First Report of Coxiella burnetii Seroprevalence in Tibetan Sheep in China

Query (Q) fever is a vector-borne zoonosis caused by the obligate intracellular pathogen Coxiella burnetii. Animals, including dogs, cats, cattle, and sheep, can be infected by C. burnetii. However, little information is available about C. burnetii infection in Tibetan sheep in China. Antibodies against C. burnetii in Tibetan sheep serums, which were collected from Maqu County, Tianzhu County and Nyingchi Prefecture, China, between 2011 and 2013, were examined by enzyme-linked immunosorbent assay (ELISA). Overall, 14.39% (304/2112, 95% confidence interval [CI] 12.90-15.89) of the examined Tibetan sheep were positive for C. burnetii infection. The C. burnetii seroprevalence in male and female Tibetan sheep was 12.94% (95% CI 10.26-15.61) and 14.98% (95% CI 13.18-16.78), respectively. The seroprevalence varied from 13.19% (95% CI 10.08-16.30) to 14.96% (95% CI 12.31-17.62) in Tibetan sheep in different areas. In addition, the seroprevalence ranged from 13.16% (95% CI 9.83-16.50) to 15.10% (95% CI 13.15-17.04) in different age groups. The results of the present survey indicate that C. burnetii infection is highly prevalent in Tibetan sheep in China. This is the first report of C. burnetii infection in Tibetan sheep in China, extending the host range for C. burnetii. Further studies are warranted to understand better the epidemiological situation of C. burnetii transmission in these areas and elsewhere.