Synthetic-fibre filters for preventing dracunculiasis: 100 versus 200 micrometres pore size.

Filtering of drinking water to remove the copepod intermediate hosts of Dracunculus medinensis is a primary strategy for control of guinea-worm disease. Since filters of different porosities are used, we tested the efficiency of synthetic-fibre filters of 100 microns and 200 microns pore size in removing the various stages of 3 species of copepods from water samples. The 200 microns mesh retained the larger copepodid stages including adults (C III-VI), but permitted passage of smaller copepodids and all naupliar stages. The 100 microns mesh retained all but the earliest naupliar stages (N I-II) which are unlikely to harbour guinea-worm larvae.