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West Nile Virus

close up of a Culex Tarsalis mosquito feeding

What is the West Nile Virus?

West Nile is a mosquito-borne virus that can cause meningitis (inflammation of the layers of tissue that cover the brain and spinal cord) or encephalitis (inflammation of the brain).

How is the West Nile Virus spread?

West Nile virus is spread to humans by the bite of an infected mosquito. A mosquito becomes infected when biting a bird that has the West Nile virus. You cannot get West Nile virus from someone who has the disease. Also, being bitten by an infected mosquito will not necessarily make you sick. If illness occurs, it would occur within 3-15 days of being bitten by an infected mosquito.

What are the symptoms of the West Nile Virus?

Most people who become infected with West Nile virus have no symptoms. Some experience mild illness such as fever, headache, and body aches. Some people may develop mild rash or swollen lymph glands. Symptoms of encephalitis, which are only experienced by a few people, can include, rapid onset of severe headache, high fever, stiff neck, confusion, loss of consciousness (coma), or muscle weakness. Those at risk for getting the most serious complications of West Nile infection (such as encephalitis) are persons 50 years of age and older. The symptoms may not be the same for every person. In some cases, West Nile virus can be fatal.

Who is at risk for the West Nile Virus?

Everyone who lives or has recently traveled in areas where West Nile virus activity has been identified.

How is the West Nile Virus diagnosed?

West Nile virus is usually diagnosed by laboratory tests of blood serum or cerebrospinal fluid.

How is the West Nile Virus treated?

No specific treatment is available for West Nile virus infection. For West Nile encephalitis, intensive supportive therapy may be required i.e., hospitalization, intravenous fluids and prevention of secondary infections such as pneumonia or urinary tract infections.

How can I reduce my risk of becoming infected with West Nile Virus?

  • Avoid Mosquitoes - Limit time outdoors during dawn and dusk; make sure that doors and windows have tight-fitting screens; place mosquito netting over infant carriers when you are outdoors with infants.
  • Stop Mosquito Breeding - Drain water from pool covers, plastic wading pools, buckets, and flower pots when not in use; clean, chlorinate and filter swimming pools, spas and water fountains regularly; stock ornamental ponds and water fountains that cannot be chlorinated with mosquito fish.
  • Use Repellents, when choosing mosquito repellents, check product labels for one of the following active ingredients: DEET (n,n dimethyl-m-toluamide), Picaridin (KBR 3023), oil of lemon eucalyptus (p-methane 3,8-diol, or PMD). Remember to use mosquito repellent according to label instructions.
  • Wearing loose-fitting, light-colored, long-sleeve shirts and pants when mosquitoes are most active (during dusk and dawn hours) provides added protection from mosquito bites.