The local county health department and the area hospital established a rabies exposure assessment and treatment clinic in the emergency department. Based on information from a voluntary sign-in log for visitors, IDPH used a variety of tools (i.e., media campaign, Internet locator sites, directory assistance, and law enforcement) to reach persons from 10 states (Arizona, California, Florida, Illinois, Iowa, Minnesota, New Mexico, New York, Ohio, and Wisconsin) and Australia; 200 visitors were identified. On August 29, IDPH personnel began contacting the 200 visitors. In addition, efforts were made to contact 150 potentially exposed persons who attended an August 14 "barnwarming" at which the bear was present. On September 3, a dispatch was published in MMWR1 to notify other health departments of efforts to locate zoo visitors. By September 1, an estimated 99% of potentially exposed persons had been contacted.