March 25, 2010
To protect yourself from exposure to WNV, try to stay indoors during the evening and early morning hours, the times when mosquitoes are most active. While outdoors, wear light-colored, long sleeve clothing, and use an insect repellent containing DEET, according to its label directions.
The GHD asks all citizens to eliminate any standing water on their property, such as birdbaths (clean them twice per week), pet water dishes, clogged rain gutters, tire piles, and buckets. Containers that can hold an inch or two of water can breed mosquitoes. Report any standing water that you are not able to eliminate yourself to the GHD. Also report any dead blue jays or crows found in your neighborhood. These dead birds are good signs of virus activity and indicate where mosquito control efforts need to be concentrated. If you have questions or would like to report dead birds or standing water, please call the Garland Health Department’s mosquito control hotline at (972) 205-3720. Further questions on WNV should be directed to the City of Garland’s website, www.ci.garland.tx.us, or 972-205-3460.
West Nile Virus Facts:
West Nile Virus (WNV) is a viral infection of wild birds and mammals that can be spread to people by infected mosquitoes.
WNV is similar to several other animal viruses that can be spread by infected mosquitoes. These insect-borne viruses are collectively called arboviruses (arthropod-borne viruses) and include St. Louis encephalitis (SLE), Eastern Equine encephalitis (EEE), Western Equine encephalitis (WEE), and Venezuelan Equine encephalitis (VEE).
WNV has been recognized as a distance viral disease since the late 1930's. Outbreaks have been reported in Africa, Israel, and Eastern Europe.
WNV was first reported in the United States during an outbreak in New York City in 1999. There were approximately 62 confirmed cases and seven deaths. The infection occurred again in 2000 in New York City, but with fewer cases.
The disease-causing virus has now been confirmed in most of the continental United States.WNV is now considered a naturally-occurring infection of birds in the US. Several species of mosquitoes can become infected while feeding on infected birds. These mosquitoes can then inject the virus into other warm-blooded animals (like other birds, rodents, cats and dogs, horses, etc.) and humans. Rodents, dogs, and cats do not routinely show symptoms and may not be affected by the virus. Some species of birds (specifically blue jays and crows) seem especially susceptible. The presence of dead or dying blue jays or crows in a community may be an early warning sign to the presence of WNV in the wild bird population and in mosquitoes. Equines (horses and donkeys) are also affected by the virus. The disease can be fatal in equines; however, most horses which develop disease recover fully.
Disease experts with the Center for Disease Control (CDC) in Atlanta, Georgia report that only a fraction of the population of mosquitoes in an area experiencing a WNV outbreak are actually carrying the virus. Additionally, the majority of people who are exposed to WNV through the bite of an infected mosquito will not become ill (an estimated one percent of exposed persons go on to develop illness).
Of the small minority of exposed people who develop WNV symptoms, it is generally those persons over 50 years old who experience the most serious form of West Nile virus infection. Specifically, persons over 50 are more likely to develop an infection of the covering of the brain and spinal cord (meningitis) or an infection of the actual brain itself (encephalitis). Of the group that develops meningitis or encephalitis, previous outbreaks have shown that as many as 11 percent may progress to a fatal form of the disease, with persons 70 years of age or older being at highest risk.
The GHD requests that citizens report the presence of dead or dying blue jays or crows by date and address by calling 972-205-3720. To properly dispose of dead birds on your property, simply turn a plastic trash bag inside out, grab the bird with the inverted bag, and turn the bad right-side out. Tie the bad and place it in your green trash container for disposal. Please wash hands with soap and warm water after handling any dead animal (not for prevention of WNV, but to protect against bird mites or bacteria).
The GHD will continue to collect live mosquitoes from throughout the city and ship them to the Texas Department of State Health Services (TDSHS) laboratory in Austin for testing (for all known arboviruses).
The GHD controls mosquitoes in three ways: Environmental Health Specialists (EHSs) require property owners who possess breeding sites (containers of water or standing water) to remove the breeding sources. EHSs also treat standing water (a control method called larviciding) with agents which kill immature mosquitoes (the larvae or "wigglers"). To reduce adult mosquito populations, the GHD sprays a low-toxicity pesticide from a truck-mounted, low volume sprayer (a control method called adulticiding).
The GHD has analyzed technical and toxicological data on essentially all known, currently available EPA-approved mosquito adulticides. The only pesticides the GHD uses for spraying are those which contain man-made derivatives of pyrethrins (e.g resmethrin or permethrin). These formulations, when mixed and sprayed according to label directions, are considered by the US Environmental Protection Agency (EPA) to be safe with respect to adults, children, and pets.
Truck spraying is performed either in the period from 10:30pm to 2:00am or the period from 3:00am to sunrise. The active ingredient in the spray (resmethrin or permethrin) is generally toxic to mosquitoes only when the pesticide droplets are suspended in air. The actual amount of dilute insecticide that lands on a typical 1/4 acre lot in Garland is only 1/3 of a teaspoon. Less than 5/100ths of a teaspoon (2 or 3 medicine dropper drops) of active ingredient lands on a typical homesite as microscopic droplets. After dropping to the ground, this non-persistent pesticide decomposes in sunlight and in contact with moisture in less than 24 hours. The insecticide used by the GHD is considered by many public health agencies as the safest mosquito adulticide currently available.
The GHD strongly urges Garland residents to avoid being bitten by mosquitoes. Prevention strategies include:
Limit outdoor activity near dawn and dusk
When outdoors during peak mosquito activity, consider wearing long pants and long sleeve, loose-fitting shirts.
Treat exposed skin with a repellent that contains the active ingredient DEET. Always use repellents and insecticides according to label directions, and avoid getting repellent into the eyes.
Ensure that window screens fit tightly and are in good condition.
Eliminate any containers in your yard that can hold water (e.g. tires, cans, flower pots holding free-standing water, clogged rain gutters)
Report to the Health Department any properties that contain neglected swimming pools or that contain stagnant water bodies.
Symptoms of West Nile virus infection in humans include:
Fever
Headache
Muscle aches
Confusion
Nausea
Rash
Stiff Neck
Arboviral illnesses like West Nile and St. Louis encephalitis generally appear in people from June through November. Anyone who experiences symptoms consistent with WNV should see a physician as soon as possible.
The incubation period for WNV (the period between being bitten my an infected mosquito and showing the first symptoms) varies from three days to 15 days.
As with most viral infections, there is no specific treatment for West Nile virus infection. Hospital treatment is supportive.
For additional information on West Nile virus or other public health issues, please call the Garland Health Department at 972-205-3460. The Center for Disease Control and Prevention has extensive information on West Nile virus and other diseases at its website: www.cdc.gov