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West Nile Virus (cont.)

When Should I Call the Doctor About West Nile Virus Infection?

West Nile virus is transmitted by mosquitoes mainly during the summer months, and infections generally appear between the months of May to October. Rarely, transmission via blood transfusions, organ transplants, and mother-to-fetus or mother-to-infant from breastfeeding has been reported.

  • People who have been bitten by a mosquito in the geographic area where West Nile virus is known to appear and who experience signs or symptoms of serious illness should see their doctor immediately.
  • Most people with mild symptoms of low-grade fever and muscle aches do not have West Nile virus and will not require specific diagnostic testing.

Anyone who has symptoms of severe illness such as mental-status changes, high fever, neck stiffness, sensitivity to light, or confusion should go to an urgent-care center or hospital emergency department immediately. The West Nile encephalitis that occurred during the initial 1999 New York outbreak was especially notable for its severe muscle weakness. This is another important warning symptom.

How Is West Nile Virus and West Nile Encephalitis Diagnosed?

Diagnosing West Nile virus infections is generally done through a combination of observing signs and symptoms along with specialized molecular biologic testing for the virus itself.

  • Only people with severe symptoms will require further testing. There is no cure for West Nile and therefore little to gain by widespread testing of people with mild symptoms.
  • Confirmatory diagnosis of West Nile virus infection is generally done by a DNA test called polymerase chain reaction (PCR) or viral culture of fluid removed from around the spinal cord (lumbar puncture procedure). A doctor sends both blood samples and spinal fluid samples, obtained by lumbar puncture (also called a spinal tap), to a specialized laboratory for these tests. This testing helps exclude dengue fever, equine encephalitis, Lyme disease, and other infections from WNE.

Are There Home Remedies for West Nile Virus?

Home care for people who suspect they may have become infected with West Nile virus is limited to relief of symptoms. There is no specific treatment for the virus.

Mild illness does not require therapy other than medications to reduce fever and pain. Avoid aspirin use in children because it presents a risk for a fatal condition known as Reye's syndrome.

Severe symptoms require hospital treatment.

Last Reviewed 11/21/2017

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Read What Your Physician is Reading on Medscape

West Nile Encephalitis »

West Nile encephalitis (WNE) is distinguished from other arthropod-borne causes of viral encephalitis (eg, western equine encephalitis, eastern equine encephalitis [EEE], Japanese encephalitis, Venezuelan encephalitis) based on its geographic distribution, clinical features, and laboratory findings.

Read More on Medscape Reference »

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