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Abstract: Urogenital schistosomiasis is a tropical disease transmitted through skin contact with rivers, lakes, ponds and streams that are contaminated with human waste and harbor specific aquatic snail species. Schistosomiasis is a disease of poverty with 97% of the burden concentrated in sub-Saharan Africa; school aged children being the most at risk group. The predominant control strategy in en... read moredemic African countries is preventive chemotherapy; however, the need to combine this intervention with primary prevention measures such as water and sanitation improvements is gaining recognition. In this thesis, data from multiple field surveys of water-related conditions are employed in combination with remote sensing data to explore environmental and behavioral drivers of schistosomiasis transmission in rural Ghanaian communities. A particular focus is on the dynamic use patterns of safe groundwater sources and infectious surface water bodies. Some of the factors that negatively affect safe water use are seasonal availability, functionality, price of water, and water quality. Furthermore, how users perceive water quality is potentially more important in the context of schistosomiasis transmission as compared to its actual safety. For example, elevated iron and hardness concentrations, while not harmful to health, deter people from using safe groundwater sources, thereby increasing schistosomiasis risk. Environmental parameters did not have a significant bearing on schistosomiasis risk because a relatively homogeneous geographic region was selected for the study. However, the present work showed that knowledge of specific water contact sites, which can be gained through field data collection, increases the capacity of remote sensing variables to predict schistosomiasis risk. The major conclusion of the thesis is that reliance on contaminated ponds and streams for meeting daily water needs in the rural Eastern Region of Ghana contributes to high reinfection rates, severely limiting the efficacy and sustainability of chemotherapy with praziquantel. In order to reduce local transmission, the reasons underlying people's continued use of unsafe water sources in the presence of safe sources need to be addressed. In the meantime, drug treatment should be more specifically targeted on a community basis in terms of frequency and coverage.
Thesis (Ph.D.)--Tufts University, 2017.
Submitted to the Dept. of Civil Engineering.
Advisor: Elena Naumova.
Committee: Jeanine Plummer, Patrick Webb, Karen Kosinski, and David Gute.
Keywords: Environmental health, and Epidemiology.read less
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