Disease surveillance and emergency services at the 1982 World's Fair.

We designed a special surveillance system to detect health complaints of visitors to the 1982 World's Fair. Heat-related illness occurred during the first month of the Fair but was substantially reduced by public education, environmental modification, and provision of additional water fountains. There was no disruption of emergency health services in the communities surrounding the Fair. Advance planning and the provision of on-site medical services can minimize the public health impact of large gatherings.