What
Is West Nile Virus?
West Nile virus (WNV) is a potentially serious illness.
Experts believe WNV is established as a seasonal epidemic
in North America that flares up in the summer and continues
into the fall. This fact sheet contains important information
that can help you recognize and prevent West Nile virus.
What
Can I Do to Prevent WNV?
The easiest and best way to avoid WNV is to prevent mosquito bites.
-
When
you are outdoors, use insect repellents containing
DEET (N, N-diethyl-meta-toluamide). Follow the
directions on the package.
-
Many
mosquitoes are most active at dusk and dawn. Be
sure to use insect repellent and wear long sleeves
and pants at these times or consider staying indoors
during these hours. Light-colored clothing can
help you see mosquitoes that land on you.
-
Make
sure you have good screens on your windows and
doors to keep mosquitoes out.
-
Get
rid of mosquito breeding sites by emptying standing
water from flower pots, buckets and barrels. Change
the water in pet dishes and replace the water in
bird baths weekly. Drill holes in tire swings so
water drains out. Keep children's wading pools
empty and on their sides when they aren't being
used.
What
Are the Symptoms of WNV?
WNV affects the central nervous system. Symptoms vary.
-
Serious Symptoms in a Few People. About one in
150 people infected with WNV will develop severe illness.
The severe symptoms can include high fever, headache,
neck stiffness, stupor, disorientation, coma, tremors,
convulsions, muscle weakness, vision loss, numbness
and paralysis. These symptoms may last several weeks,
and neurological effects may be permanent.
- Milder
Symptoms in Some People. Up to 20 percent of the people
who become infected will display symptoms which can include
fever, headache, and body aches, nausea, vomiting, and
sometimes swollen lymph glands or a skin rash on the chest,
stomach and back. Symptoms can last for as short as a
few days, though even healthy people have been sick for
several weeks.
How
Does West Nile Virus Spread?
-
Infected
Mosquitoes. Most often, WNV is spread by the bite
of an infected mosquito. Mosquitoes are WNV carriers
that become infected when they feed on infected birds.
Infected mosquitoes can then spread WNV to humans and
other animals when they bite.
-
Transfusions,
Transplants, and Mother-to-Child. In a very small
number of cases, WNV also has been spread through blood
transfusions, organ transplants, breastfeeding and even
during pregnancy from mother to baby.
- Not
through touching. WNV is not spread through casual
contact such as touching or kissing a person with the
virus.
How
Soon Do Infected People Get Sick?
People typically develop symptoms between 3 and 14 days after
they are bitten by the infected mosquito.
How
Is WNV Infection Treated?
There is no specific treatment for WNV infection. In cases
with milder symptoms, people experience symptoms such as
fever and aches that pass on their own. In more severe cases,
people usually need to go to the hospital where they can
receive supportive treatment including intravenous fluids,
help with breathing and nursing care.
What
Should I Do if I Think I Have WNV?
Milder WNV illness improves on its own, and people do not
necessarily need to seek medical attention for this infection
though they may choose to do so. If you develop symptoms
of severe WNV illness, such as unusually severe headaches
or confusion, seek medical attention immediately. Severe
WNV illness usually requires hospitalization. Pregnant women
and nursing mothers are encouraged to talk to their doctor
if they develop symptoms that could be WNV.
What
Is the Risk of Getting Sick from WNV?
People
over 50 at higher risk to get sick. People over the
age of 50 are more likely to develop serious symptoms
of WNV if they do get sick and should take special care
to avoid mosquito bites.
Being
outside means you're at risk. The more time you're
outdoors, the more time you could be bitten by an infected
mosquito. Pay attention to avoiding mosquito bites if
you spend a lot of time outside, either working or playing.
Risk
through medical procedures is very low. All donated
blood is checked for WNV before being used. The risk of
getting WNV through blood transfusions and organ transplants
is very small, and should not prevent people who need
surgery from having it. If you have concerns, talk to
your doctor.
Pregnancy
and nursing do not increase risk of becoming infected
with WNV. The risk that WNV may present
to a fetus or an infant infected through breastmilk is
still being evaluated. Talk with your care provider is
you have concerns.
What
Is the CDC Doing About WNV?
CDC is working with state and local health departments,
the Food and Drug Administration and other government agencies,
as well as private industry, to prepare for and prevent
new cases of WNV.
Some things CDC is doing include:
-
Coordinating
a nation-wide electronic database where states share
information about WNV
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Helping
states develop and carry out improved mosquito prevention
and control programs
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Developing
better, faster tests to detect and diagnose WNV
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Creating
new education tools and programs for the media, the
public, and health professionals
- Opening
new testing laboratories for WNV
What
Else Should I Know?
If you find a dead bird: Don't handle the body with
your bare hands. Contact your local health department for
instructions on reporting and disposing of the body.
For
more information call the CDC public response hotline
at (888) 246-2675 (English), (888) 246-2857 (Español),
or (866) 874-2646 (TTY)
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