title: Spatial risk profiling of Schistosoma japonicum in Eryuan county, Yunnan province, China.
abstract: Bayesian spatial risk profiling holds promise to enhance our understanding of the epidemiology of parasitic diseases, and to target interventions in a cost-effective manner. Here, we present findings from a study using Bayesian variogram models to map and predict the seroprevalence of Schistosoma japonicum in Eryuan county, Yunnan province, China, including risk factor analysis. Questionnaire and serological data were obtained through a cross-sectional survey carried out in 35 randomly selected villages with 3,220 people enrolled. Remotely-sensed environmental data were derived from publicly available databases. Bivariate and non-spatial Bayesian multiple logistic regression models were used to identify associations between the local seroprevalence and demographic (i.e. age and sex), environmental (i.e. location of village, altitude, slope, land surface temperature and normalized difference vegetation index) and socio-economic factors. In the spatially-explicit Bayesian model, S. japonicum seroprevalence was significantly associated with sex, age and the location of the village. Males, those aged below 10 years and inhabitants of villages situated on steep slopes (inclination =20 degrees ) or on less precipitous slopes of >5 degrees above 2,150 m were at lower risk of seroconversion than their respective counterparts. Our final prediction model revealed an elevated risk for seroconversion in the plains of the eastern parts of Eryuan county. In conclusion, the prediction map can be utilized for spatial targeting of schistosomiasis control interventions in Eryuan county. Moreover, S. japonicum seroprevalence studies might offer a convenient means to assess the infection pressure experienced by local communities, and to improve risk profiling in areas where the prevalence and infection intensities have come down following repeated rounds of praziquantel administration.
authors.affiliation: Department of Public Health and Epidemiology, Swiss Tropical Institute, PO Box, CH-4002 Basel, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Steinmann
authors.forename: Xiao-Nong
authors.initials: XN
authors.lastname: Zhou
authors.forename: Barbara
authors.initials: B
authors.lastname: Matthys
authors.forename: Yuan-Lin
authors.initials: YL
authors.lastname: Li
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Li
authors.forename: Shao-Rong
authors.initials: SR
authors.lastname: Chen
authors.forename: Zhong
authors.initials: Z
authors.lastname: Yang
authors.forename: Weng
authors.initials: W
authors.lastname: Fan
authors.forename: Tie-Wu
authors.initials: TW
authors.lastname: Jia
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001499:Bayes Theorem; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003710:Demography; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D018570:Risk Assessment / Q000379:methods*; D012549:Schistosoma japonicum; D012554:Schistosomiasis japonica / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D016036:Seroepidemiologic Studies