Friday, December 02, 2016

Japan: H5N6 Spreading Rapidly Via Migratory Birds


Similar to what we are seeing with H5N8 in Europe and the Middle East, HPAI H5N6 has aggressively taken wing in both South Korea and Japan, and is showing up both in migratory birds and farmed poultry.
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.
Overnight that website has undergone a major transformation, with reports re-organized, a back filling of data, and the addition of eight  new reports in the past 24 hours.

It should be noted that not all of these reports have been validated as being due to H5N6.  Some are simply Influenza A positive in field tests, and additional testing will be needed to determine the subtype. 
Newly added prefectures to the AI list include Fukushima, Hyogo, Miyagi, Iwate, and Ibaraki. 

As in Europe, reports are coming in almost hourly, and any listing is already outdated before it can be published.
While it is possible that we are seeing increased vigilance and reporting bias in Japan and South Korea (and in Europe with H5N8), we've not seen this level of wild bird deaths reported previously. 
China, where both of these viruses emerged in 2014, has never reported much in the way of `real-time' wild bird surveillance, and over the past two years has become less open in their reporting on avian influenza in general. 

Our history with H5N8 outside of China is considerably broader than H5N6, and as I wrote a couple of weeks ago in Europe: Unusual Mortality Among WIld Birds From H5N8, its arrival and spread in North America over the winter of 2014-15 was notable for its dearth of wild bird mortality events.

Exactly why H5N6 and H5N8 appear to be spreading faster, farther, and with more virulence than we've seen before is  - as yet - unknown.

But neither virus appears to be slowing down, and so regions and countries that have not yet been visited need to be alert to the possibility they could be next.

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