Study on serological and molecular prevalence of Coxiella burnetii in aborted cows in Shahrekord industrial dairy herd by ELISA and PCR procedures

Q fever is a zoonosis with a worldwide distribution caused by an intracellular rickettsia known as Coxiella burnetii. This study aimed to determine the seroprevalence and molecular epidemiology of C.burnetii in bovine abortion cases in the Zagros dairy industry in Shahrekord, analyzed by ELISA and PCR methods. This study, conducted from September 2016 to July 2017, collected serum samples from 96 cows that had aborted at least two months prior to the study. Additionally, 72 milk samples were obtained, including 20 bulk tank milk samples at two-week intervals, and 52 individual milk samples from the cows whose blood serum was taken. Anti-Coxiella burnetii antibodies in blood serum were detected using an ELISA assay kit, and the genomic detection of C. burnetii in milk samples was confirmed by Nested-PCR method. The results showed that the overall prevalence of C. burnetii infection in the Zagros dairy industry in Chaharmahal and Bakhtiari Province was 41.6% ELISA positive (40 positive samples). The molecular epidemiology of C. burnetii infection tested by PCR was 5% in bulk tank milk (1 positive sample) and 23.07% in individual milk samples. These findings indicate that Q fever in Chaharmahal and Bakhtiari Province has a high prevalence and is likely endemic. Moreover, seemingly healthy cows can play a role in the transmission of C. burnetii..