West Nile Virus FAQ's

What is West Nile virus?
West Nile virus (WNV) is a mosquito-borne virus that causes disease in humans and animals. The virus was first discovered in the U.S. in 1999 in New York City. How WNV came to the U.S. is unknown at this time.

How do people get West Nile virus?
People get West Nile virus from the bite of a mosquito that is infected with WNV.

Who gets West Nile virus?
Anyone who is bitten by a mosquito that is infected with WNV can get the disease. Elderly persons and those with depressed immune systems are more likely to develop a serious illness if infected.

What are the symptoms of West Nile virus?
Many people who are infected with WNV will have either no symptoms or only a mild headache. They may not even know they are infected. Other persons may have a number of symptoms including fever, body aches, rash, and swollen lymph glands (West Nile Fever). People who have a severe infection (West Nile Meningitis/Encephalitis) may have a stiff neck, and muscle weakness, and they may become disoriented. Such people may have seizures, go into a coma, and, in rare occasions, may die.

How soon do symptoms appear?
Most people will begin to have symptoms of disease about 6 days after they are bitten by an infected mosquito, but some people may become ill as early as 3 days after being bitten, or as late as 15 days.

How does the disease spread?
Wild birds can carry the West Nile virus, and the virus is spread from bird-to-bird by mosquitoes. Infected mosquitoes can transmit WNV to humans or other animals while biting them.

Can you get West Nile virus from another person?
No. There is no evidence that West Nile virus can be transmitted directly to humans by animals or by other humans.

If bitten by a mosquito, should I be tested for WNV?
No. Illnesses related to mosquito bites are rare. However, you should see a doctor immediately if you develop symptoms such as high fever, confusion, muscle weakness or severe headaches. Patients with mild symptoms are likely to recover completely and do not require any specific medication or laboratory testing.

If I travel to an area where birds with WNV have been reported and I am bitten by a mosquito, am I likely to get sick?
No. Even in areas where mosquitoes do carry the virus, very few mosquitoes (usually less than one out of 500) are infected. The chance that one mosquito bite will be from an infected mosquito is very small.

Can WNV be transmitted through blood transfusions?
Please see the Centers for Disease Control and Prevention (CDC) page for Q&A on blood transfusions: http://www.cdc.gov/ncidod/dvbid/westnile/qa/transfusion.htm.

I am pregnant. If I get WNV, is my baby at risk?
There has been one case of mother-to-child transmission of WNV in the United States, but more information is needed in order to understand the risks with pregnancy. Pregnant women should take the proper steps to avoid infection by wearing protective clothing and using repellents containing DEET. When WNV activity is in an area, pregnant women who become sick should see their doctor.

What is the treatment for West Nile virus?
Mild cases of West Nile virus often require no treatment at all. More severe cases may require hospitalization.

Is there a vaccine for West Nile virus?
There is no vaccine for West Nile virus at this time.

What can be done to prevent West Nile virus?

It is wise to protect yourself from mosquitoes:

• Reduce time spent outdoors (especially when mosquitoes are biting - between dusk and dawn).
• Wear long pants and long-sleeved shirts when outside.
• Apply mosquito repellent to exposed skin areas when outside (for adults use DEET at 30-35% concentration and for children (between 2-12 years) use less than 10% concentration. DO NOT use for children under 2 years old).
• Make sure screen doors and window screens are in good condition.
• Eliminate standing water sources around housing areas (i.e., water in old tires, cans, birdbaths, poorly kept swimming pools, etc.).
• Keep weeds and tall grass cut short; adult mosquitoes look for these shady places to rest
  during the hot daylight hours.
• Use mosquito netting when sleeping outdoors or in an unscreened structure and to protect small babies any time.

Public health measures may be taken in communities where mosquitoes are a concern. These may include:

• Aerial spraying of pesticides
• Elimination or draining of places where mosquitoes live and breed
• Other use of pesticides to kill mosquitoes

Why should I use a mosquito repellent that contains DEET?
DEET (N,N-diethyl-m-toluamide) is the most effective and best-studied insect repellent available (Fradin MS, Day JF. Comparative efficacy of insect repellents against mosquito bites. N Engl J Med. 2002;347(1):13-8). The more DEET a repellent contains, the longer it can protect you. A higher percentage of DEET does not mean it will protect you better, just that it will last longer. However, DEET concentrations higher than 50% do not increase the length of protection. For example, a product containing 23.8% DEET provides about 5 hours of protection.

Is DEET safe?
Yes, products containing DEET are very safe when used according to the directions. Always follow these steps:

• Use enough repellent to cover exposed skin or clothing. Don=t apply repellent to skin that is under clothing. Heavy application is not necessary to achieve protection.
• Do not apply repellent to cuts, wounds, or irritated skin.
• After returning indoors, wash treated skin with soap and water.
• Do not spray aerosol or pump products in enclosed areas.
• Do not apply aerosol or pump products directly to your face. Spray your hands and then rub them carefully over the face, avoiding eyes and mouth.
  See http://npic.orst.edu/factsheets/DEETgen.pdf for more information.

Should pregnant or nursing women use DEET?
There are no reported adverse events following use of repellents containing DEET in pregnant or nursing women.

I like to do outdoor activities. Am I at greater risk for WNV?
Any person bitten by a mosquito infected with WNV is at risk. The mosquito that most likely carries the disease breeds in the stagnant water of mud puddles, ditches, flower pots, old tires, clogged gutters, and similar types of water. It is important to use mosquito repellent when doing any outdoor activity - especially when fishing, camping, or boating at night. Window screens on campers and boats should be kept Abug-tight@ as should netting on tents and other outdoor gear. Keeping a campsite neat and getting rid of mosquito breeding sites is always recommended. Electric Abug zappers@ do not help since they usually attract more mosquitoes than they kill.

Are hunters who field dress wild game birds at risk for WNV?
There is no evidence that WNV can be transmitted directly from birds or mammals to humans through direct blood contact. However, hunters are always urged to take proper precautions and wear rubber gloves when field dressing game.

Can a person get WNV by eating infected game birds?
Proper cooking kills the WNV. There is most likely no danger associated with eating well-cooked wild game that might be infected.

Where can I get more info?

Vernal Office County-State Building 147 East Main Street Vernal, Utah 84078 (435) 781-5475	Roosevelt Office 281 East 200 North Roosevelt, Utah 84066 (435) 722-5085
Flaming Gorge Community Health Center Manila, Utah 84046 (435) 784-3494	Duchesne Office 50 East 100 South Duchesne, Utah 84021 (435) 738-2202
Dental Clinic 198 West 200 North Vernal, Utah 84078 (435) 781-0875