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West Nile Virus News
Information on Mosquitoes
Have a neighbor who speaks Spanish? Give them this.
Insect Repellent Use and Safety
West Nile Virus FAQ
Overview of West Nile Virus
Transmission
Testing & Treatment
Prevention
West Nile Virus in Birds
West Nile Virus in Dogs or Cats
West Nile Virus and Wild Game Hunters
E-mail Complaint or question regarding WNV or mosquitoes
Overview of West Nile Virus
Q. What Is West Nile encephalitis?
A. "Encephalitis" means an inflammation of the brain and can be caused by viruses and bacteria, including viruses transmitted by mosquitoes. West Nile encephalitis is an infection of the brain caused by West Nile Virus (WNV), commonly found in Africa, West Asia, and the Middle East. It is closely related to St. Louis encephalitis virus found in the United States. It is believed that the WNV has only been in the United States since the summer of 1999.
Q. Who is at risk for getting West Nile encephalitis?
A. All residents of areas where virus activity has been identified are at risk of getting West Nile encephalitis; persons greater than 50 years of age have the highest risk of severe disease.
Q. Is the disease seasonal in its occurrence?
A. West Nile encephalitis cases occur primarily during the time when very active mosquito activity occurs, which may be in the late summer or early fall.
Q. What are the symptoms of West Nile encephalitis?
A. Most infections are mild and symptoms include fever, headache, and body aches, often with skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis and, rarely, death.
Q. What is the incubation period for West Nile encephalitis?
A. Usually 5 to 15 days.
Q. How many cases of West Nile encephalitis occurred in the U.S. last year?
A. Prior to August 1999, West Nile virus had never been reported in the U.S. In 1999, 61 cases of severe disease and 7 deaths occurred in the New York area. During 2006 in Tennessee there were a total of 22 confirmed cases in Humans and of that number 14 were Shelby County residents.
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Transmission
Q. How do people get West Nile encephalitis?
A. By the bite of a mosquito (primarily the Culex species) that is infected with West Nile virus.
Q. What is the basic transmission cycle?
A. Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. After an incubation period of 10 days to 2 weeks, infected mosquitoes can then transmit West Nile virus to humans and animals while biting to take blood.
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. 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, avoid barehanded contact when handling dead animals, including dead birds. Use gloves to place the carcass in a garbage can.
Q. Besides mosquitoes, can you get West Nile virus directly from other insects or ticks?
A. Infected mosquitoes are the primary source for West Nile virus and caused the 1999 outbreak in the New York City metropolitan area. Ticks infected with West Nile virus have been found in Asia and Africa. Their role in the transmission and maintenance of the virus is uncertain. However, there is no information to suggest that ticks transmitted West Nile virus to patients in the New York area outbreak.
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Testing & Treatment
Q. What should a person do if he/she thinks they have West Nile encephalitis?
A. Seek medical care as soon as possible.
Q. How is West Nile encephalitis treated?
A. There is no specific therapy. In more severe cases, intensive supportive therapy is indicated, i.e., hospitalization, intravenous (IV) fluids and nutrition, airway management, ventilatory support (ventilator) if needed, prevention of secondary infections (pneumonia, urinary tract, etc.), and good nursing care.
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Prevention
Q. What precautions are being taken to prevent an outbreak of West Nile encephalitis in Memphis?
A. In 2000 the Vector Control Section of the Memphis and Shelby County Health Department added sampling for West Nile virus in mosquito and bird populations to their Surveillance Program already in place for SLE. Throughout the year the Vector Control staff is actively working to eliminate possible mosquito breeding areas, and as appropriate begins rapid mosquito control measures, such as targeted application of larvicide and adulticide, are implemented.
Q. Is there a vaccine against West Nile encephalitis?
A. Unfortunately not at this time.
Q. What can be done to reduce the risk of becoming infected with West Nile virus?
A.
- Stay indoors at dawn, dusk, and in the early evening.
- Wear long-sleeved shirts and long pants whenever you are outdoors. Light colored clothes are less attractive to mosquitoes.
- Apply insect repellent sparingly to exposed skin. An effective repellent will contain 20% to 35% DEET. For children, avoid products containing more than 10% DEET.
- Insect repellants should not be applied to very young children (< 3 years old). Repellents may irritate the eyes and mouth, so avoid applying repellent to the hands of children.
- Spray clothing with repellents containing DEET, as mosquitoes may bite through thin clothing.
- Whenever you use an insecticide or insect repellent, be sure to read and follow the manufacturer's DIRECTIONS FOR USE, as printed on the product.
- You can decrease your chances of contracting WNV by following some simple precautions:
 Mosquito proof your yard by flushing any standing water in birdbaths where mosquitoes breed, twice weekly.
Empty water from small wading pools and store indoors.
If you have an ornamental pool, you can stock the pool with mosquito fish or treat the water with a larval control product.
Provide fresh clean water in pet's bowls daily.
Remove old tires, cans, non-working appliances or container that will hold water. Repair leaky plumbing.
Clean out rain gutters.
Ensure proper screening around door and windows of your home.
For information on mosquitoes, contact the Memphis and Shelby County Health Department's Vector Control Section at (901) 324-5547. For St. Louis Encephalitis or West Nile Virus information, contact the West Nile Virus Hotline at (901) 544-7503 or the Epidemiology Section at (901) 544-7717.
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West Nile Virus in Birds
Q. Do birds infected with West Nile virus become ill or die?
A. In the 1999 New York area epidemic, there was a large of crows found dead. Through September 2000, West Nile virus has been identified in several different species of dead birds. Most of these birds were identified through the reporting of dead birds by the public. The birds that appear to be the most susceptible to the WNV are crows, blue jays and hawks.
Q. Have any dead birds been tested in Memphis and Shelby County?
A. In 2001 a total of forty-four (44) blue jays found in Shelby County testing positive for WNV. These were the first birds to test positive for West Nile virus in Tennessee. In 2002 there were 82 birds testing positive from Shelby County, and in 2003, 24 birds tested positive. Once positive finds occur throughout the county, dead birds are no longer tested which accounts for the lower number.
Q. How can I report a sighting of dead bird(s) in my area?
A. The Health Department is no longer is testing or picking up non-decomposed dead crows and blue jays for West Nile Virus testing. Once the birds tested positive it confimed that West Nile Virus was in the community and these birds are considered local and and not migratory. Therefore there is no need to test birds.
If a resident finds a dead bird in their yard, the following are recommendations for the resident to dispose of remains:
- Pick the bird up using a glove or plastic bag
- Place bird in a bag, Ziploc or other plastic bag that can be tied up.
- Discard in the trash.
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West Nile Virus in Dogs or Cats
Q. Can West Nile virus cause illness in dogs or cats?
A. West Nile virus has been isolated from several dead cats in 1999 and 2000. A serosurvey of dogs and cats in the epidemic area showed a low infection rate.
Q. Can infected dogs or cats be carriers for, and transmit West Nile virus to humans?
A. West Nile virus is transmitted by infectious mosquitoes.
Q. Can a dog or cat infected with West Nile virus infect other dogs or cats?
A. No. There is no documented evidence that West Nile virus is transmitted from animal-to-animal
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West Nile Virus and Wild Game Hunters
Q. Are duck and other wild game hunters at risk for West Nile virus infection?
A. Because of their outdoor exposure, game hunters may be at risk if they become bitten by mosquitoes in areas with West Nile virus activity. The extent to which West Nile virus may be present in wild game is unknown.
Q. What should wild game hunters do to protect against West Nile virus infection?
A. Hunters should follow the usual precautions when handling wild animals. If they anticipate being exposed to mosquitoes, they should apply insect repellents to clothing and skin, according to label instructions, to prevent mosquito bites. Hunters should wear gloves when handling and cleaning animals to prevent blood exposure to bare hands and meat should be cooked thoroughly.
Q. Who should wild game hunters contact for information about the risk for West Nile virus infection in specific geographic areas?
A. Hunters should check with their local health department or visit the Tennessee Department of Health's West Nile Virus website at http://www2.state.tn.us/health/CEDS/wnvhome.htm.
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The following websites contain excellent educational material about West Nile Virus and other arboviruses, mosquito control activities, steps individuals can take to protect themselves, and West Nile Virus surveillance results throughout the United States:
www.cdc.gov/ncidod/dvbid/westnile/index.htm
The Centers for Disease Control and Prevention (CDC) West Nile Virus Homepage with a wealth of information plus many links to other WNV sites.
www.epa.gov/pesticides/factsheets/skeeters.htm
The EPA site with mosquito control guidelines, factsheets on mosquito sprays, etc.
http://nptn.orst.edu & click on "West Nile Virus Resource Guide".
This is the National Pesticide Telecommunications Network (NPTN) with insect repellant information and links to a multitude of other West Nile Virus sites.
For additional information on mosquitoes, contact the Memphisand Shelby County Health Department's Vector Control Section at 324-5547. For West Nile encephalitis information, contact the Epidemiology Section at 576-7717.
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E-mail Memphis and Shelby County Health Department Vector Control Office with Questions about West Nile Virus, control of mosquitoes, etc.
All e-mail will be answered within one business day. | 
