Opinion of the Scientific Panel Animal Health and Welfare (AHAW) related with the Migratory Birds and their Possible Role in the Spread of Highly Pathogenic Avian Influenza.

Abstract

A qualitative risk assessment was conducted to determine 1) the likelihood of introduction of Asian lineage H5N1 highly pathogenic avian influenza virus by migratory birds into the EU, 2) the likelihood of it becoming endemic in wild birds in the EU and 3) the likelihood of transmission of infection to domestic poultry. The conclusions reached included that the probability of the virus being released into the EU varied between low and high, depending on the species of migratory birds. A minority opinion was noted concluding that the risk was medium across species. In the light of this risk, it was recommended to educate poultry keepers in currently affected countries outside the EU in relation to minimum biosecurity standards. Surveillance should be enhanced in these countries in domestic poultry and wild birds, and vaccination programmes should be considered for controlling the infection. Trade with poultry and their products needs to be managed considering the risks of spreading virus between geographical areas. Research needs to be conducted to improve surveillance methods in poultry and widl birds. Wild bird migration data needs to be analysed to better understand the flyways used by the various species. The risk of the virus becoming endemic in European wild bird populations was considered to vary between low and high depending on species. A minority opinion was received concluding that this risk was medium across species. This risk could be reduced by intensifying surveillance in wild birds within the EU, and use the data to inform biosecurity measures in domestic birds. The behaviour of wild birds within the EU needs to be better studied so that the dynamics of transmission within and between species are better understood. The final step of the risk assessment indicates that there is a negligible risk of the virus infecting domestic poultry kept under a high biosecurity standard and not in high poultry density areas. The risk increases to very low if they are kept in high poultry density areas. For backyard and free-range poultry, and any poultry not kept under high biosecurity standards, it was concluded that the risk of introduction of Asian lineage H5N1 highly pathogenic avian influenza virus to the flock was low to medium. These risks emphasize the need to make better use of existing and new migratory bird behaviour data. Passive and active surveillance for AI in wild birds needs to be intensified. It should focus on the species identified in this risk assessment. Biosecurity measures for poultry holdings need to be reviewed, and research needs to be conducted to optimise their effectiveness. Poultry holdings should not be built in the vicinity of wetland areas. New vaccines and their use need to be researched.