Surges in grocery sales of over-the-counter drugs could alert officials to anthrax outbreaks, scientists say. Currently, authorities rely on data from medical and public health sources to detect large-scale anthrax exposure. But according to a report published today in the Proceedings of the National Academy of Sciences, tracking the sales of such common medications as cough syrup might be more effective than traditional detection methods in revealing outbreaks early on and could therefore help reduce mortality in such cases.

People infected with anthrax generally seek medical attention only once severe symptoms develop, after which death can follow within hours, note study authors Anna Goldenberg and colleagues from Carnegie Mellon University. But initially, the bacterium behind anthrax causes merely flu-like symptoms. At that point, victims are more likely to self-medicate with things like cough syrup than they are to visit a doctor. The researchers thus reason that the "outbreak footprint" would probably exist in the records of over-the-counter medication sales earlier than in medical or public health data.

To evaluate their proposed detection system, Goldenberg and her team simulated an outbreak based on data from the purportedly accidental anthrax release that occurred in Sverdlovsk, Russia, in 1979. They determined that in the case of an outbreak, cough syrup sales would jump unexpectedly by at least 36 percent within the first three days.

Although they control for factors such as seasonal outbreaks of the flu, "false alarms can still occur for various reasons," the researchers note. "But the purpose of such systems is early warning, and they require careful follow-up with medical assessment and other information on possible exposure to a bioagent."