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| Kostroma Oblast - Credit Wikipedia |
#13,458
Amid dozens of reports of HPAI H5 (presumably H5N8) in Western Russia over the past two months we have a new report of HPAI H5N2 - the second reported from Russia - once again from Kostroma Oblast.
Roughly 8 months ago, in OIE: Outbreak In Kostroma, Russia Now Identified As HPAI H5N2, we learned of the first appearance of this HPAI H5N2 virus in Russia, where it forced the culling of 600,000 birds.Today the OIE is reporting a second outbreak in Kostroma Oblast, affecting a poultry farm with nearly 500,000 birds. This report also confirms that this virus is of clade 2.3.4.4. - which suggests this may be a relatively new reassortment - likely from either HPAI H5N8 or HPAI H5N6.
Source of the outbreak(s) or origin of infection
Unknown or inconclusive
Epidemiological comments
The virus isolate was identified as H5N2 subtype by PCR and nucleotide sequencing. The comparative analysis of the obtained nucleotide sequences of the H gene and N gene fragments revealed that the isolate belongs to the Asian genetic lineage of highly pathogenic avian influenza (Clade 2.3.4.4.) which spread in the Russian Federation as well as in Asian, European, Middle Eastern and African countries in 2016-2018. The hemagglutinin cleavage site has a –REKRRKRGLF- structure, characterizing the virus as potentially highly virulent.
Clade 2.3.4.4. H5 viruses have proven themselves to be highly promiscuous, reassorting readily with other flu viruses, and generating a number of viable hybrids. Last year we saw the emergence and spread of HPAI H5N6 (see Tottori University: Shimane HPAI H5N6 A New Reassortment) while the year before a new H5N5 virus was spreading in parts of Europe.
Going back even farther, in 2014-2015 we saw a reassorted clade 2.3.4.4. HPAI H5N2 virus help spark the largest avian epizootic in North American history (along with HPAI H5N8), affecting at least 15 states and parts of Canada.This second appearance of HPAI H5N2 in Kostroma Oblast suggest this reassorted virus is likely circulating in wild or migratory birds - and while we don't know much how this particular reassortment behaves - this will raise fresh concerns over this fall's bird migration into Europe, the Middle East and Africa.
