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Avian Flu – General Information
The Bird
Conservation Network is providing the following information and
links for those interested in the latest information:
What is avian
influenza?
Avian influenza, or “bird flu”, is a
contagious disease of animals caused by viruses that normally infect
only birds and, less commonly, pigs. Avian influenza viruses are
highly species-specific, but have, on rare occasions, crossed the
species barrier to infect humans. [CDC]
Do migratory birds
spread the avian flu?
The role of migratory birds in the
spread of highly pathogenic avian influenza is not fully understood.
Wild waterfowl are considered the natural reservoir of all influenza
A viruses, usually in the low pathogenic form. They have probably
carried influenza viruses, with no apparent harm, for centuries.
Considerable circumstantial evidence suggests that migratory birds
can introduce low pathogenic viruses to poultry flocks, which then
mutate to the highly pathogenic form. [CDC]
What about stopping the infected birds?
The control of
avian influenza infection in wild bird populations at this stage, is
not feasible - from a logistical, environmental and biodiversity
point of view. Indiscriminate culling of wild migratory bird
populations would be ineffective in preventing further spread of
avian influenza and their hunting would likely cause dispersion of
the birds. [UN Food and Agriculture Organization] Wild birds play a
critical role in the earth’s ecology through the pollination of
one-third of our food supply and in the control of insect
populations.
How do people become
infected?
Direct contact with infected poultry,
or surfaces and objects contaminated by their feces, is presently
considered the main route of human infection. Exposure is considered
most likely during slaughter, de-feathering, butchering, and
preparation of poultry for cooking. [CDC]
Does the virus
spread easily from birds to humans?
No. Though more than 100 human cases
have occurred in the current outbreak, this is a small number
compared with the huge number of birds affected and the numerous
associated opportunities for human exposure, especially in areas
where backyard flocks are common. It is not presently understood why
some people, and not others, become infected following similar
exposures. [CDC]
What is the best action to prevent the spread of the disease?
The most
efficient control techniques involve improved biosecurity, primarily
of the poultry industry, to reduce the likelihood of contact between
domestic stock and wild birds or infected water sources. This needs
to be coupled with swift and complete culls of infected poultry
flocks in the event of an outbreak. Further measures that should be
considered include stricter controls on wild bird markets, and
movements of domestic poultry. Such measures should be introduced
worldwide. Countries currently free of the disease should consider a
ban on imports of all wild birds for the pet trade and of domestic
poultry from affected regions. Preventing public access to infected
sites is also clearly a sensible precaution. [BirdLife
International]
Does
the February 2004 US order to ban the importation of select species
apply to birds already in the
United States?
There
is no current evidence to suggest that birds infected with influenza
A (H5N1) have been imported and are causing disease in the
United States. Therefore this order
does not include restrictions upon the domestic movement of birds
already in the
United States. [CDC]
ADDITIONAL RESOURCES:
Newsweek
Magazine, 11/14/05 issue:
Tracking Disease: Changing the environment changes the way viruses
evolve and spread. A leading wildlife biologist explains how this
knowledge can prevent future outbreaks. -
http://www.msnbc.msn.com/id/9936993/site/newsweek/
American Bird Conservancy Position Statement on Avian Influenza -
http://www.abcbirds.org/flu.htm
National Audubon Society - Avian Influenza Information
- http://www.audubon.org/bird/AvianBirdFlu.php
Center for Conservation Medicine at the Wildlife Trust -
http://www.wildlifetrust.org/enter.cgi?p=news/2005/0929_1_SARS.htm
Centers for Disease Control -
http://www.cdc.gov/flu/avian/
United Nations Food and Agricultural Organization-
http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/special_avian.html
USGS
National Wildlife
Health
Center
-
http://www.nwhc.usgs.gov/research/avian_influenza/avian_influenza.html
BirdLife International Statement on Avian Influenza - http://www.birdlife.org/action/science/species/avian_flu/
Wetlands International Statement on Avian Influenza - http://www.wetlands.org
Cornell (Univ.) Laboratory of Ornithology -
http://www.birds.cornell.edu/
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