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West Nile Virus and Your Health

Most people who are infected with West Nile Virus (WNV) have no symptoms and never know they have the disease. Others get mildly sick and recover. But for a small number of people – mainly the elderly and people with weakened immune systems – WNV can lead to encephalitis, an inflammation of the brain.


Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.

About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

If you are experiencing symptoms of WNV, contact your health care provider.


Although the majority of people who are infected will not show any symptoms at all, it’s important to protect yourself and your family from infection. When dealing with West Nile virus, prevention is your best bet. Fighting mosquito bites reduces your risk of getting this disease, along with others that mosquitoes can carry.

Avoid mosquito bites by:
  • Using insect repellent.
  • Wearing light-colored long pants and long-sleeved shirts to cover exposed skin.
  • Limiting outside exposure during the evening hours when mosquito activity is at its highest.
  • Eliminating mosquitoes inside your house.
Mosquito-proof your home by:
  • Ridding your backyard of standing water. Common places include old tires, buckets, wheelbarrows, gutters, and pet dishes.
  • Emptying plastic wading pools, birdbaths, plant pots, or drip trays every four to five days.
  • Draining standing puddles, ditches, tree holes, or tree stumps.
  • Ensuring your swimming pools and decorative ponds/fountains are clean and operational.
  • Fixing or installing window and door screens around your home, and properly maintaining your evaporative cooler.
  • Avoiding over-watering your lawn.
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