Thursday, December 21, 2017

South Korea: MAFRA Confirms HPAI H5N6 At Duck Farm in Yeongam


Yesterday, we saw that South Korea Reported A `Second Strain' Of Newly Reassorted H5N6 Virus, isolated from samples collected on Dec. 10th in Yeongam.  While not providing specifics, we learned that this HPAI H5N6 virus differed slightly from the HPAI H5N6 viruses collected in mid-November from Gochang (50 miles to the north) and on Jeju Island.
Both viruses are reassortants of last winter's European H5N8 virus and a European LPAI HxN6 virus, and not the Asia H5N6 virus which arrived South Korea last year.
Yesterday South Korea's MAFRA (Ministry of Agriculture) also announced an outbreak of H5 AI (pathogenicity unknown) at a duck farm in Yeongam, affecting 30,000+ birds.  Today we learn that lab tests have come back, and the virus is identified as HPAI H5N6.

What we don't know yet - and probably wont for a week or longer - is whether this latest HPAI H5N6 virus closely matches the Gochang/Jeju strain, the `second strain' collected in Yeongam 10 days ago, or is yet another variation on the H5N6 theme.

This (translated) statement from MAFRA.

Chonnam Yeongam Duck Duck H5N6 Type AI Highly pathogenic virus confirmed

Date Registered 2017-12-21 15:00:00

The Ministry of Agriculture, Forestry and Livestock Food and Beverage (Minister of Agriculture and Rural Affairs: Kim Young-lok) conducted a final inspection of the agricultural, livestock and livestock quarantine headquarters on 12.19 days (Tue) of Hwangyong duck farm (about 31,300 rearing size) (H5N6) virus, according to the company.

Prior to the confirmation of a high incidence of illness as a reinforcement measure against AI blockage,

- Inspection of the farmhouse (No. 136) of the same duck family in the breeding farm was carried out for 7 days for all poultry farms and workers in Yeongam-gun.

HPAI H5 viruses - particularly those belonging to clade - have proven themselves highly mutable over the past several years, constantly reinventing themselves as they spread geographically and mix with new LPAI viruses (see J Vet Sci: Evolution, Global Spread, And Pathogenicity Of HPAI H5Nx Clade

The HPAI H5N8 virus that arrived in Europe last winter - sparking their largest avian epizootic in April - was a reassortment created sometime in 2016 (probably in Russia or China), and a far cry from the H5N8 virus that first appeared in South Korea in 2014 (see EID Journal: Reassorted HPAI H5N8 Clade - Germany 2016). 
While rampaging through Europe, this reassorted H5N8 virus spun off both H5N5 and H5N6 subtypes - and while H5N5 appeared at the time to be the more robust of the two - it turns out that this `European' H5N6 is the one to have survived the summer and has returned this fall to both East Asia and Northern Europe. 
While the pace of HPAI outbreaks in South Korea this fall is far slower than last year, with the 2018 Winter Olympic Games - which will be held in Pyeongchang County - now only six weeks away (Feb 9th-25th), the South Korean government is understandably anxious to do everything they can to head off any avian flu `distractions'  that could affect the attendance or enjoyment of the games.

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