Molecular Detection and Genetic Characterization of Toxoplasma gondii from Horses in Three Provinces of China

Horse meat and milk are an important source of nutrition for many Chinese. Previous studies have shown a fairly high prevalence of Toxoplasma gondii infection in horses. However, there is no data concerning the molecular characterization of T. gondii in horses in China. The present study tested 231 cervical lymph node samples of horses from northern China (97 from Jilin, 54 from Liaoning, and 80 from Xinjiang) for the presence of the T. gondii B1 gene by seminested PCR. The B1-positive samples were genotyped at nine nuclear loci, that is, SAG1, alternative SAG2, SAG3, BTUB, c22-8, GRA6, c29-2, PK1, and an apicoplast locus, using PCR-restriction fragment length polymorphism technique. A total of 14 (6.06%) out of 231 samples were T. gondii positive. The overall prevalence of T. gondii in the horses was 5.15% (5/97) for Jilin Province, 5.55% (3/54) for Liaoning Province, and 7.50% (6/80) for Xinjiang Uygur Autonomous Region. Of the 14 positive samples, only 2 were successfully genotyped at all loci, 5 were successfully genotyped at 5-8 loci, and all typed samples belong to ToxoDB genotype no. 9. To our knowledge, this is the first molecular characterization of the T. gondii isolates from horses in China.