A shortage of fresh drinking water is causing an outbreak of diarrhea in Bangladesh after last week's Cyclone Sidr lashed the country leaving almost 3,500 dead, local authorities said Wednesday.

A simple, affordable household filtration device can reduce the incidence of diarrhea, one of the leading causes of disease and death in developing countries, by up to 40 percent, researchers at the University of North Carolina at Chapel Hill have shown.