* Illustration: Studio Tonne * If you want to stop a disease outbreak — or a bioterrorist attack — you have to act fast. But health information typically moves at the pace of the receptionist at your doctor's office. The goal of Essence, the Department of Defense's Electronic Surveillance System for the Early Notification of Community-based Epidemics, is to pick up the tempo. Begun in 1999 to collect health data in the Washington, DC, area, Essence now monitors much of the Military Health System, which includes 400 facilities around the world.
"You don't have to be accurate to detect things," says Jay Mansfield, director of strategic information systems at the Global Emerging Infections Surveillance and Response System, one of the agencies that developed Essence. "But you do need to be precise." Reports from every clinic, doctor, and pharmacy get broken into broad syndrome categories rather than specific diseases. One doctor might diagnose bronchitis and another pneumonia, but Essence doesn't care. It's just looking for similar illnesses and where and when they occur. "It's like a fire alarm," Mansfield says. "It goes off if there's smoke, so you can get in the kitchen and see what's going on."
Because 100 megabytes of data come in every day — the team stores 18 months' worth, about 2.5 terabytes — there's often more smoke than fire. A pharmacy running out of antidiarrheals could signal an outbreak of E. coli or just a two-for-one sale. Essence expanded to include new sources (like radiology and laboratory tests) this spring, which means the data issues just got even more complicated. The trick is parsing the data as it comes in so that patterns emerge in hours instead of days. "We detected a gastrointestinal outbreak in Korea," Mansfield says. "I called my boss, and he asked me, 'When did it happen?'"
Korea is 13 hours ahead of Washington. So Mansfield simply answered: "Tomorrow."
