What is West Nile virus?

West Nile virus is a virus commonly found in Africa, West Asia, and the Middle East. It is carried by mosquitoes. West Nile can cause disease in humans, birds, horses, and some other mammals. The virus was found in the U.S. in 1999 and in Utah in August 2003.

How do people get West Nile virus?

• By far, the most common way is through the bite of an infected mosquito. That’s why prevention is key!
• Very rarely it can be transmitted by:
  • Blood transfusion or transplant
  • Mother to baby (no baby has died)
  • Lab workers through a needlestick (bird sample not human)

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Is there a vaccine available to protect humans from West Nile virus?

No. Currently there is no West Nile virus vaccine available for humans. Many scientists are working on this issue, and there is hope that a vaccine will become available in the next few years.

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Who gets West Nile virus?

Anyone who is bitten by an infected mosquito can get the disease. Persons over the age of 50 or those with poor immune systems are more likely to develop a serious illness if they are infected.

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How does the disease spread?

Wild birds can carry West Nile virus, and the virus is spread to birds by mosquitoes. Infected mosquitoes can give West Nile virus to humans or other animals while biting them. Not all mosquitoes carry West Nile virus.

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Can you get West Nile virus from another person or animal?

No. There is no proof that West Nile virus can be passed between humans or from animals. You get West Nile virus from mosquitoes.
I like to do outdoor activities. Am I at greater risk for West Nile virus?
Outdoor activities are an important part of a healthy lifestyle. Just because West Nile virus is in Utah does not mean that people should stay indoors! You can continue to enjoy the outdoors and easily protect yourself by using mosquito repellent with DEET.

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How can I tell if I was bitten by a mosquito carrying West Nile virus?

Mosquitoes carrying West Nile virus do not look or act differently than any other mosquito. The bite from a mosquito carrying West Nile virus does not look different than any other mosquito bite. You can’t tell when you are bitten by a mosquito that is carrying West Nile virus.

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I have some really large mosquitoes at my house, do they carry West Nile virus?

There are some insects that look just like mosquitoes but are a lot larger. They are not mosquitoes and do not carry West Nile virus.

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Katie Mullaly
Public Information Officer
Summit County Health Department
650 Round Valley Drive
Park City, Utah
Phone: 435-333-1503
Fax: 435-333-1580
kmullaly@utah.gov

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