[Effect of water supply on the incidence of trachoma: preliminary results of a prospective study in Mali].

This prospective study (January 1993-January 1994) was carried out in two groups of villages of the district of Ouelessebougou (Mali). The objective of the study was to assess the impact of installing water supply boreholes on the incidence of trachoma. A prospective group of 4 villages, where boreholes were sunk at the beginning of the study, was compared to a control group of 4 villages where there are no boreholes. The examination concerned children below the age of 10 years (N = 700) and was carried out using binocular loupes, according to the simplified procedure for trachoma grading proposed by the WHO. Our results show that in the prospective group, the annual rate of incidence of inflammatory trachoma was 8% (cl: 5.8-10.7) while in the control group it was 14% (cl: 9.6-10.9). RR: 0.58 (0.37-0.90). Likewise the rate of spontaneous healing was 12% (Cl: 9.1-14.9) in the prospective group and 5% (cl: 2.4-9) in the control group. Relative Risk was 2.60 (1.36-4.9). These statistically significant results show that the risk of contracting trachoma is reduced by half in the villages where a borehole has been sunk.