title: Seroprevalence of Entamoeba histolytica infection among Chinese men who have sex with men.
abstract: BACKGROUND
  Men who have sex with men (MSM) were found to be one of the high-risk populations for Entamoeba histolytica (E. histolytica) infection. Accompanied by the prevalence of human immunodeficiency virus (HIV) among MSM, invasive amebiasis caused by E. histolytica has been paid attention to as an opportunistic parasitic infection. However, the status of E. histolytica infection among MSM has been barely studied in mainland China.
  
  
  METHODS
  Seroprevalance of E. histolytica was determined using an enzyme-linked immunosorbent assay based on a cross-sectional study conducted in Beijing and Tianjin, China. Factors potentially associated with E. histolytica infection were identified by logistic regression analysis.
  
  
  RESULTS
  A total of 602 MSM were included in the study and the laboratory data on serostatus of E. histolytica were available for 599 of them (99.5%). 246 (41.1%) and 51 (8.5%) of the study participants were E. histolytica seropositive and HIV seropositive, respectively. Univariate analyses suggested preferred anal sex behaviors were associated with E. histolytica seropositivity. In multivariate logistic regression analysis, "only has receptive anal sex" (OR: 2.03; 95% CI: 1.22 3.37), "majority receptive anal sex" (OR: 1.83; 95% CI: 1.13, 2.95), and "sadomasochistic behavior (SM)" (OR: 2.30; 95% CI: 1.04, 5.13) were found to be significantly associated with E. histolytica infection.
  
  
  CONCLUSIONS
  High seroprevalence of E. histolytica infection was observed among MSM from Beijing and Tianjin, China. Receptive anal sex behavior and SM were identified as potential predictors. Therefore, E. histolytica and HIV co-infection needs to be concerned among MSM due to their sharing the common risk behaviors.
authors.affiliation: MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Mufei
authors.initials: M
authors.lastname: Li
authors.forename: Xiangwei
authors.initials: X
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.forename: Cong
authors.initials: C
authors.lastname: Gao
authors.forename: Qi
authors.initials: Q
authors.lastname: Jin
authors.forename: Lei
authors.initials: L
authors.lastname: Gao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002681:China; D003430:Cross-Sectional Studies; D004748:Entamoeba histolytica / Q000276:immunology*; D004749:Entamoebiasis / Q000453:epidemiology*; D004797:Enzyme-Linked Immunosorbent Assay; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D055815:Young Adult