Ai L, Dong S J, Zhang W Y, Elsheikha H M, Mahmmod Y S, Lin R Q, Yuan Z G, Shi Y L, Huang W Y, Zhu X Q
College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
Ann Trop Med Parasitol. 2010 Jan;104(1):65-72. doi: 10.1179/136485910X12607012373713.
Among the helminths infecting ruminants in China are three taxa belonging to the genus Fasciola: F. hepatica, F. gigantica and the so-called 'intermediate form' that appears to lie between these two species. Based on the sequences of the second internal-transcribed spacers (ITS-2) within the parasites' nuclear ribosomal DNA (rDNA), a pair of primers (DSJf/DSJ3) specific for F. hepatica and a pair (DSJf/DSJ4) specific for F. gigantica were designed and used to develop PCR-based assays. These assays allowed the identification and differentiation of F. hepatica, F. gigantica and the 'intermediate' Fasciola, with no amplicons produced from heterologous DNA samples. The results of sequencing confirmed the species-specific identity of the amplified products. The assays showed good sensitivity, giving positive results with as little as 0.11 ng of F. hepatica DNA and 0.35 ng of F. gigantica DNA. This meant that the DNA from a single Fasciola egg or a single infected snail was sufficient for identification of the Fasciola taxon. The developed PCR assays could provide useful tools for the detection, identification and epidemiological investigation of Fasciola infection in humans, other mammals and snails.
在中国，感染反刍动物的蠕虫中，有三个分类单元属于片形吸虫属：肝片形吸虫、巨片形吸虫以及介于这两个物种之间的所谓“中间形态”。基于寄生虫核糖体DNA（rDNA）内第二内部转录间隔区（ITS-2）的序列，设计了一对针对肝片形吸虫的特异性引物（DSJf/DSJ3）和一对针对巨片形吸虫的特异性引物（DSJf/DSJ4），并用于开发基于PCR的检测方法。这些检测方法能够鉴定和区分肝片形吸虫、巨片形吸虫以及“中间型”片形吸虫，异源DNA样本不会产生扩增子。测序结果证实了扩增产物的物种特异性身份。这些检测方法显示出良好的灵敏度，对低至0.11 ng的肝片形吸虫DNA和0.35 ng的巨片形吸虫DNA均可给出阳性结果。这意味着来自单个片形吸虫卵或单个受感染蜗牛的DNA足以鉴定片形吸虫分类单元。所开发的PCR检测方法可为检测、鉴定和流行病学调查人类、其他哺乳动物及蜗牛中的片形吸虫感染提供有用的工具。
