One of the hallmarks of Clade 22.214.171.124 H5 viruses (which include both H5N8 and H5N6 subtypes) has been its enhanced ability to successfully reassort with other (mostly LPAI) viruses it encounters in its travels, and in doing so spinning off new genotypes, and occasionally, new subtypes as well.
Within weeks of arriving in North America in late 2014, H5N8 had generated viable H5N1 and H5N2 subtypes. While the H5N1 subtype was only found in a few birds, the HPAI H5N2 subtype became a major player in 2015's North American epizootic.
A recent study published in the Journal Science (Oct. 2016), called the Role for migratory wild birds in the global spread of avian influenza H5N8, noted:
`. . . . we found that the hemagglutinin of clade 126.96.36.199 virus was remarkably promiscuous, creating reassortants with multiple neuraminidase subtypes.'In another study, published last November in EID Journal: HPAI A(H5Nx) Viruses With Altered H5 Receptor-Binding Specificity, researchers postulated:
`Altered receptor-binding properties might affect the balance between HA and NA, enable the virus to acquire different NA subtypes, and might result in altered host range and spreading.'
Whatever the reason, clade 188.8.131.52. H5N8 has shown a remarkable ability to continually reinvent itself, which has put us on watch for any signs of new subtypes emerging in Europe.
Although nearly all of the reports during the fall of 2016 were of H5N8, in December several nations (Italy, The Netherlands, and Montenegro) reported the discovery of a new HPAI H5N5 reassortant virus in a small number of wild birds.
A week ago - and for the first time in Europe - HPAI H5N5 Was Detected In A German Poultry Operation. Three days later HPAI H5N5 Was Detected At Two More Poultry Farms.
It remains to be seen how persistent this H5N5 virus will be, but it has been described as `highly aggressive' by the Friedrich-Loeffler-Institut (FLI), which published an updated avian flu risk assessment last week (see FLI Risk Assessment On HPAI H5).
Today we have reports of an HPAI H5N2 virus having been detected in wild birds in Baden-Württemberg, in the Southwest of Germany. A full genetic analysis is still awaited, but a preliminary report from the FLI suggests this may be a new reassortant of the H5N8 virus.
First, an excerpt from a (translated) report appearing on the Landtag of Baden-Württemberg website.
One end of the bird flu is in the southwest is currently not in sight: so far nearly 800 dead wild birds were reported according to the Ministry, around 300 of the virus type H5N8 was detected. Recently three other suspected cases were confirmed at the weekend. It would involve a buzzard and a Mute Swan in Ulm and a buzzard in Wachtelhau (Kreis Sigmaringen), the Authority informed on Saturday. As before, only wild birds from avian influenza affected. Corresponding findings were recorded for example in Bodenseekreis and the following districts of Constance, Ravensburg, Sigmaringen, Emmendingen, Rastatt and Ulm.
In poultry flocks in Schleswig-Holstein next to the pathogen H5N8 also the type H5N5 had emerged recently. This had not been discovered in the southwest, said the spokeswoman of the Ministry in Stuttgart. However, in a mallard in Muggensturm (Kreis Rastatt) was the pathogen H5N2 been proven. Maybe if it were a genetically modified variant of H5N8, said the spokeswoman. But for the people it is not contagious.
A German media report this morning reads:
Sigmaringen, 30.01.2017The Ministry of rural areas and consumer protection announced on Saturday that three new cases of the bird flu virus in wild birds have been identified in Baden-Württemberg.by press releaseIt involves a Buzzard and a mute swan in Ulm, as well as a common buzzard in quail Hau (Kreis Sigmaringen).All necessary regulatory measures on the ground are already taken by the housing, as well as further biosecurity measures. On a Mallard already in December in Muggensturm (district of Rastatt), the new subtype H5N2 of highly pathogenic avian influenza virus was detected now by the Friedrich-Loeffler-Institute.This virus was first detected in the country. Perhaps it's a genetically modified variant of the highly contagious bird flu virus H5N8. Details of the new virus subtype are not yet known. The H5N1 bird flu virus has already cost millions of birds life. You died or were slaughtered emergency, so that the disease is not spreading.
While it seems reasonable that this HPAI H5N2 is related to the clade 184.108.40.206. H5N8 virus - given the hodgepodge of avian flu viruses (HPAI & LPAI) of both European and Eurasian lineage detected in Europe over the past 16 months, we'll have to wait for a more complete genetic analysis to be certain.
But related or not, the appearance of another HPAI H5 virus in Europe could further complicate an already complicated situation.