How do
people get West Nile Virus?
[Top]
The main way that humans become infected
is after being bitten by an infected mosquito. There is no evidence
of human-to-human transmission.
In 2002, additional ways of getting
infected were recognized, but this represents a very small proportion
of cases. These include receiving an infected organ in transplants,
receiving infected blood in transfusions, mother-to-baby in pregnancy
and possibly via breastfeeding, and laboratory exposure to WNV-infected
products.
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 may also be at increased risk. For everyone,
being outside means you're at risk. The more time you're outdoors,
the greater your chances of being bitten by an infected mosquito.
Pay attention to avoiding mosquito bites if you spend a lot of time
outside, either working or playing.
Symptons
of infection in humans [Top]
Most people who get infected with
WNV have no illness or at most, have an infection similar to a mild
flu with fever, headache and fatigue. People with mild infections
may experience fever, headache, body aches, skin rash and swollen
lymph glands. This is called West Nile Fever.
Occasionally, the virus will multiply
in the central nervous system and cause meningitis or encephalitis.
People with more severe infections may experience high fever, neck
stiffness, stupor, disorientation, coma, tremors, occasional convulsions
and paralysis. This is called West Nile Encephalitis. If you develop
any of these symptoms, contact your health care provider.
While most WNV infections are mild,
West Nile Encephalitis can result in death or serious brain damage.
Fewer than 1% of people infected with WNV develop encephalitis,
and even fewer die from complications. Rarely, people infected with
WNV have developed a form of flaccid paralysis that may not improve
significantly over time. This is still being studied.
Information
for pregnant and breastfeeding women [Top]
There has been one documented case of transplacental
(mother-to-child) transmission. A newborn was born with medical
problems, and it is unknown whether the West Nile infection contributed
to these problems or if it was coincidental. This issue is still
being studied by the Centers for Disease Control and Prevention
(CDC). Pregnant women, like everyone else, should focus on reducing
their exposure by avoiding mosquitoes, wearing long sleeves and
pants when outside and wearing repellents containing DEET. There
are no reported side effects from the use of repellents containing
DEET in pregnant or breastfeeding women. Because the health benefits
of breastfeeding are well established, and the risk for WNV transmission
through breastfeeding is unknown but considered very small, no change
in breastfeeding habits is recommended. Lactating women who are
ill or are having difficulty breastfeeding for any reason, as always,
are advised to consult their physicians.
Blood donations
and organ transplants [Top]
Donating blood is safe, and is encouraged
now and in the future. If you are sick, however, you should wait
to donate blood until you are well. A person who has had West Nile
virus can still donate blood after they completely recover. All
blood and organs donated in the U.S. are screened for West Nile
Virus. The benefits of receiving needed transfusions or transplants
far outweigh the potential risk for infection.
Is there
a treatment or vaccine for West Nile Virus? [Top]
There is no specific treatment for WNV
infection, nor is there a proven vaccine for humans. Bed rest, fluids
and other supportive care is routinely recommended, and most people
fully recover from the infection; however, in some severe cases,
hospitalization may be needed.
For more information about WNV and human
infection, visit the Centers for Disease Control and Prevention
Web site at: www.cdc.gov/ncidod/dvbid/westnile/index.htm
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