Safety of community drinking-water and outbreaks of waterborne enteric disease: Israel, 1976-97

Waterborne disease remains a major public health problem in many countries. We report findings on nearly three decades of waterborne disease in Israel and the part these diseases play in the total national burden of enteric d isease. During the 1970s and 1980s, Israel's community water supplies were frequently of poor quality according to the microbiological standards at th at rime, and the country experienced many outbreaks of waterborne enteric d isease. New regulations raised water quality standards and made chlorinatio n of community water supplies mandatory, as well as imposing more stringent guidelines on maintaining water sources and distribution systems for both surface water and groundwater. This was followed by improved compliance and water quality, and a marked decline in the number of outbreaks of waterbor ne disease; no outbreaks were detected between 1992 and 1997. The incidence of waterborne salmonellosis, shigellosis, and typhoid declined markedly as proportions of the total burden of these diseases, but peaked during the l ime in which there were frequent outbreaks of waterborne disease (1980-85). Long-term trends in the total incidence of reported infectious enteric dis eases from all sources, including typhoid, shigellosis, and viral hepatitis (all types) declined, while the total incidence of salmonellosis increased . Mandatory chlorination has had an important impact on improving water qua lity, in reducing outbreaks of waterborne disease in Israel, and reducing t he total burden of enteric disease in the country.