Role of Migratory Birds in the Spread of Avian Influenza in Europe Assessed

April 26, 2006 — 

The European Food Safety Authority (EFSA) has released a statement on the findings of an expert panel charged with evaluating the impact of migratory birds on the introduction and spread of H5N1 highly pathogenic avian influenza (HPAI) in the EU member states. The working group was asked to review the current information available to determine: 1) the risk posed by wild birds and particularly migratory birds in the spread of the Asian lineage H5N1 HPAI virus strain; 2) the risk that populations of wild birds will become a reservoir of the Asian lineage H5N1 HPAI virus; and 3) the risk that the virus may pose for entry, exposure, contamination, transmission and spread to birds and poultry on the EU territory.

The scientific statement confirms that certain species of wild and migratory birds can transmit the virus, lists those bird species most likely to expose domestic poultry to H5N1 and identifies free range and backyard flocks and poultry holdings near wetlands as being most at risk. The likelihood that infected birds could transmit the virus to susceptible avian species at points of concentration was found to be very high.

The statement also provides the following list of recommendations to minimize the probability of HPAI entering the EU:

• Local poultry keepers need to be educated in relation to the need of establishing a minimum set of biosecurity measures to minimize the risk of introduction and spread of infection. These will involve reduced opportunity for contact between poultry and wild birds.
• It is essential to enhance surveillance of poultry and wild birds, and develop contingency plans for AI outbreaks as well as strengthen biosecurity.
• Vaccination should be considered as a tool to supplement biosecurity measures.
• The trade of poultry and poultry products needs to be controlled more strictly, notably in relation to movements where the outbreaks may occur.

The working group also evaluated the likelihood of the virus becoming endemic in wild bird populations in the EU. They concluded that the probability will depend on the species present in a specific area and also on the climate. The group made the following recommendations to reduce the probability of virus transmission to domestic poultry:

• Staff hygiene should be assessed where there is a risk of staff contact with waterfowl or other infected animals.
• Building access for wild birds or other infected animals needs to be prevented.
• Use of water and feed that may be contaminated by infected birds needs to be prevented.
• Since the risk of infection in the vicinity of migratory waterfowl refuges may be higher than in other locations, it would be better to avoid locating poultry units to be set up newly near to such refuges. For existing production units located in such areas, biosecurity measures need to be strengthened and compliance may need to be audited.
• In geographical areas where HPAI infection is likely to pose a risk to domestic poultry, these birds should not be kept outside.
• If there is an outbreak of HPAI in wild birds, game birds and ducks should not be released to the wild during the risk periods, particularly if this is done in large numbers and the birds are attracted to return by being fed subsequently.
• If there is an outbreak of HPAI in wild birds, then hunting or collecting wild waterfowl by some other method should not occur and the public should be encouraged to take basic hygiene precautions.

Source:
EFSA Scientific Statement