Women in Bangladesh who fold their saris filter out more of the disease-carrying organisms that cause cholera than the women who filter through unfolded cloths, or who don’t filter at all. While folding saris to make eight layers filters out almost all of the harmful organisms, this method means that women gathering water had to wait seven minutes for the water to seep through the cloth.
—Fight cholera with Sarees, Says StudyTimes of India)
That’s a usability issue — the material (saris) are cheap & plentiful, but getting them to work effectively takes time. People don’t like changing their habits if they don’t see any immediate benefit — not even when their lives depend on it. As it happens, folding a sari so it has four layers is still effective enough to cut cholera cases in half, and it doesn’t slow down the water nearly as much.
This is great news of a low-tech, low-cost strategy for fighting disease.
On a completely different note, here is the abstract of the article in which the researchers publish their findings. “Based on results of ecological studies demonstrating that Vibrio cholerae, the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple filtration procedure was developed whereby zooplankton, most phytoplankton, and particulates >20 µm were removed from water before use. Effective deployment of this filtration procedure, from September 1999 through July 2002 in 65 villages of rural Bangladesh, of which the total population for the entire study comprised 133,000 individuals, yielded a 48% reduction in cholera (P < 0.005) compared with the control." Is this good scientific writing? Can scientists do better, especially when people's lives are at stake?