Background and implications

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There are numerous strains of the avian influenza virus, many of which circulate in wild birds at low levels, and most pose no significant problems for bird or human health.

The unusually virulent strain currently causing concern is referred to as H5N1. Avian influenza H5N1 is spreading from south-east Asia where it is out of control in several countries, and has now been detected in several European and middle-eastern countries and in Africa. It is spread in several ways.

Globally, the most important of these has been unrestricted movements of poultry and poultry products. The outbreaks in Europe in winter 2005-2006 appear to have been due mainly to movements of infected swans, ducks and geese away from severe winter weather in the Black Sea region.

The risk to humans with the virus in its current form is very low. However, the current outbreak of avian influenza is already having a serious impact on people around the globe, their livestock and their economies. Whilst the number of human cases is relatively low, the loss of human life is a tragic consequence of the disease, especially as improved public information could have prevented the majority of infections.

The RSPB is working with BirdLife International, the Wildfowl and Wetlands Trust, the British Trust for Ornithology, Defra and others to evaluate the risk on an ongoing basis.

We are participating in the Government's surveillance programme, to monitor waterbirds for the infection. The public has been asked by the government to report any suspicious die-offs of wild birds to the government helpline, tel: 08459 335577 (England, Scotland or Wales) or 02890 524999 (Northern Ireland).

If you come across a dead duck, goose, or swan, wader or gull and you are within a survey area (see the link to the right for details) you should not touch it, but report it to the Defra helpline (England, Scotland & Wales) on 08459 33 55 77 or the DARD helpline (Northern Ireland) on 02890 524999.

Please be aware that the helpline can be very busy, so follow the recorded instructions when calling.

Avian influenza H5N1 had never been recorded in wild birds before the recent outbreaks. It probably originated in domestic poultry in south-east Asia.

In 2003, outbreaks occurred across much of south-east Asia. Outbreaks continued to flare up in China, Thailand, Vietnam and Indonesia in 2004, and in 2005, there was further geographical spread to Kazakhstan, Mongolia, regions of Russia, Ukraine, Croatia, Turkey and Romania.

Early in 2006, there was further spread in the Black Sea and Caspian Sea regions and then west to Sweden, Denmark, France, Germany and the UK. The disease was also confirmed in Africa for the first time, with an outbreak confirmed in a battery farm in northern Nigeria. It has now also been found in domestic poultry in a number of other African countries, and Pakistan.

In mid-February 2006, the disease was confirmed in mute swans in Greece and Italy, bringing it to the EU or the first time. Since then, the virus has been isolated in more mute swans and a number of other species across Europe, including pochards, herons, tufted ducks, a smew and several birds of prey.

In 2007, H5N1 continued to circulate in south-east Asia, Egypt and west Africa, and was confirmed in the summer in domestic poultry and wild birds in the Czech Republic, Germany and France.

There are several ways by which H5N1 might be transmitted. Globally, the most important of these has been the unrestricted movement of poultry and poultry products. This is how the disease spread through south-east Asia and probably how it reached Nigeria.

The virus has been isolated and contained in wild-caught birds in customs or quarantine in Belgium, England and Taiwan. The passive transfer of infected material on vehicle wheels or feet is another possible route of transfer.

The only way to control the disease is through continued surveillance, improved biosecurity, good public information, effective border controls, and swift action to contain an outbreak through efficient culls of infected poultry flocks.

All the major authorities, including the Food and Agriculture Organization of the United Nations, the World Health Organisation and the UK Government have stated publicly that culls of wild birds would be unfeasible and may make the situation worse by dispersing potentially infected individuals.

The discovery of H5N1 in quarantined birds in Essex in October 2005 illustrates the risk posed by the import of wild-caught birds into the EU. Recent evidence that some species of wild bird may be able to carry and shed the virus without developing symptoms means that it is not possible to design an effective quarantine system.

In July 2007, a permanent ban on the import of wild-caught birds into the EU came into effect owing to concerns about the diseases such birds might introduce. Only captive birds from a limited number of approved breeding centres in certain countries are now allowed.

The RSPB believes imports should remain prohibited unless they are able to meet strict conservation and biosecurity criteria. Although the current ban is based solely on health grounds, the RSPB believes that there are compelling reasons for a ban on conservation grounds alone and has lobbied the EU to this effect.

Besides the disease risk, the trade threatens wild bird populations, risks the spread of non-native species in the EU and has animal welfare implications. 

There is only one recorded instance where a human case may have resulted from contact with infected wild birds. The overwhelming majority of 335 human cases worldwide to date have resulted from close contact with infected domestic poultry. The disease is currently not easily transmitted from human to human.

Although the risk of contracting the disease from a wild bird is very low, you are advised not to touch any sick or dead birds, their droppings, or water near them.

It is extremely unlikely that avian influenza could be transmitted to people by feeding birds in the garden, but good hygiene at bird feeding stations is sensible, in any case. Follow the link below for advice.

The H5N1 virus is generally highly pathogenic (causes a high level of mortality) to wild birds and we have concerns that infection or attempts to cull wild birds or destroy their habitat, in misguided attempts to control the disease might adversely affect the conservation status of some species.

Two globally threatened species have already been affected. It is estimated that between 5% and 10% of the world population of the bar-headed goose Anser indicus perished in the outbreak at Lake Qinghai, in China in spring 2005.

The virus was isolated from a red-breasted goose Branta ruficollis found dead in Greece in February 2006. This is of concern, as 90% of the world population of 88,000 is confined to just five roosts in Romania and Bulgaria - both affected countries. 

The Dalmatian pelican Pelecanus crispus is vulnerable as it breeds in colonies in freshwater wetlands and coastal lagoons. The world population of 15,000 is confined largely to the Baltic and Black Sea regions. Many of the countries in which it breeds have already been affected by H5N1.

The H5N1 avian influenza virus in its current form does not transmit easily from birds to mammals. However, a few cats have caught the disease through eating infected birds in Thailand and three cats were found to be infected with H5N1 on the island of Rügen in the German Baltic. These individuals were in an area where hundreds of wild waterbirds had died of the disease. 

The risk of a domestic cat in the UK contracting the disease is remote. The vast majority of garden birds killed by cats are not those species most at risk of carrying the disease. 

The RSPB, along with the RSPCA, the British Veterinary Association and the Feline Advisory Bureau, urges people not to abandon pet cats (or any other pets); this would be cruel and may have an additional impact on wildlife.
 
As always, people should observe good hygiene with respect to pet animals, and should illness present itself, consult their veterinary surgeon at the earliest opportunity.