[Detection of amino acid substitutions of asparaginic acid for glycine and asparagine at the receptor-binding site of hemagglutinin in the variants of pandemic influenza A/H1N1 virus from patients with fatal outcome and moderate form of the disease].

The paper analyzes the amino acid sequence of the receptor-binding site of hemagglutinin (HA) in the variants of pandemic influenza A/H1N1 swl from 18 patients with moderate (n=1) and fatal (n=17) forms of the disease in 2009. Nine samples contained asparaginic acid at position 222 of HA1 (D). This site exhibited mutations in 9 samples: D222G (n=3), D222N (n=3), and D222G/D222N (n=3). In one patient with the moderate form of the disease, D222G mutation was revealed after the second passage in the developing chick embryos; this mutation was not found in the primary sample from the patient. The findings suggest the mutant variants of the virus start to circulate among the population, which requires, firstly, continuation of molecular virological monitoring of the pandemic situation and, secondly, further study of the impact of amino acid substitutions at the receptor-binding site of HA1 on the increased virulence of influenza A virus.

[The characteristics of the epidemic strains of the influenza B viruses that caused the 1990-1991 epidemic in the USSR]. / Kharakteristika épidemicheskikh shtammov virusov grippa B, vyzvavshikh épidemiiu 1990--1991 gg. v SSSR.

Epidemics of influenza in towns of Russia were found to have been caused by influenza type B virus. Strains similar to B/Yamagata/16/88 were first isolated in the country. The study of antigenic and biological properties showed that the epidemic strains could be divided into 2 groups: similar to B/Victoria/2/87 and to B/Yamagata/16/88, that is, representing two branches of the evolutionary tree. In both groups the viruses were heterogeneous both in antigenic and biological properties.