An Epidemic of Waterborne Infectious Hepatitis in France

In an epidemic of infectious hepatitis in a French municipality, epidemiologic evidence pointed to an extensively contaminated municipal distribution system as the vehicle. The median incubation period of American personnel was 38 days with a range of 29 to 57 days. Prolonged exposure is not thought to have occurred and is therefore not considered to have influenced the length of the incubation period. Nor was there evidence that the length of the incubation period was influenced by the chlorination practiced. However, in-line chlorination is thought to have been a key factor in the remarkably low incidence of diagnosed hepatitis in an Army housing area receiving water from the municipal distribution system.