FGBI "ARRIAH" conducted a study of identified isolates of the avian influenza virus, which led to outbreaks of the disease in 12 regions of Russia

Employees of the reference laboratory for avian viral diseases of the Federal State Budgetary Institution "ARRIAH" conducted a study of the nucleotide sequences of the H gene fragment of the identified avian influenza virus isolates. 

As a result of genetic analysis, it was found that all virus isolates from these regions do not differ from each other and belong to the Asian genetic line of highly pathogenic avian influenza virus subtype H5, clade 2.3.4.4b, which received epizootic distribution in 2016-2023. in Asia, Europe, Africa, North and South America. The hemagglutinin cleavage site has the structure REKRRKR, which is typical for highly virulent avian influenza viruses. According to the international databases GenBank and GisAid (EpiFlu), the most genetically close to these isolates are viruses of the H5N1 subtype, identified in 2023 in a number of European countries - the Czech Republic, the Netherlands, Belgium, England, Austria and Italy. At the same time, the isolates identified in the Russian Federation showed 100% similarity with the European isolates of the virus. According to the GisAid genetic database, these isolates have been circulating in Europe for several months, at least since January 2023. Isolates from the Russian Federation were similar to those isolated in Egypt and Spain in 2022 (99.6% similarity). 

Russian isolates of the H5N1 subtype virus, identified in May 2023 and associated with the death of gulls, are genetically close to the H5 subtype avian influenza viruses identified earlier in the period from 2020 to 2023 in the regions of the Russian Federation (99.2-99.6% similarity level ). The highest level of similarity is observed with H5N1 avian influenza viruses detected in the Kaliningrad region in April 2023.