Cloth filter could cut cholera deaths

Floods in Bangladesh increase the risk of cholera

Simply filtering drinking water though cloth from old clothes can cut new cholera cases in half, researchers have found.

The technique was tested in Bangladesh, where it could potentially save many lives.

The method can save thousands of lives during massive epidemics

Dr Rita Colwell

Cholera is a waterborne disease that causes severe diarrhoea. It kills tens of thousands of people a year world-wide.

Scientists have long known that the bacteria that cause cholera live in a mutually beneficial symbiotic relationship with tiny aquatic organisms called plankton.

Researchers from the US National Science Foundation decided to test the theory that filtering plankton out of drinking water would also remove the cholera bacteria.

They found that an old sari cloth, folded at least four times, was as successful as specially designed nylon filters at removing plankton from water.

Tests

The scientists then tested the effectiveness of both sari cloth and nylon filters at preventing new cholera cases in Bangladesh villages over an 18-month period.

Villages trained to use sari cloth experienced about half the historic average of new cholera cases.

The nylon filter produced marginally less impressive results.

The researchers say that not only does the use of old sari cloth, and similar fabrics worn in other parts of the world, appear to be an effective way to combat cholera, the material is cheap and convenient to obtain.

Lead researcher Dr Rita Colwell told BBC News Online: "The method can save thousands of lives during massive epidemics, particularly those of children under the age of five."

Dr Claire-Lise Chaignat, coordinator of the World Health Organization's global taskforce on cholera control, said the technique sounded "very promising".

She said: "Cholera affects only the poorest of the poor who have hardly any access to safe water or proper sanitation.

"A simple method of cleansing water for these people would be very interesting."

The research is published in the Proceedings of the National Academy of Sciences.