What is West Nile Virus?
West Nile Virus (WNV) is a mosquito-borne virus that can infect humans, birds, horses and other mammals. WNV was first detected in the United States in 1999. It is not known how the WNV was introduced into the United States but it may have entered in an infected traveler, bird, or mosquito.

WNV has been present in Africa, West and Central Asia, and the Middle East for a long time. The majority of people and animals that are infected with WNV have no symptoms or only a mild illness. In rare cases, WNV can cause a more serious condition called encephalitis, or an inflammation of the brain.

Show All Answers

1. What is West Nile Virus?
2. How do people become infected with West Nile Virus?
3. How do mosquitoes become infected with West Nile Virus?
4. What is "encephalitis"?
5. Who is at risk of getting sick from West Nile Virus?
6. What are the symptoms of West Nile Virus infection?
7. Is there a treatment for West Nile Virus infection?
8. Is there a vaccine to prevent West Nile Virus infection?
9. Can I get WNV from another person or an animal?
10. Can I get WNV directly from birds?
11. If bitten by a mosquito, should I be tested for WNV?
12. What time of year are mosquito-borne viruses spread?
13. How can I help protect myself and my family from West Nile Virus?
14. Which animals can get infected with West Nile Virus?
15. Can a person get West Nile Virus infection by eating infected birds?
16. What is Maricopa County doing to prepare for West Nile Virus?
17. Where can I get more information on West Nile Virus (WNV)?