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Environmental Epidemiology

Air pollution
Our ongoing collaborative work in Quito, Ecuador investigated the causes of acute respiratory infections in the region. We described the prevalence of infections, most common in children, and revealed two distinct air pollutants responsible for increasing the risk of acute respiratory infections: exposure to carbon monoxide fumes from vehicular traffic and long-lasting air borne debris from the Guagua Pichincha Volcanic Eruptions in April 2000. We also analyzed data from seven large U.S. cities and demonstrated that hospital admissions for congestive heart failure showed a consistent association with daily variations in ambient carbon monoxide and fine particulate levels with an increased effect at low temperatures. Our future projects in Ecuador will involve hazard exposure related research by conducting a study of the volcano activity and its impact on human health.

Water pollution
Understanding how incubation periods and modes of transmission differ between groups can lead to earlier detection of potential outbreaks. Our work in time-series analysis has produced innovations in surveillance methods for detecting waterborne outbreaks in a variety of global settings. We have recently demonstrated the applicability of passive surveillance data in determining geographic and temporal patterns of waterborne pathogen incidence, but cautioned that surveillance data are sensitive to patterns of diagnosis and reporting in periods of suspected outbreak.

Cryptosporidium oocysts are common and widespread in ambient water and can persist for months in this environment. Studies conducted in various locations have noted an increase in cryptosporidiosis during the warm and rainy season. We are conducting a meta-analysis to examine how an increase in rotavirus and cryptosporidiosis relates to precipitation and ambient temperature worldwide. We are investigating the potential of using remote sensing data as a proxy for exposure to borne infection globally. The source and occurrence of Cryptosporidium in watersheds has been characterized, although continued improvements in monitoring methods and analytical techniques would increase our understanding of these issues. We are currently studying such methods that can lead to discovering specific contamination sources that will ultimately contribute to public health protection.

In a pilot study conducted in partnership with the Nicaragua Research Center for Aquatic Resources (CIRA/UNAN) and the Committees for Potable Water and Sanitation (CAPS), student Alice Tin researched methods to improve the sanitary conditions of latrines and to reduce the incidence of diseases such as diarrhea and enteric diseases in rural communities where there is no networked sewage system. A survey instrument was developed and evaluated and digital maps were created for the pilot communities of Ciudadela San Martín, Llano Grande, La Reforma and El Hatillo. The survey gathered essential information on water sources, toilet facilities, sanitation practices and the social acceptance of using latrine additives while the maps marked important community infrastructure and delineated the hydrogeography of the study area.  Learn more about improving latrine sanitation >

Selected Publications:

Rioux CL, Tucker KL, Mwamburi M, Gute DM, Cohen SA, Brugge D. Residential traffic exposure, pulse pressure and C-reactive protein: Consistency and contrast among exposure characterization methods. Environmental Health Perspectives (2010). E-published ahead of print.   

Mor SM, Tumwine JK, Ndeezi G, Srinivasan MG, Kaddu-Mulindwa DH, Tzipori S, Griffiths JK. Respiratory cryptosporidiosis in HIV-seronegative children, Uganda: potential for respiratory transmission. Clin Infect Dis. 2010;50(10):1366-72.    

Jagai J, Naumova E. Clostridium difficile-associated disease in the elderly, United States. Emerg Infect Dis. 2009; 15:343-44.   

Jagai JS, Castronovo DA, Monchak J, Naumova EN. Seasonality of cryptosporidiosis: A meta-analysis approach. Environ Res. 2009; 109:465-78.   

Muchiri JM, Ascolillo L, Mugambi M, Mutwiri T, Ward HD, Naumova EN, Egorov AI, Cohen S, Else JG, Griffiths JK. Seasonality of Cryptosporidium oocyst detection in surface waters of Meru, Kenya as determined by two isolation methods followed by PCR. J Water Health. 2009;7(1):67-75.

Mor SM, DeMaria A, Jr., Griffiths JK, Naumova EN. Cryptosporidiosis in the elderly population of the United States. Clin Infect Dis. 2009; 48:698-705.

Mor SM, Tumwine JK, Naumova EN, Ndeezi G, Tzipori S. Microsporidiosis and malnutrition in children with persistent diarrhea, Uganda. Emerg Infect Dis. 2009; 15:49-52.   

Mor SM, Tzipori S. Cryptosporidiosis in children in Sub-Saharan Africa: a lingering challenge. Clin Infect Dis. 2008 Oct 1; 47(7):915-21.