Information courtesy of the Centers for Disease Control (CDC).
 

Q.  What is West Nile Virus?
A.  West Nile Virus is a mosquito-borne disease. West Nile virus (WNV) is a potentially serious illness. West Nile virus is transmitted by mosquitoes and causes an illness that ranges from mild to severe. Mild, flu-like illness is often called West Nile fever. More severe forms of disease, which can be life-threatening, may be called West Nile encephalitis or West Nile meningitis, depending on where it spreads.
 

Q.  Is West Nile Virus now established in the United States?
A. The continued expansion of West Nile Virus in the United States indicates that it is permanently established in the Western Hemisphere.
 

Q. How do people get infected with West Nile virus (WNV)?
A. The main route of human infection with West Nile virus is through the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. The virus eventually gets into the mosquito's salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness.
 

Q. If I live in an area where birds or mosquitoes with West Nile virus have been reported and a mosquito bites me, am I likely to get sick?
A. No. Even in areas where the virus is circulating, very few mosquitoes are infected with the virus. Even if the mosquito is infected, less than 1% of people who get bitten and become infected will get severely ill.  The chances you will become severely ill from any one mosquito bite are extremely small.
 

Q. Can you get West Nile encephalitis from another person?
A. No. West Nile encephalitis is NOT transmitted from person-to-person. For example, you cannot get West Nile virus from touching or kissing a person who has the disease, or from a health care worker who has treated someone with the disease.
 

Q. How many types of animals have been found to be infected with West Nile virus?
A. Although the vast majority of infections have been identified in birds, WNV virus has been shown to infect horses, cats, bats, chipmunks, skunks, squirrels, and domestic rabbits.
 

Q. Can you get West Nile virus directly from birds?
A. There is no evidence that a person can get the virus from handling live or dead infected birds.  However, persons should avoid bare-handed contact when handling any dead animals and use gloves or double plastic bags to place the carcass in a garbage can.
 

Q. How does West Nile virus actually cause severe illness and death in humans?
A. Following transmission by an infected mosquito, West Nile virus multiplies in the persons blood system and crosses the blood-brain barrier to reach the brain. The virus interferes with normal central nervous system functioning and causes inflammation of brain tissue.
 

Q. How long does the West Nile virus remain in a person after they are infected?
A. There is no scientific evidence indicating that people can be chronically infected with West Nile virus.  What remain in a persons body for long periods of time are antibodies and "memory" white blood cells (T-lymphocytes) that the body produces to the virus. These antibodies and T-lymphocytes last for years, and may last for the rest of a person's life. Antibodies are what many diagnostic tests look for when clinical laboratories testing is performed. Both antibodies and "memory" T-lymphocytes provide future protection from the virus.
 

Q. If a person contracts West Nile virus, does that person develop a natural immunity to future infection by the virus?
A. It is assumed that immunity will be lifelong; however, it may wane in later years.
 

Q. I think I have symptoms if West Nile Virus. What should I do?
A. Contact your doctor if you have concerns about your health. If you develop symptoms such as high fever, confusion, muscle weakness, and severe headaches, you should see your doctor immediately.
 

Prevention:  

Q. What can I do to reduce my risk of becoming infected with West Nile virus? 

 A. Here are preventive measures that you and your family can take:

Protect yourself from mosquito bites:

- Apply insect repellent sparingly to exposed skin. The more DEET a repellent contains the longer time it can protect you from mosquito bites. A higher   percentage of DEET in a repellent does not mean that your protection is better, just that it will last longer. DEET concentrations higher than 50% do not increase the length of protection. Choose a repellent that provides protection for the amount of time that you will be outdoors. Products containing 10% or less DEET are the most appropriate for children aged 2-12.

- Repellents may irritate the eyes and mouth, so avoid applying repellent to the hands of children. 

- When possible, wear long-sleeved shirts and long pants whenever you are outdoors.

- Place mosquito netting over infant carriers when you are outdoors with infants.

- Consider staying indoors at dawn, dusk, and in the early evening, which are peak mosquito biting times.

- Install or repair window and door screens so that mosquitoes cannot get indoors.
 

Q. What can be done to prevent outbreaks of West Nile virus?
A. Prevention and control of West Nile virus and other arboviral diseases is most effectively accomplished through integrated vector management programs. These programs should include surveillance for West Nile virus activity in mosquito vectors, birds, horses, other animals, and humans, and implementation of appropriate mosquito control measures to reduce mosquito populations when necessary. Additionally, when virus activity is detected in an area, residents should be alerted and advised to increase measures to reduce contact with mosquitoes.
 

Q. Is there a vaccine against West Nile encephalitis?
A. No, but several companies are working toward developing a vaccine.
 

Q. Where can I get information about the use of pesticide sprays that are being used for mosquito control?
A. The federal agency responsible for pesticide evaluation is the Environmental Protection Agency (EPA).
 

For more information, please contact the Environmental Health Department by This e-mail address is being protected from spambots. You need JavaScript enabled to view it , by calling 972-462-5177 or click on the websites listed below:
 

Texas Department of State Health Services: West Nile Information

Center for Disease Control: West Nile Virus

Environmental Protection Agency: Pesticides and Mosquito Control