Credit Wikipedia
# 8183
A bit of a surprise this afternoon as multiple media outlets in South Korea are describing their current avian flu outbreak (see South Korea Confirms HPAI Outbreak In Poultry) as not coming from H5N1 as originally suspected, but from a rarely reported H5N8 strain.
First a machine translation of a couple of the reports, after which I’ll return with a little more about this avian flu strain.
AI for the first time in Korea What is onset .. H5N8 type
AP | 01/17/14 21:42 input (revised 17/01/14 21:52)
(Three kinds AP) Kim Seung - Wook reporter = Jeonbuk avian influenza outbreaks in Gochang (AI) is a highly pathogenic form of H5N8 was confirmed last.
Is four times the national past outbreaks of highly pathogenic AI H5N1 type was small, but all types of domestic outbreak of H5N8 is the first time.
Agriculture, forestry and livestock quarantine 17 am Central time, even in the past, such as outbreak of H5N1 AI virus believed to brother, but an analysis of nucleotide sequences of serotype H5N1 type and other forms of H5N8 was confirmed.
Another report, this time from Kyodo News.
Culling of highly pathogenic avian influenza in Korea duck, fear of expansion
The 17th, avian influenza virus toxic (H5N8 type) is detected from the duck farm in North Jeolla Province Takashi-gun high in the southwest, SEOUL, South Korea] Joint Agriculture, Forestry and Livestock Ministry of Food 20 001 Hinayaku of duck of this farm It revealed that it has sacrificed Senba.
On the same day, suspicion of avian influenza infection have been reported in duck farmers going with Buan County, a distance of about 10 km from the farmers, fear of the expansion came out. The increase in the second from the top in the "warning" alarm level, the ministry has strengthened the protection posture.
According to the ministry, the virus of the H5N8 type to have been detected in South Korea that for the first time.
Assuming that these reports are correct, this would be the first large outbreak of H5N8 in poultry that I am aware of, certainly in the past decade anyway.
There are two broad categories of avian influenza; LPAI (Low Pathogenic Avian Influenza) and HPAI (Highly Pathogenic Avian Influenza).
- LPAI viruses are quite common in wild birds, cause little illness, and only rarely death. They are not considered to be a serious health to public health. The concern is (particularly with H5 & H7 strains) that LPAI viruses have the potential to mutate into HPAI strains.
- HPAI viruses are more dangerous, can produce high morbidity and mortality in wild birds and poultry, and can sometimes infect humans with serious result. The type of bird flu scientists have been watching closely for the past decade has been HPAI H5N1 (and to a lesser extent HPAI H7s & H9s).
And indeed, LPAI (low path) H5N8 has been detected in the past, including from samples collected from ducks in 2002 in New York State (see below) and in Europe, as with A/mule duck/Bulgaria/328/2011(H5N8)
Credit FluDb.org
As we’ve seen with the relatively benign LPAI North American H5N1 vs. the virulent Asian HPAI H5N1 virus, there can be major differences in the virulence and behavior of similarly named strains.
Last year, in the journal Veterinary Microbiology, this report was published on its detection in China between 2009-2010, and in this case, it appears to have been a highly pathogenic version in Chickens.
Characterization of three H5N5 and one H5N8 highly pathogenic avian influenza viruses in China
Veterinary Microbiology, Volume 163, Issues 3–4, 3 May 2013, Pages 351-357
Kunkun Zhao, Min Gu, Lei Zhong, Zhiqiang Duan, Yan Zhang, Yanmei Zhu, Guo Zhao, Mingjun Zhao, Zhaoyang Chen, Shunlin Hu, Wenbo Liu, Xiaowen Liu, Daxin Peng, Xiufan LiuAbstract
One H5N8 and three H5N5 highly pathogenic avian influenza (HPAI) viruses which derived their HA genes from the Asian H5N1 lineage were isolated from poultry during 2009-2010 in mainland China. Pathogenicity studies showed that these viruses were all highly virulent to chickens, while they varied from moderate to high virulence in mice and from mild to intermediate virulence in mallards.
Phylogenetic analyses showed that these viruses were reassortants bearing the H5N1 backbone while acquiring PB1, NP and NA genes from unidentified non-H5N1 viruses, and had developed into three distinct genotypes (B-D). Molecular characterization indicated that all these viruses might resist to antiviral agents.
Our findings highlight the emergence and development of HPAI H5 viruses of other NA subtypes in H5N1 endemic areas and their potential threat to poultry industry and public health.
More evidence (as if we needed it) of the dynamic nature of these avian viruses and their ability to evolve, reassort into new hybrids, and perhaps, pose additional threats to poultry and humans alike.
