What are symptoms of West Nile virus?

(CNN) - Asked by Todd, Mississippi
I heard that someone in my area died recently of West Nile virus. I try to avoid mosquito bites but sometimes still get bitten. What symptoms would I expect if I have the infection?

Expert Answer
Thanks for your question. West Nile virus, so called because it was first reported in the West Nile District of Uganda in 1937, made its way to the United States by 1999.

As you mentioned, the virus is transmitted by mosquitoes, so the best way to prevent getting the infections is to avoid mosquito bites by using insect repellents, covering up with clothing, and if possible staying indoors at dusk and dawn.

Fortunately, most people (about 80%) do not show any signs of illness when infected with the virus and never know they have it. The remaining 20% or so may develop fever, aches, nausea or vomiting that can last days to weeks. About one out of 150 people will experience severe symptoms such as high fever, muscle weakness or paralysis, seizures and coma, which may possibly result in long-term neurological problems or even death.

Of note, individuals over age 50 are more likely to have serious illness from West Nile virus.

Anyone with the symptoms of severe illness, especially within about two weeks after a mosquito bite, is advised to seek medical care. Laboratory tests of the blood and/or spinal fluid can confirm infection with the disease.

Animals such as horses and birds may also get infected with the virus, and while it does not appear that animals can transmit the disease to humans, it's best to use caution when handling animals that may be sick from West Nile virus.

- Dr. Jennifer Shu
  Pediatrician,
  Children's Medical Group