Symptoms
About 80% of those infected with West Nile Virus will have no symptoms. About 20% will experience mild to moderate flu-like symptoms such as:
fever
nausea, vomiting
headaches
body aches
skin rashes
swollen lymph nodes
These symptoms typically last for only a few days and have no long-term health impact.
Less than 1% (about 1 in 150) of those infected will develop more serious disease, in which there is brain involvement. This can lead to life-threatening encephalitis and/or meningitis. Symptoms of encephalitis include:
high fever
extreme muscle weakness
neck stiffness
stupor, disorientation
tremors, convulsions
coma
paralysis (rarely)
The fatality rate of those with the more serious form of the disease ranges from 3-15% and is highest among the elderly. Individuals with compromised immune systems also have an increased risk of severe disease.
This article was last reviewed on October 24, 2007.
This article was last modified on April 8, 2009.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.
On This Site