A Threat to U.S. Poultry

Worldwide, avian influenza (AI)—the bird flu—is a virus

that infects wild birds (such as ducks, gulls, and shorebirds) and domestic poultry (such as chickens, turkeys,

ducks, and geese). AI viruses are divided into two

groups based upon the ability of the virus to produce

disease in poultry: low-pathogenic avian influenza

(LPAI) and highly pathogenic avian influenza (HPAI).

LPAI, or “low-path” avian influenza, naturally occurs

in wild birds and can spread to domestic birds. In most

cases, it causes no signs of infection or only minor

signs of illness in birds. However, some LPAI virus

strains (H5 and H7) are capable of mutating into HPAI

viruses and are therefore closely monitored.

HPAI, or “high-path” avian influenza, is often fatal in

chickens and turkeys. HPAI spreads rapidly and has a

high death rate in birds.

The U.S. Department of Agriculture's (USDA) 

Animal and Plant Health Inspection Service (APHIS)

works to keep HPAI from becoming established in the

U.S. poultry population. It is essential for the U.S.

poultry industry and bird owners to be aware of this

disease and protect their birds.

Clinical Signs

Birds affected with HPAI might show one or more of

the following signs:

• Sudden death without clinical signs

• Lack of energy and appetite

• Decreased egg production

• Soft-shelled or misshapen eggs

• Swelling of the head, eyelids, comb, wattles, and 

hocks

• Purple discoloration of the wattles, combs, and legs

• Nasal discharge

• Coughing, sneezing

• Incoordination

• Diarrhea

Economic Impact of an HPAI Outbreak

The United States is the world’s largest producer and

exporter of poultry meat and the second-largest egg

producer. The total U.S. poultry production is valued at

$29 billion yearly. A major outbreak of HPAI would be

costly to the poultry industry, consumers, and taxpayers. It also would lead trading partners to ban U.S.

poultry and products.

USDA has experience responding to and eradicating HPAI. HPAI has been detected and eradicated

three times in U.S. poultry: in 1924, 1983, and 2004.

For example, the 1983–84 HPAI H5N2 outbreak resulted in the depopulation of approximately 17 million

chickens, turkeys, and guinea fowl in Pennsylvania

and Virginia to contain and eradicate the disease.

Managing this outbreak cost nearly $65 million and

also caused retail egg prices to increase by more than

30 percent.

Introduction and Spread of HPAI Virus

Exposure of poultry to migratory waterfowl, imports of

poultry and poultry products, movement of poultry

equipment, and people can be a source for potentially

introducing HPAI into U.S. poultry and/or privately

owned flocks of birds. Once introduced, HPAI can be

spread from bird to bird through direct contact. HPAI

viruses also can be spread by manure, equipment,

vehicles, egg flats, crates, and people whose clothing

or shoes have come into contact with the virus. Contaminated manure can contain high levels of virus and

could be a significant source of infection for other

birds. Proper biosecurity—precautions taken to minimize the risk of introducing an infectious disease into

an animal population—is critical to protecting the U.S.

poultry population.

Biosecurity Measures on the Farm

Poultry producers should strengthen biosecurity practices to prevent the introduction of HPAI into their

flocks. The following are some sound biosecurity practices:

• Keep an "all-in, all-out" philosophy of flock 

management.

• Protect poultry flocks from coming into contact with 

wild or migratory birds and their feces. 

• Keep poultry away from any source of water that 

could have been contaminated by wild birds.

• Permit only essential workers and vehicles to enter 

the farm.

Birds affected by HPAI could

show swelling of the head and

face.

Hemorrhaging of the skin and

legs is just one of the signs birds

might exhibit when infected with

the virus that causes HPAI.

Purple discoloration of the comb could be an indicator of HPAI.

HPAI can devastate 

a healthy broiler

flock, leaving high

rates of mortality and

economic losses.

Here, healthy turkeys are compared with turkeys exhibiting signs of

diarrhea and depression due to HPAI. 

• 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 equipment or vehicles to, or borrow 

them from, other farms.

• Avoid visiting other poultry farms. If you do visit 

another farm or live-bird market, do not work with 

your flock until you have changed into clean 

footwear and clothing.

• Do not bring birds from slaughter channels, 

especially live-bird markets, back to the farm.

Biosecurity Measures for BackyardFlock Owners

APHIS recommends that owners of backyard flocks 

follow these six tips to prevent poultry disease: 

• Keep your distance: restrict access to your 

property and your birds, keep new birds separate 

from the rest of their flocks for 30 days; 

• Keep it clean: clean and disinfect your clothes, 

shoes, equipment, and hands; 

• Don’t haul disease home: if you have been near 

other birds or bird owners, clean and disinfect 

poultry cages and equipment before going home; 

• Don’t risk disease from your neighbor: do not 

borrow lawn and garden equipment, tools, or 

poultry supplies from other bird owners; 

• Know the warning signs: sudden increase in bird 

deaths, sneezing, coughing, nasal discharge, 

watery or green diarrhea, lack of energy, poor 

appetite, drop in egg production, swelling around 

the eyes, neck, and head, and purple discoloration 

of wattles, combs, and legs; and

• Report sick birds: call your local or State 

veterinarian, or USDA–APHIS Veterinary Services 

toll-free at 1–866–536–7593.
Highly Pathogenic

Avian Influenza:

A Threat to U.S. Poultry

The U.S. Department of Agriculture (USDA) prohibits discrimination in

all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial

status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s

income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who

require alternative means for communication of program information

(Braille, large print, audiotape, etc.) should contact USDA’s TARGET

Center at (202) 720–2600 (voice and TDD). To file a complaint of

discrimination, write to USDA, Director, Office of Civil Rights, 1400

Independence Avenue, S.W., Washington, D.C. 20250–9410, or call

(800) 795–3272 (voice) or (202) 720–6382 (TDD). USDA is an equal

opportunity provider and employer.

This leaflet supersedes Program Aid No. 1836, “High-Pathogenicity

Avian Influenza: A Threat to U.S. Poultry,” issued August 2005 and

slightly revised March 2006.

Issued November 2007

United States Department of Agriculture

Animal and Plant Health Inspection Service

Program Aid No. 1949

Biosecurity Measures at Live-Bird Markets

To prevent a possible outbreak of HPAI, poultry producers and distributors in the live-bird marketing system

must use biosecurity precautions. Retail live-bird markets operate in many major cities. AI viruses can be

introduced into any part of the system (farms, distributors, markets) through infected birds or contaminated

crates and trucks. Once the virus is established in the

system, the movement of birds, crates, or trucks can

spread the virus. 

To prevent the possible spread of disease, the 

following protective measures should be taken:

• Use plastic instead of wooden crates for easier 

cleaning.

• Keep scales and floors clean of manure, 

feathers, and other debris.

Allowing a backyard flock to commingle with wild waterfowl poses

the risk of introducing HPAI into U.S. poultry.

If HPAI were detected in U.S. poultry, measures such as quarantine, control, and cleanup would be implemented to prevent opportunities for the virus to spread.

• Clean and disinfect all equipment, crates, and 

vehicles before the next pickup of birds.

• Keep incoming poultry separate from unsold 

birds, especially if birds are from different lots.

• Clean and disinfect the marketplace after every day

of sale.

• Do not return unsold birds to the farm.

For more specific information about biosecurity and

cleaning and disinfection practices, contact any Extension agent, State animal health official, or local APHIS

Veterinary Services office.

Disease Surveillance Activities

To protect the U.S. poultry population, USDA quarantines and tests live birds imported into the United

States to ensure that they do not have any foreign animal diseases, such as HPAI. All imported live birds

(except from Canada, which must have appropriate

permits) must spend 30 days at a USDA quarantine

facility where they are tested for the AI virus before

entering the country. Non-U.S.-origin pet birds (except

from Canada which must have appropriate permits)

also are tested and quarantined at a USDA facility.

USDA maintains trade restrictions on the importation of poultry and poultry products originating from

countries and/or regions where HPAI has been detected in commercial or traditionally raised poultry. Additionally, USDA has increased its monitoring for illegally

smuggled poultry and poultry products through an antismuggling program in coordination with the U.S.

Department of Homeland Security–Customs and 

Border Protection.

In addition to these import restrictions, APHIS and

State veterinarians 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 industry who report suspicious cases.

APHIS and State animal health officials work cooperatively with the poultry industry to conduct surveillance.

Surveillance is done on breeding flocks, commercial

production flocks, and backyard flocks and at slaughter

plants, distributors, live-bird markets, swap meets,

exhibitions, livestock auctions, and diagnostic laboratories. Additionally, APHIS, the U.S. Department of the

Interior, and individual States conduct wild-bird surveillance for HPAI viruses, which helps protect poultry.

Disease Response Activities

USDA works closely with its Federal, State, and tribal

partners, as well as industry stakeholders, to coordinate emergency response to livestock and poultry disease outbreaks, including AI. 

USDA provides expertise, funding, and support

personnel to States when LPAI (H5 or H7) is detected.

When HPAI is detected, USDA and State personnel

are primary responders to control and eradicate the

disease from poultry.

In the event of an HPAI outbreak in the United

States, APHIS veterinarians would work with States

and industry to respond quickly and decisively following these five basic steps:

• Quarantine—restrict movement of poultry and 

poultry-moving equipment into and out of the 

control area;

• Eradicate—depopulate infected and exposed birds;

• Monitor region—broad area of testing;

• Disinfect—kills virus; and

• Test—confirm that the poultry farm is free of the AI 

virus.

USDA also maintains a bank of AI vaccine that

could be used to protect healthy birds outside a control

area, if necessary.

More Information 

USDA efforts to protect against and respond to bird flu:

www.usda.gov/birdflu

Report Sick Farm Birds: If your farm birds are sick or

dying, call your State Veterinarian or USDA’s Veterinary Services toll free at 1–866–536–7593.

Report Dead Wild Birds: Dead wild birds can be

reported to State or Federal wildlife agencies. Information on how to make contact with wildlife officials in

your State is available at www.usda.gov/birdflu, or

call 1–866–4USDA–WS.

Biosecurity for Birds:

http://.healthybirds.aphis.usdagov/

Current information on animal diseases and suspected

outbreaks: www.aphis.usda.gov

U.S. Government efforts to protect human health:

www.avianflu.gov 

For more information about HPAI or biosecurity practices, contact:

USDA, APHIS, Veterinary Services

National Center for Animal Health Emergency 

Management

4700 River Road, Unit 41

Riverdale, MD 20737–1231

Telephone (301) 734–8073

Fax (301) 734–7817