Detection of Coxiella burnetii and risk factors for infection in ruminants in a central county of Iran

Q fever is an important zoonosis caused by Coxiella burnetii. This study assessed the prevalence of C. burnetii DNA in blood samples of ruminants and identified the risk factors of infection. In a cross-sectional study, 480 blood samples from 56 herds in Isfahan, Iran were tested for the presence of IS1111 transposon of C. burnetii by nested polymerase chain reaction (PCR). The general information of the herds was collected by a checklist. Univariate tests and a multivariate binary logistic regression model were used and P values less than 0.05 were considered statistically significant. In total, 7.5% of the cattle, 10% of the sheep, and 6.8% of the goats were positive and 25 herds had at least a positive sample. The multivariate logistic regression model showed a lower prevalence rate in herds with fewer than 170 animals (OR: 0.24; 95% CI: 0.11-0.56; P = 0.001). Moreover, ruminants in commercial farms were at lower risk than those in traditional farms (OR: 0.08; 95% CI: 0.01-0.87; P = 0.038). This study confirmed ruminants as important reservoirs of C. burnetii infection in Isfahan County, Iran. Animals in larger herds and traditional farms seem to play a significant role in the transmission of infection. Further studies are recommended on other biological samples such as vaginal mucus or feces.