Updated risk of H5N1 HPAI incursion to poultry in Great Britain via wild birds

Avian influenza (AI) is a highly contagious viral infection, which can affect all species of birds. Highly pathogenic avian influenza (HPAI) viruses can spread rapidly, causing serious disease with high mortality in many bird species. Wild birds are recognised as the reservoir for low-pathogenicity AI virus and have been shown to play a role in the long-distance transmission of HPAI viruses. In April 2006, H5N1 HPAI (Eurasian lineage) was detected in a dead Whooper swan ( Cygnus cygnus ) in Scotland, marking the first detection of H5N1 HPAI virus in Great Britain since 1959. At the time of the outbreak, risk tools were developed collaboratively between the Veterinary Laboratories Agency, the British Trust for Ornithology, the Wildfowl and Wetlands Trust and Defra to support assessments of the likelihood of the introduction and spread of H5N1 HPAI via wild bird migratory movements to and within Great Britain (Crick and others 2006). A risk-based surveillance model was developed to identify areas in which commercial poultry were at the greatest risk of incursion of H5N1 HPAI from wild birds (Snow and others 2007). The resulting risk map was used by government to prioritise AI surveillance activities including the testing of wild birds found dead for H5N1 HPAI as mandated within the EU AI surveillance framework (Hesterberg and others 2009). This geospatial risk modelling tool has recently been updated to provide revised estimates of these geographical areas and was used as part of the evidence base to assess the risk of incursion from wild …