Changes in the incidence of gastroenteritis and the implementation of public water treatment.

There are few data available on the incidence of endemic waterborne disease in the developed world. This study aims to determine if there was a measurable decline in gastroenteritis related faecal specimens following the introduction of water treatment. The rate of faecal specimens for gastroenteritis was obtained for 17 communities one year before and after the introduction of water treatment in two states of Australia between 1992 and 1996. Of these 17 systems, 10 had filtration added to existing disinfection, while seven had both disinfection and filtration or disinfection alone added to no existing treatment. The rate of faecal sampling varied from a reduction of 55% to an increase of 198%. Large changes in water quality parameters occurred following treatment but there was no significant correlation between these changes and changes in the rate of faecal specimens. In this study there was no consistent change in gastrointestinal related faecal specimens despite marked changes in water quality. This suggests that the reduction in endemic gastrointestinal disease as a result of the introduction of water treatment was small as a percentage of all gastroenteritis. However, water treatment remains essential to protecting public health.