Is it bioterrorism? Investigating an infectious disease outbreak.

In the aftermath of September 11, the Anthrax exposures and recent Ricin incidents have opened America's eyes to the possibility of biological pathogens as terror agents. A key challenge is differentiating a naturally occurring outbreak from a bioterrorism event. Enhanced awareness and training of physicians is a vital part of bioterrorism preparedness. At 7 am the first patient of the morning in a small family practice clinic presented with a complaint of persistent nausea, vomiting, and diarrhea for 12 hours. Vital signs revealed orthostatic hypotension and physical examination was consistent with dehydration. Intravenous fluids were started and stool samples were collected. By 7:30, two other patients presented with similar symptoms and the waiting room was overflowing. Local public health officials were notified immediately of a possible biological outbreak. Over the course of the next 2 days, the practice saw over 65 patients with the same gastrointestinal complaints. Stool samples were consistent with Salmonella. The source of the outbreak was localized to a knife used to slice meats served at a work-related Christmas party. Biological outbreaks occur frequently even without bioterrorism. This outbreak affected Air Force pilots and air traffic controllers. With so many sick, the airfield was minimally manned and almost shut down. The clinic's resources were rapidly stretched thin with regard to manpower, space for patients, and intravenous fluids. It is easy to imagine how our military, especially air fields and medical clinics, might become a bioterrorism target. The next attack may be hard to differentiate from a natural event. Providers should be trained in an epidemiological approach to discriminate between biological warfare events and natural outbreaks of infectious diseases. Vigilance and communication with medical, law enforcement, and public health officials is vital.

Lisa Firestone, Harvard School of Public Health, Boston, MA. Brooks Air Force Base School of Aerospace Medicine, San Antonio, TX.