Sari against cholera

A folded sari -- available to every woman in Bangladesh -- can filter drinking water clean of the particles carrying cholera, cutting in half the number of cases of the disease, researchers reported yesterday.

The study, published in this week's issue of the Proceedings of the National Academy of Sciences, shows that low-tech solutions can save lives, the international team of researchers said.

"The beauty of this method is that it is simple. It is cheap," Anwar Huq of the University of Maryland, who helped lead the study, said in a telephone interview. "They can use old saris. The biggest advantage is it is readily available in each and every household in Bangladesh."

Tests covering 133,000 people in 65 Bangladeshi villages showed that when women were taught to use a folded sari to filter drinking water, incidences of cholera dropped by 48 per cent. The researchers now plan a large-scale education campaign.

Cholera is a deadly disease carried by bacteria that infect organisms in the water, from plankton to shellfish. It causes severe diarrhea that can be easily treated by modern medicine -- but it killed nearly 3,000 people in 2001, according to the World Health Organization.

These numbers probably only represent the tip of the iceberg, the scientists said, because the poorest people are usually the victims and the cause of their deaths is often not reported.

The team has been working on the idea of filtering drinking water for years. In 1996, they carried out a small study that showed a folded sari could filter out much of the cholera-carrying plankton. The most recent report is the result of testing the idea across much of Bangladesh.

"This is our first complete analysis," Huq said.

Folding a sari to give eight layers filters out virtually all the cholera, but women -- who gather the water in Bangladeshi society -- did not tend to do this, Huq said.

"The flow of water becomes very slow. We could not implement it in the village because women collecting water were not ready to spend five to seven minutes to wait for the water to collect," he said.

"With four layers it was a zip."

Bangladeshi villagers often filter water through a piece of cloth, but they do not usually fold it. Folding the thin sari cloth greatly increased its filtering power, the researchers found.

Once the cloth dries out, the bacteria die.

Now the team wants to find out if other items of clothing used in other countries will work as well.