Detection of Neospora caninum from farm-bred young blue foxes (Alopex lagopus) in China.

Neospora caninum has been detected in several wild mammalian species, i.e., deer, coyotes, dingoes, and foxes. Farm-bred foxes were rarely reported to be affected by the parasite. In this study, we detected for the first time the infection of N.caninum in farm-bred young blue foxes (Alopex lagopus) in China. Neospora-like tissue cysts were observed in brains and kidneys of the foxes by histopathological and immunohistochemical examinations. One hundred and three sera from the clinically normal vixens were tested for the presence of N.caninum and Toxoplasma gondii antibodies by two commercial ELISA test kits. Twenty-eight of 103 (27.2%) sera were positive for N. caninum and 1 serum (0.97%) was positive for T. gondii. A portion of the Nc5 gene of N. caninum was amplified from the DNA extracted from the fox brains by semi-nested PCR, further confirmed the existence of N. caninum among the farm-bred fox herd in China.