EUROPA - Animal Health & Welfare - Animal Diseases - Avian influenza (2024)

Avian influenza is a highly contagious viral disease which occurs in poultry and other birds, that is caused by several different types of Influenza A viruses. It is primarily a bird disease, although there have been cases of avian influenza viruses being transmitted from infected birds to humans and other animals.

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Most avian influenza viruses are of low pathogenicity, meaning that they do not cause serious disease in birds. Wild birds (ducks, geese and gulls, in particular) often carry these viruses without showing any symptoms. Indeed, these birds are considered to be the main "reservoir" of avian influenza viruses in nature. From these birds, the low pathogenic viruses may also sometimes spread to domestic poultry. Some of these low pathogenic viruses can mutate into highly pathogenic viruses after transmission from wild birds to domestic flocks, causing very serious disease and major epidemics in poultry and other birds. The infamous Asian strain (H5N1) of the avian influenza virus is an example of such a virulent highly pathogenic virus.

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H5N1 is a strain of avian influenza, and the virus currently causing concern worldwide is a highly pathogenic form of that strain. It has a high mortality rate in birds, and has been transmitted directly from birds to humans and other animals in certain countries. The current global outbreak of highly pathogenic H5N1, which emerged in South-East Asia in 2003, is the most widespread and severe ever recorded.

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The first outbreaks of the highly pathogenic strain of H5N1 avian influenza were actively reported in South-East Asia in 2003, although the virus had most likely been circulating in the region since as early as 1996. Avian flu is still endemic in this region and eradication is proving extremely difficult. Starting in spring 2005, the virus spread northwards, affecting birds in Northern China, Mongolia, Russia and Kazakhstan. By the end of 2005, it was clear that the Asian strain of the H5N1 virus also arrived in Europe, with Croatia, Romania, Turkey, Ukraine and the European part of Russia all affected by the virus to varying extents. Early 2006 saw a significant outbreak of the virus in domestic poultry in Turkey, and by February 2006, the disease was also being reported in wild birds in a number of EU Member States, Bulgaria and other Balkan countries. There have also been some outbreaks of H5N1 in poultry in the EU, but thanks to the strong EU eradication and control measures in place, these have so far been quickly contained. Many African and Middle Eastern countries also began reporting confirmed cases of H5N1 avian influenza in the first half of 2006.

For the latest information on avian influenza outbreaks globally, see the OIE daily update at: http://www.oie.int/downld/AVIAN INFLUENZA/A_AI-Asia.htm

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Certain wild birds may act as carriers of avian influenza viruses. Currently, an increasing number of different wild bird species are being found to be infected with the highly pathogenic H5N1 Asian strain of the virus. There has been increasing evidence that migratory wild birds affected by the disease have contributed to the global spread of the H5N1 virus over long distances, for example, from Asia to Europe.

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EU legislation on avian influenza is laid down in Directive 92/40/EEC, and the new Directive 2005/94/EEC, which must be transposed by Member States by July 31, 2007. This legislation sets out rules on the surveillance, control and eradication measures that must be taken in the event of a highly pathogenic avian influenza outbreak. The new Directive also provides for the use of preventive vaccination against avian influenza, under certain conditions and subject to specific requirements. The Avian Influenza Control Directive also gives the Commission full flexibility to take ad hoc measures in the case of an outbreak of avian influenza, as it is impossible to provide for every possible scenario in framework legislation. Such measures must be agreed with Member States within the framework of the Standing Committee on the Food Chain and Animal Health (SCFCAH), before they can be adopted by the Commission.

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A number of legislative Decisions in relation to avian influenza have put forward by the Commission and agreed by Member States in the Standing Committee on the Food Chain and Animal Health (SCFCAH). These aim to respond to the latest avian influenza situation and to new threats, and are kept under continual review. For example, following confirmation that the H5N1 virus was spreading westwards from Asia, new rules for the surveillance of wild birds and heightened bio-security measures were agreed. Import bans on poultry and poultry products from affected third countries were also implemented. Decisions on measures to be taken in the event of a highly pathogenic outbreak of avian influenza in wild birds, and in poultry, were adopted by the Commission as the risk of the H5N1 virus heightened in the EU, and these have been implemented in any Member State in which there was an outbreak to date. In June 2006, the Commission adopted Decision 2006/416/EC which strengthens the legal framework for Member States to apply control measures in case of an outbreak of highly pathogenic avian influenza in poultry and other captive birds, as laid down in the new Avian Influenza Directive. In particular, the Decision sets out a much clearer legal base for "special cases" e.g. the control of highly pathogenic avian influenza in zoo or ornamental birds.
The latest Decisions agreed in SCFCAH can be found here.

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If there is a suspected outbreak of highly pathogenic avian influenza in poultry flocks, all poultry on the holding concerned must be kept indoors or confined in an isolated area where they will have no contact other poultry. No poultry may enter or leave the affected holding. People, animals, vehicles, poultry products, animal feed or anything else liable to transmit the avian influenza virus cannot move to or from the holding without the authorization of the competent national authority. Bio-security measures, such as the disinfection of entrances and exists of poultry houses and the holding itself, must be applied. National authorities must carry out an epidemiological inquiry on the possible source of the disease. If the Member State authorities consider it necessary, they may also immediately cull and destroy all the poultry in the holding, pending confirmation of the disease.

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In the case of a confirmed outbreak of avian influenza in poultry, the affected Member State must put in place the strict measures set out in the new Avian Influenza Directive due to be implemented by July 2007, and that are reflected as transitional measures in Decision 2006/415/EC and 2006/416/EC.

The following measures must be taken on that holding when there is an outbreak in poultry:

In addition, national authorities must establish a protection zone with a radius of 3km around the site of infection and a surveillance zone with a minimum radius of 10km around the protection zone. Wider risk areas must be set up around the protection and surveillance zones, which should act as a buffer between the infected and non-infected part(s) of the Member State and neighbouring countries.

In these zones, there are a series of restrictions and controls must be applied. These include a block on live poultry and birds, meat, eggs and poultry products leaving the areas except under very limited conditions. Stringent bio-security measures must also be applied, and monitoring of poultry and birds must be stepped up. If the Member State authorities deem it necessary, further culling in holdings close to, or which had interaction with, the infected holding may be carried out. For more information, see: MEMO/06/79.

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The priority when a case of highly pathogenic avian influenza is detected in wild birds in a certain region is to prevent the spread of the virus to poultry and captive birds. Therefore, Member States where avian influenza is suspected or confirmed in wild birds must immediately apply EU measures which were first set out in the EC Decision on avian flu in wild birds (see IP/06/180), and then revised in mid-2006 to take into account experience gained over the previous months. National authorities must set up a control zone and a monitoring area around the location where the infected wild bird was found, unless thorough assessment of the situation indicates that there is no risk of disease spreading to poultry in the area. In the control zone, poultry must be kept indoors, the movement of poultry is banned except directly to the slaughterhouse, and the dispatch of meat outside the zone is forbidden except under very controlled and limited circ*mstances. In both the control zone and the monitoring area, on-farm biosecurity measures must be strengthened, hunting of wild birds is banned and disease awareness of poultry owners and their families must be carried out.

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Recognising the importance of disease surveillance for the early detection and control of highly pathogenic avian influenza, the EU has intensified its programmes for the surveillance of avian influenza both in wild birds and poultry. Member States have drawn up and implemented national surveillance programmes, for which the Commission has made almost €2.9 million available for the period July 2005 to December 2006 (see IP/06/172). Guidelines on enhanced surveillance for avian influenza in wild birds were also issued by the Standing Committee on the Food Chain and Animal Health. Between July 2005 and May 2006, around 100 000 tests for H5N1 were carried out on wild birds across the EU, the results of the increased surveillance for avian influenza in wild birds were presented in a report by the Commission and Community Reference Laboratory for Avian Influenza (see IP/06/704). The intensified surveillance has allowed a clearer overview of the avian influenza situation in the EU to be established, and has helped in rapidly detecting and responding to any outbreaks that occurred.

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There is much discussion about the pros and cons of using vaccination as a preventive measure against avian influenza. On one hand, vaccination can help reduce the infection, transmission and mortality rate of avian influenza and reduces the amount of the virus shed by a bird if it does become infected. On the other hand, vaccination does not provide 100% protection against avian influenza, and the virus can be more difficult to detect in a vaccinated flock which could delay the implementation of control and eradication measures. Strict surveillance and control measures must be carried out on vaccinated poultry under EU legislation, and these, along with the initial work and costs required to administer the vaccine, can make it prohibitively expensive to vaccinate commercial birds.

Preventive vaccination may be used in a targeted way, for example among zoo animals, to prevent them from needing to be culled. The new Avian Influenza Directive also enables Member States to carry out preventive vaccination programmes on certain species of poultry, under specific conditions, if they are at high risk of avian influenza. Vaccination has also been used in certain categories of poultry in specific areas in Italy, where low pathogenic avian flu viruses frequently recur.

The use of vaccination will always be strictly monitored and the EU rules will require that vaccinated birds can be differentiated from infected birds (DIVA strategy - Differentiating between Infected and Vaccinated Animals) and that specific surveillance and control measures are in place. This is very important both for disease control and for trade purposes, as in this way, restrictions on trade in poultry and poultry products from the vaccinated areas can be minimised. Eventual restrictions on trade will be decided on a case-by-case basis.

For more information on avian influenza vaccination, see Memo/06/92.

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In the event of certain animal health crises, including an outbreak of highly pathogenic avian influenza, farmers are compensated by national authorities for the losses incurred in applying disease eradication measures such as culling of livestock and disinfection measures. Member States may obtain up to 50% EU co-funding for the compensation paid to farmers, which is provided from the EU veterinary fund. In addition, EU funding may be provided for up to 100% of the costs of supplying, and 50% of the costs of applying, emergency vaccination in such a situation. It should be noted that there is no EU funding for preventive vaccination.

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Due to the avian flu situation, consumption of poultry and eggs has fallen dramatically in some Member States, leading to a sharp reduction in prices. Until recently, EU legislation only allowed co-financing to compensate the egg and poultry sector in cases where there was a disease outbreak or where farmers were prevented from moving their poultry because of veterinary restrictions imposed. In view of situation with regard to H5N1 avian influenza however, the European Commission put forward a proposal to enable market support measures for the eggs and poultry sector to be provided from the EU budget. The measure was approved by the European Parliament and adopted by Council on 25 April. Under the new support measures, EU co-financing will cover up to 50% of the cost of market support measures linked to a drop in consumption and prices of eggs and poultry.

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Cases of domestic cats found to be infected with the H5N1 were confirmed in both Germany and Austria in early 2006. Germany also confirmed a case of a stone marten (small wild mammal) infected with H5N1. The infected animals were all found within surveillance zones where there had been outbreaks of H5N1 in wild birds. The fact that these animals have been detected shows the strength of the EU surveillance system. Other carnivores, such as civet cats in Asia, have also been shown to be susceptible to H5N1 and most likely caught the virus through close contact with/ eating infected birds. There is no evidence of humans catching avian flu from cats or mammals. In light of the current situation, however, the European Centre for Disease Prevention and Control (ECDC) and the Standing Committee on the Food Chain and Animal Health issued guideline recommendations for people in areas where H5N1 has been detected in wild birds, advising them not to let their cats roam freely outside, to avoid wild or stray cats, and to contact their vet immediately in the case of sick/dead cats or dogs which may have been in contact with wild birds.

See: http://www.ecdc.eu.int/avian_influenza/pdf/ECDC_advice_cats_H5N1.pdf

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The EU has actively offered assistance to third countries affected by H5N1 avian influenza, and has worked closely with international bodies in their efforts to combat it. EU experts and resources needed to tackle avian influenza have been sent to a number of accession, neighbouring and other third countries when requested.

At an international Pledging Conference held in Beijing in January 2006, the Commission and EU Member States committed a total of around 211 M€ towards the fight against avian influenza and preparations for a possible human influenza pandemic. The Commission and the World Bank have established a multi-donor trust fund, called the Avian and Human Influenza Facility, through which a large part of the EU pledged funds will be administered to countries in need of assistance in Asia, Eastern Europe and the Mediterranean region. A significant amount of international funding will also be made available to African countries to help them prevent and control avian influenza and increase human pandemic preparedness. As a follow up to the Beijing Pledging Conference, senior officials met in Vienna on 7 June 2006 to discuss the technical as well as political questions related to providing assistance to developing countries in fighting avian influenza and preparing for a possible human pandemic. Further follow up meetings on this issue will be held every 6 months, with the next one scheduled to take place in Africa in December 2006.

For more information, see: http://ec.europa.eu/world/avian_influenza/index.htm

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Useful links

European Centre for Disease Prevention and Control
WHO page on influenza
World Organisation for Animal Health (OIE)
UN Food and Agriculture Organisation (FAO)

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