Concetta Fabiani

H3N2 influenza viruses from domestic chickens in Italy: an increasing role for chickens in the ecology of influenza?

In Italy, multiple H3N2 influenza viruses were isolated from chickens with mild respiratory disease and were shown to replicate in the respiratory tracts of experimentally infected chickens; this finding is the first to show that H3N2 influenza viruses can replicate and cause disease in chickens. H3N2 influenza viruses in pigs on nearby farms seemed a likely source of the virus; however, antigenic and molecular analyses revealed that the gene segments of the viruses in chickens were mainly of Eurasian avian origin and were distinguishable from those isolated from pigs and wild aquatic birds in Italy. Thus, several different H3 influenza viruses were circulating in Italy, but we failed to identify the source of the chicken H3N2 influenza viruses that have disappeared subsequently from Italian poultry. Until recently, the transmission of influenza viruses (other than the H5 and H7 subtypes) from their reservoir in aquatic birds to chickens was rarely detected and highly pathogenic and non-pathogenic viruses were considered to be restricted to poultry species. However, the recent reports of the transmission of H9N2 and H5N1 influenza viruses to chickens in Hong Kong and, subsequently, to humans and our findings of the transmission of H3N2 influenza viruses to domestic chickens in Italy suggest an increased role for chickens as an intermediate host in the ecology of influenza.

Evaluation of the antiviral drug susceptibility of influenza viruses in Italy from 2004/05 to 2009/10 epidemics and from the recent 2009 pandemic.

Antiviral monitoring of influenza viruses circulating in Italy has been carried out since 2007 by the National Influenza Centre (NIC), using both phenotypic and sequence-based assays. Here, we report results of the susceptibility evaluation to neuraminidase (NA) inhibitors (NAIs, zanamivir and oseltamivir) and adamantanes of nearly 300 influenza type A and B seasonal viruses isolated in Italy during six recent seasons, together with over 30 pandemic (H1N1) 2009 virus strains. The present work is the first such study conducted in Italy, aimed to develop national data on antiviral drug profile and to establish a nationwide surveillance programme on antiviral susceptibility. Sequencing of the NA gene was undertaken either to confirm the phenotypic findings or to identify any NA change, in potentially resistant viruses (outliers), which might be associated with reduced susceptibility to NAIs. The 50% inhibitory concentration values (IC(50)s) showed slightly different sensitivities of the seasonal Italian isolates to the two NAI drugs, depending on the specific NA subtype. We found mean zanamivir IC(50)s of 0.74, 1.33 and 7 nM, and oseltamivir IC(50)s of 0.67, 2.34 and 30.1 nM for the N2, N1 and B NAs, respectively. The pandemic (H1N1) 2009 viruses showed IC(50)values overall comparable to the seasonal N1 viruses from previous years, showing mean zanamivir IC(50)s of 1.02 nM and mean oseltamivir IC(50)s of 2.82 nM. Oseltamivir resistance was found in a total of 19 seasonal N1viruses of 2007/2008 and 2008/2009, and in three pandemic (H1N1) 2009 strains. A gradual increase of resistance to adamantanes was observed among the N2 viruses isolated in recent seasons; no resistant viruses were found among the seasonal N1 strains, whereas all the pandemic (H1N1) 2009 isolates analysed were resistant to the M2 blockers.

Modified vaccinia virus Ankara expressing the hemagglutinin of pandemic (H1N1) 2009 virus induces cross-protective immunity against Eurasian 'avian-like' H1N1 swine viruses in mice.

To examine cross‐reactivity between hemagglutinin (HA) derived from A/California/7/09 (CA/09) virus and that derived from representative Eurasian “avian‐like” (EA) H1N1 swine viruses isolated in Italy between 1999 and 2008 during virological surveillance in pigs.

Influenza A(H7N7) Virus among Poultry Workers, Italy, 2013.

To the Editor: In August 2013, an outbreak of infection with highly pathogenic influenza A(H7N7) virus occurred in Emilia-Romagna, Italy, and >1 million birds were culled (1). Prevention measures were immediately applied, and all workers involved in culling activities wore personal protective equipment (PPE), including face masks with eye protection. These workers were monitored for clinical symptoms, and 3 workers with laboratory-confirmed cases of conjunctivitis caused by infection with influenza A(H7N7) virus were reported during the 3-week outbreak (2). Workers did not receive chemoprophylaxis.

Immunogenicity of modified vaccinia virus Ankara expressing the hemagglutinin stalk domain of pandemic (H1N1) 2009 influenza virus

Abstract Background: Vaccination offers protection against influenza, although current vaccines need to be reformulated each year. The development of a broadly protective influenza vaccine would guarantee the induction of heterosubtypic immunity also against emerging influenza viruses of a novel subtype. Vaccine candidates based on the stalk region of the hemagglutinin (HA) have the potential to induce broad and persistent protection against diverse influenza A viruses. Methods: Modified vaccinia virus Ankara (MVA) expressing a headless HA (hlHA) of A/California/4/09 (CA/09) virus was used as a vaccine to immunize C57BL/6 mice. Specific antibody and cell-mediated immune responses were determined, and challenge experiments were performed by infecting vaccinated mice with CA/09 virus. Results: Immunization of mice with CA/09-derived hlHA, vectored by MVA, was able to elicit influenza-specific broad cross-reactive antibodies and cell-mediated immune responses, but failed to induce neutralizing antibodies and did not protect mice against virus challenge. Conclusion: Although highly immunogenic, our vaccine was unable to induce a protective immunity against influenza. A misfolded and unstable conformation of the hlHA molecule may have affected its capacity of inducing neutralizing antiviral, conformational antibodies. Design of stable hlHA-based immunogens and their delivery by recombinant MVA-based vectors has the potential of improving this promising approach for a universal influenza vaccine.