Virus spurs disease-tracking system

West Nile prompts CDC to act

The U.S. Centers for Disease Control and Prevention and other public health agencies have been monitoring major illnesses for decades. But for many years, it was mostly a paper system based on mailed and faxed documents. The West Nile virus, blamed for seven deaths in New York City last summer, has prompted the CDC to develop computer-based systems for tracking the spread of illness in real time.

When the mosquito-borne virus started spreading late last summer, US health officials had difficulty following its progress. State and city health departments were sending reports in a variety of electronic formats to various e-mail addresses. Lab tests on suspected infections took days because the few laboratories capable of performing such tests were often hundreds of miles from the infected area.

Since then, the CDC quietly took steps to streamline the disjointed monitoring system. The outbreak of West Nile "has served as a wake-up call," says Dennis White, a director overseeing West Nile for New York state's Health Department. "Nobody expected an exotic illness to show up in New York City."

The struggle to track West Nile has evolved into one of the most elaborate attempts yet to build a national surveillance network for tracing the path of emerging diseases. Experts say that if necessary, it could also be used to follow the spread of other diseases such as the Ebola virus, drug-resistant tuberculosis and "even those illnesses that might be introduced through bio-terrorism," says Richard Pollack, an entomologist at Harvard University's School of Public Health.

Reports detailing both positive and negative test results for West Nile can be found on a new federal Web site,