title: Molecular epidemiology of human Blastocystis in a village in Yunnan province, China.
abstract: The purpose of this study was to improve our understanding of the molecular epidemiology of human Blastocystis, focusing on 239 randomly selected individuals in a single village in Yunnan province, China. Emphasis was placed on the relative frequency of different Blastocystis subtypes and underlying risk factors. We used a cross-sectional study design, by employing a pre-tested questionnaire to obtain demographic data and behavioural risk factors, and collected faecal samples for culture and subsequent identification of Blastocystis. DNA was extracted from Blastocystis isolates and the subtypes were identified using 7 subtype-specific sequenced-tagged site (STS) primers. Overall, 78 faecal samples were Blastocystis culture-positive (32.6%, 95% confidence interval: 26.7-38.6%). The majority (n=73, 93.6%) were single infections with one of the known subtypes, whereas 2 isolates consisted of 2 concurrent subtypes. The remaining 3 isolates could not be identified with the currently known STS primers. Risk factors for a Blastocystis infection were drinking unboiled water, consumption of raw water plants and pig ownership. The consumption of raw water plants was positively associated with subtype 1 infections, and drinking unboiled water with subtype 3 infections. In conclusion, human Blastocystis was common in this village in southwest China, and different subtypes were associated with distinct transmission routes or sources of infection, and hence Blastocystis subtypes might be linked to specific environmental compartments.
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People's Republic of China.
authors.forename: Lan-Hua
authors.initials: LH
authors.lastname: Li
authors.forename: Xiao-Nong
authors.initials: XN
authors.lastname: Zhou
authors.forename: Zun-Wei
authors.initials: ZW
authors.lastname: Du
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Wang
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Wang
authors.forename: Jin-Yong
authors.initials: JY
authors.lastname: Jiang
authors.forename: Hisao
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Peter
authors.initials: P
authors.lastname: Steinmann
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Wu
authors.forename: Jia-Xu
authors.initials: JX
authors.lastname: Chen
authors.forename: Shao-Hong
authors.initials: SH
authors.lastname: Chen
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016844:Blastocystis / Q000145:classification / Q000235:genetics*; D016776:Blastocystis Infections / Q000453:epidemiology* / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D002681:China; D003430:Cross-Sectional Studies; D016054:DNA, Protozoan / Q000032:analysis; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D012307:Risk Factors
chemical_list: D016054:DNA, Protozoan