# Mathematical Model Estimates Impact of Large-Scale Anthrax Attack

The specter of military action against Iraq brings with it the fear of attacks at home, perhaps with chemical or biological weapons. According to a report published online today by the Proceedings of the National Academy of Sciences, a large-scale anthrax attack on a major U.S. city could cost 123,000 lives under current preparedness plans. Taking certain precautions, however, could cut the number of casualties to 1,000.

Lawrence M. Wein of Stanford University, together with David L. Craft of the Massachusetts Institute of Technology and Edward H. Kaplan of Yale University, devised a computer program that compares response strategies for a scenario in which a kilogram of anthrax is dropped on a city with 11 million inhabitants. The researchers, who have previously modeled the response to a theoretical smallpox attack, determined that 123,000 people would die in their so-called base scenario. In this scheme, every person in every neighborhood that had a confirmed case of anthrax infection took antibiotics, but distribution of the drugs came up to four days after the diagnosis. This delay would lead to a greater number of deaths, the scientists say, because more people would become symptomatic and the demand for more aggressive treatment would overwhelm medical facilities.

Wein notes that for antibiotic treatment to be most effective, "our response needs to be measured in hours, not days." A reasonable goal, he says, is for antibiotics to be distributed within 12 hours of a confirmed attack. "If we can vote in a single day," he says, "we should be able to hand out pills in a day." Indeed, the researchers determined that if drugs such as Cipro were handed out prior to an attack or within several hours of one, the number of deaths would be halved from the base scenario. Further reductions would require educational campaigns aimed at making sure people finish their entire course of medication, they note. But to ensure more significant cuts to the death toll, greater numbers of medical personnel would be required. The scientists posit that to reduce the number of casualties to 1,000, the besieged city would need one medical professional for every 700 people affected by the attack. Such a ratio could be achieved, Wein notes, by utilizing resources such as the Red Cross, the National Guard and VA hospitals, developing a national corps of volunteer pulmonary specialists willing to travel to afflicted regions, and training more nonemergency medical personnel to effectively treat anthrax patients. Such precautions are important, he says, because "our security against a biological terror attack rests in a very strong emergency response."