[Field epidemiology: possible beginning of community health. An example: epidemic caused by water]

The authors illustrate one facet of field epidemiology. They describe an example: a waterborne disease outbreak. The investigations were undertaken in a town in Moselle (F), on the general population with health professionals, school teachers, counselors and water service workers. They estimate that one thousand people had suffered from gastroenteritis (attack rate greater than 60%). Water was polluted and people became ill at the same time and in the same place. There is a strong statistical association between drinkers of polluted water and gastroenteric illness (relative risk: 10). This study has provided population information and resulted in motivation of the responsible people. In the conclusion of the epidemiological investigation they have carried out coherent measures for the protection of the water distribution system.