Most frequently asked questions (FAQ) about avian influenza

Q: What is Avian Influenza?
A: Avian influenza is a respiratory disease of birds caused by a virus which occurs in low pathogenic and high pathogenic varieties. Outbreaks of low pathogenic avian influenza (LPAI) are common around the world, and are generally easily controlled, whereas the highly pathogenic versions of avian influenza (HPAI) are more serious due to the very high mortality rate in affected birds. 

The current variant of highly pathogenic avian influenza now present in Asia, the Middle East and parts of Africa and Europe is the H5N1 strain. The name “H5N1” refers to the arrangement of proteins on the surface of the virus where “H” refers to the hemagglutinin protein and “N” to the neuraminidase protein. An avian influenza virus is identified by the presence of a combination of H and N subtypes of which there are sixteen H subtypes (H1-H16) and nine N subtypes (N1-N9).

Avian influenza is most common in wild waterfowl species , but has also been reported in many common species of poultry, including chickens, ducks, turkeys, geese, pheasants and quail, as well as in a variety of other birds like parrots, cockatoos, and parakeets. Some species are more resistant to infection or can be asymptomatic transmitters of the disease.

Q:  How is Avian Influenza spread?
A:  Avian influenza is primarily spread by direct contact between healthy and infected birds, or through indirect contact with contaminated equipment or other materials .  The virus is present in the faeces of infected birds and in secretions from their noses, mouth and eyes. The virus can spread into domestic flocks kept outdoors through faecal contamination from wild birds, whereas infection among indoor flocks is spread via airborne secretions and faeces.  The spreading of the virus through faeces and secretions is often referred to as the “shedding” of the virus.

Q:   What happens when avian influenza is detected or suspected in a bird or flock?
A:  High Pathogenic Avian Influenza (HPAI) is a reportable disease by the World Organization for Animal Health (OIE).  OIE has developed animal health standards classifying the highly pathogenic strains as reportable diseases.  Any outbreak should be immediately reported to local and national animal health authorities.

Q: What can be done to prevent Avian Influenza?
There is no single solution to prevent avian influenza , but there are three types of measures that are used in conjunction with each other. Firstly, biosecurity and surveillance measures must be introduced , these include:

• quarantining infected farms;
• restrictions on the movement of poultr y in areas surrounding confirmed or suspected infections;
• stringent hygiene measures such as using protective clothing and disinfecting vehicles passing through infected areas to prevent the spread of the virus through contaminated clothes or equipment;
• surveillance of wild birds and domestic poultry in areas surrounding confirmed or suspected infections

Secondly, “stamping out” or culling of infected birds is also used to prevent the virus spreading;

• All birds in a specified location (e.g. a farm) must be culled.
• The carcasses of culled birds must be appropriately disposed of; this is usually done via burial or burning.
• Birds in specified zones surrounding an outbreak may also be culled.

Thirdly, to prevent further spread of the infection, a vaccination programme can also be implemented taking the following into account:

• Vaccination is a prevention strategy,
• Vaccination does not always prevent infection, but the vaccinated bird does not become ill and die as unvaccinated infected birds do.
• If a vaccinated bird becomes infected, it either does not excrete (“shed”) the virus or sheds much lower levels of virus than an infected unvaccinated bird and subsequently stops shedding the virus.

Q: What can be done to cure an infected bird of avian influenza?
A: There is currently no cure for highly pathogenic avian influenza. Current practice in most regions of the world requires the culling of infected birds, not treatment, hence prevention is extremely important. .

Q: What is the risk of mammals such as cats being infected by H5N1?
A: Experience in Asia during 2003 and 2004 shows that domestic cats are at risk of infection, sometimes fatal infection of the H5N1 virus. It is therefore advisable to avoid contact between cats and wild birds or poultry in infected areas. There is no evidence of any transmission of the H5N1 form of avian influenza from cats to humans.

For more information on H5N1 mammal infection, please see WHO statement of 28 February 2006: http://www.who.int/csr/don/2006_02_28a/en/index.html

Q: Does avian influenza present a risk to human health?
A: Firstly, it is important to note that all reported human cases of H5N1 avian influenza (in Southeast Asia and Turkey ) have occurred in people who have had close, direct contact with infected birds . So far there is no evidence of any human to human transmission of the H5N1 virus

For information on diagnosis and treatment of humans infected with avian influenza, please see:
http://www.who.int/csr/disease/avian_influenza/guidelinestopics/en/index1.html
For details of human cases of avian influenza please see: http://www.europa.eu.int./comm/health/ph_threats/com/Influenza/ai_human_en.htm

Q:  Does the spread of H5N1 strain of avian influenza threaten the safety of the food supply?
A: Firstly, the chance of infected poultry entering the food supply is extremely low. Secondly, in the unlikely event that contaminated poultry products reaches the food supply stage, the level of virus would be extremely low and present no danger of infection provided that the food is properly cooked.

Q: Is it true that large commercial poultry operations facilitate the spread of the disease?
A: No, in fact just the opposite is true. Large commercial poultry operations, which raise birds indoors, use biosecurity measures designed to keep birds as disease-free as possible as well as continuous monitoring by veterinarians. Many of these safeguards are not available to producers when flocks are raised outdoors.