人芽囊原蟲(Blastocystis hominis)是人類腸胃道最常見的原蟲類寄生蟲，在許多開發中國家都有很高的盛行率。本研究是針對來台工作的印尼籍外籍勞工進行人芽囊原蟲的分子流行病學研究。研究中共收集了128位印尼籍勞工糞便檢體，經由顯微鏡檢查共三十位(21.8%)具腸道寄生蟲感染，其中28位為人芽囊原蟲感染。利用人芽囊原蟲的小次單元核醣體基因(small subunit ribosomal RNA gene, SSU rRNA)進行聚合酶(polymerase chain reaction, PCR)反應以進行基因分型時，28個檢體中有25個樣本(89.2%，25/28)有PCR反應，基因型別中以ST3為最常見的感染型(52.0%，13/25)，其次為ST2 (36.0%，9/25)，另外有3位感染ST1 (12.0%，3/25)。演化樹分析中發現的ST2和ST3的基因序列主要和已發表的人類感染來源序列間有很高的親源性，並且於序列間自己形成一個主要的叢集，ST1的序列和源於紅毛猩猩與豬隻的感染序列有很高的親源性，顯示部份人類與動物的感染可能源自於共同的感染來源。人芽囊原蟲為人畜共通疾病，其感染途徑主要是經由糞口傳染，而目前研究顯示源自不同動物而發現的基因型別也越來越多。因此未來需要更多衛生教育與人員管理，將可減少人芽囊原蟲散播與感染。

Blastocystis hominis is one of the most common intestinal protozoans in human. The prevalence of Blastocystis hominis infection is higher in developing countries. The aim of this study was to determine the molecular epidemiology of Blastocystis hominis in Indonesian immigrant workers in Taiwan. Total 128 fresh fecal samples were collected and examined by microscope for parasitology study. Thirty of the total 128 examined immigrants (21.8%) are positive for intestinal parasitic infections, and 28 immigrant workers are Blastocystis hominis infection. After DNA extracted from positive for Blastocystis hominis infection stool samples, Small subunit ribosomal RNA (SSU-rRNA) genotyping was performed by nested polymerase chain reaction and phylogenetic analysis. The 25 of the 28 (89.2%, 25/28) samples are positive in PCR study and the most common genotypic is subtype 3 (52.0%, 13/25), the second is subtype 2 (36.0%, 9/25) and subtype 1 is following (12.0%, 3/25). In phylogenetic analysis, the ST2 and ST3 sequences were clustered and with high simulated to the isolates found in human. The ST1 sequences also appears to specific related the isolates from of Pongo pygmaeus and pig origin infection. The studies indicated that some of Blastocystis hominis in humans were closely related to animals. Considering that Blastocystis hominis is a zoonotic infection, which is transmitted by the fecal-oral route, and many studies have shown that existence of different host specificity among many different genotypes of Blastocystis. More public education and proper management in the future may help to reduce Blastocystis hominis transmission and contamination. (J Intern Med Taiwan 2014; 25: 199-205)