West Nile Virus Fact Sheet 

What is West Nile Virus?


West Nile Virus (WNV) is a potentially serious mosquito-borne illness.
Experts from the Centers for Disease Control and Prevention (CDC) believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall.

Have there been any cases of WNV in Arkansas?

Yes, cases of West Nile Fever and West Nile Encephalitis have been documented in the state.

How does WNV Spread?

  • Most often, WNV is spread by the bite of an infected mosquito.  Mosquitos become infected when they feed on infected birds.  Infected mosquitoes can then spread WNV to humans and other animals when they bite.
  • In a very small number of cases, WNV has also been spread thru blood transfusion, organ transplants, breastfeeding and even during pregnancy from mother to baby.  WNV cannot be spread through casual contact such as touching or kissing a person with the virus.

What are the symptoms of WNV?

  • Most people infected with WNV will not have any signs of illness.  Approximately 80 percent of people who are infected with WNV will not show any symptoms, but there is no way to know in advance if you will develop an illness or not.
  • Mild illness can occur in up to 20 percent of the people who become infected.  Symptoms can include fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back.  Symptoms can last from a few days to several weeks.  You should call your health care provider if you have questions about your symptoms.
  • A small number of people (about 1 in 150) who get infected with WNV develop severe disease called West Nile encephalitis or West Nile meningitis (inflammation of the brain or the area around the brain).  The serious symptoms can cause disease that affects the nervous system.  In some cases it can cause damage to the body’s nervous system, and in extreme cases can cause death.  Symptoms of severe illness include headache, high fever, stiff neck, mental confusion, muscle weakness, tremors (shaking), convulsions, coma, and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. See your health care provider if you develop these symptoms.

How soon do infected people get sick?

People typically develop symptoms between 3 and 14 days after they are bitten by an infected mosquito.

How is WNV treated?

There is no specific treatment for WNV infection.  In milder cases of WNV, people experience symptoms such as fever and aches that pass on their own.  In more severe cases, people may need to receive supportive medical treatment, from a qualified medical professional.

What should I do if I think I have WNV?

Milder cases of WNV, improves on its own, and people do not necessarily need to seek medical attention.  If you develop symptoms of severe WNV illness, such as severe headaches or confusion, seek medical attention immediately.  Severe WNV illness usually requires hospitalization.  Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be WNV.

What is the risk of getting sick from WNV?

Anyone can become infected with WNV, however, people over 50 are more likely to become ill and develop serious symptoms when infected. 

The risk of contracting WNV through a medical procedure is very low.  All donated blood is checked for WNV before being used.  The risk of getting WNV through blood transfusion and organ transplants is very small, and should not prevent people who need surgery from having it.  You should talk to your doctor if you have concerns.

Pregnancy and nursing do not increase the risk of becoming infected with WNV.  The risk that WNV may present to a fetus or an infant infected through breast milk is still being evaluated.  You should talk to your doctor if you have concerns.

What can I do to prevent WNV?

There is no vaccine available for people.
The best way to prevent West Nile virus disease is to avoid mosquito bites. Do this by practicing the “Three D’s”. 
  1. Drain standing water from your yard, and empty standing water in flowerpots, buckets and kiddie pools.
  2. Don’t go out at dusk and dawn when mosquitoes feed without protective clothing (long sleeves and pants).
  3. Do use insect repellents such as those with the active ingredient DEET when you go outdoors.