[Molecular genetic analysis of avian influenza virus subtype H5N1 isolated in the territory of the republic of Tyva in 2006]
2007
Andriyasov, A.V. | Manin, T.B. | Pchelkina, I.P. | Kolosov, S.N. | Chvala, I.A. | Shcherbakova, L.O. | Drygin, V.V.
The cause and time relationship between the influenza virus (IV) epizooty in RF in 2005-2006 and mass mortality of waterfowls (great-crested grebe, coot, and black-headed gull) on lake Ubsu-Nur in the Republic of Tyva in 2006 has been researched. The investigation and comparative analysis conducted to study the primary structure of amplified cDNA fragments showed that all the studied samples of the pathological material contained genome fragments of field avian IV isolate, type A, subtype H5N1. A genetic analysis of nucleotide sequences of H5 and N1 gene fragments showed that in all the isolates studied the primary structure of HA protein cleavage site was the sequence PQGRERRRKKR*GLF allowing to refer them to the group of high pathogenic strains of avian influenza virus. A comparative analysis of the primary structure of the fragment of hemagglutinin gene has found a belonging of the isolates studied to the same genetic group of strains from South-Eastern Asia and China. As is shown, some isolates (both Chinese and Russian) may be replaced with 1-2 amino acids and 2-3 nucleotides, whereas for the Russian ones a correlation of certain substitutes with geographical place of IV isolation is possible. It is concluded that the source of disease of wild waterfowls in lake Ubsu-Nur were migrating birds from South-Eastern Asia, and the great-crested grebe was a bioindicator during the outbreak of avian influenza in the Republic of Tyva.
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