Photo Credit – FAO
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For several months now we’ve been watching reports out of Vietnam concerning the newly discovered clade 2.3.2.1 C of the H5N1 virus. This is the most recent variation of clade 2.3.2.1 that has been circulating for several years in South East Asia and China.
Just over a year ago (see FAO Warns On Bird Flu) concerns were raised over this clade, as the poultry vaccine currently in use was ineffective against it.
H5N1 – like all flu strains – is a constantly moving target, mutating and evolving, looking to evade host defenses. Which means that new clades, and variations within each clade, continue to emerge.
You can see the evolution of the virus in the chart below, starting with Clade 0, first detected in 1996.
All of which means we are not watching just one H5N1 virus strain, we are watching at least 20 genetically separate clades of the virus, with many minor variants of each clade thrown in the mix.
Since first reported in July, this latest clade ( 2.3.2.1 C) has made headlines across Vietnam due to its rapid spread. A few earlier reports include:
Vietnam: Ministry Bans Transport Of Waterfowl Over H5N1 Fears
V Said, C Said
Vietnam Reports A Possible Change In The H5N1 Virus
Today, some encouraging news out of Vietnam as they announce early tests results on a new poultry vaccine that shows promise against this emerging clade.
This from the the Saigon-Daily.
Vietnam develops vaccine for toxic bird flu virus
Wednesday, Oct 03, 2012
At a meeting of the Steering Board for Bird Flu Prevention on October 2 in Hanoi, it was announced that Vietnam has now developed a vaccine that can control the new highly toxic strain of bird flu virus.
Pham Van Dong, head of the Department of Animal Health, said that health officials tested the newly developed vaccine on a flock of chickens and the test results were positive.
In future, they will conduct experimental tests on water-fowl and if test results are once again positive, the new vaccine will be used throughout the country.
The new bird flu strain, 2.3.2.1 C, has recently spread to Vietnam and is now present in affected areas in the northern and central provinces of Hoa Binh, Tuyen Quang, Thai Binh, Ha Tinh and Quang Ngai.
Of these, Quang Ngai Province has reported the highest number of dead poultry with nearly 24,000 birds having died so far.
The Department of Animal Health said that the bird flu pandemic will develop unpredictably because illegal transportation and sale of poultry of unmarked origin is far too rampant.
The Mekong Delta provinces were hence quick to implement the campaign ‘Month for disinfection at farms and prevention and control of bird flu’ in October. During the campaign, farm owners will have to tidy their farms and disinfect their surroundings at least once a week as well as disinfect transportation and cages after use.
Slaughterhouses and poultry markets will have to be disinfected once a day, when the butchering is over.
While we continue to see isolated human infections around the world (see A WHO Flu Review), H5N1 remains largely an avian-adapted virus, and for now primarily a threat to poultry.
The concern, of course, is that with continual changes to the virus, one of these days it may better adapt to human or mammalian physiology.
