WNV is a virus of birds. In nature it is spread from bird to bird by mosquito bites. Some types of mosquitoes feed only on birds while others feed both on birds and people. People and other animals are infected by the bite of the mosquito that gets the virus from feeding on an infected bird. The virus has also been transmitted with infected blood through transfusion. Because the virus must enter the bloodstream to cause an infection it is not likely to be caught by having casual contact with infected birds, animals or people.

If bitten by an infected mosquito it may take 5 to 15 days to become ill. Most people infected with WNV experience only mild illness, but death does occur in rare cases. WNV may cause headache, swollen glands, muscle aches, other flu-like symptoms, and often a rash. In severe cases it may cause an infection of the brain. Older people are more likely to become very ill from WNV.

Besides birds and people, WNV has been found in horses. It may also infect sheep, cattle, cats, dogs and other animals. Mosquitoes can only become infected by feeding on birds.

WNV infected birds and humans have now been found throughout the United States, including North Carolina.

North Carolina Department of Environment and Natural Resources (NCDENR)

Protecting Outdoor Workers from West Nile Virus Exposure