West Nile Virus: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 6/9/2017

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


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

Medically Reviewed by a Doctor on 6/9/2017
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