Considering that highly pathogenic H5N6 was only first detected last April in South Central China, where it infected local poultry and killed one person (see Sichuan China: 1st Known Human Infection With H5N6 Avian Flu), it is suddenly starting to turn up in a number of widely separated locations.
In August, we learned of outbreaks in three separate provinces of Vietnam (see Vietnam Orders Intensified H5N6 Surveillance), and today Xinhua News is reporting an outbreak last month in Heilongjiang province, more than 2000 miles due north of Vietnam.
First today’s report, then I’ll be back with more.
BEIJING, Sept. 1 (Xinhua) -- Northeast China's Heilongjiang Province has reported an outbreak of the H5N6 bird flu virus in poultry, the Ministry of Agriculture (MOA) announced Monday.
Over 20,000 geese at a farm in Harbin, the provincial capital, showed symptoms of avian flu and almost 18,000 died last month, according to the MOA.
The National Avian Influenza Reference Laboratory on Monday confirmed the epidemic was H5N6.
The infected area has been sealed off and sterilized with almost 69,000 poultry culled and safely disposed, the MOA said.
Bird flu, or avian influenza, is a contagious disease of animal origin caused by viruses that normally infect only birds and, less commonly, pigs. It can be fatal to humans.
Over the past 18 months we’ve seen an impressive number of new avian influenza subtypes emerge, starting with the H7N9 virus which has already caused two substantial waves of human infection in China, and followed by H10N8, H6N1 (in Taiwan), H5N8 (only in poultry), and now H5N6.
These upstart viruses are the result of ongoing reassortment between avian viruses that are circulating in poultry and wild birds. While we tend to think of these subtypes as a single entity, in truth, each had developed a number of clades, with variants within each clade.
In EID Journal: H7N9 As A Work In Progress, we learned that the H7N9 avian virus continues to reassort with local H9N2 viruses, making the H7N9 viruses that circulated in wave 2 genetically distinct from those that were seen during the 1st wave.
While in EID Journal: Describing 3 Distinct H5N8 Reassortants In Korea, we saw hints of the genetic diversity already present very early in the Korean outbreaks.
And last June, in EID Journal: Mutations Of A(H10N8) Virus in Chicken Eggs and MDCK Cells we saw hints that this new virus ``might be undergoing rapid adaptation to mammals and developing antiviral drug resistance’.
Thus far, these viruses remain primarily adapted to avian physiology and do not spread efficiently in humans. The concern is that with so many new viruses, and so many variants, one of these days a human-adapted virus will emerge.
There is a school of thought that says only H1, H2, and H3 viruses are likely to spark a human pandemic (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?), but it is a theory based on only about 120 years of documented pandemic history.
For more on these emerging viruses, and the regions of the world most prone to produce them, you may wish to revisit: