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