Review of Interspecies Transmission of Influenza A Viruses: Implications for the Equine Population

摘要

The importance of influenza-virus infection in the horse population throughout the world is well docu-mented. 1–3 As every equine practitioner undoubt-edly is well aware of, vaccination against influenza has been and remains the cornerstone of influenza prevention in the horse. Although many publica-tions have documented the ability of inactivated equine-influenza vaccines to protect against homol-ogous viral challenge,4,5 equine-influenza infections have remained a serious health and economic prob-lem throughout the world.6,7 Vaccine failure pri-marily can be blamed on the sustained genetic evolution of the influenza virus genome (antigenic drift), but the occasional introduction of gene seg-ments (antigenic shift) or entire viruses from other species also accounts for the vast genetic and anti-genic diversity of influenza viruses. This review focuses on the transmission of influenza viruses be-tween species, discussing both direct transmission of viruses from aquatic birds to mammals and virus transmission between mammalian species. This includes a discussion of potential implications of such interspecies transfer of influenza for the equine population.