Crawford County Home & Garden
Outdoor Pests
West Nile Virus and West Nile Encephalitis - Frequently Asked Questions
What is West Nile virus (WNV)?
West Nile virus (WNV) is a virus that is spread by infected mosquitoes. The
virus usually infects birds, but it can be spread to humans by mosquitoes that
feed on infected birds and then bite humans. The virus cannot be spread by
person-to-person contact.
Historically, West Nile virus has been found in parts of Africa, West Asia,
Eastern Europe, and the Middle East. The virus was identified in the United
States for the first time during 1999. West Nile virus is closely related to the
virus that causes St. Louis encephalitis (SLE), which has caused illnesses in
Arkansas residents in the past.
Have any people in the United States been infected with this virus?
Yes. There was an outbreak of West Nile virus in New York City and the
surrounding region during the late summer and fall of 1999 and again during the
summer and fall of 2000. Birds, humans, and horses in the New York City area
were infected with the virus and were ill. During 1999, 62 humans were diagnosed
with West Nile encephalitis in New York City and 7 of those humans died. During
2000, 21 humans were diagnosed with West Nile encephalitis in New York, New
Jersey, and Connecticut; 2 of those humans died. By October 2001, it was present
in 27 states and Canada. Since 1999, over 142 people have been diagnosed, and 14
have died with West Nile virus.
Is West Nile virus in Arkansas?
In 2001, four dead birds found in Saline, Crawford and Union counties in
Arkansas tested positive for West Nile virus, but no human cases have been
diagnosed to date in Arkansas.
How concerned
should I be about West Nile Virus?
The disease caused by West Nile virus is very similar to St. Louis
Encephalitis (SLE), which has already been reported in Arkansas in the past. SLE
and WNV are in the same family of viruses. The mosquitoes that transmit SLE and
WNV usually prefer to bite birds. Human infections with these mosquito-borne
viruses are very rare and can be prevented by taking simple measures to avoid
mosquito bites.
What
measures are being taken to protect Arkansas residents?
The best protection against any mosquito-borne virus is to prevent mosquitoes
from biting. Personal protection methods and mosquito abatement techniques are
listed at the end of this fact sheet. In addition to prevention, identification
of the virus in a bird, mosquito, horse, or human assists public health
officials in providing specific recommendations to an affected area.
Surveillance for WNV includes testing of dead birds, especially crows and blue
jays which are very sensitive to infection with WNV. Many blue jays and crows
infected with WNV in the US die from the disease. If you find a dead bird with
no obvious cause of death, notify an Environmentalist Specialist at your local
health unit to report it. If the bird is a recently dead blue jay or crow, bring
it in to the local health unit to have it tested for WNV. Blood samples from
live wild birds are also being tested for WNV and SLE.
In addition to looking for West Nile virus in birds, we will provide
assistance to veterinarians to have horses with symptoms of encephalitis tested
for West Nile virus. Laboratory samples from humans who are suspected of having
a mosquito-borne viral encephalitis will also be tested for West Nile virus and
other mosquito-borne viruses that occur in Arkansas.
If West Nile virus or any other mosquito-borne disease is detected in
Arkansas, press releases will be issued and public education will be provided to
increase awareness of personal protective measures to prevent mosquito exposure.
Your county may also begin other control measures to reduce the number of larval
and/or adult mosquitoes.
What symptoms will I have if I am infected with West Nile virus?
Symptoms usually occur 3-15 days after the bite of an infected mosquito. Most
people who are infected with West Nile virus will have no symptoms or may have a
mild flu-like illness with a fever, headache, and body aches before they
recover. In some individuals, particularly the elderly, the virus can cause a
serious illness called encephalitis, which is an inflammation of the
brain. Symptoms of encephalitis may include high fever, severe headache, nausea,
stiff neck, confusion, muscle weakness, paralysis, disorientation, convulsions,
coma, and rarely, death. Less than 1% of humans infected with West Nile virus
will develop serious illness. If you have any concerns about your health, you
should contact your healthcare provider.
What should I do if a mosquito bites me (or a member of my family)? Should I be
tested for West Nile virus or other mosquito-borne diseases?
There are no antibiotics or other drugs that can be taken to prevent illness
after a mosquito bite. If an illness does occur after a mosquito bite,
particularly with fever, confusion, muscle weakness, or severe headaches, or if
your eyes become unusually sensitive to light, you should consult your physician
immediately. Your health care provider will determine what kind of treatment you
require and whether or not you should have any specific laboratory tests
performed.
Is there a treatment
for West Nile virus?
No. There is no specific treatment, medication, or cure for illnesses caused
by West Nile virus. However, the symptoms and complications of the disease can
be treated. Most people who get the illness recover from it.
Is there a vaccine for
West Nile virus?
There is no vaccine to protect humans against West Nile virus
infection. In August 2001 a vaccine to help protect horses against West
Nile virus infection was conditionally approved by the U. S. Department of
Agriculture. Please contact your veterinarian for information about obtaining
the vaccine for your horse.
If West Nile virus is detected in my county/town/neighborhood, should I stay
indoors?
No. The risks of acquiring a mosquito-borne disease are so low that staying
indoors is not necessary. However, you can take some simple precautions while
you are outside, such as wearing long sleeves and long pants and applying an
insect repellent (containing DEET) according to label directions.
Why
isn’t my neighborhood being sprayed for mosquitoes?
Health officials in your county will decide whether or not to spray your
community for mosquitoes. In some areas, spraying is not the most beneficial or
the most cost-effective way to control mosquito populations or mosquito-borne
diseases. Again, the best way to protect yourself and your family against these
diseases is to follow simple precautions that are detailed at the end of this
sheet.
I have seen dead
birds. Should I report them?
During the summer that West Nile virus was discovered in the United States
many birds in the New York City area died for no apparent reason. Further
investigation revealed that the birds were dying of West Nile virus infections.
Many birds (many species of birds) die when they are infected with West Nile
virus, so health officials in the Northeast have successfully used dead bird
reports to track the spread of the virus.
Please contact your local health unit if you find dead birds near your home.
You may find the phone number of your local health unit in the government
listings of your phone book. Some of the reported crows, blue jays, and raptors
(raptors are birds of prey such as owls, hawks, or eagles) will be collected and
tested for West Nile virus. If your local health unit asks that, you submit dead
birds for testing, please follow their instructions for handling the birds.
Otherwise, dead birds may be disposed of by double-bagging and placing them in
the regular trash, or burying them three feet deep. Reports of birds that are
not collected for testing are still very useful. These dead bird sightings will
be recorded and combined with reports from throughout the state so that we may
determine if the virus is present in Arkansas and quickly identify where it
might be.
Remember that birds may die for many reasons. Some birds die of old age, some
are hit by cars or run into power lines, some are considered pests and are
poisoned by humans, some die from other viral or bacterial infections.
Will
the dead birds in my area make my family or me sick?
Dead birds infected with this type of virus have never been known to be a
source of illness for people. This viral infection is spread to people by the
bite of an infected mosquito. However, you should not handle any dead animal
with your bare hands. Wear gloves or use a shovel to handle dead birds or any
other dead animal.
Where have there been infected mosquitoes, birds, and other animals?
You may find
maps
of the current distribution of West Nile virus in the United States on the
web.
What
animals other than birds can get West Nile virus? Do I have to worry that my
pets or livestock will get West Nile virus?
Many species of wild and domestic animals (such as dogs and cats) can become
infected with West Nile virus by the bites of infected mosquitoes. However, most
animals other than birds will not become ill or die when they are
infected with the virus. Several West Nile virus-infected horses have become ill
and died in the United States. Please contact a veterinarian to evaluate and
treat any pets or domestic animals that become ill.
Do I have to worry that my
poultry (chickens, turkeys) will get West Nile virus? Should I continue to
eat their eggs?
The U.S. Department of Agriculture’s Animal and Plant Health Inspection
Service (APHIS) has performed studies to learn more about what happens to
chickens and turkeys when they are infected with West Nile virus. It is expected
that most chickens and turkeys that are infected with West Nile virus will make
antibodies to the virus and will not become ill or die. Some exotic breeds of
poultry that live outdoors are susceptible and may die if infected. You may
continue to eat your chickens' eggs. There is no evidence that West Nile virus
or other mosquito-transmitted viruses appear in chickens' eggs. You should
always cook your eggs thoroughly to prevent food-borne illnesses.
What is the
treatment for an animal that is infected with West Nile virus? Should an
infected animal be destroyed?
There is no specific treatment, medication, or cure for illnesses caused by
West Nile virus in dogs, cats, horses, or other animals. However, the symptoms
and complications of the disease can be treated with supportive therapy that is
consistent with standard veterinary practices for animals infected with a viral
agent. Full recovery from the infection is likely and there is no reason to
destroy an animal that is infected.
Can
infected dogs or cats (or other animals) be carriers (i.e. reservoirs) for
West Nile virus and transmit the virus to humans or other animals?
West Nile virus is transmitted by infected mosquitoes. There is no documented
evidence of person-to-person, animal-to-animal, or animal-to-person transmission
of West Nile virus. Veterinarians should take normal infection control
precautions when caring for an animal suspected to have this or any viral
infection.
Will horses
affected by the virus be quarantined?
No. Since infected horses do not appear to be carriers for the disease,
quarantine is unnecessary.
Is there
anything I can do to protect my horse or pet from West Nile virus?
Yes. You should limit your animals’ exposure to mosquitoes. The best way to
do this is by removing any potential sources of water in which mosquitoes can
breed. Dispose of any water-holding containers on your property. Drill holes in
the bottom of containers that are left outdoors. Clean clogged roof gutters.
Keep swimming pools properly cleaned and maintained. Routinely empty, clean, and
refill livestock watering troughs.
It may be advisable to keep horses, pets, and other animals inside at night
to reduce the probability of them being bitten by a mosquito. Horses can be kept
inside a barn, with the barn doors closed.
A vaccine to help protect horses from infection with West Nile virus was
conditionally licensed by the U.S. Department of Agriculture in August 2001 and
will be available in the near future. You should contact your veterinarian if
you have questions about this vaccine.
When I vaccinate my horse against Eastern Equine Encephalitis (EEE), Western
Equine Encephalitis (WEE), or Venezuelan Equine Encephalitis (VEE), will that
protect against infection with the West Nile virus?
No. The equine encephalitis viruses and West Nile virus belong to different
families, so the vaccines are not expected to provide cross-protection. There is
a vaccine for horses for West Nile Virus.
Are wild game hunters at risk
for West Nile virus infection?
Because of their outdoor exposure, hunters may be at risk if they are bitten
by mosquitoes in areas where there is West Nile virus activity. Hunters should
take precautions to avoid mosquito bites, such as applying mosquito repellent to
clothing and skin according to label instructions. Hunters should also follow
the usual precautions when handling wild animals. They should wear gloves when
handling and cleaning animals to prevent blood exposure to bare hands and meat
should be cooked thoroughly.
How can I prevent
myself from being infected with West Nile virus?
The best way to prevent infections with West Nile virus and other
mosquito-borne diseases is to avoid getting mosquito bites. Other viruses
that are transmitted by mosquitoes, including those that cause St. Louis
Encephalitis (SLE) and Eastern Equine Encephalitis (EEE), already exist in
Arkansas and you can take the following precautions to protect yourself and your
family against them:
- Minimize time spent outdoors when mosquitoes are most active (usually
dusk and dawn).
- If you go outdoors when mosquitoes are active, cover up by wearing shoes,
socks, long-sleeved shirts, and long pants. Consider using a mosquito repellant
that contains DEET (N,N-diethyl-methyl-meta-toluamide) on exposed skin. Use
products containing 10% or less DEET for children and no more than 30% for
adults. Do NOT use products containing DEET on infants. Carefully read and
follow directions on the container and wash treated skin when mosquito exposure
has ended.
- Make sure your home, porch, and patio have tight-fitting screens that
keep mosquitoes out.
- All mosquitoes need standing water for the first stages of development.
Eliminate stagnant water around your home, where mosquitoes can lay eggs, by
disposing of old tin cans, jars, tires, plant pots, and any other container that
can hold water. In the spring, inspect rain gutters and downspouts and remove
any leaves and other debris. Stack wheelbarrows, tubs, buckets, barrels, boats
or canoes, etc. upside down so that water cannot accumulate in them. Empty
stagnant bird baths, lily ponds, small wading pools, etc. at least once a week.
Properly maintain backyard swimming pools to discourage the development of
mosquitoes. Cover any pool not in use so rainwater and leaves do not accumulate
in it. Be sure the cover does not hold pockets of water.
**Note: Vitamin B and “ultrasonic” devices are NOT effective in
preventing mosquito bites.**
Whom should I contact
for more information?
- For Information about local mosquito control programs and how to report
dead birds, please call Your local health unit. You may find the phone
number in the government listings of your phone book.
-
CDC web site
- For information about the use of insect repellents containing DEET or
pesticides to control mosquitoes, visit the
Environmental Protection Agency's (EPA) website.
- For maps of the current distribution of West Nile virus in the United
States, visit the
National Atlas website.
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