The objective of this proposal is the development of a dynamic model of the influence of anthropogenic changes due to rice farming on the transmission of Schistosoma japonicum in the endemic areas of The Philippines. The model will include several species, their population biology and behavior, including humans, snails and animal reservoir hosts of S. japonicum. We define rice farming, its spatial and temporal variation and its multiple impacts on physical, hydrologic and animal determinants of human S. japonicum infection as anthropogenic environmental change. The model will allow the prediction of the potential effects of anthropogenic environmental changes stemming from variation in rice farming over time and space on the transmission of S. japonicum to humans. Rice farming factors include: variation in rice farming practices, agricultural expansion and intensification; domesticated animal numbers, transmission behaviors and management practices; water use and management practices. Developing generalizable predictive ecological models of schistosomiasis transmission to humans is a fundamental component of the ongoing effort to develop cost-effective and acceptable disease control strategies. There are at present no published models for S.japonicum, which remains endemic in The Philippines and China despite 20 years of treatment of infected humans. After an initial 12-18 month period of determining the equilibrium conditions of transmission in several sites, and use of extant data from the last 40 years on human, snail and animal infection we will develop a dynamic transmission model of S. japonicum. We will then cure all humans in each site and observe the incidence rate and intensity of S. japonicum infection in humans over 18 months. This will permit statistical analyses to determine the relationships of specific transmission factors to the outcome of human infection. It will also allow more accurate construction of an age- structured, population dynamic model of S. japonicum transmission with improved predictabilty and generalizability.

National Institute of Health (NIH)
Fogarty International Center (FIC)
Research Project (R01)
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Special Emphasis Panel (ZAI1-GSM-F (S1))
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Jessup, Christine
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Brown University
Public Health & Prev Medicine
Schools of Medicine
United States
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Carabin, H; McGARVEY, S T; Sahlu, I et al. (2015) Schistosoma japonicum in Samar, the Philippines: infection in dogs and rats as a possible risk factor for human infection. Epidemiol Infect 143:1767-76
Soares Magalhães, Ricardo J; Salamat, Maria S; Leonardo, Lydia et al. (2015) Mapping the Risk of Soil-Transmitted Helminthic Infections in the Philippines. PLoS Negl Trop Dis 9:e0003915
Tarafder, Mushfiqur R; Carabin, Helene; McGarvey, Stephen T et al. (2011) Assessing the impact of misclassification error on an epidemiological association between two helminthic infections. PLoS Negl Trop Dis 5:e995
Tarafder, M R; Carabin, H; Joseph, L et al. (2010) Estimating the sensitivity and specificity of Kato-Katz stool examination technique for detection of hookworms, Ascaris lumbricoides and Trichuris trichiura infections in humans in the absence of a 'gold standard'. Int J Parasitol 40:399-404
Finkelstein, Julia L; Schleinitz, Mark D; Carabin, Helene et al. (2008) Decision-model estimation of the age-specific disability weight for schistosomiasis japonica: a systematic review of the literature. PLoS Negl Trop Dis 2:e158
Tallo, Veronica L; Carabin, Helene; Alday, Portia P et al. (2008) Is mass treatment the appropriate schistosomiasis elimination strategy? Bull World Health Organ 86:765-71
Madsen, Henry; Carabin, Helene; Balolong, Don et al. (2008) Prevalence of Schistosoma japonicum infection of Oncomelania quadrasi snail colonies in 50 irrigated and rain-fed villages of Samar Province, the Philippines. Acta Trop 105:235-41
Riley, Steven; Carabin, Helene; Belisle, Patrick et al. (2008) Multi-host transmission dynamics of Schistosoma japonicum in Samar province, the Philippines. PLoS Med 5:e18
Fernandez Jr, T J; Tarafder, M R; Balolong Jr, E et al. (2007) Prevalence of Schistosoma japonicum infection among animals in fifty villages of Samar province, the Philippines. Vector Borne Zoonotic Dis 7:147-55
Tarafder, Mushfiqur R; Balolong Jr, Ernesto; Carabin, Helene et al. (2006) A cross-sectional study of the prevalence of intensity of infection with Schistosoma japonicum in 50 irrigated and rain-fed villages in Samar Province, the Philippines. BMC Public Health 6:61

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