How is WNV spread?
WNV is usually spread by the bite of an infected mosquito. Mosquitoes carry the virus after they become infected by biting a bird that is infected with the virus. In addition to humans and birds, other animals, such as horses, that mosquitoes bite can become infected. In a small number of cases, WNV also has been spread through blood transfusions and organ trans-plants (since 2003, blood banks screen for WNV). WNV is not spread by casual contact, such as touching and kissing.
