Toxoplasma gondii infection in domestic ducks, free-range and caged chickens in southern China.

Toxoplasma gondii is widely distributed in humans and other animals including domestic poultry throughout the world, but little is known of the prevalence of T. gondii in chickens and ducks in People's Republic of China. In the present study, antibodies to T. gondii were investigated in 349 domestic ducks (Anas spp.), 361 free-range, and 244 caged chickens (Gallus domesticus) raised in commercial flocks in Southern China's Guangdong Province using the modified agglutination test (MAT). Antibodies to T. gondii (MAT titer of 1:5 or higher) were found in 56 (16%) of 349 ducks, 41 (11.4%) of 361 free-range, and 10 (4.1%) of 244 caged chickens. The results indicate soil contamination due to T. gondii oocysts because free-range chickens feed from the ground, and suggest that the meat from the domestic poultry may be an important source for human infection by T. gondii in People's Republic of China.