West Nile Virus: A Dangerous Season Returns
When human West Nile infection does crop up in an area, the danger is highest in people over age 50 and those who are immune suppressed, especially organ-transplant recipients who've received immunosuppressive drugs. West Nile fever, the least severe of the infection's complications, can produce pounding headaches and debilitating fatigue. The virus's most serious manifestations—West Nile encephalitis and meningitis, which refer to swelling of the brain and of the spinal cord, respectively—can produce losses of motor skills, permanent brain damage, and even death. During Colorado's 2003 West Nile outbreak, the rates and physical symptoms associated with acute flaccid paralysis, another potential outcome of West Nile infection, were "as bad as what you saw in the worst polio outbreaks in the 1950s," according to Lyle Petersen, director of the CDC's Fort Collins-based Division of Vector-Borne Infectious Diseases.
That year, Petersen learned the hard way how unforgiving the virus can be. "I did the typical thing you shouldn't do," he says. "Right around dusk, I went out with my daughter to collect the mail, and I thought, Well, I'm only going to be outside for a minute or two, so I'm not going to bother to put on insect repellent. Then I ran into a friend of ours, and we started talking." A few days later, Petersen, his daughter, and the neighbor all had West Nile. "I was flat on my back for a week, with splitting headaches, horrible muscle pain," he recalls. "Then I got a skin rash and had fatigue for about a month. I could barely walk up the stairs."
The lesson, says Petersen, is: "Wear your insect repellent in July and August and September, even if you're going to be outside for a few minutes."