West Nile virus is a mosquito-borne virus that can cause disease in humans and some animals. The virus first appeared in United States in 1999 around New York City after being imported from overseas. Since then, the virus has spread throughout the continental United States, including Vermont.
West Nile virus has been has been found in all counties of Vermont and continues to be detected in mosquitoes each year. However, it is a relatively rare cause of illness in people.