What is West Nile virus encephalitis?
West Nile virus (WNV) encephalitis is a mosquito-borne viral disease, which can cause an inflammation of the brain. WNV is commonly found in Africa, West Asia, the Middle East and Europe. For the first time in North America, WNV was confirmed in the New York metropolitan area during the summer and fall of 1999. WNV successfully over-wintered in the northeastern United States and was present in humans, horses, birds, and mosquitoes in 2000, 2001 and 2002.