An outbreak of typhoid fever due to contamination of the municipal water supply in northern Israel.

An outbreak of typhoid fever followed a large outbreak of dysentery in northern Israel. Both outbreaks resulted from contamination of a drilled well that supplied water to the municipal water system. The well was contaminated with sewage from a broken main-pipe coming from Shefaram (an Arab town). The outbreak of typhoid involved 77 persons, of whom 75 were hospitalized. In 67, phage-type C1 (the phage type dominant in Shefaram since the 1950s) was isolated. The incubation period was relatively long, between 12 and 40 days (median 22) following exposure. Over 50% of the cases were children aged 0 to 14, and only two patients were older than 35 years; the sex ratio among the patients was 1:1. The incidence rate in Shefaram was 2.3 times higher than in the Krayot (outlying suburbs of Haifa). This difference was due mainly to the high incidence in young females in Shefaram. The opposite was observed during the outbreak of dysentery, when the attack rates of the disease were higher in the Krayot. Relapses occurred in 12% (9 cases). This outbreak demonstrates the potential that still exists for serious outbreaks due to contamination of the municipal water supply.