Many cities, especially in developing countries, have poor sanitation infrastructure characterized by a number of interconnected problems, including uncontained wastewater flows, lack of functional sewerage networks, open sewers, poor drainage, highly contaminated urban waterways, inadequate treatment of wastewater, and unsafe disposal of biosolids. Residents of cities with poor sanitation are exposed to a range of pathogens via a number of pathways, contributing to a high burden of disease. One pathway that has not yet been adequately characterized in these settings is the aeromicrobiological (AMB) pathway: the transport of pathogens in aerosols where uncontained fecal waste exists in close proximity to population centers. In this project the PI aims to advance our understanding of the role bioaerosols play in transmission of pathogens in these environments. Findings will be applicable to many settings in the US and other developed countries as well; these settings include areas of intensive animal agriculture, wastewater infrastructure, and biosolids management. Field studies will be integrated with innovative, hands-on, undergraduate engineering courses focused on environmental problems affecting global public health in underserved communities.
The PI seeks to determine whether bioaerosols represent a source of persistent exposure to enteric pathogens in cities with poor sanitation. The objectives of a series of studies are to determine: (i) the prevalence, concentration, and potential viability of important human enteric pathogens in air samples from three cities in the developing world representing a range of conditions, across seasons and multiple years, via culture-dependent and culture-independent methods; (ii) particle size and source apportionment of aerosols containing enteric pathogens to develop models for transport and exposure; (iii) environmental and built environment variables that may be associated with the presence, concentration, and viability of these pathogens, including season, temperature and relative humidity, rainfall events, localized population density, and proximity to uncontained fecal wastes; and (iv) infection risks associated with potential exposures to pathogens through the AMB pathway, via quantitative microbial risk assessment (QMRA). This work will expand our understanding of how enteric pathogens are released, transmitted, and controlled in these highly contaminated settings, creating new knowledge at the intersection of engineering and global public health.