Scientific Opinion on monitoring for the emergence of possible new pandemic strains of influenza in animals

Following the emergence in 2009 of the new pandemic H1N1 influenza virus, which contained gene segments from pig, bird and human influenza viruses, it was apparent that a better scientific understanding is required of influenza viruses to protect public and animal health. The latest scientific data on biological properties of the virus, transmissibility, host susceptibility and epidemiology has been evaluated in order to identify factors that could be monitored in animals and that would suggest a risk of emergence of a new pandemic influenza strains. Virological studies and animal models have highlighted the importance of individual virus proteins but virulence and transmissibility are polygenic effects and no single genetic marker can be reliably associated with increased pathogenicity or transmissibility. It was concluded that current monitoring of the influenza gene pool in humans has been able to provide an alert for the emergence of new human influenza strains of public health significance. In contrast, there is an incomplete view of the influenza virus strains circulating among pigs and birds at the global level. Interpretation of the origins and pandemic potential of influenza viruses do require knowledge of the influenza gene pools in both pigs and birds, as well as other animal species. It is recommended that there should be long term support for a passive monitoring network in pigs and birds in order to promote greater understanding of the evolution of influenza viruses at the global level. Maximum benefit can only be obtained by applying an integrated approach involving the medical and veterinary networks including development of harmonised tools and approaches, exchange of virus strains and sequence data and enhancing the coordination and dissemination of the findings from the human, swine and avian networks.