South Korea: MAFRA Reports 2 Outbreaks of HPAI H5N9 in Poultry & Ducks

[Michael Coston]

South Korea: MAFRA Reports 2 Outbreaks of HPAI H5N9 in Poultry & Ducks
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#19,404

Over the 2024-2026 flu season, South Korea's MAFRA Reported Increased Infectivity & Pathogenicity of last Year's Avian Flu Strains, which - for the first time - included 3 HPAI subtypes (H5N1, H5N6, and H5N9).

Notably, their Animal and Plant Quarantine Agency also reported H5N1's infectivity was more than 10 times higher than in previous years.

Last year MAFRA reported 62 outbreaks in poultry, and 63 detections in wild birds. While details were scant at the time, last September a highly technical report published in Virus Researchadded considerable detail. Briefly it reported:

• Last year South Korea was visited by a diverse panoply of H5Nx genotypes (n=16), with at least two - H5N9 N9-G2 and H5N1 25G2 - displaying unusually high infectivity in chickens.
• H5N1 25G2 was also deadly to ducks, whereas H5N9 N9-G2 spread efficiently in ducks, albeit without producing serious illness.
• H5N1 25G2 was the source of nearly half (n=30) of last year's 62 South Korean poultry outbreaks, but it was only detected in environmental samples once, making its prevalence in wild birds unknown.

This year's avian flu season has already started in South Korea, with a report of H5N1 In wild leopard cat in Seosan, South Chungcheong Province less than a week ago, and - over the past 4 days - 2 seperate outbreaks of H5N9.

The first, reported on Nov 4th, is from the north of the country near the DMZ, while the second is in the far south of the country.

(translated)

Nationwide disease control measures strengthened following the first outbreak of highly pathogenic avian influenza (AI) at a laying hen farm in Yeoncheon, Gyeonggi Province.

2026.11.04 18:00:00 Quarantine Policy Bureau Avian Influenza Prevention Division

The Central Disaster Management Headquarters for Highly Pathogenic Avian Influenza ( headed by Minister of Agriculture, Food and Rural Affairs Song Mi-ryeong , hereinafter the Headquarters ) announced on Wednesday , November 4 , that highly pathogenic avian influenza (H5N9 type ) was confirmed at a laying hen farm ( approximately 91,000 birds ) located in Yeoncheon-gun, Gyeonggi-do .

Accordingly, it was announced that on November 4 ( Wed ), a meeting of the Central Disaster and Safety Countermeasure Headquarters, presided over by Director General of Food Policy Park Jeong-hun and attended by relevant agencies and local governments, would be held to review the outbreak situation of highly pathogenic avian influenza and quarantine measures, and to strengthen quarantine management .

1. Situation of Occurrence

The owner of a laying hen farm in Yeoncheon, Gyeonggi Province, reported an increase in chicken deaths to the Northern Gyeonggi Animal Health Laboratory, and as a result of a detailed examination , it was confirmed on November 4 ( Wed ) as highly pathogenic avian influenza (H5N9 type ) . This outbreak is the first case at a domestic poultry farm in the '26/'27 season .

Considering the recent continued detection of highly pathogenic avian influenza in wild birds and the high incidence of outbreaks in laying hen farms last season, thorough disease control management, such as adherence to biosecurity protocols and strengthened disinfection, is required at poultry farms nationwide .

Of the 62 cases that occurred in the '25/'26 season, 31 were at laying hen farms ( 17 were at large laying hen farms with over 100,000 birds ).

In particular , it is a serious situation requiring intensive management, such as disinfection , surveillance , and inspection, centered on large-scale laying hen farms and densely populated areas that suffer significant damage in the event of a highly pathogenic AI outbreak .

(Continue . . . .)

Quarantine management strengthened following the confirmation of highly pathogenic avian influenza at a broiler duck farm in Jangheung, Gwangju, Jeonnam.

2026.11.06 18:50:00 Quarantine Policy Bureau Avian Influenza Prevention Division

The Central Disaster Management Headquarters for Highly Pathogenic Avian Influenza ( headed by Minister of Agriculture , Food and Rural Affairs Song Mi-ryeong , hereinafter the Headquarters ) announced on November 6 (Fri) that highly pathogenic avian influenza (H5N9 type) was confirmed at a broiler duck farm ( approximately 22,000 ducks) located in Jangheung , Gwangju , South Jeolla Province .

Accordingly, it was announced that on November 6 ( Fri ), a meeting of the Central Disaster and Safety Countermeasure Headquarters was held under the chairmanship of Director of the Disease Control Policy Bureau Lee Dong-sik, with the participation of relevant agencies and local governments , to review the situation regarding the outbreak of highly pathogenic avian influenza and disease control measures, and to strengthen disease control management .

1. Situation of Occurrence

At a broiler duck farm in Jangheung, Gwangju, Jeollanam-do, the farm owner reported an increase in mortality to Jangheung-gun , and as a result of a detailed inspection , it was confirmed on November 6 ( Fri ) as highly pathogenic avian influenza (H5N9 type ) . Including this outbreak, two cases of highly pathogenic avian influenza have occurred at domestic poultry farms during the winter of '26/'27 .

* Status of outbreaks at poultry farms this winter ('26.11.3.~): 1 case ( Laying hens in Yeoncheon, Gyeonggi-do )

With additional outbreaks occurring just two days after the first outbreak at a poultry farm on November 3 , and the risk of further outbreaks being very high in farms with inadequate quarantine measures , all poultry farms nationwide need to strengthen biosecurity and report any suspected symptoms to the quarantine authorities without delay .

In particular , as the first outbreak of the season has been confirmed at a duck farm, thorough disease control management is required for duck farms under the jurisdiction of affiliates .

(Continue . . . )


While two outbreaks does not a flu season make, for South Korea to kick off their avian flu season with back-to-back H5N9 outbreaks (hundreds of miles apart) is worthy of mention.

Last year, H5N9 made up just 5 of 62 (8%) of South Korea's poultry outbreaks and 10% of wild bird (environmental) samples. It will be of great interest to see if H5N9 continues to spread.

Also worth mentioning, last year H5N9 was described as highly lethal in chickens, but without producing serious illness in ducks. Friday's announcement cites `an increase in mortality' on the affected duck farm.

Of course, the H5N9 subtype returning this fall could be a different genotype than was seen last year.

As we discussed as recently as yesterday (see EM&I: Emergence of a Distinct Evolutionary Cluster of Clade 2.3.4.4b H5 Viruses in China during 2024-2025 with Rapid Evolution and Antigenic Divergence), HPAI is constantly reinventing itself.

In addition to H5N9 in South Korea, H5N5 is making moves (see HPAI H5N5: A Variation On A Theme) in high latitude regions of the Northern Hemisphere, and H5N6 continues to simmer in China.

Although it seems unlikely that today's H5N1 juggernaut could be toppled by any of these competing subtypes, it wasn't all that long ago (2020) that H5N8 was the dominant subtype.

A reminder that HPAI is highly unpredictable, and its threat can change over time.


https://afludiary.blogspot.com/2026/11/south-korea-mafra-reports-2-outbreaks.html