Photo Credit – FAO
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Over the past few weeks we’ve seen a growing number of reports out of Vietnam regarding a newly emerging sub-clade of the H5N1 virus (see Vietnam Reports A Possible Change In The H5N1 Virus).
While the origin of this virus is in dispute (see V Said, C Said), what is clear is the concern being expressed by officials over this new threat.
This new sub-clade has been dubbed 2.3.2.1 C, and is the third variation of the 2.3.2.1 clade 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.
The myriad of H5N1 viruses we have today have all essentially evolved from clade 0, first identified in 1996. You can see the history of the virus in the chart below. H5N1 – like all flu strains – is a constantly moving target, continually evolving, looking for an evolutionary advantage.
Some less successful clades have died out along the way, but many co-circulate around the globe today.
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.
Which brings us to today’s report from the SGGP (Sài Gòn Giải Phóng), the official newspaper of the Vietnamese government.
Ministry fears spread of virus, bans transport of water fowl
Wednesday, Sep 19, 2012
The Ministry of Agriculture and Rural Development has decided to stop transport of live water-fowl from North and Central Vietnam to the South, in an effort to curb spread of the new highly toxic strain of avian flu virus.
Pham Van Dong, deputy director of the Department of Animal Health, stated this at a meeting held yesterday in Hanoi by the National Steering Committee for Avian Flu Prevention and Control.
The new strain, 2.3.2.1 C, which has been detected, is highly toxic and therefore extremely deadly.
The virus strain has recently spread to Vietnam and is now present in affected areas in the northern and central provinces of Hai Phong, Ha Tinh, Ninh Binh, Nam Dinh, Bac Kan, Thanh Hoa and Quang Ngai.
Fearing the virus may spread to South Vietnam, the Department of Animal Health was asked to isolate the virus and ban transport of live water-fowl from infected areas.
Dong said that slaughterhouses practicing good hygiene should be mentioned to localities from the central province of Thua Thien-Hue to Ho Chi Minh City.
Because the new strain is different from the earlier A/H5N1 virus, the ministry has urged for experiments and tests to confirm whether the vaccine used to combat A/H5N1 is also effective against the new strain. If the existing vaccine is ineffective, studies on new vaccines should be conducted soon.
The Central Veterinary Diagnosis Center has been asked to study the new strain to help find a specific medication to fight the virus.
Although the above story describes this new strain (2.3.2.1 C) as `highly toxic and therefore extremely deadly’ this would appear to be referring mainly to its effect on poultry.
Vietnam has reported only 4 human infections this year (2 fatal), and none have been reported since last March (see WHO Update Avian influenza – situation in Viet Nam – update).
Thus far, we have scant hard data on the threat this new clade poses to humans.
While we continue to see isolated human infections around the world, 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 adapt to human or mammalian physiology.
And so the world remains at Pre-pandemic Phase III on the H5N1 virus, and we continue to watch for signs that the virus is moving towards becoming a bigger threat.
