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Has West Nile
virus been detected in Illinois?
West Nile virus
was first identified in Illinois on Sept. 5, 2001. By the end of 2001, the
virus had been found in seven Illinois counties in birds, mosquito pools and
horses. In 2002, the virus has been identified in birds, mosquito pools and
a horse.
Have there
been any human cases of West Nile encephalitis in Illinois?
Yes. Illinois
reported its first case of West Nile disease on Aug. 6, 2002. The Illinois
Department of Public Health has asked physicians to report all suspect cases
of West Nile disease and to submit specimens so that testing for West Nile
virus can be done.
What is the
transmission cycle of WNV in the environment?
Mosquitoes become
infected with WNV when they feed on infected birds. These infected
mosquitoes then can transmit WNV to humans and to other birds and animals
when a mosquito bite occurs.
Is it only
humans who become ill when infected with WNV?
No. Certain
animals also can become ill when infected with WNV. For example, horses
exposed to WNV can develop encephalitis. Also, certain birds – particularly
crows and blue jays – can become ill and die with WNV infection.
What are the
symptoms of West Nile encephalitis?
Most people who
are infected have no symptoms or may experience mild illness, such as a
fever and headache, before fully recovering. In some individuals,
particularly the elderly, WNV can cause serious disease that affects the
brain. It can cause permanent neurological damage and be fatal. Symptoms
generally occur three to 15 days following the bite of an infected mosquito
and range from a slight fever, headache, rash, swollen nodes and
conjunctivitis (irritation of the eye) to the rapid onset of a severe
headache, high fever, stiff neck, disorientation, muscle weakness, coma or
death. Less than 1 percent of persons infected with West Nile virus will
develop severe illness.
What
percentage of WNV cases are fatal?
The case fatality
rate ranges from 3 percent to15 percent.
Who is at risk
of contracting West Nile encephalitis?
All residents in
areas with WNV activity are at risk of getting West Nile encephalitis; those
at highest risk of severe disease are persons 50 years of age or older and
those whose immune systems are weakened by illness or medical treatment (for
example, chemotherapy).
Is there a
treatment for West Nile encephalitis?
There is no
specific therapy for West Nile encephalitis. In more severe cases, intensive
supportive therapy – hospitalization, intravenous (IV) fluids, airway
management, respiratory support (ventilator) if needed, prevention of
secondary infections (pneumonia, urinary tract, etc.) and good nursing care
– are indicated.
Is there a
vaccine for West Nile encephalitis?
No human vaccine
for West Nile virus encephalitis exists.
If I travel to
an area where birds with WNV have been reported and I am bitten by a
mosquito, am I likely to get sick?
No. Even in areas
where mosquitoes do carry the virus, very few mosquitoes (usually less than
one out of 500) are infected. The chance that one mosquito bite will be from
an infected mosquito is very small.
If bitten by a
mosquito, should I be tested for WNV?
No. Illnesses
related to mosquito bites are rare. However, you should see a doctor
immediately if you develop symptoms such as high fever, confusion, muscle
weakness or severe headaches. Patients with mild symptoms are likely to
recover completely and do not require any specific medication or laboratory
testing.
Why is the
state testing birds (especially crows) for WNV?
Crows appear to
be highly sensitive to the virus and provide an early warning system for
detecting WNV activity in a community. Knowledge of infected birds in a
neighborhood or community allows public health officials to alert citizens
about the increased risk of mosquito-borne diseases.
What should I
do if I find a dead bird?
If a dead crow
or blue jay is found between May 1 and the end of October and appears to
have died from natural causes, you should report this information to your
local health department. Your local health department will let you know if
it is still collecting and testing dead birds. If the local health
department has stopped collecting birds, you will be provided with
instructions on how to safely dispose of the bird.
What time of
year are mosquito viruses spread?
Viruses are most
likely to be spread during the warm weather months when mosquitoes are most
active, usually beginning in the spring and lasting until the first hard
frost. Most human cases occur in late summer and fall.
Are bird and
wild game hunters at risk for WNV?
Because of their
outdoor exposure, hunters may be at risk if they are in areas with WNV
activity and are bitten by mosquitoes. If they anticipate being exposed to
mosquitoes, they should apply insect repellent to clothing and skin,
according to label instructions, to prevent mosquito bites. Hunters should
follow the usual precautions when handling wild animals and birds. They
should wear gloves when handling and cleaning birds or animals to prevent
blood exposure to bare hands.
Can a person
contract West Nile encephalitis by eating infected game birds?
Proper cooking
kills the WNV. Consequently, there is no danger associated with eating wild
game that might be infected.
Can West Nile
encephalitis be prevented?
The best way to
prevent West Nile encephalitis or any other mosquito-borne illness is to
reduce the number of mosquitoes around your home and neighborhood and to
take personal precautions to avoid mosquito bites. Here are some
suggestions:
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the virus was introduced to the U.S., it may
have entered this country in an infected traveler, bird or mosquito.
To
report 