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One of the hallmarks of Clade 2.3.4.4 H5 avian influenza viruses (which include both H5N8 and H5N6 subtypes) has been its 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.
A 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 2.3.4.4 virus was remarkably promiscuous, creating reassortants with multiple neuraminidase subtypes.'Within weeks of arriving in North America in late 2014, H5N8 had generated viable H5N1 and H5N2 subtypes. Two years later, in Europe, HPAI H5N8, spun off a number of reassortants (H5N6, H5N9, etc.), but one of the most virulent (in poultry) was H5N5.
Germany's Friedrich-Loeffler-Institut (FLI) described this new HPAI H5N5 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.
Although a relatively minor player compared to H5N8, this newly emerged H5N5 virus was described as `highly aggressive' by Germany authorities, and began turning up in other European countries as well (Slovenia, Greece, Poland, The Czech Republic, Macedonia, etc.).
After the epizootic ended in the early summer of 2017, reports of HPAI H5N5 pretty much ended in Europe, although an HPAI H5N5 subtype turned up in Taiwanese poultry in 2019.
Five days ago, in A Roundup Of HPAI Reports From Germany, Russia, The Netherlands & Japan, German authorities reported their first detection of an HPAI H5N5 since March of 2017, in wild birds in Mecklenburg-Western Pomerania.
We've no genetic sequencing data on this virus, but a recent preprint article (see Novel Incursion of a HPAI H5N8 Virus in the Netherlands, October 2020), described the recently arrived H5N8 virus as genetically distinct from earlier incursions, making it likely that this H5N5 virus is genetically distinct from the 2017 virus as well.
Today Denmark also announces the discovery of HPAI H5N5 in a dead falcon recovered close to their border with Germany.
Peregrine falcon found dead with serious bird flu on Lolland
The first finding of the serious bird flu H5N5 was made at Sakskøbing on Lolland. All poultry farmers must protect their animals against contact with wild birds.
Press release , Published: November 6, 2020
A peregrine falcon, which has been found at Sakskøbing on Lolland, has been found to be infected with the serious bird flu type H5N5. It shows laboratory analyzes from the Statens Serum Institut.
- The finding is not surprising. In the past week, we have received reports from Northern Germany about the finding of bird flu in wild birds. It is extremely important that all owners of birds and poultry take the situation seriously and ensure that their herds are covered so that they do not come into contact with wild birds, says the head of the Danish Veterinary and Food Administration's Veterinary East, Birgit Hendriksen.
In recent weeks, authorities in Germany, the Netherlands and the United Kingdom have reported findings of avian influenza type H5N8. So far, only a single find of the H5N5 type has been reported in Germany, and which has now also been found in the peregrine falcon on Lolland. No human infection has been reported with the types of avian influenza viruses currently circulating in Europe. But the disease is serious for poultry and birds.
The Danish Veterinary and Food Administration decided yesterday to raise the threat level for bird flu from very low to high , which is the highest level. From today, all owners of poultry herds must secure their animals against contact with wild birds with i.a. roofing or fencing. At the same time, a ban has been introduced on events with poultry and birds.
On Wednesday, the Danish Veterinary and Food Administration submitted barnacle geese found at Højer in Southern Jutland for testing for bird flu at the Statens Serum Institut. The board expects a response late Friday or Monday.
The Danish Veterinary and Food Administration asks everyone who finds dead birds to report the finding via the app FugleinfluenzaTip.
Whether you have a hobby poultry or are a professional poultry breeder, remember to adhere to basic infection control measures such as changing and disinfecting footwear before entering your chicken farm.
Hunters should pay attention to the hygiene after hunting, so that they do not carry infection home in the chicken farm, i.a. by washing boots and keeping game separate from poultry.
Read the executive order on requirements for poultry farmers on prevention HERE
Read the executive order banning events with poultry HERE
