NOAA Ocean Service Distinguished Scholar Finds New Way to Predict Cholera Outbreaks

Carolyn Sotka
Oceans and Human Health Initiative
NOAA National Ocean Service

January 15, 2009 — Rita Colwell, a distinguished scholar from the NOAA Oceans and Human Health Initiative, recently developed a new way to use satellite sensors to predict cholera outbreaks.  Her study used various ocean observation sensors to measure chlorophyll, sea surface temperature, rainfall, and ground temperature in the Bay of Bengal.

Colwell found that cholera outbreaks typically follow increases in sea temperature. These higher temperatures lead to increases in phytoplankton. The phytoplankton, in turn, serves as food for copepods, tiny crustaceans that naturally carry the cholera pathogen.

As the copepods thrive on the abundant phytoplankton, they find their way into drinking water supplies along the coasts. In addition to predicting when and where cholera is likely to occur, Colwell and her team found that filtering drinking water through four or more folds of sari cloth - a material widely available in the region – helps to remove the copepods, which can reduce cholera by 40 to 50 percent.

Colwell's model serves as a robust early warning system for cholera in many regions of the world, and is a useful tool for public health planning and decision making to implement warnings about drinking water contamination.

The study also informs other health early warning systems for U.S. seafood-related pathogen problems now in development by OHHI-funded scientists and partners.

Her most-recent study appears in the Nov. 2008 Proceedings of the National Academies of Science. Using Earth observation data from cholera outbreaks occurring between 1998 and 2006, Colwell and colleagues developed a model to predict cholera outbreaks in Kolkata, India and Matlab, Bangladesh.

The Distinguished Scholars program builds NOAA's Oceans and Human Health capacity by bringing world-renowned scientists in to work with OHHI on cutting-edge science and its applications.  Colwell is focusing on genetic applications for disease surveillance in the marine environment and the development of integrated global observations for disease surveillance.  She is working with scientists at the Center of Excellence for OHH at the NOS Hollings Marine Laboratory in Charleston and the OHHI national office.

Colwell is a distinguished university professor at the University of Maryland, College Park and at John Hopkins University Bloomberg School of Public Health in Baltimore, Md.  She was one of two outstanding scientists selected in fiscal year 2006 to be OHHI Distinguished Scholars.