West Nile virus (WNV) is most commonly transmitted to humans by
mosquitoes. You can reduce your risk of being infected with WNV
by using insect repellent and wearing protective clothing to
prevent mosquito bites. There are no medications to treat or
vaccines to prevent WNV infection. Fortunately, most people
infected with WNV will have no symptoms. About 1 in 5 people who
are infected will develop a fever with other symptoms. Less than
1% of infected people develop a serious, sometimes fatal,
neurologic illness.