School of Veterinary and Life Sciences, Murdoch University, Murdoch, 6150 Western Australia, Australia.
Int J Parasitol. 2013 Nov;43(12-13):943-56. doi: 10.1016/j.ijpara.2013.06.001. Epub 2013 Jul 13.
Giardia duodenalis (syn. Giardia lamblia and Giardia intestinalis) is a common intestinal parasite of humans and mammals worldwide. Assessing the zoonotic transmission of the infection requires molecular characterization as there is considerable genetic variation within G. duodenalis. To date eight major genetic groups (assemblages) have been identified, two of which (A and B) are found in both humans and animals, whereas the remaining six (C to H) are host-specific and do not infect humans. Sequence-based surveys of single loci have identified a number of genetic variants (genotypes) within assemblages A and B in animal species, some of which may have zoonotic potential. Multi-locus typing data, however, has shown that in most cases, animals do not share identical multi-locus types with humans. Furthermore, interpretation of genotyping data is complicated by the presence of multiple alleles that generate "double peaks" in sequencing files from PCR products, and by the potential exchange of genetic material among isolates, which may account for the non-concordance in the assignment of isolates to specific assemblages. Therefore, a better understanding of the genetics of this parasite is required to allow the design of more sensitive and variable subtyping tools, that in turn may help unravel the complex epidemiology of this infection.
十二指肠贾第鞭毛虫（又名蓝氏贾第鞭毛虫和贾第虫）是一种常见的人类和哺乳动物肠道寄生虫。评估感染的人畜共患传播需要进行分子特征描述，因为在十二指肠贾第鞭毛虫中有相当大的遗传变异。迄今为止，已经确定了 8 个主要的遗传群（组合），其中 2 个（A 和 B）存在于人类和动物中，而其余 6 个（C 到 H）是宿主特异性的，不感染人类。基于序列的单一基因座调查在动物物种中鉴定出了组合 A 和 B 中的许多遗传变异（基因型），其中一些可能具有人畜共患潜力。然而，多基因座分型数据表明，在大多数情况下，动物与人类并不具有相同的多基因座类型。此外，由于存在产生 PCR 产物测序文件中“双峰”的多个等位基因，以及可能在分离株之间交换遗传物质，这可能导致将分离株分配到特定组合的不一致性，因此，对这种寄生虫的遗传进行更好的理解是必需的，以设计更敏感和可变的亚型工具，从而有助于揭示这种感染的复杂流行病学。
