Copepod filters for guinea-worm control--users have their say.

In Nigerian communities where dracunculiasis is endemic a sewn filter is commonly used to remove the copepod intermediate host of guinea-worm from drinking-water. Unfortunately, it is not easy to handle, and the bucket lid filter used on a much smaller scale is comparatively expensive. A field investigation revealed that a large majority of people favoured the introduction of a user-friendly plastic funnel filter developed in India. Under Nigerian conditions this device requires the diameter of its outlet to be increased to permit a suitably fast flow of water and thus to avoid excessively rapid blocking of the monofilament filter material.