While HPAI H5N8 remains, by far, the biggest avian flu threat in Europe, a novel HPAI H5N5 virus - first reported six weeks ago in wild birds in the Netherlands - is increasingly being detected across the continent.
Over the past 10 days we've seen this virus reported in wild birds in Slovenia & Greece, and in wild birds and on several poultry farms in Germany.
Described as `highly aggressive' by German Agriculture Minister Robert Habeck, this virus appears to be a reassortant of HPAI H5N8 and a local LPAI virus.
Germany's Friedrich-Loeffler-Institut (FLI) describes this new virus as:
Since mid-December 2016 a further subtype, H5N5, has been circulating in wild birds, which now has first been introduced into a poultry holding. This virus is is likely to be a reassortant based on the original H5N8. Mixed viruses, so-called reassortants, of avian influenza viruses are generated, if several virus subtypes are present in one infected animal and exchange genetic material during replication. Generation of reassortants must be expected when different high and low pathogenic influenza viruses are circulating in one population.
Today the OIE announced the discovery of this newest HPAI incarnation in Southern Poland, near their border with the Czech Republic. And as we've seen previously, the dead birds were mute swans.
So far we've seen this upstart virus turn up in The Netherlands, Italy, Montenegro, Germany, Greece, Slovenia, and now Poland.
Given this broad geographic range (> 1000 km), it must be assumed that this virus is circulating reasonably well among wild and migratory birds, despite its high mortality in some species.Whether this virus can successfully compete with H5N8 - as we saw a reassortant H5N2 virus do in 2015 during North America's epizootic - remains to be seen. But as the FLI warned, this may not be the last HPAI virus we see spin off from H5N8 during its European tour.