Appendicitis epidemic following introduction of piped water to Anglesey.

The extension of piped water supplies in Anglesey, North Wales, 30 years ago and the consequent introduction of domestic hot water systems was followed by an epidemic of appendicitis. This occurred while appendicitis rates were falling elsewhere in Britain. The diet of Anglesey is unremarkable. This is further evidence that epidemics of appendicitis occur during the transition to 'western' hygiene, an important component of which is the provision of domestic hot water systems and fixed baths.