Seroprevalence and Risk Factors of Infection in Growth Stages of Pigs in Hunan Province, Subtropical China.

infection is prevalent in humans and animals worldwide. In the present study, a total of 612 serum samples were examined using indirect hemagglutination test (IHAT) for infection. Antibodies to were detected in 49 (8.0%, confidence interval [95% CI]: 5.9-10.2) serum samples (IHA titer ≥1:16). The seroprevalence ranged from 4.4% (95% CI: 0-10.5) to 14.3% (95% CI: 0-40.2) among different regions in Hunan province of subtropical China. The highest seroprevalence was found in breeding sows (18.8%). The seroprevalence was higher in winter (18.3%, 95% CI: 8.5-28.1) and spring (10.9%, 95% CI: 5.7-16.1) than in summer (6.4%, 95% CI: 2.8-10.1) and autumn (4.9%, 95% CI: 2.2-7.7), and the differences were statistically significant excepting summer. In addition, developmental stage and season were identified as risk factors for infection. Our findings revealed the seroprevalence of in growth stages of pigs in the Hunan province of subtropical China, indicating that it may cause public health and economic problems. To our knowledge, this is the first report of the comprehensive survey of seroprevalence in pigs in the Hunan province of subtropical China.