Stockholm, March 22 (DPA) US researcher Rita Colwell, known for her work on infectious waterborne diseases like cholera, was Monday named winner of the 2010 Stockholm Water Prize.

The award, worth $150,000, was created in 1990 to recognise achievements in water science, water management, water action or awareness building.

Colwell, 76, was cited for 'pioneering research', including 'exceptional contributions to control the spread of cholera'.

Cholera is estimated to cause some 120,000 deaths each year and infects three to five million people.

Colwell observed in the 1960s that Vibrio cholera, the causative agent for cholera, could survive by attaching to zooplankton. She also made a pioneering discovery that certain bacteria can enter a dormant stage that could revert to an infectious state under the proper conditions.

Rivers, lakes and oceans can therefore serve as reservoirs for these bacteria. Previously, it was thought that cholera spread from person to person, food or drinking water and that its presence in the environment could only be due to sewage.

As a result of her work, scientists are now able to link changes in the natural environment to the spread of disease. Other implications include taking into account the effects of climate change, weather conditions or shifts in ocean circulation.

Colwell is a professor at the University of Maryland and John Hopkins University's Bloomberg School of Public Health in the US. She has written or co-authored 17 books and more than 700 scientific publications, and has served as an advisor to several governments.

The award is to be presented at a ceremony in Stockholm during the World Water Week in September.