Symptoms of West Nile virus may include feverWest Nile Virus is commonly transmitted by mosquitoes. Most people, about 70-80%, who become infected will not develop symptoms and not know they are carriers.

20% of the people infected will develop what seems like an uncertain illness developing a fever, headache, body aches, joint pains, vomiting, diarrhea or rash. It is commonly mistaken for the flu, and most people recover completely even though fatigue and weakness can last for weeks.

Some people may develop more severe symptoms. Less than 1% will develop a serious neurologic illness like encephalitis or meningitis. Symptoms may include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. Recovery from severe West Nile Virus may take several weeks or months, although some of the neurologic effects may be permanent. 10% of those who develop a neurologic infection may die.