title: Individual and village-level study of water contact patterns and Schistosoma japonicum infection in mountainous rural China.
abstract: OBJECTIVE
  To describe the exposure patterns related to schistosomiasis transmission in 10 villages in rural Xichang County, Sichuan, China.
  
  
  METHODS
  Individual and village-level study of water contact exposure and Schistosoma japonicum reinfection; after initial infection survey and treatment, reinfection was determined 2 years later for 1604 individuals, of whom 578 also participated in a cross-sectional survey to assess their water contact behaviours.
  
  
  RESULTS
  The highest intensity of reinfection was observed in farmers aged 20-29 years, with no difference between sexes. While water contact measured as m(2)-minutes of contact was not associated with reinfection, an exposure metric computed by spatially weighting water contact by cercarial risk was correlated with both infection status and intensity. Village-level indicators based on snail density, number of infected snails, mouse bioassay data, and averaged individual-level exposures were associated with village reinfection rates.
  
  
  CONCLUSIONS
  Age-acquired immunity may be present in this population, but the study lacked sufficient power to discern differences in the exposure infection relationship with age.
authors.affiliation: School of Public Health, University of California, Berkeley, CA 94720, USA. seto@berkeley.edu
authors.forename: Edmund Y W
authors.initials: EY
authors.lastname: Seto
authors.forename: Yu J
authors.initials: YJ
authors.lastname: Lee
authors.forename: Song
authors.initials: S
authors.lastname: Liang
authors.forename: Bo
authors.initials: B
authors.lastname: Zhong
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice / Q000469:parasitology; D008875:Middle Aged; D015995:Prevalence; D012423:Rural Health; D012549:Schistosoma japonicum / Q000302:isolation & purification; D012554:Schistosomiasis japonica / Q000453:epidemiology / Q000635:transmission*; D012908:Snails / Q000469:parasitology; D011795:Surveys and Questionnaires; D014867:Water / Q000469:parasitology*
chemical_list: D014867:Water