What is avian influenza?

Avian influenza, also known as bird flu, fowl pest, or fowl plague, is a respiratory disease of birds caused by a Type A influenza virus. Avian influenza occurs world wide and was first described more than 100 years ago in Italy. In birds signs of avian influenza may range from mild respiratory signs, such as coughing and sneezing, to very rapidly spreading severe illness resulting in death of all infected individuals. There are 15 strains of influenza virus that are known to infect birds. Usually birds and pigs are the only species affected. However, some strains, such as the H5N1 virus that has been found in Asia, Europe and Africa, can cause disease in other mammals.

Why is avian influenza currently raising concerns?

Influenza viruses can change rapidly. This can cause an outbreak to shift from causing only mild illness in birds to causing rapid high mortality rates. A viral change during the course of an epidemic may also alter which species can be infected by the virus. Avian influenza is currently of concern because of the potential for people to become infected with the H5N1 virus. However, avian influenza will not become widespread in people unless the virus gains the ability to be transmitted from person to person easily.  To date, human cases have been traced to close contact between humans and live poultry or ducks.

Where is the current outbreak of avian influenza happening?

Between December 2003 and October 10, 2005, H5N1 avian influenza was isolated from birds in Cambodia, China, Hong Kong, Indonesia, Japan, Kazakhstan, Korea, Laos, Malaysia, Mongolia, Romania, Russia, Thailand, Turkey, and Vietnam.  The first reported case of H5N1 avian influenza in humans occurred in Hong Kong in 1997. To date, laboratory-confirmed human cases have occurred in Cambodia, China, Indonesia, Thailand, Vietnam, Azerbaijan, Turkey, Iraq, Djibouti and Egypt. 

How do birds get avian influenza?

Migratory waterfowl, such as wild ducks, are the natural reservoir for avian influenza and are the most resistant to clinical disease, meaning that they can carry and spread the virus without showing any signs of illness themselves. The feces of infected waterfowl are the likely source of some outbreaks of avian influenza in domestic birds. Domestic ducks may also carry the virus and infect other birds. The virus is shed in saliva, nasal secretions, and feces. Respiratory droplets and dust contaminated with the virus spread the disease to other birds. Footwear, supplies, vehicles, and equipment that are contaminated with bird droppings or feathers and dust from infected birds can also spread the disease from one place to another.

How do people get avian influenza?

Presently, the H5N1 avian influenza virus does not spread easily from person to person. Human beings who have contracted the disease had close contact with infected, live poultry or ducks or handled equipment that was contaminated with feces, feathers, or dust from infected birds.

Have countries having outbreaks of avian influenza been able to control or stop the spread?

Japan, the Republic of Korea, and Malaysia have announced control of their poultry outbreaks and are now considered free of the disease.

What are the signs of “bird flu” in domestic turkeys and chickens?

There are two forms of illness:

·         The mild form causes mild signs (low pathogenic avian influenza or LPAI) such as sneezing and coughing, ruffled feathers, and a drop in egg production. These signs might go undetected.

·         The severe form (highly pathogenic avian influenza or HPAI) spreads rapidly through poultry flocks causing sudden death of poultry. This form can kill almost 100 percent of birds in an infected flock. Signs of the severe form may include depression, weakness, loss of appetite, a drop in egg production, soft-shelled or misshapen eggs, nervous signs, swelling and blue discoloration of combs and wattles due to poor circulation, coughing, sneezing, nasal discharge, and diarrhea.

What should poultry producers do if their birds appear to have signs of avian influenza?

If domestic poultry (farm birds) exhibit signs of avian influenza, producers should consult their veterinary professional and notify federal or state animal health officials as they normally would.  Nationally, sick or dead farm birds can be reported to USDA toll-free at 1-866-536-7593, or in Tennessee, contact the State Veterinarian’s Office at 615-837-5120. 

What are the signs of “bird flu” in wild birds?

Wild birds, especially migratory waterfowl (geese, ducks) and shore birds generally do not become ill as a result of infection with avian influenza. Some reports from Asia indicate that the H5N1 virus has caused illness and death in wild birds.

What should be done with dead wild birds that are found?

Dead shorebirds or waterfowl (ducks, geese, etc.) can be reported to USDA-Wildlife Services at 1-866-4USDAWS (487-3297) as part of a national monitoring program for bird flu.  If you find one or two dead song birds, it’s very unlikely to be related to bird flu as it is not uncommon for bird losses to naturally occur from a variety of causes.  A dead bird should be disposed of using a plastic glove or bag and placing it in the trash. Be sure to wash your hands afterwards.  However, if the cause of death is not obvious (i.e. flew into window, killed by an animal or other trauma) and there are more than four dead song birds, you can also report dead song birds to USDA-Wildlife Services.  USDA-WS will determine on a case by case basis whether testing is necessary. 

Do migratory birds spread highly pathogenic avian influenza viruses?

Migratory wild waterfowl are known to be a natural reservoir of influenza A viruses. Although migratory birds are capable of spreading influenza viruses including H5N1, the role of bird migration is not well understood.

Are persons, like duck hunters, at risk in handling migratory waterfowl?

There is no known risk in Tennessee. Transmission from wild birds to humans has not been documented and there is no indication that North American waterfowl are infected with H5N1 avian influenza. Waterfowl hunters should follow normal precautions. For example, do not handle or eat sick game. Wear rubber or disposable latex gloves while handling and cleaning game and thoroughly wash hands and all knives, equipment and surfaces that come in contact with game. Use appropriate hygiene and cook meat thoroughly as a normal preventative measure against foodborne illness.

Is there a vaccine or cure for avian influenza in people?

There is currently no vaccine available to protect people from avian influenza. The human influenza vaccine will not offer protection against avian influenza. A vaccine was developed for the 1997 H5N1 avian influenza; unfortunately, the virus has changed considerably since then and that vaccine is not recommended for use against the current strain.  Nevertheless, it is a good idea to follow the recommendations of the Centers for Disease Control and Prevention regarding flu shots.  Please consult a medical professional or your local health department for more information regarding recommended vaccinations. 

Can other animals get this strain of avian influenza?

Yes, reports indicate that in addition to affecting chickens, ducks, swine, and human beings this strain may affect domestic cats, tigers, leopards, ferrets, eagles and falcons. Work is under way to determine the extent to which other wildlife and domestic species may be infected. It is believed that all birds can transmit avian influenza to some extent. Therefore, the U.S. restricts importation of all birds (Class Aves) and feathers from countries affected by the outbreak of avian influenza. This should prevent the disease from being introduced into the U.S. by exotic bird species or pet birds.

Is it safe to eat poultry and eggs?

The consumption of properly handled and prepared poultry and poultry products is safe.  There have been no reported human cases of avian influenza associated with the preparation or consumption poultry meat or eggs.  In countries where outbreaks have occurred, affected chickens have been from small backyard flocks and communities in which free-range chickens and ducks co-mingle. In general, people should avoid contact with sick and dying birds and always follow proper storage, handling and cooking procedures to protect against food borne illnesses.   

What is the US doing to protect commercial poultry populations?

To date the United States does not have H5N1 avian influenza, and it does not import poultry from the affected countries. In addition, several safeguards are in place in the United States to protect the health of chickens on farms and to ensure the quality of poultry and eggs purchased by consumers. In modern commercial poultry and egg production systems, birds are housed indoors in climate-controlled buildings to prevent contact with wildlife that may spread diseases that the chickens are susceptible to, including avian influenza.  There is ongoing surveillance of flocks to test birds that show signs of respiratory disease or unexpected mortality. If a flock is suspected of having avian influenza, the farm is placed under quarantine until the diagnosis is confirmed. If the diagnosis is confirmed, restrictions are placed on the movements of birds, equipment, and personnel to and from the facility and the flock will be de-populated on-site. Birds from infected farms are not sent for processing or sold for consumption. An investigation is conducted to determine the source of the virus, and any flocks thought to be at risk of contamination are also placed under quarantine and may be de-populated as a preventive measure. Farms in areas where an outbreak is ongoing do not receive new chickens until the area is determined to be free of disease.  So, the risk of H5N1 avian influenza moving from backyard flocks in Asia to commercial flocks in the United States is very low.