Human World

Rita Colwell explains how satellite imagery helps in cholera early warning system

Infectious diseases are closely related to the environment, and in particular, climate. That’s according to research by marine microbiologist Rita ColwelI.

Rita Colwell: Let me give you an example. Cholera is a devastating disease in the developing world.

Cholera is transmitted by tainted water and food, and it’s caused by bacteria, which Colwell said lives on microscopic animals of the sea called zooplankton.

Rita Colwell: It shows a definite seasonality, and so the cholera epidemics in Bangladesh are intense in the spring, and then even more intense in the fall, related to the plankton blooms. So we have been able to track these interactions using satellite imagery, using chlorophyll as a marker.

The chlorophyll is in phytoplankton, which the bacteria-carrying zooplankton feed on. More of their food means more risk of disease outbreak.

Rita Colwell: We can use that as an early warning system, particularly for the developing countries.

Colwell added that as Earth’s climate warms, surface waters remain warm for longer and lengthen the “cholera season” for countries like Bangladesh.

Rita Colwell: And indeed, because the bacteria are part of the natural environment, we could again begin to see epidemics of cholera in the U.S. and in Europe that we haven’t see in almost 100 years.

Colwell said that understanding the interactions between disease and environment will help us predict and manage them.

Our thanks today to NASA: explore, discover, understand.

Our thanks to Rita Colwell.
Rita Colwell is Chairman of Canon US Life Sciences, Inc. and Distinguished Professor at the University of Maryland at College Park. She is also a professor at the Johns Hopkins University Bloomberg School of Public Health and former director of the National Science Foundation.

Image Credit: Zooplankton image by Matt Wilson/Jay Clark and NOAA

March 11, 2008
Human World

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