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1. What is the West Nile Virus?

It's one of a group of viruses spread by mosquito bites.

West Nile Virus (WNV) is a flavivirus commonly found in Africa, West Africa, and the Middle East. It is closely related to St. Louis Encephalitis virus found in the United States. WNV was first discovered in the United States in 1999. The virus can infect humans, birds, mosquitoes, horses, and some other mammals.

West Nile Virus can cause mild to severe illness. Most people who get infected do not get sick. Some get a mild, flu-like illness. In rarer cases, the virus can affect the brain and spinal cord, cause encephalitis, and can be fatal.

Spraying informed is the best way to defend against WNV. Learning about the virus and ways to prevent infection is key. Steps you take can help protect you from other mosquito-borne diseases, too.

2. How does the West Nile Virus spread?

Generally, WNV is spread by the bite of an infected mosquito. Mosquitoes are WNV carriers that become infected when they feed on infected birds. These mosquitoes can then spread WNV to humans and other animals when they bite.

3. Is the West Nile Virus contagious?

WNV is not spread through casual contact such as touching or kissing a person with the virus.

In a very small number of cases, WNV has spread through blood transfusions, organ transplants, breastfeeding, and even during pregnancy from a mother to a baby.

4. How soon do you get the symptoms once you have been bitten?

People typically develop symptoms between three and 14 days after they are bitten by an infected mosquito.

5. What are the symptoms of West Nile Virus?

West Nile Virus (WNV) can affect the central nervous system. The severity of symptoms can vary from person to person.

• No symptom in most people: Approximately 80 percent of people who are infected with WNV will not show any symptoms and will not know they have it.
• Mild infection in some people: Up to 20 percent of the people who become infected will display mild flu-like symptoms, including headache and body aches, nausea, vomiting, as well as swollen lymph glands, or a skin rash on the chest, stomach, and back. Symptoms typically last a few days. This is known as West Nile Fever.
• Serious infection in a few people: About one in 150 people infected with WNV will develop severe illness, such as West Nile Encephalitis, West Nile Meningitis, or West Nile Meningoencephalitis. The symptoms can include headache as well as neck stiffness, confusion, and high fever. These symptoms may last several weeks or even months. The neurological effects may be permanent.
• WNV is known to cause death in rare circumstances.

6. How is West Nile Virus treated?

There is no specific treatment for WNV infection. In mild cases, people experience symptoms such as fever and aches that go away on their own. In more severe cases, people may need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing, and nursing care.

7. Does the Health Department offer free testing?

If you think you have WNV or have WNV symptoms, go see your primary care physician. If you are uninsured, seek care from your local community healthcare center. If your symptoms are severe, go to the hospital emergency room as soon as possible.

8. Can I get the virus twice?

We don't think so. It is assumed that a person would develop a natural immunity to future infection by the virus, and that this immunity would be lifelong. However, this immunity may wane in later years.

9. My child or I was bitten by a mosquito, what should I do?

A bite by a mosquito alone doesn't warrant being tested for WNV. Most mosquitoes are not infected with WNV. Even in areas where mosquitoes may be found that carry the virus, few mosquitoes are infected. However, seek medical attention immediately if you or your child develop(s) symptoms such as high fever, confusion, muscle weakness, severe headaches, stiff neck, or if his or her eyes become sensitive to light.

10. What should I do if I think I have WNV?

If you think you may have WNV, see your doctor or health care provider as soon as possible. They will be able to run the tests needed to diagnose and treat your condition.


Mild WNV illness often improves on its own. If you develop symptoms of the more sever form of WNV illness, such as unusually severe headaches or confusion, seek medical attention immediately.

11. What is Dallas County doing?

Dallas County uses an Integrated Mosquito Management (IMM) program to abate mosquito populations. IMM uses various techniques that included the following tools:

• Adulticide - The spraying of EPA approved products from tucks and planes to reduce mosquito populations.


• Larvicide - The use of EPA approved products to kill mosquito larvae in standing water or stocking water with mosquitofish.


• Personal Protection - Changing personal habits to reduce mosquito bites. This means you and how you can protect yourself, your family, and community.


• Public Awareness - Informing the public by press release, public information campaigns, websites, pamphlets, and presentations.


• Source Reduction - Remove water sources that support mosquito breeding habitats.


• Surveillance - The collection of mosquitoes to determine the location, species, quantity, and virus potential.

12. What can I do?

Mosquito Proof. Remember the "Best Offense is a Good Defense."

 

Dress 

• Wear long, loose, and light-colored clothing to avoid mosquito bites when outside

DEET 

• Use insect repellent products with “DEET” or other EPA approved repellents and follow product

Drain 

• Get rid of all standing water
• Empty, remove, cover, or turn upside down any containers that will hold standing water (bottles, cans, tires, buckets, flower pots, etc.)
• Change water in pet dishes, wading pools, and birdbaths several times a week
• Cover trash containers so they will not collect water

Dusk and Dawn 

• Stay indoors during dusk and dawn hours, when mosquitoes are most active

13. What should I do if I see dead birds in my yard?

Dallas County does not collect dead birds for testing. Mosquitoes are the vectors that transmit WNV to people so the focus is on surveillance of mosquitoes only. If you would like to report a bird within obvious trauma that appears to have died within the last 24 hours, contact your city's Health Department. To dispose of a dead bird, avoid bare-handed contact and use gloves or an inverted plastic bag to place it in an outside garbage receptacle.

14. Can dogs, cats, and other pets get West Nile Virus?

Yes, but rarely, if ever, get sick. No cases of WNV have been confirmed in dogs or cats. The virus can infect many species of animals, but few actually develop symptoms. Most infections have been identified in birds, but WNV has been shown to infect dogs, cats, horses, and domestic rabbits, as well as bats, chipmunks, skunks, and squirrels.

15. Are pesticides harmful to people?

Effect on human health is one of the primary factors considered in regulation of pesticides. Pesticides that can be used for mosquito control have been judged by the EPA not to pose an unreasonable risk to human health. People who are concerned about exposure to a pesticide, such as those with chemical sensitivity or breathing conditions such as asthma, can reduce their potential for exposure by staying indoors during the application period, usually nighttime.

A CDC report, (MMWR, July 11, 2009), examined illnesses in nine states associated with exposure to pesticides used to control mosquito populations from 1999-2002. This study found that "application of certain insecticides posed a low risk for acute, temporary health effects among persons in areas that were sprayed and among works handling and applying insecticides." For more information, view this MMWR article.

16. Where can I learn more information?

For more information on pesticides and health, consult the US Environmental Protection Agency (EPA), which oversees the registration of these chemicals. The National Pesticide Information Center (NPIC) can also provide information through a toll-free phone number at 1 (800) 858-7378.