Areas of risk
West Nile virus is found in Africa, Europe, the Middle East, North America, and Western Asia1
Key facts
Mosquitoes become infected when they feed on birds infected with WNV.
These mosquitoes then spread the virus to people and other animals.1
West Nile virus is the leading cause of mosquito-borne disease in the US.2
In 2022, 1,035 cases of West Nile were reported to the CDC.
71% of WNV cases were neuroinvasive.3
Severe West Nile virus4
~1 in 150
people who are infected develop severe symptoms affecting the central nervous system
~1 in 10
people with disease affecting the central nervous system die
West Nile at a glance
Primary vector5,6
Culex
Biting habits:
- Evening to morning
Symptoms4
Most common:
- Fever
Other:
- Headache
- Body aches
- Joint pain
- Vomiting
- Diarrhea
- Rash
Available treatment4
None
Prevention4
Protective measures
References: 1. West Nile virus. World Health Organization. Accessed March 13, 2023. https://www.who.int/en/news-room/fact-sheets/west-nile-virus 2. West Nile virus. Centers for Disease Control and Prevention. Updated December 15, 2022. Accessed March 13, 2023. https://www.cdc.gov/westnile/index.html 3. West Nile Virus – Preliminary Maps & data for 2022. Centers for Disease Control and Prevention. Updated December 13, 2022. Accessed March 13, 2023. https://www.cdc.gov/westnile/statsmaps/preliminarymapsdata2022/index.html 4. Symptoms, diagnosis, & treatment. West Nile virus. Centers for Disease Control and Prevention. Updated October 14, 2022. Accessed March 13, 2023. https://www.cdc.gov/westnile/symptoms/index.html 5. Mosquito-borne diseases. Baylor College of Medicine. Accessed March 13, 2023. https://www.bcm.edu/departments/molecular-virology-and-microbiology/emerging-infections-and-biodefense/mosquitoes 6. Mosquito bite prevention (United States). Centers for Disease Control and Prevention. October 13, 2016. Accessed March 13, 2023. https://www.cdc.gov/chikungunya/pdfs/fs_mosquito_bite_prevention_us.pdf