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By Kimberly Powell
 West
Nile virus is a mosquito-borne disease that has emerged in recent years in
temperate regions of Europe and North America, presenting a threat to public and
animal health. The most serious manifestation of West Nile virus is
encephalitis, a sometimes fatal infection of the brain. The West Nile Virus made
its first North American appearance in New York in 1999, and was discovered in
Pennsylvania the following year, when health department officials found the
virus in mosquitoes, birds and a horse.
As of
August 21, 2002, 269 cases of illness from West Nile virus have been reported in
the United States, including 13 deaths, according to the Center for Disease
Control. It has not yet been found to have affected humans in western
Pennsylvania, though a number of birds have been killed by the West Nile virus
in Allegheny and surrounding Pennsylvania counties, including an owl at the
Pittsburgh Zoo. Before you panic, however, it is important to remember that less
than 1% of those bitten by an infective mosquito are likely to experience severe
symptoms. Many will have no symptoms, while others will feel like they have a
mild case of the flu.
How do people get West Nile
virus?
Mosquitoes
spread West Nile virus after they feed on infected birds and then bite people,
other birds and animals. It is not spread by person-to-person contact and there
is no evidence that people can get the virus by handling infected animals. West
Nile virus cases occur primarily in the late summer or early Fall, although the
mosquito season is April through October.
Who is most at risk?
People over 50
years of age have the highest risk of developing a severe illness because as we
age, our bodies have a harder time fighting off disease. People with
compromised immune systems are also at increased risk. However, anyone can get
the virus.
What are the symptoms of West
Nile virus?
People with
mild infections may experience fever, headache, body aches, skin rash and
swollen lymph glands. People with more severe infections may experience high
fever, headache, neck stiffness, stupor, disorientation, coma, tremors,
occasional convulsions and paralysis. If you have any of these symptoms,
contact your doctor.
What is West Nile encephalitis?
Encephalitis means an
inflammation of the brain and can be caused by viruses and bacteria, including
viruses transmitted by mosquitoes.
West Nile
encephalitis (WNE) is caused by West Nile virus (WNV), a flavivirus previously
only found in Africa, Eastern Europe, and West Asia. WNV is closely related to
St. Louis encephalitis virus (SLEV) which is found in the United States and to
Kunjin virus (KV) which is found in Australia, some Western Pacific islands and
parts of South East Asia.
Is there a treatment or
vaccine?
There is no specific treatment for West Nile virus infection, or a vaccine.
While most people fully recover from the virus, in some severe cases
hospitalization may be needed
What do
I do if I find a dead bird?
Dead birds in an area may mean that West Nile Virus is circulating between the
birds and mosquitoes in that area. Over
110 species
of birds are known to have been affected with the West Nile virus. Crows and
blues jays are particularly affected, though most infected birds do survive.
You can
play an important role in monitoring West Nile virus by reporting dead birds to
state and local health departments. If you find a dead bird, avoid touching it
with your bare hands, and contact your county's drop-off location. Different
counties and communities of western Pennsylvania have different policies in
place for collecting and testing birds, so see the
Dead Bird Drop-Off Locations page to find
out how to report dead birds in your area.
Next Page >
How to Protect Yourself from Mosquitoes
URL:
http://pittsburgh.about.com/library/bl_west_nile.htm
©
2002
Kimberly & Albrecht Powell. Licensed to About.com. All
Rights Reserved.
Some information provided by CDC.
Mosquito image © 2001
CDC/James Gathany. |
