West Nile virus (WNV) is a virus spread by mosquitoes that bite from dusk till dawn. WNV has been found in the United States since 2003.
What Are the Symptoms of WNV?
No symptoms in most people.
Approximately 70-80% infected with WNV will not show symptoms.
Flu-like illness in some people.
20% of infected people will develop fever and flu-like symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people recover completely, but fatigue and weakness can last for weeks or months.
Severe symptoms in few.
Less than 1% of people infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain). Symptoms include headache, high fever, neck stiffness, coma, tremors, seizures, or paralysis. Recovery may take several weeks or months and some effects may be permanent. About 10 percent of people who develop neurologic infection due to West Nile virus will die.