| Q. |
What is the West Nile
virus (WNV)? |
x |
WNV
is a virus that was first discovered in Uganda in the 1930's. It is very
similar to another virus that is present in the United States, St. Louis
Encephalitis virus. |
| x |
x |
| Q. |
Where did West Nile virus
come from? |
x
x |
WNV
has been commonly found in humans and birds and other vertebrates in Africa,
Eastern Europe, West Asia, and the Middle East, but until 1999 had not
been documented in the Western Hemisphere. |
| x |
x |
| Q. |
How long has West Nile
virus been in the U.S.? |
x |
Scientists
believe the virus has been in the eastern U.S. since the early summer of
1999, possibly longer. |
| x |
x |
| Q. |
Is the disease seasonal
in its occurrence? |
x
x |
In
the temperate zone of the world, West Nile encephalitis cases occur primarily
in the late summer or early fall. In the southern climates where
temperatures are milder, WNV can be transmitted year round. |
| x |
x |
| x |
Transmission
of West Nile Virus |
| Q. |
How do people get West
Nile encephalitis? |
|
Most
commonly, people become infected by the bite of a mosquito infected with
WNV. |
| x |
x |
| Q. |
What is the basic transmission
cycle? |
x
x
x
x |
Mosquitos
become infected when they feed on infected birds, which circulate the virus
in their blood. Infected mosquitos can then transmit WNV to humans
and animals while biting to take blood. During blood feeding, the
virus may be injected into the animal or human, where it may multiply,
possibly causing illness. |
| x |
x |
Q.
x |
If I live in an area
where birds or mosquitoes with West Nile virus have been reported and a
mosquito bites, me, am I likely to get sick? |
x
x
x |
No.
Even in areas where the virus is circulating, very few mosquitoes are infected
with the virus. Even if the mosquito is infected, less than 1% of people
who get bitten and become infected will get severely ill. The chances
you will become severely ill from any single mosquito bite are extremely
small. |
| x |
x |
| Q. |
Can you get West Nile
encephalitis from another person? |
x
x |
No.
West Nile encephalitis is NOT transmitted from person-to-person through
casual contact. There is evidence that WNV may be transmitted through organ
transplants and blood transfusions if the donor was infected. |
|
x |
| Q. |
Can you get West Nile
virus directly from birds? |
|
There
is no evidence that a person can get the virus from handling infected birds,
whether live or dead. However, persons should avoid bare-handed contact
when handling any dead animals. Use gloves and double plastic bags to handle
any dead bird. |
| . |
x |
| Q. |
How does West Nile virus
actually cause severe illness and death to humans? |
| . |
Following
transmission by an infected mosquito, WNV can multiply in the person's
blood system and cross the blood-brain barrier to reach the brain. The
virus can interfere with normal central nervous system functioning and
cause inflammation of brain tissue. |
| x |
x |
| Q. |
What proportion of people
with severe illness due to West Nile virus die? |
|
Less
than 1% of persons infected with West Nile virus will develop severe illness.
Among those who have developed a severe illness with WNV, between 3% and
15% have died. Most of the deaths have occurred among the elderly. |
| . |
. |
| . |
Prevention
of West Nile Virus |
| Q. |
What can be done to prevent
outbreaks of West Nile virus? |
| . |
Everyone
has a role to play in eliminating the standing water in which mosquitoes
may breed. Once virus activity is detected in the area, residents should
increase their efforts to reduce contact with mosquitoes. |
| . |
. |
| Q. |
Is there a vaccine against
West Nile encephalitis? |
| . |
No,
but several companies are working towards developing a vaccine. There
is a vaccine available for horses, but its effectiveness in not fully known
at the present time. |
| . |
. |
| Q. |
What can I do to reduce
my risk of becoming infected with West Nile virus? |
| . |
1.
Stay indoors at dawn, dusk, and in the early evening. |
| . |
2.
Wear long-sleeved shirts and long pants whenever you are outdoors. |
| . |
3.
Apply insect repellent sparingly to exposed skin. An effective repellent
for adults will contain 35% DEET (N,N-diethyl-meta-toluamide), with concentrations
of 10% or less for children aged 2-12. Repellents may irritate the eyes
and mouth, so avoid applying repellent to the hands of children. |
| . |
4.
Whenever you use an insecticide or insect repellent, be sure to read and
follow the manufacturer's DIRECTIONS FOR USE, as printed on the product. |
| . |
5.
Install or repair window and door screens so that mosquitoes cannot get
indoors. |
| . |
. |
|
Symptoms
of West Nile Virus |
| Q. |
Who is at risk for getting
West Nile encephalitis? |
| . |
All
residents of areas where virus activity has been identified are at risk
of getting West Nile encephalitis. Persons over 50 years of age and those
with weakened immune systems have the highest risk of severe disease. |
| . |
. |
| Q. |
What are the symptoms
of West Nile encephalitis? |
| x |
Most
infections are mild, and symptoms include fever, headache, and body aches,
occasionally with skin rash and swollen lymph glands. More severe infection
may be marked by headache, high fever, neck stiffness, stupor, disorientation,
coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. |
| . |
. |
Q.
x |
What's the incubation
period in humans (time from infection to onset of symptoms) for West Nile
encephalitis? |
| . |
Usually
3 to 15 days. |
| . |
. |
| . |
West
Nile Virus and Birds |
| Q. |
Do birds infected with
West Nile virus die or become ill? |
| x |
In
the 1999 New York area epidemic, there was a large die-off of American
crows. WNV infection has been identified in dozens of species of birds
in the United States. Most of these birds were identified through reporting
of dead birds by the public. |
| . |
. |
| Q. |
How can I report a sighting
of dead bird(s) in my area? |
| x |
As
part of their West Nile virus surveillance efforts, the Orange County Vector
Control District is selectively testing birds that may have been dead for
less than 24 hours. To contact a Vector Control representative, call (714)
971-2421, extension 146. The State of California has also established a
toll-free telephone number for the public to report birds that have been
dead for less than 24 hours. That number is 1-877-WNV-BIRD. |
| X |
X |
| . |
For
more information on West Nile Virus, check these helpful websites: |
| 1. |
The
Centers for Disease Control and Prevention WNV page
http://www.cdc.gov/ncidod/dvbid/westnile/index.htm |
| . |
x |
| 2. |
The
State or California's WNV web site
http://www.westnile.ca.gov/ |
| . |
. |
| 3. |
Click here
for some pertinent information on keeping those pesky insects under control. |
