Prevalence of Coxiella burnetii in cattle and buffalo populations in Punjab, India.

Q fever is an important zoonosis of animal and public health significance but there is very limited information about its prevalence in the Punjab state of India. The current study was designed to estimate Q fever prevalence in cattle and buffalo populations of the state. We randomly selected 22 villages, one from each of the 22 districts of Punjab. Households in these villages were randomly selected using village voter lists to ensure representative sample collection. Blood, vaginal swab and milk samples were collected from the animals in these enrolled households. Serum samples were screened using Coxiella burnetii specific IgG ELISA whereas milk and genital swab samples were subjected to a Trans-PCR assay. The agreement (Cohan's Kappa) between shedding of C. burnetii in milk and genital secretions and between ELISA and Trans-PCR was estimated. The selected PCR products were sequenced, and phylogenetic analyses were performed. We collected 610 blood samples, 610 genital swabs and 361 milk samples from 610 bovines (378 cattle and 232 buffaloes) in 179 households. Considering all tests in parallel and after adjusting for clustering, we estimated an overall individual animal prevalence of Q fever of 7.0% (95% CI: 4.7, 9.4). There was a low agreement between shedding of C. burnetii in milk and genital secretion (kappa: 14.3%; 95% CI: 5.6, 22.9) and between ELISA and Trans-PCR (10.3%; 95% CI: 3.2, 17.4%). Phylogenetic analysis confirmed all samples to be of C. burnetii. The results suggest that the disease is present in the state and further epidemiological information should be collected to determine its zoonotic potential and its impact on animal and public health in Punjab, India.