Background：The distribution of Toxoplasma gondii genotypes varies across the continents．Recent population structure studies revealed that a few major clonal lineages of T. gondii predominated in different geographical regions．T.gondii in South America is genetically and biologically divergent，whereas this parasite is a remarkable clone in North America and Europe with a few major lineages including Types Ⅰ，Ⅱ and Ⅲ．Information on genotypes and mouse virulence of T. gondii isolates from China is SCarce and insufficient to investigate its population structure，evolution，and transmission．Methodology／Principal Findings：We analyzed 23 T.gondii isolates from different hosts in this study(four from human and nineteen from cats)．Genotyping of these isolates using 10PCR-restriction fragment length polymorphism(PCR-RFLP)markers(SAG1，SAG2，SAG3，BTUB，GRA6，c22．8，c29-2，L358，PK1 and Apico)from DNA obtained from tachyzoites and／or cysts revealed five genotypes；among them three genotypes were atypical and two were archetypal.These atypical genotypes were designated as Chinese 1(ToxoDB＃9)，ToxoDB＃204，and ToxoDB＃205，respectively．Fifteen strains belong to the Chinese 1 lineage，which Was previously reported as a widespread lineage from swine，cats，and human in China．Two human isolates fall into the type Ⅰ and Ⅱ lineages and no type Ⅲ isolates were observed．The remaining isolates belong to two new atypical genotypes which were analyzed for the first time in China．Our results show that these genotypes of T.gondii isolates are intermediately to highly virulent in mice except for the stmin TgCtwh6，which caused parasitemia for 35 days post infection in mice although it Dossesses the uniform Chinese 1 genotype．Additionally，phylogenetic network analYses of all isolates of genotype Chinese 1 are identical，and there is no variation based on the 5equence data generated at four introns(EF1，HP2，UPRT1 and UPRT7)and two dense granule proteins GRA6 and GRA7．Conclusion／Significance：A limited genetic diversity was found，and genotype Chinese 1(ToxoDB＃9)is dominant circulating in mainland China.
Lin Wang Yong Wang Fangli Lu Zhao-Rong Lun Qingli Luo Xuelong Wang Jilong Shen He Chen Daohua Liu Xingxing Huo Jiangmei Gao Xiaorong Song Xiucai Xu Kaiquan Huang Wenqi Liu
Department of Parasitology，Provincial Laboratory of Microbiology & Parasitology and Key Laboratory o Department of Pathogen Biology，Nanjiing Medical University，Nanjing，Jiangsu，China Department of Parasitology，and Key Laboratory of Tropical Disease Control，Ministry of Education，Zhon Department of Parasitology，Provincial Laboratory of Microbiology & Parasitology and Key Laboratory o Department of Parasitology，Provincial Laboratory of Microbiology & Parasitology and Key Laboratory o Clinical Laboratory，the First Affiliated Hospital of Anhui Medical University，Hefei，Anhui，China Provincial Institute of Parasitic Diseases Control Anhui，Hefei，Anhui，China State Key Laboratory of Biocontrol，School of Life Sciences，Key laboratory of Tropical Diseases Contr Clinical Laboratory，the First Affiliated Hospital of Anhui University of Traditional Chinese Medicin Department of Parasitology，Tongji Medical College，Huazhong University of Science and Technology，Wuha