Zhou Peng, Sun Xiu-Tao, Yin Chuang-Cheng, Yang Jian-Fa, Yuan Zi-Guo, Yan Hai-Kuo, Zhu Xing-Quan, Zou Feng-Cai
Laboratory of Animal Parasitology, Shanghai Veterinary Research Institute, CAAS, Shanghai 200241, China.
J Parasitol. 2011 Dec;97(6):1193-5. doi: 10.1645/GE-2851.1. Epub 2011 Jul 1.
The genetic diversity of Toxoplasma gondii varies in different geographical regions. Isolates of T. gondii in South America, for example, are genetically and biologically divergent from those in North America and Europe, where the population structure is highly clonal and composed mainly of 3 distinct lineages, i.e., Types I, II, and III. However, little is known of the T. gondii genotypes in the People's Republic of China. Toxoplasma gondii infection in pigs causes significant economic loss and presents a risk for human infection. We conducted a survey to determine the genetic diversity of this parasite in slaughtered pigs from Yunnan Province, southwestern China. In total, 412 DNA samples were extracted from hilar lymph nodes and livers of pigs from slaughterhouses in Yunnan Province in southwest China, 56 of which were found to be positive for the T. gondii SAG3 gene. These positive DNA samples were typed at 10 genetic markers, including 9 nuclear loci, i.e., SAG1, SAG2, SAG3, BTUB, GRA6, L358, PK1, c22-8, c29-2, and an apicoplast locus Apico. Of these, 5 isolates were genotyped with complete data for all loci. Only 1 genotype (ToxoDB 9) was identified, previously reported as a widespread lineage from pigs, cats, and human patients in China. The results indicate that this genotype may be the major T. gondii lineage in China and possibly all of eastern Asia. This is the first report of genetic typing of T. gondii isolates from pigs in China's southwestern Yunnan Province, the results of which have implications for the prevention and control of T. gondii infections in humans and other animals.
刚地弓形虫的遗传多样性在不同地理区域有所不同。例如，南美洲的刚地弓形虫分离株在遗传和生物学特性上与北美和欧洲的分离株不同，在北美和欧洲，其种群结构高度克隆，主要由3个不同的谱系组成，即I型、II型和III型。然而，关于中华人民共和国境内刚地弓形虫的基因型，人们了解甚少。猪感染刚地弓形虫会造成重大经济损失，并对人类感染构成风险。我们开展了一项调查，以确定中国西南部云南省屠宰猪体内这种寄生虫的遗传多样性。总共从中国西南部云南省屠宰场的猪的肺门淋巴结和肝脏中提取了412份DNA样本，其中56份被检测出刚地弓形虫SAG3基因呈阳性。这些阳性DNA样本在10个遗传标记处进行分型，包括9个核基因座，即SAG1、SAG2、SAG3、BTUB、GRA6、L358、PK1、c22 - 8、c29 - 2，以及一个顶质体基因座Apico。其中，5个分离株获得了所有基因座的完整分型数据。仅鉴定出1种基因型（ToxoDB 9），此前在中国猪、猫和人类患者中均有广泛报道。结果表明，该基因型可能是中国乃至整个东亚地区刚地弓形虫的主要谱系。这是中国西南部云南省猪源刚地弓形虫分离株基因分型的首次报告，其结果对人类和其他动物刚地弓形虫感染的预防和控制具有重要意义。
