General Health Articles

What You Should Know About West Nile Virus
(c) 2002 By Becky Sisk, Ph.D.

The West Nile virus (WNV) was first documented in Uganda in 1937. The first case in the United States was reported in New York City in 1999. Additional human cases are identified and deaths are reported daily. Here's what you need to know.

WHO CONTRACTS WNV?

WNV affects all races and men and women equally. The elderly, chronically ill, or immunosuppressed are more likely to become seriously ill or die from WNV.

HOW IS WNV TRANSMITTED?

-- WNV is carried from animal to animal by mosquito bites. Birds (especially crows) are the most common victims, but WNV has infected horses and smaller animals as well.
-- Birds, horses, humans, and other animals do not transmit the disease. Mosquitoes do. Therefore, you will not get WNV if you handle animals who are infected.
-- The more mosquito bites you have, the more likely you are to become infected. This does *not* mean that you should run to the doctor or your emergency room when a mosquito bites you. The likelihood that you have become infected is extremely small.

HOW DO DOCTORS DIAGNOSE WNV?

-- The signs and symptoms of WNV are fever, headache, loss of appetite, nausea and vomiting, muscle pain, eye pain, rash, and enlarged lymph glands. According to a recent article in the Annals of Internal Medicine, the incubaton period of WNV is from three to 14 days.
-- WNV is dangerous when it develops into viral encephalitis or viral meningitis. Symptoms of viral encephalitis include confusion and a gradual loss of consciousness. Symptoms of viral meningitis include a stiff neck and neurological signs your doctor will recognize.
-- Doctors diagnose WNV through a history and physical examination. They also order a blood test to detect the antibody to the WNV and or to find the virus itself in the blood. A case is considered to be "probable West Nile virus" when the WNV antibody is identified and "confirmed West Nile virus" when the virus itself is identified in the blood.

HOW DO DOCTORS TREAT WNV?

Treatment for WNV is entirely supportive because there is no medication that specifically fights the disease. As with any infection, be sure to drink plenty of fluids, get adequate rest, and take fever reducers, such as acetaminophen or aspirin, if you have symptoms of WNV. If you have the symptoms and have been bitten by a mosquito recently, contact your physician.

People who have viral encephalitis or viral meningitis often require intensive care, medications to treat seizures, a breathing machine, and replacement of fluids and electrolytes.

HOW CAN YOU PREVENT WNV?

-- Drain any collections of stagnant water found in your yard, neighborhood, or work place.
-- Use mosquito repellants containing "DEET," carefully following package directions.
* Use a repellant that is no more than 10% DEET for children.
* Treat clothing, skin, bedding, tents and tent screens as well as people.
* Avoid getting mosquito repellant on the hands to prevent getting DEET into the mouth, eyes, ears.
-- Wear long sleeves and long pants when outdoors.
-- Avoid wearing bright colors or using perfumes outdoors. Both may attract mosquitoes.
-- Stay indoors from dusk to dawn, when mosquitoes are more active.
-- Report dead birds or other animals to state and local health departments.
-- Cooperate with local health department and governmental efforts to rid the community of mosquitoes. They use two types of chemicals: Natural compounds that kill the larvae and methoprine to kill adults. Methoprine can cause eye irritations or skin rash, though the incidence is rare.

HOW CAN YOU FIND OUT MORE INFORMATION ABOUT WNV?

Go to the following resources to find out more about WNV. The CDC site has the very latest information, including an up-to-date map showing the most current cases.

Centers for Disease Control (2002). Prevention: Avoid mosquito bites to avoid infection. Retrieved August 12, 2002. http://www.cdc.gov/ncidod/dvbid/westnile/index.htm .

Cunha, B.A. (2002). West Nile encephalitis. Retrieved September 15, 2002. http://www.emedicine.com/med/topic3160.htm . (Requires free registration to access).

Petersen, L.R., & Marfin, A.A. (2002). West Nile virus: A primer for the clinician. Annals of Internal Medicine(137), 173-179.

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Becky Sisk, PhD., is a registered nurse and your Wizard at 
"Promoting Good Health for Seniors," http://wz.com/health/PromotingGoodHealthforSeni.html/ She is also the owner and webmaster of NurseScribe, http://www.enursescribe.com/ .  ****************************************************************