Department of Parasitology, College of Basic Medicine, Nanchang University, Nanchang 330031, People's Republic of China.
Infect Genet Evol. 2012 Aug;12(6):1172-7. doi: 10.1016/j.meegid.2012.04.016. Epub 2012 Apr 25.
The aim of the present study is to detect the frequency and distribution of cross infection and hybridization of human and pig Ascaris in China. Twenty high polymorphic microsatellite loci were selected to screen 258 Ascaris worms from humans and pigs from six provinces in China. The software programs Structure, Baps and Newhybrids were used to determine the case of cross infection and hybridization of human and pig Ascaris. Results showed that cross infection was detected in all sampled locations and of the total 20 cross infection cases, 19 were indentified as human infections by pure-bred pig type Ascaris in contrast to only one case of pig infection by pure-bred human type Ascaris. Similar to the findings in cross infection, hybrid Ascaris was also detected in all locations and both host species and most of hybrids (95%) were detected from human host. The distribution of cross infection and hybrids showed significant difference between the two host species and among three categories of genotype in terms of G1, G2 and G3, and also between the south and north regions (for hybrids only). The results strongly suggest pig Ascaris as an important source of human ascariasis in endemic area where both human and pig Ascaris exist. In consideration of current control measures for human ascariasis targeting only infected people, it is urgently needed to revise current control measures by adding a simultaneous treatment to infected pigs in the sympatric endemics. The knowledge on cross transmission and hybridization between human and pig Ascaris is important not only for public health, but also for the understanding of genetic evolution, taxonomy and molecular epidemiology of Ascaris.
本研究旨在检测中国人群和猪蛔虫交叉感染和杂交的频率和分布。选择 20 个高度多态性微卫星标记，对来自中国六个省份的 258 条人蛔虫和猪蛔虫进行筛选。使用 Structure、Baps 和 Newhybrids 软件程序来确定人蛔虫和猪蛔虫的交叉感染和杂交情况。结果表明，所有采样地点均检测到交叉感染，在总共 20 例交叉感染病例中，19 例被鉴定为人感染纯种猪型蛔虫，而只有 1 例猪感染纯种人型蛔虫。与交叉感染的发现类似，杂种蛔虫也在所有地点均有检测到，且大多数杂种（95%）均来自人类宿主。交叉感染和杂种的分布在两种宿主物种之间以及 G1、G2 和 G3 三种基因型类别之间存在显著差异，在南北地区（仅针对杂种）之间也存在显著差异。这些结果强烈表明，在存在人群和猪蛔虫的流行地区，猪蛔虫是人类蛔虫病的重要传染源。鉴于目前针对感染人群的人类蛔虫病控制措施，迫切需要修改当前的控制措施，即在共生流行地区对感染猪进行同时治疗。了解人群和猪蛔虫之间的交叉传播和杂交对于公共卫生以及理解蛔虫的遗传进化、分类学和分子流行病学都非常重要。
