[The heterogeneity of an influenza virus A population due to differences at individual hemagglutinin H3 sites]. / Geterogennost' populiatsii virusa grippa A, obuslovlennaia otlichiiami v otdel'nykh saitakh gemaggliutinina H3.

Using monoclonal antibodies to hemagglutinin and nucleoprotein of various influenza virus strains, the populations of long-passaged strain A/Hong Kong/1/68 and of recently isolated strain A/sparrow/Ukraine/83 belonging to the H3N2 serovariant were shown to have subpopulations of virions differing in the structure of antigenic sites of hemagglutinin and in nucleoprotein domain which correlated with the degree of electrostatic interaction of virions with an ion-exchanger. The results of the study indicate a possibility of separation in the course of stepwise ion-exchange chromatography on DEAE-Sephadex A-50 of antigenic variants of influenza virus strains which is very important for the understanding of the mechanisms of population variability as well as for investigation of individual epitopes of hemagglutinin and nucleoprotein domains of influenza virus in evaluation of antigenic relationships of virions belonging to the same strain of a certain serotype.

[The determination of the interdependence of the infectivity of different groups of birds with the influenza virus by using mathematical modelling]. / Opredelenie vzaimozavisimosti infitsirovannosti razlichnykh grupp ptits virusom grippa s pomoshch'iu matematicheskogo modelirovaniia.

When studying sera in the hemagglutination-inhibition reaction which has been taken from 772 fowls of 82 species caught in certain regions of the Dnieper in 1981-1987 the antibodies to 29 strains of the influenza virus are revealed, all of them being of human and animal origin. The serological examination has shown the circulation of the influenza virus with hemagglutinin H13 in a wide range of water fowls, the level of antibodies to it being dependent on the species of fowls and season. Using the mathematical simulation it was possible to establish the relation of the influenza virus infection in groups of semisynanthropic and tame fowls to the titre of antibodies determined in the synanthropic species as well as ecological insulation of the so-called "wild fauna".

[Isolation of the influenza virus from the tree sparrow and a study of the infectivity of this virus in wild birds of the central Dnieper River area]. / Vydelenie ot polevogo vorob'ia virusa grippa i izuchenie infitsirovannosti dikikh ptits Srednego Dnepra étim virusom.

An influenza virus belonging to the serovariant A/H3N2 and registered as A/sparrow/Ukraine/83 was isolated from a member of synanthropic birds, a tree sparrow, near Kanev. This virus showed low pathogenicity and immunologic activity in experimental infection of sparrows and other birds. Sera from a number of avian and mammal species had antibodies to this virus which indicates that synanthropic and semi-synanthropic birds may be a connecting link in spread of influenza virus.