Skip to main content

West Nile Virus Infection

Medically reviewed by Last updated on Jun 5, 2024.

What is West Nile virus (WNV) infection?

WNV is carried by mosquitoes. The virus spreads to humans when they are bitten by infected mosquitoes. An infected mother who is pregnant or breastfeeding may pass the virus to her child.

What increases the risk of WNV infection?

People who travel to places where WNV is common have a higher risk of infection. Those staying or working outdoors may have an increased risk for the infection. Some factors may cause a mild WNV infection to develop into the more severe form of the disease. You may be at increased risk for a more severe form of the disease if:

What are the signs and symptoms of WNV infection?

Most people who have WNV never know they are infected. You may have flu-like symptoms such as fever, headache, eye pain, muscle pain, fatigue, runny nose, cough, and sore throat. You may have loss of appetite, nausea, vomiting, abdominal pain, or diarrhea. A red skin rash may develop. The severe form of WNV infection may include fever with one or more of the following:

How is WNV infection diagnosed?

Your healthcare provider will ask you for a detailed health history. This includes information about your past travels or activities, exposures and contacts, or diseases you may have had. You may need one or more of the following tests:

How is WNV infection treated?

No medicine is available to treat WNV. If you develop severe signs and symptoms of WNV infection, you may need to stay in the hospital. You may have one or more of the following to relieve your signs and symptoms:

How can I manage my symptoms?

How can a WNV infection be prevented?

Where can I find more information?

Call your local emergency number (911 in the US) or have someone call if:

When should I seek immediate care?

When should I call my doctor?

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

© Copyright Merative 2024 Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes.

Learn more about West Nile Virus Infection

Treatment options

Symptoms and treatments

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.