Most people who contract West Nile virus experience no symptoms at all. Up to 20 percent of infected people experience symptoms like fever, headache, body aches, nausea, vomiting, swollen glands, and a rash on the chest, stomach and back. These typically last a few days, though some people can be sick for weeks. About one in 150 people infected with the virus develop severe illness, which can lead to coma, convulsions, vision, and even paralysis. The neurological effects can be permanent.