West Nile Virus: Symptoms & Signs

Medically Reviewed on 9/10/2019

Most people infected with the West Nile virus do not develop an illness or any symptoms from the infection. However, an illness with fever occurs in about one out of every five people who become infected. The illness produces flu-like symptoms, including

Rarely, in less than 1% of people who are infected, a serious illness with neurological complications develops. These people may develop inflammation of the brain (encephalitis) or the membranes surrounding the brain and spinal cord (meningitis). In this case, symptoms like high fever, stiff neck, disorientation, coma, tremors, seizures (convulsions), or paralysis can occur. Other possible symptoms of severe West Nile virus illness can include difficulty walking and sleepiness. Long-term persistent effects of the severe illness can cause

Causes of West Nile virus

The West Nile virus is a type of arbovirus ("arbo" comes from ARrthropod-BOrne). It is a member of the Flavivirus genus and the family Flaviviridae. People get the infection from a bite from an infected mosquito.

Related Symptoms & Signs

Other west nile virus symptoms and signs

Next Article


Bowel regularity means a bowel movement every day. See Answer

Subscribe to MedicineNet's General Health Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

United States. Centers for Disease Control and Prevention. "West Nile Virus." Feb. 12, 2015. <http://www.cdc.gov/westnile/symptoms/>.