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. CONCLUSION: 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.
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. CONCLUSION: 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: Angela Pinot de Moira; Anthony J C Fulford; Narcis B Kabatereine; John H Ouma; Mark Booth; David W Dunne Journal: PLoS Negl Trop Dis Date: 2010-09-14
Authors: Xiao-Nong Zhou; Shan Lv; Guo-Jing Yang; Thomas K Kristensen; N Robert Bergquist; Jürg Utzinger; John B Malone Journal: Parasit Vectors Date: 2009-02-04 Impact factor: 3.876