Nonetheless, most outbreaks come to the attention of health authorities because an alert clinician is concerned enough to call the health department. The emergence of West Nile virus infection in North America in 1999 was uncovered only after the New York City health department responded to a call from a physician who had recently seen two patients with encephalitis.(5) Similarly, a single case of inhalational anthrax of suspicious origin in Florida in 2001 resulted in a massive investigation involving multiple government agencies, but it all started with an astute diagnosis and prompt report to the health department by a physician.(6)
Another reporting source for apparent clusters of both infectious and noninfectious disease is patients or other members of the community. For example, an individual may call the health department and report that she and some friends came down with severe gastroenteritis after attending a banquet a night or two earlier. Similarly, a local citizen may call about several cases of cancer diagnosed among his neighbors and express concern that these are more than coincidental. Most health departments have routine procedures for handling calls from the public regarding potential communicable disease outbreaks, and some states have guidelines for how to respond to noninfectious disease cluster reports.(7–9)