Last week alone, more than 100 new human cases of West Nile were reported. The virus was detected as far west as Colorado and Wyoming, infecting 371 and killing 16 people in 20 states plus the District of Columbia. This year West Nile appeared earlier in the mosquito season–mid-June instead of August–and claimed younger victims; the median age dropped from 65 to 54. Federal health officials are still trying to figure out why, but say they may be finding more West Nile precisely because they’re on the lookout for it. As Dr. Julie Gerberding, the new director of the Centers for Disease Control, recently told reporters, “We’re not in crisis mode.”
When West Nile hit New York City in 1999, the CDC realized it was a victim of its own success. Because health officials had conquered most mosquito-borne diseases decades ago, many states abolished their mosquito-control programs. The Feds rushed in with funds–some $50 million since 1999, plus $31 million more this year alone–to train entomologists, set up state testing labs and kill off the pesky insects. The CDC established a new computer surveillance sys-tem and held annual strategy sessions with state officials.
Some epidemiologists question the focus–and the millions–lavished on a virus that’s killed fewer than 20. “There’s an epidemic in gun violence that’s taking more lives than West Nile virus,” says Dr. William Steinmann, director of the Tulane Center for Clinical Effectiveness and Prevention. But the Feds say their efforts have kept West Nile from doing far more damage. “We’re basically building the infrastructure to deal with this over the next 50 years,” says Dr. Lyle Petersen, a CDC epidemiologist. “This is here to stay.”
So far, there are no remedies for West Nile. Officials eventually expect the virus to settle into a quiet pattern of mild infections with occasional outbreaks. Fewer than 1 percent of those infected will develop severe illness–most cases are mild with vague symptoms like fever, headache, body aches or a rash. Last week the Food and Drug Administration agreed to let a group of hospitalized West Nile patients test alpha interferon, a drug now used to treat hepatitis C. And though the National Institutes of Health is funding research on several vaccines, they won’t be ready for years. For now officials are trying to target juvenile mosquitoes in the water where they breed, using government-approved insecticides sparingly to kill adults. To do battle at home, the CDC recommends eliminating standing water and using insect repellent with DEET–simple precautions, but the best defense against an invader that shows no signs of going away.
