WNV affects the central nervous system. Symptoms vary.
No Symptoms in Most People
Approximately 80% of people who are infected with WNV will not show any symptoms at all.
Mild Symptoms in Some People
Up to 20% of the people who become infected will display mild symptoms, including fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms typically last a few days.
Serious Symptoms in a Few People
About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include:
- High fever
- Neck stiffness
- Muscle weakness
- Vision loss
These symptoms may last several weeks, and neurological effects may be permanent.