By Stacy Jones

Women look after children in one of Bangladesh’s cholera hospitals. Distinguished Professor Emerita Rita Colwell’s work involves using folded cloth from saris, the flowing garments  women seen here are wearing, to filter cholera-causing bacteria out of drinking water. Courtesy of Flickr user mknobil.

Saris just may save lives.

Five years after teaching Bangladeshi women to fold their light and flowing garments four or five times to filter out disease-carrying plankton from drinking water, Distinguished University Professor Emerita Rita Colwell has discovered her work has had lasting effects.

Colwell recently published a paper showing that 74 percent of women are still using the same technique she and her field team first demonstrated in 2001 to prevent the spread of cholera.

Rita Colwell became the first woman to serve as director of the National Science Foundation from 1998 to 2004. She’s best known for working with her colleagues to trace the bacteria that causes cholera to rivers and estuaries in Bangladesh.

“You must never underestimate the capacity of those who live in developing countries,” says Colwell, recipient of the 2010 Stockholm Water Prize for her work in solving water-related public health problems. “The work has been very instructive for me. It’s made it clear that safe water would do more for public health than any other public health measure or intervention.”

Cholera, an infection of the small intestine, afflicts 3 to 5 million people a year, according to the World Health Organization. It kills 200,000 annually, mostly in Africa and Asia. Colwell has spent more than 30 years carrying out field research on cholera in Bangladesh, after discovering in the 1970s that the bacteria that cause cholera there are native to estuaries and rivers. It turned upside-down the medical community’s belief that cholera spread only through person-to-person transmission.

Anwar Huq, a professor at the Maryland Pathogen Research Institute, a former research assistant at the International Center for Diarrhoel Disease Research, Bangladesh, first met Colwell in 1975. The research that led to the sari filtration method, he says, includes some of the doctorate work he did with Colwell in the early 1980s at the University of Maryland.

“It is not easy to work with Rita Colwell because her standards are very high,” Huq says, “but it has been a pleasure working with her.”

He adds that people in Bangladesh have used sari cloth for years to remove larger debris, small insects and dirt particles from their water. What they didn’t know, he says, was that folding a particular kind of cotton sari cloth several times could also help protect them from cholera.

“We are not saying that this is an alternative to a vaccine or any modern medicines, but when they have nothing else present they can use this method,” Huq says.

Earlier, they completed a three-year study funded by the National Institute for Nursing Research of the National Institutes of Health, or NINR, working in 65 Bangladeshi villages with high rates of cholera. A total of 8,250 households participated, with one-third serving as the control group and using no filter, and the other two split into groups that used nylon filters and sari filters. The result: Sari cloth produced a 48 percent reduction in cholera compared to the control.

“We tested what would be available to the poorest people. We wanted the filtration material to be very inexpensive,” Colwell says. “So we tried sari cloth, men’s T-shirts, Chinese poplin, and we eventually found that if you fold old sari cloth four to five times, it works well.”

She says she also wanted the filtration method to be simple enough to have a lasting impact on the communities most affected by the disease.

“That was part of the appeal for us,” says NINR Director Patricia Grady. “Most nurses become inventors by necessity, so the use of very low-tech, readily available and affordable material is something that has a lot of appeal to researchers and nurses.”

The method has been so effective, Colwell says, that when the filtered water was compared to unfiltered water in laboratory tests, it was found that 99 percent of the bacteria had been removed. Even families that don’t filter, but live near families who do, saw a reduction in disease-causing bacteria in their water.

Colwell, whose most recent work was supported by the Thrasher Research Fund, says she hopes to bring a similar method of filtration to Africa, since Senegal and Zimbabwe have seen huge outbreaks of water-borne diseases.