Combating Avian Flu

Since its arrival in Turkey at the end of 2005, highly pathogenic avian influenza has been spreading throughout Europe predominantly in the wild bird population, although there have been a number of cases in domestic poultry. IFAH-Europe has produced a set of regularly updated FAQs designed to answer the common questions that surround avian influenza. It is important not to confuse avian influenza (“bird flu”) with the seasonal influenza that infects humans every year.

•  Click on the link to know the answers to the most frequently asked questions about avian influenza

•  Click on the link to learn about the role of the animal health industry in avian influenza

•  Click on the link to find out more about avian influenza vaccination

•  Click on the link to see useful links related to 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 which is now present in 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.

To learn more about avian influenza vaccination, please click here .

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 Europe 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.

 

Avian influenza vaccination

Q: Are vaccines available to minimise the risk of infection with the H5N1 form of Avian Influenza?

A: Yes, several animal health companies produce vaccines protecting against H5N1, which are licensed for use currently in a number of European countries.

For more information on the role of the animal health industry, please click here

Q: How are vaccines used?

A: Entire flocks must be vaccinated and this is done by injection. Birds begin to build up immunity immediately after vaccination and after around 3 weeks their immunity is fully established. In order to increase the duration of the immune protection against the virus to one year, it is necessary to re-vaccinate 3-6 weeks after the initial vaccination.

Q: What is the outcome of vaccination?

Vaccinated healthy birds need a greater amount of virus to be infected, but it is possible for some to become infected and excrete the virus (sometimes referred to as “shedding” of the virus) although most vaccinated birds are protected from infection and do not shed any virus. However infected vaccinated birds that shed the virus shed it at such a low level that it is insufficient to infect other birds. Scientific studies show that 2-3 weeks after vaccination, transmission of the virus is completely stopped.

Experience has shown that vaccination of birds - in combination with stamping out, biosecurity and surveillance measures - is an effective additional tool for preventing viruses from spreading during the outbreak stage. Vaccination is particularly useful in areas with high poultry density. The outcome of vaccination is that vaccinated birds do not become sick and die and the spread of the virus is dramatically reduced or stopped.

Q: Is vaccination alone the solution to stopping the spread of avian influenza?

A: No, vaccination alone is not the total answer. While vaccination effectively protects treated birds and limits the spread of the disease thus assisting in eradication programs, it is a preventative measure which cannot be used when birds are already infected. The best use of the vaccine is as a component of an eradication programme under the control of animal health authorities alongside other measures such as surveillance, biosecurity and stamping out.

Q: Who decides whether or not to vaccinate in the event of an avian influenza outbreak?

The decision to vaccinate is made by the relevant authorities of individual countries, taking account of local conditions and the prevailing epidemiological situation. However, as all EU Member States are cooperating and coordinating their actions to combat avian influenza at EU level, the decision to vaccinate must therefore also be approved at EU leve l. On 22 February 2006, the EU Standing Committee on the Food Chain and Animal Health (SCFCAH) which comprises Member State experts agreed that France and the Netherlands could use vaccination as a preventative measure for outdoor flocks in specific geographic areas.

To learn more about EU coordinated action against avian influenza, please see:
http://europa.eu.int/comm/dgs/health_consumer/dyna/influenza/links.htm

Q: Is it safe to eat the meat and eggs from vaccinated poultry?

A: Yes. Meat and eggs from healthy vaccinated chickens pose no human health threat.

 

Q: What is the animal health industry's contribution to the combating avian influenza?

A: A number of animal health companies produce H5 vaccines protecting against H5N1 that are effective in preventing clinical disease in birds. These vaccines help control the spread of avian influenza by increasing the resistance of the vaccinated bird and by reducing shedding of the virus by infected birds.

Animal health companies also contribute to the control efforts of avian influenza with their wealth of knowledge in the field, and by manufacturing products to control disease vectors.

For more information on vaccination, please click here

Q: Can the animal health industry supply enough avian influenza vaccines?

A: Up until now, the companies making avian influenza vaccines have been able to meet demand for their products.

Vaccine production is a complicated process. The production and testing takes at least four months, including all controls on quality, safety and efficacy of the product. Animal health companies need advance warning of a country's intention to implement vaccination in order to be able to supply the requisite amount of vaccines.

 

Useful Links related to Avian Influenza

Please find below links to the websites of organizations that are involved in combating avian influenza and a brief description of their role.

International organizations:
www.oie.org
http://www.oie.int/downld/AVIAN%20INFLUENZA/A_AI-Asia.htm (latest update on avian influenza)

The OIE – International Office for Animal Health (Office International des Epizooties) is an intergovernmental organization responsible for collecting, analyzing and disseminating animal disease data including on avian influenza.

http://www.who.int/topics/avian_influenza/en/ (WHO avian influenza homepage)
http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html (WHO avian influenza FAQs)
The World Health Organisation is coordinating the global response to human cases of H5N1

http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/special_avian.html
The animal production and health division of the Food and Agriculture Organisation (a UN body) has developed guidelines for biosecurity and surveillance in the event of avian influenza outbreaks.

EU institutions

http://europa.eu.int/comm/dgs/health_consumer/dyna/influenza/index.cfm
The website of the European Commission's DG SANCO (Health & Consumer Protection) provides up to date information on avian influenza outbreaks in Europe and the measures implemented in response to the outbreaks.

http://www.ecdc.eu.int/
The European Centre for Disease Prevention and Control coordinates EU wide surveillance, monitoring and early warning systems for communicable diseases including avian influenza.

Animal Health industry

http://www.intervet.com/news/company_news/current.asp
http://www.avian-influenza.com/control/introduction.asp
The animal health company Intervet produces avian influenza vaccines.

http://www.merial.com/index.asp
The animal health company Merial produces avian influenza vaccines.

http://www.wyeth.com/divisions/fort_dodge.asp
The animal health company Fort Dodge produces avian influenza vaccines.

http://www.ceva.com
The animal health company Ceva produces avian influenza vaccines.

Other useful websites;

www.poultrysite.com

 

May 2006