West Nile Virus

West Nile virus (WNV) is most commonly transmitted to humans by mosquitoes. You can reduce your risk of being infected with WNV by using insect repellent and wearing protective clothing to prevent mosquito bites. There are no medications to treat or vaccines to prevent WNV infection. Fortunately, most people infected with WNV will have no symptoms. About 1 in 5 people who are infected will develop a fever with other symptoms. Less than 1% of infected people develop a serious, sometimes fatal, neurologic illness.  It sucks to be in that 1%.


Additional routes of human infection have also been documented. It is important to note that these methods of transmission represent a very small proportion of cases:

  • Blood transfusions
  • Organ transplants
  • Exposure in a laboratory setting
  • From mother to baby during pregnancy, delivery, or breastfeeding 

West Nile virus is not transmitted:

  • From person-to-person or from animal-to-person through casual contact. Normal veterinary infection control precautions should be followed when caring for a horse suspected to have this or any viral infection.
  • From handling live or dead infected birds. You should 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 consuming infected birds or animals. In keeping with overall public health practice, and due to the risk of known food-borne pathogens, always follow procedures for fully cooking meat from either birds or mammals.