UB Expert: Most People Exposed to West Nile Virus Never Have Symptoms, But Prevention is Best Defense in this High Incidence Year

BUFFALO, N.Y. -- While the death toll from the West Nile virus cases in the U.S., currently 41, is alarming, most people exposed to it never develop symptoms, notes Tom Russo, MD, professor of medicine at the University at Buffalo School of Medicine and Biomedical Sciences.

The most recent numbers for West Nile virus cases reported to the Centers for Disease Control and Prevention are 1,118.

"Approximately 80 percent of infected individuals will be asymptomatic," says Russo. "About 20 percent will develop mild disease characterized by fever, headache and body aches. Less than 1 percent will develop severe disease, manifested by neurologic symptoms, such as high fever, stiff neck, muscle weakness or paralysis, stupor or coma and convulsions.

"People over the age of 50 are most vulnerable," he continues. "If symptoms do develop, it is usually between three and 14 days after the mosquito bite."

Russo adds: "Although there is only one case in Western New York to date, data from the Erie County Public Health Department have shown that the number of infected mosquitoes in the region is higher this year than in recent years. Therefore, prevention is critical."

Since there is no treatment for West Nile virus, he says that the best advice is to avoid mosquito bites, by trying not to go outdoors from dusk to dawn when mosquitoes are most active.

"If you do have to go out, wear long sleeves and long pants and do apply insect repellant," he advises. "Also, make sure you have screens on windows and the screens do not have holes in order to prevent mosquitoes from entering your home. Mosquitoes breed in standing water so drain all standing water on your property, make sure that gutters and other structures are free of water and debris, drill a hole in tire swings to promote drainage and be sure to empty bird baths and kiddie pools."