All About the West Nile Virus
West Nile Virus (WNV) is a mosquito-borne virus that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord). Only an estimated 1-3% of WNV infections result in serious disease.
Most people who are infected will show no symptoms at all, or have mild flu-like symptoms such as headache, fever, and body aches. Rarely do symptoms get more severe.