Given the promiscuous behavior exhibited by previous HPAI H5 viruses (notably H5N8 & H5N6) - which has resulted in the generation of dozens of genotypes and several new subtypes (see Virology: Five Distinct Reassortants of HPAI H5N6 In Japan - Winter 2016–2017) - it has been more or less expected we'd see similar behavior with the recently emerged (European origin) H5N6 virus which arrived in East Asia in mid-November.
Until now, however, all of the new H5N6 viruses recovered from Japan, South Korea, and Taiwan have been characterized as being closely related.Today, via a short announcement from South Korea's MAFRA and an English language media report from China, we learn that a second strain of H5N6 has been identified in South Korea.
First this brief, slightly syntax-challenged, translation from MAFRA:
Gochang, Yeongam AI virus is likely to be infected by migratory birds.
Registration date 2017-12-20 10:00:00
The Jeonbuk Gochang virus was found to be a genetic component of Jeju North Korean wild bird isolate, Jeollanam-do, Korea, Jeonbuk, Korea, and Jeonbuk, Yeongam duck farms, Jeju, Korea, The viruses of Yeoncheon virus were analyzed to be the same as those of Suncheonman virus.
It was found that the Jeonbuk Gochang virus and Chonnam Yeongam virus were found to be somewhat low in homology. (Between Gochang and Yeongam) 99.61 ~ 100%, (Yeongam and Suncheon Bay) 99.61 ~ 100% ** (between Gochang and Yeongam) 97.31 ~ 99.13%
Xinhua News has a more readable analysis, which follows:
Highly pathogenic bird flu found in S.Korea: quarantine agency
2017-12-20 06:13:17 GMT2017-12-20 14:13:17(Beijing Time) Xinhua English
SEOUL, Dec. 20 (Xinhua) -- At least two strains of highly pathogenic bird flu were found in South Korea this winter, the country's quarantine agency said Wednesday.
The Animal and Plant Quarantine Agency (APQA) announced the result of its DNA analysis of viruses discovered at duck farms in Gochang and Yeongam in the country's southwestern region.
The viruses, which were detected in Gochang on Nov. 19 and in Yeongam on Dec. 10, were highly pathogenic avian influenza (AI) of H5N6 strain, which is a genetic reassortment of the highly pathogenic H5N8 strain originating from Europe and the low-pathogenic N6 virus.
The bird flu viruses were estimated to have entered South Korea through migratory birds, according to the APQA.
The virus found in Gochang was identical to the one discovered in the country's southern resort island of Jeju from Nov. 27 to Dec. 2, but the one detected in Yeongam had a slightly different sequence.
About 76,000 ducks were culled earlier this month at five duck farms within a 3-km radius of the affected site. In 2016, over 30 million ducks and chickens were slaughtered to contain one of the country's worst bird flu outbreaks.
Although the differences were slight - and thus far, unspecified - they are a reminder that these HPAI viruses are a work in progress; that they continue to evolve, occasionally manage to reassort with other viruses, and can (potentially) adapt to other hosts over time.
Hopefully we'll get a more detailed analysis on these changes in the coming days.