West Nile Virus

West Nile Virus was first found in Iowa during the late summer of 2001, in a bird in Scott County. Learn the facts and what you can do to protect yourself and your family from this virus and other diseases spread by mosquitoes.

What is West Nile Virus?

West Nile Virus (WNV) is a virus carried by mosquitoes and can cause an infection called West Nile Encephalitis. "Encephalitis" is an inflammation of the brain, which can be caused by bacteria or viruses.

What are the signs and symptoms of WNV?

Most infections are mild and include the following symptoms:

  • Fever
  • Headache
  • Body aches
  • Occasional skin rash
  • Swollen lymph glands

Symptoms of a more severe infection include:

  • High fever
  • Neck stiffness
  • Stupor
  • Disorientation
  • Coma
  • Tremors
  • Convulsions
  • Paralysis
  • Rarely, death

How is WNV transmitted?

WNV is transmitted when an infected mosquito bites a human or animal. Mosquitoes become infected when they feed on infected birds. Humans cannot be infected directly from birds, and WNV cannot be spread person to person.

If I live in an area where WNV has been reported and a mosquito bites me, am I likely to get sick?

No. Even in areas where mosquitoes do carry the virus, very few mosquitoes (less than 1%) are infected. If the mosquito is infected, less than 1% of people who are bitten and become infected will get severely ill. The chance you will become severely ill from a mosquito bite is extremely small.

How is WNV infection treated?

There is no specific treatment for WNV. General treatment is given to reduce pain and control swelling of the brain.

How can WNV be prevented?

The most effective ways to prevent the spread of WNV, as well as any other mosquito-borne diseases, are to reduce the mosquito population and to prevent mosquitoes from biting people.

What types of animals get WNV?

Although the vast majority of infections have been identified in birds, WNV has been shown to infect horses and some other animals as well. Dogs and cats have shown a low infection rate. If you have any concerns about your pets, please contact your veterinarian.

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