Protein and nucleic acid analysis of influenza B viruses isolated in Italy in 1984

Detection of two antigenic subpopulations of A(H1N1) influenza viruses from pigs: antigenic drift or interspecies transmission?

Serological analysis of a group of 63 influenza H1N1 viruses isolated from pigs in Italy in the period 1976-1988 revealed the presence of two distinct antigenic subpopulations: some viruses possessed a haemagglutinin indistinguishable from that of viruses typically associated with pigs, i.e., A/New Jersey/8/76 (H1N1), whereas others showed a close antigenic relatedness with the haemagglutinin of avian-like H1 viruses. These findings represent further evidence that influenza A viruses from avian species may be transmitted to mammals. The surface and internal proteins of some of these viruses were also analyzed biochemically to evaluate the molecular relatedness among viruses circulating in non-human hosts.

First recovery of A/equine/Fontainebleau/1/79 influenza viruses in Italy

In Italy epizootics of equine influenza often occur, but no virus isolation has been reported since 1971. This paper describes the antigenic and biochemical characterization of two equine influenza viruses isolated in Italy from 1985 to 1989. The virus isolates were shown to differ antigenically from earlier strains of the same subtype, A/equine/Miami/1/63 (H3N8). Monoclonal antibody analysis showed that the haemagglutinins of these strains were serologically indistinguishable from A/equine/Fontainebleau/1/79, a variant of A/equine/Miami, never isolated in Italy before. One of the two virus isolates was obtained from a horse immunized with a bivalent inactivated influenza vaccine, not containing A/equine/Fontainebleau/79 antigens. The vaccine failure underlines the importance of antigenic relatedness between currently circulating viruses and vaccine strains. Therefore, to improve the protection afforded by equine immunization, the vaccine composition should be decided according to the results of a virological surveillance activity, systematically conducted among horses.