Detection of Toxoplasma gondii in free-range chickens in China based on circulating antigens and antibodies.

Toxoplasma gondii is widely distributed in humans and other animals including domestic poultry throughout the world, but the data on prevalence of T. gondii in free-ranged (FR) chickens in People's Republic of China (PRC) are limited. In the present study, the seroprevalence of T. gondii infection in FR chickens was investigated in 13 provinces/municipalities of China during the period from January to June 2010. A total of 1173 serum samples were collected and assayed for T. gondii circulating antigens (TCA) and antibodies (TCAb) using enzyme linked immunosorbent assay (ELISA) technique. Out of this number, 199 samples were TCA positive (16.97%), 226 samples were TCAb positive (19.27%), 69 samples were positive for both TCA and TCAb (5.88%), and the total seropositive rate was found in 356 of 1173 (30.36%). The results of the present survey indicated that infection with T. gondii in FR chickens is widely spread in China.