As we move into the summer, concern over the prospect of an avian influenza pandemic continues. On page 591, Taisuke Horimoto and Yoshihiro Kawaoka provide a timely update on the molecular factors that are important in the emergence of pandemic strains, and discuss the most recent efforts to identify the key determinants of pathogenicity. Although it is expected that the pathogenicity of influenza viruses is multifactorial, some of the viral gene products and functions that have been implicated include the role of haemagglutinin in host-cell-receptor specificity and the role of a viral RNA-polymerase protein in viral replication and host-cell tropism.
In addition to the scientific discussions, there are wider social issues associated with any potential pandemic. In last month's issue, our editorial focused on some of the legislative aspects of pandemic preparedness, and there have been numerous other commentaries, editorials and news features in other journals and the general media that have covered other aspects of the public-health response. This month however, our editorial (page 580) focuses on an often-neglected issue — the practical difficulties of working with emerging and re-emerging pathogens.
