The 4 Ds of West Nile Virus Prevention

July 5th, 2012


By , BSN, RN

The West Nile virus has claimed its second victim in a week here in Houston and with summer coming to full flower and the abundance of rain in much of the country there is little doubt more cases will be reported.

These are the first human cases we have seen in our area but several birds and mosquitos had already tested positive for the seasonal virus. Reports out of Long Island, NY, Louisiana, Michigan, and parts of Virginia also confirm WNV is making its annual appearance in both the bugs and the birds.

Origins of West Nile Virus

West Nile virus (WNV) is a potentially serious illness that rears its ugly symptoms in North America each summer and into the fall. It was first identified in 1937 in Uganda in eastern Africa. It was first discovered in the United States in the summer of 1999 in New York state and since then, the virus has spread throughout the U.S.

Researchers believe West Nile virus is spread when a mosquito bites an infected bird and then bites a person. Mosquitos carry the highest amounts of virus in the early fall, which is why the rate of the disease increases in late August through early September. The risk of disease decreases as the weather becomes colder and mosquitos die off.

WNV can be spread in other, less common ways. In a very small number of cases WNV has been spread through blood transfusions, organ transplants, breast feeding, and even during pregnancy from mother to baby.

West Nile virus cannot be spread by casual contact. Touching or even kissing someone infected with WNV will not spread the illness.

What Are the Symptoms of WNV?

About 20 percent of people develop a mild infection called West Nile fever. Common signs and symptoms of West Nile fever include:

  • Fever
  • Headache
  • Body aches
  • Fatigue
  • Skin rash
  • Swollen lymph glands
  • Eye pain

In less than one percent of infected people the virus causes a serious neurological infection. Such infections may include inflammation of the brain (encephalitis) or of the brain and surrounding membranes (meningoencephalitis).

Serious infection may also include infection and inflammation of the membranes surrounding the brain and spinal cord (meningitis), inflammation of the spinal cord (West Nile poliomyelitis) and acute flaccid paralysis — a sudden weakness in the arms, legs, or breathing muscles. Signs and symptoms of these diseases include:

  • High fever
  • Severe headache
  • Stiff neck
  • Disorientation or confusion
  • Stupor or coma
  • Tremors or muscle jerking
  • Lack of coordination
  • Convulsions
  • Pain
  • Partial paralysis or sudden weakness

Signs and symptoms of West Nile fever usually last a few days, but sign and symptoms of encephalitis or meningitis can linger for weeks, and certain neurological effects, such as muscle weakness, may be permanent.

Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.


Within three to fourteen days after a person is infected with the West Nile virus he or she may develop West Nile symptoms. There is currently no treatment that can kill WNV.

Because West Nile is caused by a virus, antibiotics or other medications are not effective. Therefore, treatment for West Nile focuses on providing relief from symptoms as the body fights the virus.

The Four Ds of WNV Prevention

While most people never even know they have been infected with West Nile virus why take the chance of being one of the few who not only gets it but gets it bad. Here are some tips for preventing WNV, easily remembered by the use of the Four Ds:

  1. Dusk – Like the movie title, “From Dusk till Dawn” is the most dangerous time to be outside. Those are the prime mosquito feeding hours and that is when they are most likely to take a drink out of you.
  2. Dress – Wear long sleeves and long pants to avoid being bitten. This is considered a mechanical method of keeping the little bloodsuckers at bay. Keep in mind though, the sleeves must have cuffs that seal and though it looks ridiculous, if the skeeters are bad tuck your pants legs into your socks. They can infiltrate the smallest of openings.
  3. DEET – Buy an insect repellant that contains DEET and be sure to follow the manufacturers instructions. DEET (Diethyl Toluamide) is a chemical. To some people, the thought of applying it to their skin makes them uneasy. Yet DEET has been in use since 1957 and has been repeatedly tested for toxicity. The human body does absorb DEET, but is believed to eliminate it through urine within 24 hours. The Centers for Disease Control and Prevention (CDC) recommends the use of DEET and considers it safe when applied according to label instructions.
  4. Drainage – Make sure flower pots, water dishes, bird baths and children's swimming pools are properly drained so they're not breeding grounds for mosquitos.

Other measures you can take to keep mosquitos and West Nile virus at bay include installing or repairing window screens. 
Some mosquitoes like to come indoors. Keep them outside by having well-fitting screens on both windows and doors.

Make sure you report dead birds to local authorities. 
Dead birds may be a sign that West Nile virus is circulating between birds and the mosquitoes in your area. Over 130 species of birds have been identified as having been infected with West Nile virus, though not all infected birds will die. It's important to remember that birds die from many other causes besides West Nile virus. 
And whatever you do, don’t touch a dead bird with your bare hands.

West Nile virus is just another side effect of the summer months. If you are working in a doctor’s office or a community clinic or a hospital emergency room you will likely see a few cases. It’s nothing to get to excited about, just know how to recognize it and tell your patients it will likely pass with only a little discomfort. Now, I’m off to buy some new insect repellent, just in case.

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