The links between transmission of the snail vector disease, Schistosomiasis, and anthropogenic alterations to watersheds, particularly dam construction, are well established. However, little is understood about the mechanisms by which environmental changes alter the prevalence of the parasite Schistosoma japonicum in human and snail hosts. Parasite diffusion, the transport of parasites in the environment via multiple pathways, may link environmental changes to changes in disease transmission. Parasites are carried in advective flows along canals and streams as both larvae and ova. Within intermediate snail hosts, parasites are conveyed among and between aquatic and riparian habitats, and as adult worms, human and animal hosts serve as transport 'vehicles.' These diffusion pathways are subjected to significant disturbance under the pressures of anthropogenic change. This project by researchers from the University of California - Berkeley aims to comprehensively assess the role of diffusion in parasite transmission, with a specific focus on how anthropogenic change can modify diffusion parameters, thereby influencing transmission. Specific objectives are; 1) to quantify parasite diffusion along and between watersheds in Sichuan Province, Peoples Republic of China, using molecular markers of snail and parasite dispersal and tracking of human and mammalian hosts; 2) to assess the impact of natural and anthropogenic environmental features on parasite diffusion; and 3) to develop mathematical and statistical models of the ecological role of diffusion in the transmission of parasites under a variety of environmental change scenarios. These models will provide mechanistic insights into how environmental modifications can modify parasite mobility, thereby altering transmission. With these data in hand, new recommendations for interventions targeting parasite diffusion will be possible.
Among the broader impacts of this project is the demonstration how interdisciplinary research can serve the urgent needs of populations at risk of parasitic disease. To highlight the value of these partnerships, the PIs will initiate a new multidisciplinary seminar on the ecology of infectious disease and establish an undergraduate training component to capitalize on the new Public Health undergraduate major at Berkeley. The larger impact, however, will be in China where the PIs' work bridges the health, engineering and sciences sector, which have traditionally been quite independent in the organization and conduct of research.
