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New York City Department of Health
West Nile Virus
General Information on West Nile virus
Q: What is West Nile virus?
A: West Nile virus is a mosquito-borne virus that can cause
encephalitis (inflammation of the brain) or meningitis (inflammation of
the lining of the brain and spinal cord).
Q: How is West Nile virus spread?
A: West Nile virus is spread to humans by the bite of an infected
mosquito. A mosquito becomes infected by biting a bird that carries the
virus. You or your child cannot get West Nile virus from a person who has
the disease. West Nile virus is not spread by person-to-person contact
such as touching, kissing, or caring for someone who is infected.
Q: Where did the West Nile virus come from?
A: Outbreaks of the West Nile virus have occurred before in Egypt,
Asia, Israel, South Africa, parts of Europe and Australia. Before 1999,
the West Nile virus had never before been found in the United States. The
New York City Department of Health, the New York State Health Department,
and the U.S. Centers for Disease Control and Prevention (CDC), are
currently investigating how the West Nile virus got into New York City.
The most likely explanation is that the virus was introduced by an
infected bird that was imported or an infected human returning from a
country where the virus is common.
Q: Can you get West Nile virus directly from birds?
A: West Nile virus cannot spread directly from birds to people.
However, dead birds should not be handled with bare hands. Use gloves
to carefully place dead birds in a double plastic bag and then place the
dead birds in the outdoor trash.
Q: Besides mosquitoes, can you get West Nile virus
directly from other insects or ticks?
A: Infected mosquitoes are the primary source for West Nile virus
and caused the recent outbreak in the New York City metropolitan area.
There is no information to suggest that ticks transmitted West Nile virus
to patients in the New York area outbreak.
Q: What are the symptoms of West Nile virus?
A: In last year's outbreak, most people who were infected with West
Nile virus had no symptoms or experienced mild illness such as a fever,
headache and body aches before fully recovering. In outbreaks in other
parts of the world, some persons also developed a mild rash or swollen
lymph glands. In some individuals, particularly the elderly, West Nile
virus can cause serious disease that affects brain tissue. At its most
serious, it can cause permanent neurological damage and can be fatal.
Encephalitis (inflammation of the brain) symptoms include the rapid onset
of severe headache, high fever, stiff neck, confusion, loss of
consciousness (coma), and muscle weakness. Death may result in some cases.
Q: Is a woman's pregnancy at risk if she gets West
Nile encephalitis?
A: There is no documented evidence that a pregnant woman or her
fetus are at increased risk due to infection with West Nile virus.
Q: How is West Nile encephalitis treated?
A: There is no specific therapy. In more severe cases, intensive
supportive therapy is indicated, i.e., hospitalization, intravenous (IV)
fluids and nutrition, airway management, ventilatory support (ventilator)
if needed, prevention of secondary infections (pneumonia, urinary tract,
etc.), and good nursing care.
Q: Is there a vaccine against West Nile virus?
A: No.
Q: How long does it take to get sick if bitten by an
infected mosquito?
A: Being bitten by an infected mosquito will not necessarily make
you sick since most people who are infected with West Nile virus have no
symptoms or experience mild illness. If illness were to occur, it would
occur within 5 to15 days of being bitten by an infected mosquito.
Q: What should a person do if he/she thinks they have
West Nile encephalitis?
A: If a person has signs of encephalitis, with fever, muscle
weakness, and confusion, he or she should seek medical care as soon as
possible.
Q: Who is at risk for getting West Nile encephalitis
after being bitten by an infected mosquito?
A: Persons older than 50 years of age have the highest risk of
severe disease.
Q: What can I do to reduce my risk of becoming
infected with West Nile virus?
A: From April to October, when mosquitoes are most active, take the
following precautions:
- If outside during evening, nighttime and dawn hours
when mosquitoes are most active and likely to bite, children and adults
should wear protective clothing such as long pants, long-sleeved shirts,
and socks.
- If outside during evening, nighttime and dawn hours,
consider the use of an insect repellant containing 10% or less DEET (N,
N-diethyl-methyl-meta-toluamide) for children and no more than 30% DEET
for adults.
- USE
DEET ACCORDING TO
MANUFACTURER'S DIRECTIONS:
- Do not use DEET on infants or pregnant women.
- Do not allow young children to apply DEET
themselves.
- Do not apply DEET directly to children. Apply to
your own hands and then put it on the child.
- DEET is effective for approximately four hours.
Avoid prolonged or excessive use of DEET. Use sparingly to cover
exposed skin and clothing.
- Wash all treated skin and clothing after returning
indoors.
- Store DEET out of reach of children.
- Note that Vitamin B, ultrasonic devices,
incense and bug zappers have not been shown to be effective in
preventing mosquito bites.
Q: What can I do around my home to help reduce
exposure to mosquitoes?
A: Mosquitoes lay their eggs in standing water. Weeds, tall grass,
and bushes provide an outdoor home for the adult Culex pipiens
mosquito (the common house mosquito) which is most commonly associated
with West Nile virus. Mosquitoes can enter homes through unscreened
windows or doors, or broken screens.
- Make sure that doors and windows have tight-fitting
screens. Repair or replace all screens in your home that have tears or
holes.
- Remove all discarded tires from your property.
- Dispose of tin cans, plastic containers, ceramic
pots, or similar water-holding containers.
- Make sure roof gutters drain properly. Clean clogged
gutters in the spring and fall.
- Clean and chlorinate swimming pools, outdoor saunas
and hot tubs. If not in use, keep empty and covered.
- Drain water from pool covers.
- Change the water in bird baths at least once a week.
- Turn over plastic wading pools and wheelbarrows when
not in use.
- Eliminate any standing water that collects on your
property.
- Remind or help neighbors to eliminate breeding sites
on their properties.
Please Note: Some local hardware stores may carry
a product called Mosquito Dunk that contains a larvicide - Bacillus
thuringiensis israelensis (BTI) - for use in areas of standing water
around the home. The City Department of Health recommends eliminating
standing water around the home to reduce breeding sites for mosquitoes and
warns that direct handling of larvicides
may cause skin and eye irritation. If these products are purchased for
home use, we recommend careful reading of the hazards label, directions,
and details regarding storage and handling.
Q: What is the City doing to address the possible
return of West Nile virus?
A: The New York City Department of Health, along with other City,
State and federal agencies, has developed a comprehensive plan to reduce
the risk of West Nile virus returning in 2000. The main goal of this plan
is to decrease the number of adult mosquitoes by eliminating their
breeding sites, where possible, and applying
larvicides (to kill the
immature larval form of the mosquito) to areas with standing water that
can not be drained completely. The City will also regularly test adult
mosquitoes and birds for West Nile virus throughout the spring and summer.
If West Nile virus is found, focused and limited applications of
pesticides may be needed to prevent the spread to people.
Q: Is the City planning to spray pesticides by plane
or helicopter, as was done last year?
A: Reducing the adult mosquito population (adulticiding)
with pesticides approved by the US Environmental Protection Agency will be
done when necessary to prevent or address the potential for illness in the
human population. The City is hopeful that with an early and aggressive
campaign against mosquitoes, the need for aerial spraying of pesticides
will be reduced. In addition, early warning systems to detect the spread
of West Nile virus in birds and mosquitoes can help direct effective and
targeted use of pesticides.
Q: What health risks are posed to people and pets
from pesticides?
A: If pesticides are used, the products that will be applied will
be used according to guidelines set by the U.S. Environmental Protection
Agency. In the small amounts that they would be used, these pesticides
would pose negligible risks to people and to pets. Some people may be more
sensitive to pesticides and should closely adhere to the recommendations
below. Avoiding exposure to pesticides will lessen the risk of any
reactions, which may include eye irritation, rash or difficulty breathing.
There could be an odor associated with pesticides, but it will pass in a
few hours. Call the City's Poison Control Center at (212) POISONS or
(212) 764-7667 for more information, if exposure to pesticides causes any
adverse reactions.
Q. Will the public be notified in advance about
spraying activities?
A: Residents will learn about spraying schedules through public
service announcements, the media, the City's website, and a telephone
information line.
Q: If the City sprays pesticides, what should I do
during the spraying?
A: If spraying were to occur, the New York City Department of
Health recommends that all individuals take the following precautions to
avoid direct exposure to pesticides and reduce the risk of any reactions
to pesticides:
- Some individuals are sensitive to pesticides. Persons
with asthma or other respiratory conditions are especially encouraged to
stay inside during spraying since there is a possibility that spraying
could worsen those conditions.
- Whenever possible, stay indoors during spraying.
- Turn fans and air conditioners off or set them to
exhaust to reduce indoor odor.
- Remove children's toys, outdoor equipment and clothes
from outdoor areas.
(If toys are left outside, wash with soap and water before using again.)
- Wash skin and clothing exposed to pesticides with
soap and water.
- Anyone experiencing adverse reactions to
pesticides should call their doctor or the NYC Poison Control Center at
(212) POISONS or (212) 764-7667.
Q: If I live in an area where birds or mosquitoes
with West Nile virus have been reported, and I am bitten by a mosquito, am
I likely to get sick?
A: No. Even in areas where mosquitoes do carry the virus, very few
mosquitoes -- less than 1% -- are infected. The chances that any one bite
will be from an infected mosquito are very small.
Q. I've gotten a mosquito bite. Should I be tested
for West Nile virus?
A: No. Most mosquitoes are not infected with West Nile virus.
Illnesses related to mosquito bites are rare, especially in New York City.
However, you should see a doctor immediately if you develop symptoms such
as high fever, confusion, muscle weakness, severe headaches, stiff neck,
or if your eyes become sensitive to light. Patients with mild symptoms
should recover completely, and do not require any specific medication or
laboratory testing.
Q: Should I report dead birds to the Health
Department?
A: The Department of Health is taking reports on dead bird
sightings within New York City, especially crows and sparrows. While the
Department of Health is interested in collecting information about dead
birds as part of its efforts to understand West Nile virus, we will not be
picking up every dead bird reported. The Department will only be
collecting a small sample of the bird population. However, we encourage
New York City residents to report all dead bird sightings on this line to
assist the department's monitoring efforts.
If you do not receive a phone call from the Department
of Health to arrange pick up of the dead bird within 24 hours of making
the report or by the next business day, please dispose of the dead bird.
West Nile virus cannot spread directly from birds to people, however dead
birds should not be handled with bare hands. Use gloves to carefully
place dead birds in a double plastic bag and then place the dead birds in
the outdoor trash.
For more information about West Nile virus, call the
New York City Department of Health West Nile Information Line, 24 hours a
day, seven days a week, at (877) WNV-4NYC or (877) 968-4692.
April 2000 |
