West Nile virus is most commonly spread to people by the bite of an infected mosquito.
Mosquitoes become infected when they feed on infected birds. Infected mosquitoes then spread West Nile virus to people and other animals by biting them.
In a very small number of cases, West Nile virus has been spread through:
- Exposure in a laboratory setting
- Blood transfusion and organ transplant
- Mother to baby, during pregnancy, delivery, or breast feeding
West Nile virus is not spread:
- Through coughing, sneezing, or touching
- By touching live animals
- From handling live or dead infected birds. Avoid bare-handed contact when handling any dead animal. If you are disposing of a dead bird, use gloves or double plastic bags to place the carcass in a garbage can.
- Through eating infected animals, including birds. Always follow instructions for fully cooking meat.