[Epidemiological aspects of dracunculosis in Benin. 2. Relationship between periodicity of worm eruptions and the origin of drinking water].

A prospective survey was conducted in four villages in the central part of Benin. Dates of worm eruption were noted to precise the transmission period. In the same time, water was sampled to measure density of cyclopids in drinking water bodies. Relationships between the highest worm eruption period and cyclopid density led to precise the duration of Guinea worm latency in human which lasted from 10 to 13 months. The smallest density of cyclopids able to induce steady transmission was evaluated to 10 cyclopids per 10 liters of water. Authors did not find a proportional relationship between incidence and cyclopid density. A very few number of patients may introduce or maintain dracunculiasis in a community. Authors observed that village ponds produced an extend transmission over the dry season (from November to April). Reservoir dam induced a short period transmission in the beginning of dry season (from October to January).