West Nile Virus Symptoms

West Nile virus symptoms can vary. While many people don't experience any West Nile virus symptoms, some people develop symptoms that can include fever, body aches, and swollen lymph glands. A very small number of people develop severe West Nile virus symptoms, including neck stiffness, high fever, coma, and paralysis.

 

An Overview of West Nile Virus Symptoms

When a person becomes infected with the West Nile virus, symptoms can vary. Some people will have no symptoms, others may develop flu-like symptoms, and some develop serious West Nile virus symptoms.
 
No West Nile Virus Symptoms
Approximately 80 percent of people who are infected with West Nile virus will not show any symptoms at all.
 
Mild West Nile Virus Symptoms
Up to 20 percent of the people who become infected have symptoms that can include:
 
  • Fever
  • Headache
  • Body aches
  • Nausea
  • Vomiting
  • Swollen lymph glands
  • Skin rash on the chest, stomach, and/or back.
     
West Nile virus symptoms can last from a few days to several weeks. These mild West Nile virus symptoms are sometimes called West Nile fever.
 
Serious West Nile Virus Symptoms
About 1 in 150 people infected with West Nile virus will develop severe symptoms. The West Nile virus symptoms of severe disease (also called neuroinvasive disease, such as West Nile encephalitis, meningitis, or West Nile poliomyelitis) can include:
 
  • High fever
  • Headache
  • Neck stiffness
  • Stupor
  • Disorientation
  • Coma
  • Tremors
  • Convulsions
  • Muscle weakness
  • Vision loss
  • Numbness
  • Paralysis.
     
These severe West Nile virus symptoms may last for several weeks, but neurological effects may be permanent. Neurological effects can include:
 
  • Hearing and/or speech loss
  • Blindness
  • Permanent brain and/or nerve damage
  • Behavioral changes
  • Cognitive disabilities
  • Lack of muscle control
  • Seizures
  • Memory loss.
     
(West Nile Virus Symptoms Continued: Page 2)
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD