Itagaki Tadashi, Sakaguchi Keisuke, Terasaki Kunio, Sasaki Osamu, Yoshihara Shinobu, Van Dung Truong
Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan.
Parasitol Int. 2009 Mar;58(1):81-5. doi: 10.1016/j.parint.2008.11.003. Epub 2008 Dec 7.
Fasciola spp. found in Asian countries are diversified in nature, and they should therefore be characterized by spermatogenesis, ploidy and genetic differentiation as well as morphology. The present study showed that spermic diploid and aspermic triploid forms of Fasciola occurred in Vietnam. The spermic diploid specimens were accurately identified as F. gigantica, while the aspermic triploids could not be identified on the basis of their morphology by the ratio of body length and width and DNA sequences of nuclear ribosomal ITS1 and mitochondrial NDI and COI genes. The molecular data also indicated that Vietnamese aspermic triploids might be hybrids and/or their offspring between Fasciola hepatica and F. gigantica, because they showed the ITS1-Fh/Fg haplotype, which had chimeric sequences of the two species. Furthermore, the aspermic triploids seem to have originated in countries other than Vietnam and to have rapidly spread to that country with infected animals.
在亚洲国家发现的片形吸虫种类具有多样性，因此应通过精子发生、倍性、遗传分化以及形态学来对它们进行特征描述。本研究表明，越南存在精子发生的二倍体和无精子的三倍体片形吸虫。精子发生的二倍体标本被准确鉴定为巨片形吸虫，而无精子的三倍体无法根据其体长与体宽的比例以及核糖体ITS1和线粒体NDI和COI基因的DNA序列，通过形态学进行鉴定。分子数据还表明，越南的无精子三倍体可能是肝片形吸虫和巨片形吸虫之间的杂交种和/或它们的后代，因为它们显示出ITS1-Fh/Fg单倍型，该单倍型具有这两个物种的嵌合序列。此外，无精子三倍体似乎起源于越南以外的国家，并随着受感染动物迅速传播到该国。
