Background

Opisthorchis viverrini infection is a major public health problem in northern and northeastern Thailand. The chronic infection of O. viverrini is related to cholangiocarcinoma which causes high mortality in endemic areas. Therefore, the diagnosis, treatment, control and prevention of O. viverrini infection are necessary. The morphology of the egg is very similar to that of other species of human liver flukes (Opisthorchis felineus and Clonorchis sinensis) as well as that of small intestinal flukes in the family Heterophyidae. Thus, molecular characterization is crucially required to discriminate species of Opisthorchis-like eggs in fecal examination.

Methodology/Principal findings

We aimed to determine the prevalence of O. viverrini infection among villagers living in Sanamchaikate District, Chachoengsao Province, in central Thailand, where O. viverrini infection has previously been reported. A total of 2,609 fecal samples were examined for Opisthorchis-like eggs using microscopic examination. PCR-RFLP analysis of the ITS2 region was used to discriminate Opisthorchis-like eggs. The genetic structure of O. viverrini infection was demonstrated using nucleotide sequencing of cytochrome c oxidase subunit I (cox1) and NADH dehydrogenase subunit 1 (nad1). Testing of evolutionary neutrality of the cox1 and nad1 sequences of O. viverrini was performed using Tajima's D tests and Fu's Fs tests. Moreover, the haplotype networks and phylogenetic trees were constructed to study the relationships of O. viverrini isolated from different endemic areas. A high prevalence of O. viverrini infection is still observed in a rural community of Chachoengsao Province, central Thailand. The overall prevalence of Opisthorchis-like eggs using microscopic examination was 16.8%. PCR-RFLP profiles showed the predominant infection of O. viverrini (9.6%) including very low infections of other small intestinal flukes, Haplorchis taichui (0.08%) and Euparyphium albuferensis (0.08%). The genetic structure of O. viverrini populations in central Thailand was also described and revealed a non-significant difference in genetic diversity. In addition, the genetic background of the O. viverrini populations was closely related to the isolate from Lao PDR.

Conclusions/Significance

Our study highlighted the prevalence of O. viverrini infection in central Thailand indicating that control programs and health education regarding opisthorchiasis is still required in this endemic area. Additionally, the study demonstrated the genetic structure of O. viverrini, in central Thailand which could provide information on the molecular epidemiology of this parasite.

中文翻译：

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来自泰国中部农村社区居民的类似阿斯巴戟卵的分子鉴定

背景

在泰国北部和东北部，Viistrchis viverrini感染是主要的公共卫生问题。O的慢性感染。viverrini与胆管癌有关，它在流行地区导致高死亡率。因此，对O的诊断，治疗，控制和预防。viverrini感染是必要的。卵的形态与人类肝吸虫的其他物种（Opithhorchis felineus和Clonorchis sinensis）以及异蝇科小肠吸虫的形态非常相似。因此，至关重要的是要进行分子鉴定以鉴别阿波斯霍奇氏菌的种类。在粪便检查中像鸡蛋一样。

方法/主要发现

我们旨在确定O的患病率。吸虫住在Sanamchaikate区，北柳府村民的感染，在泰国中部，那里Ø。以前曾报道过viverrini感染。使用显微镜检查，总共检查了2609个粪便样品中的类似阿斯霍奇氏菌的卵。ITS2区域的PCR-RFLP分析用于区分类阿魏氏梭菌卵。O的遗传结构。使用细胞色素C氧化酶亚基I（cox1）和NADH脱氢酶亚基1（nad1）的核苷酸测序证实了viverrini感染。）。测试O的cox1和nad1序列的进化中性。viverrini使用田岛的D检验和Fu的Fs检验进行。此外，构建了单倍型网络和系统发育树以研究O的关系。维弗里尼（Viverrini）来自不同地方流行地区。O的患病率很高。在泰国中部Chachoengsao省的一个农村社区中仍观察到viverrini感染。虾皮虾的总体患病率镜检样鸡蛋样率为16.8％。PCR-RFLP图谱显示O感染最为严重。viverrini（9.6％），包括其他小肠吸虫，太白杆菌（0.08％）和Euparyphium albuferensis（0.08％）的极低感染率。O的遗传结构。还对泰国中部的viverrini种群进行了描述，发现其遗传多样性没有显着差异。另外，O的遗传背景。viverrini人群与老挝人民民主共和国的分离株密切相关。

结论/意义

我们的研究突出了O的流行。泰国中部的viverrini感染表明该流行区仍需要有关阿斯匹美氏菌病的控制计划和健康教育。此外，研究证明了O的遗传结构。位于泰国中部的viverrini，可以提供有关该寄生虫的分子流行病学信息。