Wild Bird Surveillance

Surveys of wild bird populations to screen for the presence of Avian Influenza

Avian influenza is caused by an avian influenza A virus of which there are many different types. They can be characterised by their structure or the severity of disease that they cause in poultry.

There are 2 proteins on the surface of the avian influenza virus, Haemagglutinin (H) and Neuraminidase (N). The structure of these proteins can vary; so far a total of 16 different Hs and 9 different Ns have been identified. The virus can be classified according to these i.e. H5N1, H2N2, H7N3; in this system each different virus is known as a subtype.

Avian influenza viruses that cause severe disease in poultry are known as highly pathogenic influenza (HPAI) viruses, those that cause no disease or milder disease are called low pathogenic avian influenza (LPAI) viruses. The ability to cause severe disease depends on the molecular structure of another part of the virus called the cleavage site. Subtypes H5 and H7 may cause LPAI or HPAI, all other subtypes to date have only been known to cause LPAI.

Wild bird surveillance is underway in Northern Ireland, as part of the overall UK wild bird surveillance programme (GB results available at www.defra.gov.uk)

There are three components to the wild bird survey:

Samples are collected from the live caught birds from Strangford Lough, in Northern Ireland. Birds are caught, ringed and sampled. The birds are released and samples are screened for avian influenza viruses.

This part of the survey is coordinated by the British Association for Shooting and Conservation (BASC), Countryside Alliance is also contributing to the survey in NI. As part of normal wildfowling activities hunters are collecting samples from birds that have been shot; these are then screened for the presence of avian influenza viruses. No birds are shot in addition to those that would normally be shot during hunting.

Species that are considered by experts to be more likely to play a role in the spread of HPAI H5N1 will be considered for laboratory screening. The types of birds that will be considered are gulls, ducks, geese, swans and waders. Generally speaking these birds will have webbed feet, long legs or long necks.

The survey is a strategic targeted survey and not all birds will be collected. The likelihood of a wild bird that is found dead being infected with avian influenza is very small. Dead wild birds are screened because they are a convenient source for sampling and not because their death is likely to be due to avian influenza.

As part of their ongoing Wetlands bird survey over the winter months, Environment and Heritage Service staff along with Non-government organisation partners will monitor and report any unusual mortality of wild birds to DARD.

If you find one or more gulls, waders, ducks, geese and swans (webbed feet, long legs or long neck) the DARD Helpline should be contacted at 028 905 24999.  You will be asked for details of the finding and the location.  If you find any other single dead birds, including garden birds, then you do not need to call the DARD Helpline.

Monitoring of unusual mortality events or ‘die-offs’ in wild birds is being carried out (these are incidents of unusually high mortality in wild birds in relation to the population size in the area concerned).  A number of factors may be responsible for causing a die-off including infectious diseases, adverse weather conditions, poisoning, predation and starvation.  This survey is particularly concerned with identifying infectious diseases of wildlife

If you find 10 or more dead birds of any species in the same place, the DARD Helpline should be contacted at 028 905 24999.

Other than swans, gulls, waders, ducks and geese you do not need to report dead birds unless you find 10 or more in one location.