Evolution of influ- 245 enza A/H5N1 virus (1996-2016)

Abstract

Twenty years ago in the South Chinese province of Guangdong the epizooty of highly pathogenic avian influenza (HPAI) H5N1 virus, which has laid the foundation of the largest epizooty in the contemporary history, has flashed. Hemagglutinin of prototype A/goose/Guangdong/1/1996 (H5N1) changing many times and generating new genetic subgroups participated in various reassortations; it still exists today. The present review is devoted to the retrospective analysis of HPAI/H5N1evolution for the last twenty years in the territory of Eurasia, Africa and America. The basis for the discussion is ecological model according to which new genetic variants are formed in the migration pathways with close contacts between different bird populations and in the overwintering areas where the maximum values of the immune layer occur; amplification of virus variants occurs in nesting areas among juvenile populations. The updated system of designations of genetic groups introduced by WHO/OIE/FAO H5 Evolution Working Group in 2015 is used.

Mutational and phylogenetic status of west siberian strains of BLV

“…Or, what seems much more plausible, there was an exchange of the corresponding sites of nucleic acids already directly in the livestock population on the territory of Western Siberia. Earlier studies of influenza viruses [25] and HIV [26] recorded the exchange of nucleic acid sites between viral particles, often accompanied by the formation of new strains, which indirectly confirms the assumption put forward.…”

A highly pathogenic avian influenza virus H5N1 clade 2.3.4.4 detected in Samara Oblast, Russian Federation

“…The virus has been found in representatives of the orders Ciconiiformes, Anseriformes, Charadriiformes, Pelecaniformes, Podicipedidae, Gruiformes, Falconiformes, and Passeriformes (10). Among these orders, wild waterfowl serve as the main reservoir of AI virus (11)(12)(13), and their role in virus transmission and maintenance of its epidemic cycle has been confirmed by numerous studies worldwide (14)(15)(16). Among all bird species, representatives of the orders Anseriformes and Charadriiformes play a particular role in maintaining the epidemiological cycle, carrying most subtypes of influenza A virus asymptomatically (17)(18)(19).…”