人芽囊原虫(Blastocystis hom inis,Bh)是最常见的人类肠道寄生原虫之一,高发于热带和亚热带地区,发展中国家感染率(30%~50%)明显高于发达国家(1.5%~10%)[1]。近些年来的一些临床研究表明,Bh是引起人类腹泻的一个致病因素[2],但其致病性仍颇具争议,因为多数感染者为无症状带虫 Blastocystis hominis (Bh) is one of the most common human intestinal parasites and occurs in tropical and subtropical regions. The infection rate (30% -50%) in developing countries is significantly higher than that in developed countries (1.5% ~ 10%) [1]. In recent years, some clinical studies have shown that Bh is a causative agent of human diarrhea [2], but its pathogenicity is still controversial as most of the infected patients are asymptomatic