#12,006
Excluding poultry, Japan - as of 1700 hrs (local time) December 12th has now recorded 53 separate detections (of one or more) HPAI positive wild birds across 11 Prefectures.
Not all of these reports have been validated as due to H5N6, but those that have been fully tested have all turned out to be of this subtype.
Japan's Ministry of Environment handles the non-farm detections of the virus (wild birds & environment), and their Information about the highly pathogenic avian influenza web page has been updated almost daily since H5N6 arrived in Japan in mid-November.
Since we last checked in on Wednesday (see Japan : Wild Bird H5N6 Update, the MOE has posted 22 new reports (see below).
- 2016 December 12, for the highly pathogenic avian influenza virus confirmed positive test in the death of wild birds, Kagoshima Prefecture (H28.12.12 17:00)
- For the dispatch of emergency investigation team in the highly pathogenic avian influenza-positive case in 2016 December 12-day mortality of wild birds, Ibaraki Prefecture (H28.12.12 16:00)
- 2016 December 12, for the highly pathogenic avian influenza virus confirmed positive test in Akita Omoriyama Zoo and Nagoya Higashiyama Zoo and Botanical Gardens (H28.12.12 15:00)
- 2016 December 12, for the type A avian influenza virus genetic testing positive in the death of wild birds, Aomori Prefecture (H28,12.12 15:00)
- 2016 December 12, for the type A avian influenza virus simple test positive in the death of wild birds, Iwate Prefecture (H28.12.12 10:30)
- 2016 December 11, 2011 survey results of wild bird emergency research team associated with the highly pathogenic avian influenza occur for in Niigata Prefecture (H28 .12.11 17:00)
- 2016 December 11, 2011 for the type A avian influenza virus simple test positive in the death of wild birds, Ibaraki Prefecture (H28.12.11 16:00)
- 2016 December 10, for the type A avian influenza virus simple test positive in the death of wild birds, Ibaraki Prefecture (H28.12.9 17:00)
- 2016 December 10, for investigation of the results of wild bird emergency research team associated with the highly pathogenic avian influenza occurred in Miyagi Prefecture (H28.12.10 16:00)
- 2016 December 9, for highly pathogenic avian influenza virus confirmed positive test in the death of wild birds, Kagoshima Prefecture (H28.12.9 18:00)
- 2016 December 9, for the type A avian influenza virus genetic testing positive in the death of wild birds, Niigata Prefecture (H28.12.9 17:00)
- December 9, 2016 [put up] for the dispatch of emergency investigation team in the highly pathogenic avian influenza-positive cases in Hokkaido of death wild birds (H28.12.9 15:00)
- For highly pathogenic avian influenza virus confirmed positive test in 2016 December 9, death wild bird of Niigata Prefecture H28.12.9 14:00)
- For the dispatch of emergency investigation team in the highly pathogenic avian influenza-positive case in 2016 December 9 death of wild birds, Tottori Prefecture (H28.12.9 13:30)
- 2016 December 9, for research related to breeding under death bird of Nagoya, Aichi Prefecture (H28.12.9 13:30)
- 2016 December 8, for the type A avian influenza virus simple test-positive case in the death of wild birds Hokkaido (H28.12.8 21:00)
- 2016 December 8, for the type A avian influenza virus simple test-positive case in the death of wild birds, Aomori Prefecture (H28.12.8 20:30)
- 2016 December 8, for the highly pathogenic avian influenza wild birds due to the occurrence emergency investigation team of the survey results in Hyogo Prefecture (H28.12.8 17:00)
- 2016 December 8, for the type A avian influenza virus simple test-positive case in the death of wild birds, Ibaraki Prefecture (H28.12.8 16:30)
- For the dispatch of emergency investigation team in the highly pathogenic avian influenza-positive case in 2016 December 8 death wild bird of Niigata Prefecture (H28.12.8 14:00)
- 2016 December 8, for the highly pathogenic avian influenza confirmed positive test in deterministic test negative and Hokkaido of death wild bird in the death of wild birds, Aomori Prefecture (H28.12.8 13:00)
- 2016 December 8, for the highly pathogenic avian influenza confirmed positive test in the death of wild birds, Fukushima Prefecture (H28.12.8 10:30)
While the detection of HPAI viruses in wild and migratory birds is nothing new, in the past they've been more sporadic and less pathogenic than what we've witnessed over the past couple of months with H5N6 in Asia and H5N8 in Europe.
It was only just over four months ago, in PNAS: The Enigma Of Disappearing HPAI H5 In North American Migratory Waterfowl, that researchers looked for - and failed to find - HPAI in North American wild birds in the year following our (HP) H5N1, H5N2, and H5N8 epizootic over the winter of 2014-15.
The authors concluded:
While wild ducks and other aquatic birds are known to be natural hosts for low pathogenic flu viruses associated with milder symptoms, the results of this study indicate that is not the case with the highly pathogenic flu viruses that are associated with more severe illness. The research suggests that wild ducks and other aquatic birds are not an ongoing source of highly pathogenic flu infection in domestic poultry.Although time may again prove that to be true with these latest subtypes, and they may recede next summer as they did after the North American epizootic of 2014-15, it is hard not to come away with the notion that something has changed with these new HP H5Nx clade 2.3.4.4. viruses.
One possibility, proffered by a study published last month (see EID Journal: HPAI A(H5Nx) Viruses With Altered H5 Receptor-Binding Specificity), suggested that recent amino acid changes enable clade 2.3.4.4 H5 viruses to now bind to fucosylated sialosides.
Receptor cells that differ from the sialic acid (a2,3 avian or a2,6 mammalian) that influenza viruses normally bind to.
While the full impact of this change in receptor binding remains unknown, the authors suggest `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.'
Or it could be something else entirely.
At this point, the only thing certain is that HPAI H5 appears to be well into its 4th Intercontinental Wave since it reemerged in 2003, and it doesn't show any signs (yet) of slowing down.
