Before we begin: West Nile Virus (WNV) is a virus spread by mosquito bites. Most people have few to no symptoms. But some have severe symptoms. Learn about prevention and treatment.
This tutorial walks you through everything you need to know about west nile virus. We explain it in plain language, step by step, so whether you are a student, a patient, or simply curious, you will come away with a solid understanding.
We cover what it is, why it matters, how it is diagnosed, and what you can do about it. Key facts are called out along the way.
What is West Nile Virus? West Nile virus (WNV) is an infectious disease. It is most often spread by the bite of an infected mosquito. Most people have no symptoms, while some may develop mild symptoms. But WNV can sometimes cause serious symptoms if the virus enters your brain.
How does West Nile Virus spread? WNV usually spreads to people through the bite of an infected mosquito. However, in rare cases, it can spread from person-to-person. This can happen through an organ transplant or blood transfusion. If you are preganant you can spread WNV to your fetus during pregnancy or delivery. And after delivery, it can spread to the baby during breastfeeding.
Who is more likely to develop West Nile Virus? Anyone could be bitten by an infected mosquito and get WNV. But certain people are at higher risk for more serious illness they get a WNV infection. They include people who:
Are over age 60
Have certain medical conditions, such as cancer, diabetes, high blood pressure, or kidney disease
Had an organ transplant
What are the symptoms of West Nile Virus? Symptoms can be mild to severe. But most people have no symptoms or mild symptoms.
Mild symptoms of WNV can include:
Fever
Headache
Body aches
Vomiting
Diarrhea
Skin rash
These symptoms usually go away on their own within a few days to several weeks. But some people will have weakness or fatigue that lasts for weeks or months.
Although rare, If West Nile virus enters your brain, it can be life-threatening. It may cause inflammation of the brain (encephalitis) or inflammation of the tissue that surrounds the brain and spinal cord (meningitis).
Serious symptoms of WNV can include:
High fever
Headache
Neck stiffness
Numbness
Coma
Muscle weakness
Vision loss
How is West Nile Virus diagnosed? To find out if you have WNV, your health care provider:
Will do a physical exam
Will take your medical history, including asking about your symptoms
May order blood tests
What are the treatments for West Nile Virus? There are no specific vaccines or treatments for human WNV disease. But rest, fluids, and over-the-counter pain medicines may relieve some symptoms. You may need to be hospitalized if you have serious symptoms.
Can West Nile Virus be prevented? There are no vaccines or medicines to prevent WNV. The best way to avoid WNV is to help prevent mosquito bites:
Wear insect repellent with DEET or another U.S. Environmental Protection Agency (EPA)-registered insect repellent. Make sure to follow the instructions for using the repellent.
Wear long-sleeved shirts and pants if you’re outside.
Get rid of mosquito breeding sites by emptying standing water from flowerpots, buckets, or barrels.
Stay indoors between dusk and dawn, when mosquitoes are most active.
Use screens on windows to keep mosquitoes out.
Centers for Disease Control and Prevention (CDC)
Also known as: WNV.
Related topics: WNV.
Categories: Infections, Brain and Nerves.
Source: National Institutes of Health — National Institute of Allergy and Infectious Diseases.
Key Takeaways
Understanding west nile virus is an important part of taking charge of your health. Here is what to remember:
- Know the signs — Recognizing early symptoms can lead to earlier diagnosis and better outcomes.
- Talk to your provider — If you have concerns or a family history of this condition, bring it up at your next checkup.
- Stay informed — Medical knowledge evolves. Keep learning and asking questions.
- You are not alone — Many people deal with this condition. Support groups and educational resources can help.