Cloth filter

The method used in Bangladesh is as follows: cloth is folded to make four or eight layers and the folded cloth is placed over a wide-mouthed container used to collect surface water. After use, it is usually sufficient to rinse the cloth and dry it in the sun for a couple of hours. In the monsoon seasons, it may be advisable to use a cheap disinfectant to decontaminate the material. The preferred cloth is used cotton sari cloth. Other types of clean, used cloth can be used with some effect, though the effectiveness will vary significantly. Used cloth is more effective than new cloth, as the repeated washing reduces the space between the fibers. ==Effectiveness==

The cloth is effective because most pathogens are attached to particles and plankton, particularly a type of zooplankton called copepods, within the water. By passing the water through an effective filter, most cholera bacteria and other pathogens are removed. It has been demonstrated to greatly reduce cholera infections in poor villages where disinfectants and fuel for boiling are difficult to get. In sub-Saharan Africa where guinea worm infections (dracunculiasis) are endemic, infection is prevented by use of a nylon mesh with pore size of approximately 150 μm to filter out the copepods that host the parasite. ==Background==

The cloth filter has been studied and reported on by Rita Colwell and Anwar Huq from the University of Maryland Biotechnology Institute, together with other researchers from the United States and Bangladesh. They report that: "It is common practice in villages in Bangladesh to use cloth, frequently a flat, unfolded piece of an old sari, to filter home-prepared drinks". ==See also==