Mosquitoes spread West Nile virus. Illness ranges from mild to severe.
Protect yourself and your family from mosquito bites to prevent West Nile virus.
Symptoms of West Nile include fever, head and body aches, and more. Illness can be severe.
Infected mosquitoes spread West Nile virus throughout the United States.
West Nile cases occur nationwide. State and territorial health departments report case data.
For Professionals
Treatment is supportive. Patients with encephalitis or acute flaccid myelitis require monitoring.
West Nile can present as acute febrile or neurologic illness after exposure to mosquitoes.
- Test patients’ serum or cerebrospinal fluid for West Nile virus. Additional testing may be needed.
- West Nile cycles between mosquitoes and birds. Other modes of transmission occur rarely.
- CDC publishes guidelines, scientific reports, and other resources on West Nile virus.
- Learn how to diagnose and manage West Nile virus disease.
- Health departments can use a CDC-created toolkit to communicate about West Nile outbreaks.