West Nile Virus is spread to people, horses, birds, and some other animals through the bite of an infected mosquito. The virus is not passed from person to person. There is no specific treatment; care is based on treating signs and symptoms. There is no vaccine to prevent it in humans. The virus is spread by mosquitoes that are most active at night, from dusk to dawn. Please read the fact sheets below to help you and your family avoid infection.