What is the Bird Flu?
What is the bird flu?
Because of the widespread concern about avianinfluenza or the "bird flu" and its
effect on people & birds, we felt it necessary to provide the following
information. We have compiled the most recent data from some of the more
reliable sources such as the Centers for Disease Control & Prevention (CDC), the USGS National Wildlife Health Center & the World Health Organization (WHO).
What is it?
the bird flu or avian influenza?
What are the differences between low
pathogenic and highly pathogenic avian influenza viruses and how are influenza
Why is this new strain of avian influenza
causing such alarm?
How does it affect humans?
How has this new strain of
AI affected humans so far?
Bird Flu Symptoms?
How is avian influenza detected in
How is avian influenza in humans
How does it spread?
How does avian influenza spread among
What is the role of migratory birds in the transfer of the virus?
Can humans catch avian influenza
from wild birds?
How do people become infected with
avian influenza viruses?
Is there a risk for becoming infected
with avian influenza by eating poultry?
How can we protect ourselves?
What precautions can be taken to
reduce the risk for infection from wild birds in the United States?
What can we do to protect ourselves?
What if I am traveling to a
country affected by bird flu? ?
What is the bird flu?
Bird flu, the popular name for avian influenza (AI), is a disease primarily
found in poultry and wild birds. Avian influenza can infect chickens, pheasants,
quail, ducks, geese, and guinea fowl, as well as migratory waterfowl and
shorebirds and, less commonly, mammals (pigs, horses, and marine mammals).
Infection with avian influenza viruses in domestic poultry
causes two main forms of disease that are distinguished by low and high extremes
of virulence. The ?low pathogenic? form may go undetected and usually causes
only mild symptoms (such as ruffled feathers and a drop in egg production).
However, the ?highly pathogenic? form spreads more rapidly through flocks of
poultry. This form may cause disease that affects multiple internal organs and
has a mortality rate that can reach 90-100%, often within 48 hours.
What are the differences between low pathogenic and highly pathogenic
avian influenza viruses and how are influenza viruses grouped? What is the bird
The designation of low or highly pathogenic avian influenza refers to the
potential for these viruses to kill domestic poultry. The designation of "low
pathogenic" or "highly pathogenic" does not refer to how infectious the viruses
may be to humans.
Most strains of avian influenza are not highly pathogenic and cause few signs in
infected wild birds; however, in poultry, low pathogenic strains can mutate into
a highly pathogenic avian influenza (HPAI) strain that causes extremely
contagious, severe illness, and often death, in poultry.
Influenza viruses are also differentiated by two proteins, hemagglutinin (H) and
neuraminidase (N), which are found on the surface of the virus. There are 144
theoretical combinations of the 16 different H and 9 different N proteins that
make up the subtypes of avian influenza.
These subtypes can be further genetically differentiated into strains. A subtype
such as the highly pathogenic H5N1 avian influenza virus may have multiple
strains. These different strains may be more or less pathogenic to domestic
poultry, wild birds, and humans.
Highly pathogenic avian influenza viruses in poultry are usually H5 or H7
subtypes of Type A influenza, although low pathogenic forms of these H5 and H7
viruses also exist.
If a strain of the HPAI mutates to become easily transmissible from
human-to-human, the new strain would then be considered a human Type A influenza
Why is this new strain of avian influenza causing such
alarm? What is the bird flu virulent strain?
This particularly virulent new strain of highly pathogenic avian influenza (HPAI
H5N1) has spread throughout a large geographic area in Asia and Eastern Europe
since it was first documented in 1997 in Asia, and has caused the largest and
most severe outbreaks in poultry on record.
The human cases to date have been mostly in Eastern Europe
(Turkey) and Asia, primarily in Cambodia, China, Indonesia, Thailand, and
Vietnam, and have been the result of direct or close contact with domestic (not
wild) birds, especially chickens. Unlike most avian influenza viruses, this new
strain of H5N1 has caused mortality in over 60 species of wild birds. The H5N1
virus has been confirmed in birds in more than 50 countries.
How has this new strain of AI affected humans so far? What
is the bird flu affect on humans?
Since 2003 until present, the cumulative number of
confirmed human cases of Avian Influenza A/(H5N1) reported to WHO
(laboratory-confirmed cases only) has been 274 people in 11 countries, and of
those 274, 167 have died from the virus.
So far, there has been no sustained person-to-person
transmission of the HPAI H5N1 virus.
Most of the people who have been infected with the HPAI
H5N1 virus have acquired it through direct handling of infected poultry, eating
uncooked or undercooked poultry products, or through contact with
virus-contaminated surfaces or materials, including blood and feces.
There are no documented cases of human H5N1 disease
resulting from contact with wild birds.
Public health organizations, such as the World Health
Organization and the Centers for Disease Control and Prevention, are concerned
that the virus could mutate into a human virus that would be more easily
transmissible from person-to-person. This change could pose a global influenza
How does avian influenza spread
among birds? What is the bird flu infection in birds?
Infected birds shed influenza virus in their saliva, nasal
secretions, and feces. Domesticated birds may become infected with avian
influenza virus through direct contact with infected waterfowl or other infected
poultry, or through contact with surfaces (such as dirt or cages) or materials
(such as water or feed) that have been contaminated with the virus.
When the virus "jumps" to a new species, such as from wild
birds to domestic animals or to humans, the virus may change or mutate into a
new virus that is more adapted to the new host and is no longer the same virus
that was originally in the wild bird population.
catch avian influenza from wild birds? What is the bird flu transmission from
birds to humans?
There are no documented cases
of human H5N1 disease resulting from contact with wild birds. Recently (Feb
2007) the virus infected a man in his 30's and a 15-year-old girl, who may have
gotten the virus from a wild bird but this has not been confirmed.
As a safety precaution, exposure to domestic and wild birds potentially infected
with H5N1 should be avoided.
documented cases of transmission to humans are from poultry; these cases include
both highly pathogenic and low pathogenic strains of avian influenza.
present time, close contact with infected domestic poultry has been the primary
way that people have become infected with the HPAI H5N1 virus.
How do people become infected with avian
influenza viruses? What is the bird flu transmission to humans?
Most cases of avian influenza infection in humans have resulted from direct or
close contact with infected poultry (e.g., domesticated chicken, ducks, and
turkeys) or surfaces contaminated with secretions and excretions from infected
birds. The spread of avian influenza viruses from an ill person to another
person has been reported very rarely, and transmission has not been observed to
continue beyond one person. During an outbreak of avian influenza among poultry,
there is a possible risk to people who have direct or close contact with
infected birds or with surfaces that have been contaminated with secretions and
excretions from infected birds.
Is there a risk for becoming infected with avian influenza
by eating poultry? What is the bird flu infection possiblity through poultry?
is no evidence that properly cooked poultry or eggs can be a source of infection
for avian influenza viruses.
government carefully controls domestic and imported food products, and in 2004
issued a ban on importation of poultry from countries affected by avian
influenza viruses, including the H5N1 strain. This ban still is in place.
What precautions can be taken to reduce the risk for infection from wild
birds in the United States?
As a general rule, the public should observe
wildlife, including wild birds, from a distance. This protects you from possible
exposure to pathogens and minimizes disturbance to the animal. Avoid touching
wildlife. If there is contact with wildlife do not rub eyes, eat, drink, or
smoke before washing hands with soap and water. Do not pick up diseased or dead
wildlife. Contact your state, tribal, or federal natural resource agency if a
sick or dead animal is found.
What can we do to protect ourselves? What is the bird
flu protection protocol?
As a general rule, people
should observe wildlife, including wild birds, from a distance. This protects
people from possible exposure to diseases and minimizes disturbance to the
no known case where H5N1 has been transmitted from wild birds to humans.
However, even apparently healthy wild birds can be infected with microorganisms
other than HPAI, some of which are currently of more concern to human health in
North America than HPAI H5N1.
National Wildlife Health
Recommendations for Prevention:
Thoroughly washing hands with soap and water (or with alcohol-based hand
products if the hands are not visibly soiled) is a very effective method for
inactivating influenza viruses, including HPAI. These viruses are also
inactivated with many common disinfectants such as detergents, 10% household
bleach, alcohol or other commercial disinfectants. The virus is more difficult
to inactivate in organic material such as feces or soil.
General Public should, as a general rule, observe wildlife, including wild
birds, from a distance. This protects you from possible exposure to pathogens
and minimizes disturbance to the animal.
touching wildlife. If there is contact with wildlife do not rub eyes, eat,
drink, or smoke before washing hands with soap and water as described above.
- Do not
pick up diseased or dead wildlife. Contact your state, tribal or federal natural
resource agency if a sick or dead animal is found.
What if I am traveling to a country affected by bird
flu? What is the bird flu travel risk?
Travelers to areas affected by avian influenza in birds are not considered to be
at elevated risk of infection unless direct and un-protected exposure to
infected birds (including feathers, feces and under-cooked meat and egg
It is recommended that travelers to affected areas should avoid contact with
live animal markets and poultry farms, and any free-ranging or caged poultry.
Large amounts of the virus are known to be excreted in the droppings from
infected birds. Populations in affected countries are advised to avoid contact
with dead migratory birds or wild birds showing signs of disease.
Direct contact with infected poultry, or surfaces and objects contaminated by
their droppings, is considered the main route of human infection. Exposure risk
is considered highest during slaughter, de-feathering, butchering, and
preparation of poultry for cooking. There is no evidence that properly cooked
poultry or poultry products can be a source of infection.
Travelers should contact their local health providers or national health
authorities for supplementary information.
Bird Flu Symptoms,
Bird Flu Detection Test, Bird Flu Vaccine:
What are Avian Flu Symptoms?
How is avian influenza detected in humans?
avian influenza in humans treated? What is the bird flu vaccine?
Current Bird Flu
- Role of Migratory Birds
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