11.06.2008

EFSA - Avian Influenza

Following a request from the Commission, the AHAW panel was asked to deliver a scientific opinion on the animal health and welfare aspects of Avian Influenza and the risk of its introduction into the EU poultry holdings.
New findings on AIV characteristics
Phylogenetic analyses of strains from EU Member States indicated that all H5N1 viruses detected in the EU in poultry and wild birds since 2006 were closely related and belong to clade 2.2 and 2.3. The use of phylogeny can advise on the source of infection, but it is not possible in all circumstances to be definitive about the likely source of an introduction.
Pathogenesis and transmission
Concerning the pathogenesis and the transmission of AIV, the main conclusions were that although fecal-oral infection chains govern the transmission of AIV, accumulating evidence indicates that H5N1 virus may be excreted at higher concentrations from the respiratory tract of birds as compared to LPAI viruses.
Several domestic animals, including pigs, cats and dogs are susceptible to H5N1 HPAI viruses under natural and experimental conditions.
Diagnosis
Viral isolation in embryonated eggs still remains the “gold standard” for AI virus detection. Although it is slower, its diagnostic sensitivity is often superior or equal to many rapid tests. Virus genome detection by RT-PCR, which can be designed to detect all avian influenza A viruses or specific subtypes, provides a rapid, sensitive and convenient alternative for virus isolation.

 

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