Project Summary

This study investigates local-level risk of diarrheal diseases in rural Bangladesh using a comprehensive geographic information system (GIS) database of health and population events. This work is unique to cholera research because it involves measuring neighborhood-level socio-environmental risk factors with spatial analytical methods.

Using an ecological approach, the project has identified environmental, socioeconomic, and biological risk factors for several different diarrheal diseases including cholera and shigellosis. The project included a study that examined relationships between cholera and large flood control embankments and provided supporting evidence concerning the existence and importance of an aquatic cholera reservoir.

Project Team Members

Michael Emch

Margaret Carrel

Elisabeth Root

Sophia Giebultowicz

Caryl Feldacker

Veronica Escamilla



Carrel, M; Emch, M; Streatfield, K; Yunus, M. (submitted) The impact of flood control on cholera-environment relationships in Bangladesh.

Ali, M; Emch, M; Park, JK; Yunus, M; Clemens, J. (2011) Natural cholera infection-derived immunity in an endemic setting. Journal of Infectious Diseases. 204: 912-918. link to article

Carrel, M; Escamilla, V; Messina, J; Giebultowicz, S; Winston, J; Yunus, M; Streatfield, PK, Emch, M. (2011) Increased tubewell density decreased diarrheal disease risk in rural Matlab, Bangladesh: a zero-inflated and geographically weighted analysis. International Journal of Health Geographics.10:41.

Knappett, PSK; Escamilla, V; Layton, A; McKay, LD; Emch, M.; Williams, D; Huq, MR; Alam, MJ; Farhana, L; Mailloux, MJ; Ferguson, A; Sayler, GS; Ahmed, KM; van Geen, A. (2011) Impact of sanitation on fecal bacteria and pathogens in ponds of Bangladesh. Science of the Total Environment.

Carrel, M; Voss, P; Streatfield, PK; Yunus, M; Emch, M. (2010) Protection from annual flooding is correlated with increased cholera prevalence in Bangladesh: a zero-inflated regression analysis. Environmental Health 9(13). link to article

Emch, M; Yunus, M; Escamilla, V; Feldacker, C; Ali, M. (2010) Local population and regional environmental drivers of cholera in Bangladesh. Environmental Health. 9:2. link to article

Huq, A; Yunus, M; Sohel, M; Bhuiya, A; Emch, M; Luby, SP; Russek-Cohen, E; Nair, GB; Sack, RB; Colwell, RR. (2010) Simple sari filtration is sustainable and continues to protect villagers from cholera in Matlab, Bangladesh. mBio. 1(1):e00034-10. link to article

Savory, DJ; Cox, KL; Emch, M; Alemi, F; Pattie, DC. (2010) Enhancing spatial detection accuracy for syndromic surveillance with street level incidence data. International Journal of Health Geographics. 9(1). link to article

Carrel, M; Emch, M; Streatfield, PK; Yunus, M. (2009) Spatio-temporal clustering of cholera: the impact of flood control in Matlab, Bangladesh, 1983-2003. Health & Place. 15(3): 741-52. link to article

Emch, ME; Carrel, M. (2009) Neighbourhood effects on environmental health: neighborhoods and environmental determinants of infectious diseases. In Diez-Roux, A., (Ed.) Encyclopedia of Environmental Health, Oxford: Elsevier Ltd.

Emch, M; Root, E. (2008) Emerging and re-emerging diseases. In Moon, G., McLafferty, S., and Brown, T. A. (Eds.) Companion to Health and Medical Geography. Blackwell: Oxford, United Kingdom.

Ali, M; Goovaerts, P; Nazia, N; Haq, MZ; Yunus, M; Emch, M. (2006) Mapping the risk of endemic disease from individual-level data using Poisson kriging. International Journal of Health Geographics. 5(45):1-11. link to article

Ali, M: Park, JK; Thiem, D; von Seidlein, L; Canh, D; Emch, ME; Clemens JD. (2005) Neighborhood size and local geographic variation of health events: using Hartley’s Test of Homogeneity to select optimal neighborhood size. International Journal of Health Geographics 2005, 4:12. link to article

Emch, ME; Ali, M. (2003) Spatial cluster analysis for etiological research and identification of socio-environmental risk factors. Geographic Information Systems and Health Applications, Idea Group Publishing: Hershey, Pennsylvania, pp. 172-187.

Ali, M; Emch, ME; Donnay, JP. (2002) Spatial filtering using a raster geographic information system: methods for scaling health and environmental data. Health & Place. 8(2):85-92. link to article

Ali, M; Emch, M; Donnay, JP; Yunus, M; Sack, RB. (2002) Identifying environmental risk factors for endemic cholera in Bangladesh. Health & Place, 8(3):201-210. link to article

Ali, M; Emch, M; Donnay, JP; Yunus, M; Sack, RB. (2002) The spatial epidemiology of cholera in an endemic area of Bangladesh. Social Science & Medicine, 55(6):1015-1024. link to article

Ali, M; Emch, ME; Yunus, M; Sack, RB. (2002) Are the environmental niches of Vibrio cholerae 0139 different from those of Vibrio cholerae 01 El Tor? International Journal of Infectious Disease, 5(4):214-9. link to article

Ali, M; Emch, M; Ashley, C; Streatfield, PK. (2001) Implementation of a medical geographic information system: concepts and uses. Journal of Health, Population, and Nutrition, 19(2):100-110. link to article

Emch, ME; Ali, M. (2001) Spatial and temporal patterns of diarrheal disease in Matlab, Bangladesh. Environment and Planning A, 33(2):339-350. link to article

Emch, ME (2000) Relationships between flood control, kala-azar, and diarrheal disease in Bangladesh. Environment and Planning A, 32:1051-1063. link to article

Emch, ME (1999) Diarrheal disease risk in Matlab, Bangladesh. Social Science & Medicine 49:519-530. link to article


Robert Wood Johnson Foundation Health & Society Seed Grant, “Columbia University Infectious Disease Working Group.” 2005-06.

NOAA: Oceans and Human Health, “Cholera across Scales: Oceanic Links to Climate and Local Estuarine Influences.” 2005-07.

Collaborating Institutions

International Centre for Diarrhoeal Disease Research, Bangladesh

International Vaccine Institute