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October 2005
Q. What is avian influenza?
A. Avian influenza (AI) is a disease
found among poultry. AI viruses can be
classified into low pathogenicity and highly
pathogenic forms based on the severity of the
illness they cause in poultry. Most AI strains
are classified as low pathogenicity avian
influenza (LPAI) and cause few clinical signs in
infected birds. In contrast, high pathogenicity
avian influenza (HPAI) causes a severe and
extremely contagious illness and death among
infected birds.
Q. How is the disease spread?
A. AI is primarily spread by direct
contact between healthy birds and infected
birds, and through indirect contact with
contaminated equipment and materials. The virus
is excreted through the feces of infected birds
and through secretions from the nose, mouth and
eyes.
Contact with infected fecal material is the
most common of bird-to-bird transmission. Wild
ducks often introduce low pathogencicity into
domestic flocks raised on range or in open
flight pens through fecal contamination. Within
a poultry house, transfer of the HPAI virus
between birds can also occur via airborne
secretions. The spread of avian influenza
between poultry premises almost always follows
the movement of contaminated people and
equipment. AI also can be found on the outer
surfaces of egg shells. Transfer of eggs is a
potential means of AI transmission. Airborne
transmission of virus from farm to farm is
highly unlikely under usual circumstances.
Q. What symptoms do birds with AI
demonstrate?
A. LPAI symptoms are typically mild.
Decreased food consumption, respiratory signs
(coughing and sneezing) and a decrease in egg
production might demonstrate the presence of the
disease. Birds that are affected with HPAI have
a greater level of sickness and may exhibit one
or more of the following clinical signs: sudden
death; lack of energy and appetite; decreased
egg production; soft-shelled or misshapen eggs;
swelling; purple discoloration; nasal discharge;
coughing, sneezing; lack of coordination and
diarrhea.
Q. What should producers do if their birds
appear to have signs of AI?
A. If birds exhibit clinical signs of
HPAI or may have been exposed to birds with the
disease, producers or bird owners should
immediately notify Federal or State animal
health officials.
Q. Is it possible for an LPAI strain to
become highly pathogenic?
A. Some low pathogenic subtypes have
the capacity to mutate into more virulent
strains. While LPAI is considered lower risk,
low pathogenic strains of the virus - the H5 and
H7 strains - can mutate to highly pathogenic
forms.
Q. Is AI a reportable disease?
A. HPAI is considered a reportable
disease by the World Organization for Animal
Health (OIE). OIE has developed animal health
standards that classify all H5 and H7 viruses as
reportable diseases.
Q. Does AI threaten human health?
A. LPAI poses no known serious threat
to human health, however some strains of HPAI
viruses can be infectious to people. Since
December 2003, a growing number of Asian
countries have reported outbreaks of HPAI in
chickens and ducks. Humans also have been
affected, most of who had direct contact with
infected birds. The rapid spread of HPAI in 2004
and 2005 is historically unprecedented and of
growing concern for human health as well as for
animal health.
Q. Does HPAI currently exist in the United
States? Has it ever occurred in this country?
A. HPAI does not currently exist in
the United States. There have been three
outbreaks of the disease in poultry in this
country--in 1924, 1983 and 2004.
A HPAI epidemic occurred in the northeastern
United States in 1983-84. A highly virulent H5
virus produced severe clinical disease and high
mortality in chickens, turkeys, and guinea fowl
in Pennsylvania and Virginia. Approximately 17
million birds had to be destroyed.
In February 2004, USDA confirmed that an H5N2
strain of avian influenza in a flock of chickens
in Texas was consistent with HPAI. There was no
evidence of any human health implications of
this HPAI virus in Texas. USDA worked with state
officials to quickly eradicate the disease.
Because of the quick response, the disease was
limited to one small flock.
Q. What is USDA doing to prevent the
introduction of HPAI into the United States?
A: USDA recognizes that HPAI poses a
significant threat to animal health and has the
potential to threaten human health. Accordingly,
USDA's Animal and Plant Health Inspection
Service (APHIS) has safeguards in place to
protect against the introduction of HPAI into
the United States. APHIS maintains trade
restrictions on the importation of poultry and
poultry products from countries currently
affected by HPAI. These restrictions include:
- Prohibiting the importation of live birds
and hatching eggs from H5N1 affected countries.
- Requiring imports of poultry products from
East and Southeast Asia be processed or cooked
in accordance with a USDA permit prior to
importation to lower the risk of HPAI
contamination to negligible levels.
- Requiring all imported birds be quarantined
at a USDA bird-quarantine facility and be tested
for the avian influenza virus before entering
the country. This requirement now covers
returning U.S.-origin pet birds.
Detection
USDA also works closely with international
organizations like the World Organization for
Animal Health (OIE), the United Nations' Food
and Agriculture Organization (FAO), and World
Health Organization (WHO) to assist
HPAI-affected countries and other neighboring
Asian-Pacific countries with disease prevention,
management, and eradication activities. By
helping these countries prepare for, manage, or
eradicate HPAI (H5N1) outbreaks, USDA can reduce
the risk of the disease spreading from overseas
to the United States.
APHIS also recognizes that prevention is only
one part of a comprehensive strategy and
therefore continues to work closely with its
Federal, State, and Tribal partners and industry
stakeholders to have effective and coordinated
emergency response plans at the ready should an
outbreak of HPAI occur in the United States.
Q. What is USDA doing to monitor the U.S.
for AI among birds?
A: The USDA Animal and Plant Health
Inspection Service (APHIS) works with states to
monitor and respond to outbreaks of LPAI. APHIS
has provided funding and support personnel to
states when LPAI has been detected. When HPAI is
detected, APHIS personnel are primary
responders, due to its infectivity and high
mortality rate among poultry. Close attention is
also given to two subtypes of LPAI, the H5 and
H7 strains, because of the potential for them to
mutate into HPAI. The AI strain infecting both
birds and humans in Asia is the HPAI H5N1. There
is presently no evidence of HPAI H5N1 existing
in the U.S. - neither in animals nor humans.
In addition to international import
restrictions, APHIS and State veterinarians are
specially trained to diagnose foreign animal
diseases regularly conduct field investigations
of suspicious disease conditions. This
surveillance is assisted by university
personnel, State animal health officials,
USDA-accredited veterinarians, and members of
the industry who report suspicious cases. APHIS
and State animal health officials work
cooperatively with the poultry industry to
conduct surveillance at breeding flocks,
slaughter plants, live-bird markets, livestock
auctions, and poultry dealers.
Q. What can poultry producers do to
prevent an AI outbreak on their farms?
A. Poultry producers should strengthen
biosecurity practices to prevent the
introduction of AI into their flocks. The
following are some sound biosecurity practices:
- Keep an "all-in, all-out" philosophy of
flock management. Avoid skimming flocks-birds
left behind are exposed to work crews and
equipment that may carry poultry disease
viruses. Process each lot of birds separately,
and clean and disinfect poultry houses between
flocks.
- Protect poultry flocks from coming into
contact with wild or migratory birds. Keep
poultry away from any source of water that may
have been contaminated by wild birds.
- Permit only essential workers and vehicles
to enter the farm.
- Provide clean clothing and disinfection
facilities for employees.
- Thoroughly clean and disinfect equipment and
vehicles (including tires and undercarriage)
entering and leaving the farm.
- Do not loan to, or borrow equipment or
vehicles from, other farms.
- Change footwear and clothing before working
with your own flock after visiting another farm
or live-bird market or avoid visiting another
bird farm if possible.
- Do not bring birds from slaughter channels,
especially those from live-bird markets, back to
the farm.
If AI is detected, farms must be thoroughly
cleaned and disinfected. AI is inactivated by
heat and drying and it is also very sensitive to
most disinfectants and detergents. The area to
be disinfected must be clear of organic
material, which greatly increases the resistance
of avian influenza virus' resistance to
disinfection.
Q. Does proper food handling prevent avian
influenza?
A. The USDA Food Safety and Inspection
Service (FSIS) is working to educate the public
about safe food handling practices in response
to numerous questions from the public about the
human risk associated with avian influenza.
LPAI, the type commonly found in the U.S., is
not transmissible by eating poultry. If HPAI
were detected in the U.S., the chance of
infected poultry entering the food chain would
be extremely low. Nevertheless, proper handling
and cooking of poultry provides protection
against HPAI, as it does against other viruses
and bacteria, including Salmonella and E.coli.
USDA continually reminds consumers to practice
safe food handling and preparation every day:
- Wash hands before and after handling food;
- Prevent cross-contamination by keeping raw
meat, poultry, fish and their juices away from
other foods;
- Wash hands, cutting board, knife, and
counter tops with hot, soapy water after cutting
raw meats;
- Sanitize cutting boards by using a solution
of 1 teaspoon chlorine bleach in 1 quart of
water and
- Use a food thermometer to ensure food has
reached proper temperatures -details available
on-line at
http://www.fsis.usda.gov/ .
Current science indicates that-- as with all
foodborne pathogens-- proper cooking of poultry
minimizes the risk of illness from consumption
of poultry. Using a food thermometer is the only
sure way of knowing if your food has reached a
high enough temperature to destroy foodborne
pathogens including bacteria and viruses. USDA
recommends cooking whole birds to 180 °F as
measured in the thigh using a food thermometer.
When cooking pieces, the breast should reach 170
°F internally. Drumsticks, thighs and wings
should be cooked until they reach an internal
temperature of 180 °F. Ground turkey and chicken
should be cooked to 165° F. The minimum oven
temperature to use when cooking poultry is 325
°F. Remember to wash hands with soap and warm
water for 20 seconds before and after handling
raw poultry.
Q. Are poultry products from countries
with avian influenza allowed into the United
States?
A. No. Poultry products imported to
the U.S. must meet all safety standards applied
to foods produced in the U.S. Currently, no
poultry from flocks with confirmed cases of
avian influenza are allowed to be exported to
the United States.
Q. How do I get more information about
avian influenza?
go to http://www.usda.gov/birdflu
- or Food Safety Information: USDA Meat and
Poultry Hotline - 1-888-MPHotline
(1-888-674-6854) TTY: 1-800 256-7072
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