. While the direct risk of transmission via unpasteurized dairy products is considered low, these products should still be monitored in Q fever outbreaks.