[Properties of the influenza viruses isolated in 1976 from gulls in Astrakhan Province].

Investigation of a number of properties of influenza viruses isolated from Laridae birds in the Astrakhan region showed that in one epizootic focus avian influenza viruses with different hemagglutinins and identical neuraminidase may circulate among Laridae birds. Among viruses with the antigenic formula Hav5Nav2 clear-cut differences in virulence and plaque-forming capacity were demonstrated.