Epidemiology of cholera outbreak in Kampala, Uganda

Objective: To provide epidemiological description of the cholera outbreak w hich occurred in Kampala between December 1997 and March 1998. Design: A four-month cross-sectional survey, Setting: Kampala city, Uganda, Main outcome measures: Number of cases reported per day, attack rate per ag e group and per parish, case fatality ratio. Results: The cholera outbreak was due to Vibrio cholerae 01 El Tor, serotyp e Ogawa, Between December 1997 and March 1998, 6228 cases of cholera were r eported, of which 1091 (17.5 %) were children under five years of age. The overall attack rate was 0.62 %, Similar in the under-fives and five and abo ve age groups. The case fatality ratio among hospitalised patients was 2.5 %. The peak of the outbreak was observed three weeks after the report of th e first case, and by the end of January 1998 (less than two months after th e first case), 88.4 % of the cases had already been reported. The occurrenc e of cases concentrated in the slums where the overcrowding and the environ mental conditions resembled a refugee camp situation. Conclusion: The explosive development of the cholera outbreak in Kampala, f ollowed by a rapid decrease of the number of cases reported is unusual in a large urban setting. It appeared that each of the affected slums developed a distinct outbreak in a non immune population, which did not spread to co ntiguous areas, Therefore, we believe that, a decentralised strategy, that would focus the interventions on each heavily affected area, should be cons idered in these circumstances.