Caracteristica antigenică şi genotipică a virusurilor gripale identificate în perioadele prepandemică şi postpandemică în Republica Moldova

Abstract

Background: The influenza infection continues to be the main cause of serious infections of the upper respiratory tract, having a negative impact on the public health, health system as well as on the national economy, provoking considerable efforts of control and responsibility. Material and methods: The samples of biological material (naso-pharyngeal exudates, tracheal-bronchial lavage and cadaveric material in the cases of death) have been collected from the patients with a clinical diagnosis of alleged flu, acute respiratory infection and heavy acute viral respiratory infection (pneumonia, bronchopneumonia and acute broncholitis), through the influenza surveillance system and the routine were used. The material collected during a pandemic and post-pandemic periods has been subjected to the laboratory research using molecular biology techniques. We have used the method of isolation of influenza viruses in the cell cultures MDCK and MDCK-SIAT and, accordingly, there have been a hemaglutin-braking reaction of stems isolated from influenza viruses with the corresponding serums and antigens in accordance with the requirements and recommendations of WHO. Results: The results of antigenic and phylogenetic analysis of influenza viruses circulating in the Republic of Moldova in pre-pandemic (2008-2009), pandemic (2009-2010) and post-pandemic (2010-2011) periods are presented. The findings suggest that the displacement of the circulating seasonal influenza virus A(H1N1) by the A(H1N1)pdm virus occurred in the post-pandemic period. Conclusions: The substitution of D222G in the hemagglutinin gene of influenza virus A(H1N1)pdm, which has been identified by the phylogenetic analysis in the patients with severe acute respiratory infections and/or in dead bodies of the people, who died in the pandemic period, may be the first “virulence marker” of the A(H1N1)pdm virus.