Swedish King Carl XVI Gustaf Thursday conferred the Stockholm Water Prize on US scientist Rita R. Colwell for her pioneering research on prevention of waterborne diseases, the second most common cause of death among children under five, Xinhua reported.

Colwell, a scientist with the University of Maryland and John Hopkins University in Stockholm, has made outstanding contributions to control the spread of cholera which affects some five million people worldwide and causes deaths to an estimated 120,000 people annually.

'Through her ground-breaking research, innovations and decades of scientific leadership, she has defined current understanding of the ecology of infectious diseases and developed the use of advanced technologies to halt their spread,' said professor Leif Andersson, chairman of the Nominating Committee, at the award ceremony.

'Waterborne diseases, parasites, bacteria and viruses cause a reduced capacity for work and daily functions, which creates economic and social disruption and a reduction of a capacity of a country.

'Safe drinking water is absolutely critical to economic stability, social stability and even national security,' said Colwell.

She was joined by 17 previous Stockholm Water Prize laureates and hundreds of water experts at the City Hall of Stockholm.

The ceremony also marks the 20th anniversary of the Stockholm Water Prize and the World Water Week to be concluded Friday.