Sunday, December 4, 2011

Why is Clade 2.3.2.1 so important? #H5N1 #Birdflu

Recently, Treyfish has been hot on the trail of birds and poultry die-offs in Nepal. He posted many articles on Crows dying, and yesterday, he broke the story that it was indeed H5N1 bird flu, and the clade was 2.3.2.1. What's the big deal about the clade? Below I will give you a few resources to peruse.

From our Blog:
Crows of the bird flu virus is killed. The report of the investigation team, primarily because of Pune Atimark Avian Anfluenja A 5 N 1 'is described. National Institute Wayrolaji, the dead ravens found in Pune, this virus is very dangerous for humans. According to the Institute investigated the virus-clade 2.3.2.1 'belongs to the category.
http://pandemicinformationnews.blogspot.com/2011/12/cause-of-death-of-crows-h5n1-virus.html#links


From the FAO (Food and Agricultural Organization of the United Nations):
August 29, 2011

Bird Flu rears its head again
Increased preparedness and surveillance urged against variant strain
A further cause for concern, Lubroth said, is the appearance in China and Viet Nam of a variant virus apparently able to sidestep the defences provided by existing vaccines.

In Viet Nam, which suspended its springtime poultry vaccination campaign this year, most of the northern and central parts of the country -- where H5N1 is endemic -- have been invaded by the new virus strain, known as H5N1 - 2.3.2.1.

High alert

Viet Nam's veterinary services are on high alert and reportedly considering a novel, targeted vaccination campaign this fall. Virus circulation in Viet Nam poses a direct threat to Cambodia, Thailand and Malaysia as well as endangering the Korean peninsula and Japan further afield. Wild bird migration can also spread the virus to other continents.

"The general departure from the progressive decline observed in 2004-2008 could mean that there will be a flareup of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard," Lubroth said.

The countries where H5N1 is still firmly entrenched – Bangladesh, China, Egypt, India, Indonesia and Vietnam – are likely to face the biggest problems but no country can consider itself safe, he said.

"Preparedness and surveillance remain essential," Lubroth underlined. "This is no time for complacency. No one can let their guard down with H5N1."
http://www.fao.org/news/story/en/item/87196/icode/



From WHO (World Health Organization):
30 August 2011

Evolution of H5N1 avian influenza virus does not increase risk to public health
WHO closely monitors the evolution of influenza viruses and is aware of recent reports of an H5N1 virus (described as H5N1 clade 2.3.2.1) circulating in poultry in parts of Asia. Based on available information, this evolution of the H5N1 virus poses no increased risk to public health. It is not considered unusual because influenza viruses are constantly evolving, especially in areas where they circulate regularly in poultry.

The WHO Global Influenza Surveillance and Response System, the group of experts that studies animal and human influenza viruses that may impact human health, recognized this new clade in February 2011.

WHO also routinely assesses the public health risk from all animal influenza viruses. Based on available information, the identification of this newly-reported H5N1 virus clade does not change the current public health implications of the H5N1 avian influenza viruses for humans. Human cases of H5N1 infection remain rare and sporadic events, occurring mostly in areas where H5N1 viruses circulate regularly in poultry. Human cases could occur wherever the viruses are present in poultry and when humans might be exposed to infected birds or contaminated environments.
http://www.who.int/influenza/human_animal_interface/avian_influenza/h5n1-2011_08_30/en/index.html



From OIE (World Organization For Animal Health)
August 31, 2011
Avian influenza H5N1 clade 2.3.2.1
OIE closely follows the evolution of avian influenza in domestic and wild birds around the world, and acknowledges the recent identification of an H5N1 virus described as clade 2.3.2.1.

Small genetic changes are known to routinely occur in influenza A viruses, including those that may affect humans or animals. The emergence of the H5N1 virus, such as clade 2.3.2.1 is one of such genetic mutations taking place as part of the natural evolution of the virus. This is not immediate cause for alert but, as with the emergence of any new strain, reinforces the need for sustained monitoring of viruses in animal populations so that changes in viruses circulating in the field are detected at an earliest stage and that most appropriate disease control strategies are chosen to best protect animal and public health.

OIE recommends keeping up with active surveillance in bird populations, encouraging national Veterinary Services to be prepared to quickly report and respond to unusual animal disease events that may represent more serious disease in animals or that may pose increased risk to humans.

As is the case with human influenza vaccines whose composition needs to be reviewed every year, avian influenza vaccines need to be regularly tested to check whether they effectively combat the viruses circulating in the field. OIE Reference Laboratories and other partner laboratories are actively involved in ongoing surveillance and development of good quality vaccines that match the viruses of concern. The OIE Reference Laboratory in Harbin, China, has developed a new vaccine seed strain that experimentally protects poultry from the identified H5N1 virus clade 2.3.2.1. This vaccine, once available for field use, will be used in countries where H5N1 virus clade 2.3.2.1 has been identified. Registration and manufacturing of a poultry vaccine with the new seed strain is in progress.

OIE and OFFLU’s guidance on early detection and rapid response to animal disease events prove crucial in the prevention and control of animal influenzas, with positive implications for human health. OFFLU is a joint OIE/FAO worldwide network of expertise on avian influenza. It also provides animal influenza data to the World Health Organization regularly to assist with the selection of candidate influenza vaccines for humans.
http://www.oie.int/for-the-media/press-releases/detail/article/avian-influenza-h5n1-clade-2321/


From CIDRAP (Center for Infectious Disease Research & Policy)
August 31, 2011
The World Health Organization (WHO) and the World Organization for Animal Health (OIE) took pains today to downplay the significance of a new H5N1 avian influenza variant that another major international organization warned about this week.

In an Aug 29 statement, the United Nations Food and Agriculture Organization (FAO) said a new H5N1 strain called clade 2.3.2.1 had emerged recently in Vietnam and China and that existing poultry vaccines were ineffective against it. The statement also cited recent increases in H5N1 bird outbreaks and warned about a possible major resurgence of the virus.

The WHO said today that its Global Influenza Surveillance and Response System recognized the H5N1 variant in February. "Based on available information, this evolution of the H5N1 virus poses no increased risk to public health," the WHO statement said. "It is not considered unusual because influenza viruses are constantly evolving, especially in areas where they circulate regularly in poultry."

The agency further said clade 2.3.2.1 does not change the public health implications of H5N1 viruses, given the available information. "Human cases of H5N1 infection remain rare and sporadic events, occurring mostly in areas where H5N1 viruses circulate regularly in poultry," the statement said.

The OIE made similar points in a statement today. It said the emergence of clade 2.3.2.1 is a result of minor genetic changes that typify the natural evolution of the virus.

"This is not immediate cause for alert but, as with the emergence of any new strain, reinforces the need for sustained monitoring of viruses in animal populations so that changes in viruses circulating in the field are detected at an earliest stage and that most appropriate disease control strategies are chosen to best protect animal and public health, the OIE said.

The agency also commented that avian flu vaccines, like human flu vaccines, need to be tested regularly to see if they are effective against the viruses in circulation. The OIE reference laboratory in Harbin, China, has developed a vaccine that, in trials, has protected poultry from clade 2.3.2.1, the statement said. Once available for field use, the vaccine will be employed in countries where the new variant has been identified.

"Registration and manufacturing of a poultry vaccine with the new seed strain is in progress," the OIE said.

http://www.cidrap.umn.edu/cidrap/content/influenza/avianflu/news/aug3111h5n1.html



This will help you understand the whole numbering system:

WHO
October 2011

Updated unified nomenclature system for the highly pathogenic H5N1 avian influenza viruses
Background and Objectives
In recent years, a variety of different provisional names have been used to refer to emerging lineages of the currently circulating highly pathogenic avian influenza (HPAI) H5N1 viruses. As a result, discussion, comparison, and analysis of the various lineages proved difficult.

Avian H5N1 viruses continue to spread, continue to infect animals and humans, and continue to evolve and diversify. While most viral genes have been replaced through reassortment yielding many different genotypes, the specific H5 hemagglutinin (HA) gene identified in 1996, remarkably, has remained present in all isolates. Therefore, this H5 HA provides a constant to which the evolving strains may be effectively compared, and it was proposed to develop a standard clade nomenclature system based upon the evolution of this H5 HA. This nomenclature system would enable:

-snip-

As the viruses within these clades continue to evolve, new sublineages (potential H5N1 clades) periodically emerge. Once these sublineages meet the same three specific clade definition criteria as the initial clades (listed above), they are designated as separate clades.

These new clades are defined as second, third or fourth-order clades and assigned a numerical 'address' which links them to their original clade using a hierarchical decimal numbering system. For example, within the distinct clade 2.3, third order clades meeting the clade definition were designated as clades 2.3.1 and 2.3.2 and so on. More recently, a new monophyletic clade was identified within clade 2.3.2 and assigned a fourth order designation as clade 2.3.2.1. This logical hierarchal numbering system is objectively related to HA phylogeny, and thus removes geographic designations (e.g., the lineage previously referred to as 'Fujian-like’ became third order clade 2.3.4, while the 'Qinghai lineage' became second order clade 2.2).

http://www.who.int/influenza/gisrs_laboratory/h5n1_nomenclature/en/index.html




3 article that I pulled from this Blog:

Vietnam: H5N1 2.3.2.1 Recently discovered in Phu Tho Province
September 3, 2011
http://tinyurl.com/8yckbsw

China - Bird flu virus found in poultry markets
Wednesday, November 16, 2011
http://tinyurl.com/74hs5jw

H5N1 avian influenza virus "re-export"
Wednesday, November 16, 2011
http://tinyurl.com/c9kabqo

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