Avian Influenza

Avian Influenza (AI) is a highly contagious viral inflection caused by the influenza virus type "A" which can affect several species of food producing birds (chickens, turkeys, quails, guinea fowl, etc.) as well as pet birds and wild birds.

Influenza viruses occasionally emerge among humans as part of the natural ecology and biology of influenza viruses. Wild birds are considered the reservoir for influenza viruses because more influenza A subtypes (16) circulate among wild birds than Human or other animal species.

Normally, animal influenza viruses do not infect humans. However, avian influenza viruses can sometimes cross this barrier and directly affect humans. This was demonstrated in 1997, when an outbreak of avian influenza A (H5N1) viruses infected both domestic poultry and humans in Hong Kong, leading to 18 hospitalizations and 6 deaths. Since then, other outbreaks of avian viruses, (such as H9N2 in 1999, H7N2 in 2002, H7N7 in 2003, and H5N1 in 2004) have occurred and been found to directly infect people. Fortunately, avian viruses lack the ability to easily spread from person-to-person and therefore did not precipitate a pandemic.

WSDA has set up a surveillance program within our state to attempt to detect this virus should it reach the domestic poultry within Washington. Emergency response planning has been ongoing to help stop an outbreak before a small situation becomes a large one.

Pandemic viruses can also arise when some of the genes from animal influenza viruses mix or "reassort" with some of the genes from human influenza viruses to create a new influenza virus. This can occur when a single animal (for example, a pig or possibly a person) is simultaneously infected by both a human influenza virus and an avian influenza virus. In this situation, genes from the human and avian influenza can reassort and create a virus with surface protein derived from the avian virus (creating a new subtype) and the internal proteins derived from the human virus, enhancing the transmissibility of the hybrid virus.

The process of reassortment is not theoretical. Reassorted viruses have been frequently identified and thought to be responsible for the 1957 and 1968 pandemic viruses.

AI viruses are normally found in birds and can be expected to be found when wild waterfowl are sampled. The concern is what type of virus would be found. The current concern is that H5N1 has become established in the migratory birds in many flyways. An H5 virus of unknown N type has been found in British Columbia, Quebec, and in Manitoba Canada.

There is concern in Asia about the infection of humans handling raw poultry. The United States does not import any chicken, turkey or poultry products from Asia. The fresh products you see in the store are all produced in the United States except for a very small amount produced in Canada. Like all microorganisms, avian influenza virus is killed by the heat of normal cooking. Washing hands after handling raw poultry is always a good precaution, but there is no danger of getting avian influenza from normally and properly cooked poultry.

Dr. Leonard Eldridge, State Veterinarian, encourages bird owners to practice good biosecurity and to report signs of unusual illness among birds, such as sneezing, coughing, nasal discharge, diarrhea, listlessness and sudden death. To report disease, contact: