Avian Influenza Symptoms and Keeping Your Flock Safe

Avian Influenza is a Threat to Poultry Farming


We have received many questions about Avian Influenza, also known as “bird flu” and present the following topics to answer the most frequently asked questions. The most frequently asked question is if there is a vaccine against Avian Influenza available for poultry, followed by Avian Influenza symptoms, how to prevent Avian Influenza and what other diseases poultry owners need to watch for.

The steps you take to protect your poultry should be standard practice toward the prevention of all poultry diseases and inspire good health for your birds and you. While Avian Influenza may bring these practices to the forefront now, they are steps that should guide all decisions you make regarding the health and welfare of your flock at all times, with or without a fear of a pandemic.

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Worldwide, there are many strains of avian influenza virus that can cause varying amounts of clinical illness in poultry. You should watch for Avian Influenza symptoms in all poultry as the viruses can infect chickens, turkeys, pheasants, quail, ducks, geese and guinea fowl, as well as a wide variety of other birds. Migratory waterfowl have proved to be a natural reservoir for the less infectious strains of the disease known as low pathogenicity avian influenza.

Avian Influenza viruses can be classified into low pathogenicity (LPAI) and high pathogenicity (HPAI) based on the severity of the illness they cause. HPAI is an extremely infectious and fatal form of the disease that, once established, can spread rapidly from flock to flock. However, some LPAI virus strains are capable of mutating under field conditions into HPAI viruses.

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.

What Are Avian Influenza Symptoms and Signs?

The clinical Avian Influenza symptoms and signs of birds affected with all forms of Avian Influenza may show one or more of the following:

  • Sudden death without Avian Influenza symptoms
  • Lack of energy and appetite
  • Decreased egg production
  • Any poultry, including chicken, laying soft eggs or misshapen eggs
  • Swelling of the head, eyelids, comb, wattles, and hocks
  • Purple discoloration of the wattles, combs, and legs
  • Nasal discharge
  • Coughing, sneezing
  • Lack of coordination
  • Diarrhea

How Is Avian Influenza Spread?

Exposure of poultry to migratory waterfowl and the international movement of poultry, poultry equipment, and people pose risks for introducing Avian Influenza into U.S. poultry. Once introduced, the disease can be spread from bird to bird by direct contact. Avian Influenza viruses can also be spread by manure, equipment, vehicles, egg flats, crates, and people whose clothing or shoes have come in contact with the virus.

What Can You Do To Prevent Avian Influenza?

Materials that carry the Avian Influenza virus can be picked up on shoes and clothing, and moved from an area with sick birds to an area with healthy ones. Moving birds from one place to another can also spread diseases, especially because some birds can carry disease without showing Avian Influenza symptoms. By making biosecurity a part of your daily routine while caring for your birds, you decrease the chance of Avian Influenza showing up on your back doorstep.

To Help Keep Your Birds Healthy

  • Keep Your Distance: Restrict access to your property and your birds. Consider fencing off the area where you keep your birds and make a barrier area if possible. Allow only people who take care of your birds to come into contact with them. If visitors have birds of their own, do not let them near your birds. Game birds and migratory waterfowl should not have contact with your flock because they can carry germs and diseases.
  • Keep It Clean: Wear clean clothes, scrub your shoes with disinfectant, and wash your hands thoroughly before entering your bird area. Clean cages and change food and water daily. Clean and disinfect equipment that comes in contact with your birds or their droppings, including cages and tools. Remove manure before disinfecting. Properly dispose of dead birds.
  • Disinfectants: Cleaning and disinfecting is one of the most important steps you can take in practicing biosecurity with backyard chickens and other poultry. Below are some examples of disinfectants available on the market. Follow the directions on the label carefully for the best results.
    • Thoroughly clean and scrub objects before applying disinfectants. Disinfectants cannot work on top of caked-on dirt and manure, so thoroughly wash surfaces before disinfecting.
    • Apply disinfectants using brushes, sponges and spray units. Allow adequate contact time (follow manufacturer’s instructions.)
    • Dispose of used disinfectant according to local regulations.
    •  Examples of Disinfectants
      • Roccal®: Mix 1/2 fluid oz of Roccal per gallon of water.
      • Nolvasan® (chlorhexidine diacetate 2 percent): Mix 3 fluid oz of Nolvasan per gallon of water.
      • Household bleach (sodium hypochlorite 6 percent): Mix 3/4 cup of household bleach per gallon of water.
      • Lysol® spray for footwear
      • Hand disinfecting gels (Purell®)
  • Don’t Haul Disease Home: If you have been near other birds or bird owners, such as at a feed store, clean and disinfect car and truck tires, poultry cages, and equipment before going home. Have your birds been to a fair or exhibition? Keep them separated from the rest of your flock for two weeks after the event. New birds should be kept separate from your flock for at least 30 days.
  • Don’t Borrow Disease From Your Neighbor: Do not share birds, lawn and garden equipment, tools, or poultry supplies with your neighbors or other bird owners. If you do, bring these items home clean and disinfect them before they reach your property.
  • Know Avian Influenza Symptoms and the Warning Signs of Other Infectious Bird Diseases: Early detection is important to prevent the spread of disease.
  • Report Sick Birds and Avian Influenza Symptoms: Don’t wait. Early detection can make a difference. If your birds are sick or dying, call your local cooperative extension office, local veterinarian, the State Veterinarian, or U.S. Department of Agriculture (USDA) Veterinary Services office to find out why. USDA operates a toll-free hotline (1-866-536-7593) with veterinarians to help you. Call your veterinarian or local extension agent to examine all of your sick birds or birds that die suddenly, especially if you have been around other people’s birds or brought new birds home.

Additional Information

For more information, contact: USDA, APHIS, Veterinary Services, Emergency Programs, 4700 River Rd., Unit 41, Riverdale, MD 20737-1231, Telephone (301) 734-8073, Fax (301) 734-7817.

Additional Information On Vaccine Use

Provided By Madelaine Fletcher

APHIS Public Affairs Specialist


APRIL 20, 2006












In the United States, vaccination against Avian Influenza is not routine. However, vaccine has been used in regions or within certain poultry industry segments with a high risk of exposure to low pathogenicityAvian Influenza (LPAI). Inactivated Avian Influenza virus vaccines have been used during the past 25 years, mainly against sporadic LPAI viruses where there has been spread from wild waterfowl to poultry. For example, H3N1, H1N2 and H1N1 vaccines have been used in turkey breeders in certain areas where these virus subtypes are endemic in pigs. For subtypes other than H5 and H7, the states have regulatory authority.

If highly pathogenic Avian Influenza would be detected in U.S. poultry, APHIS will work with States to ensure an immediate stamping out response. Response measures include quarantining affected premises, humanely depopulating and disposing of affected and exposed birds, cleaning and disinfecting affected premises, and conducting surveillance activities to detect any disease spread and to ensure eradication.

If we move beyond detection and are faced with a wide scale HPAI outbreak where the commercial poultry industry was threatened, APHIS would consider the use of vaccine. However, avian influenza vaccines do not prevent infection in poultry. They do help to reduce the clinical Avian Influenza symptoms in exposed or potentially exposed birds and also reduce the shedding of the virus from bird to bird. Vaccines are useful in certain disease situations because they help reduce the spread of the virus and promote the recovery of affected birds.

Because vaccination results in antibody production, the use of vaccine can interfere with AI surveillance activities. Therefore, APHIS does not authorize the blanket use of Avian Influenza vaccine, but rather considers each potential use on a case-by-case basis.

APHIS maintains a bank of four subtypes of avian influenza antigens for use as vaccines if needed during an outbreak. It has a vaccine that has been experimentally shown to be effective against the Asian H5N1 virus.

If low pathogenicity H5 and H7 subtypes are detected in U.S. poultry, APHIS will work with States to ensure a rapid response. Response measures are focused on eliminating the infection, but may not necessarily result in immediate depopulation. Response measures could include quarantining affected premises, humanely depopulating and disposing of affected and exposed birds (either through immediate or controlled depopulation), vaccination (when appropriate), cleaning and disinfecting affected premises, and conducting surveillance activities to detect any disease spread and to ensure eradication

Trade restrictions and anti-smuggling program are critical safeguards

The USDA maintains import restrictions on live birds, raw poultry and poultry products from countries affected by HPAI to include HPAI H5N1.

Furthermore, all imported live birds (and returning U.S.-origin pet birds) must be quarantined for 30 days and tested for the AI virus before entering the country.

The USDA works closely with the Department of Homeland Security’s Customs and Border Protection to enforce restrictions. We have also increased our monitoring of domestic commercial markets for illegally smuggled poultry and poultry products.

The USDA works with trading partners and the World Organization for Animal Health (OIE) to maintain safe trade.

Originally published in Backyard Poultry June / July 2006


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Avian Influenza Symptoms and Keeping Your Flock Safe