Molecular virology: Was the 1918 pandemic caused by a bird flu? Was the 1918 flu avian in origin? (Reply)

We have proposed that the virus responsible for the 1918 human influenza pandemic was avian-like, which to us is a reasonable interpretation of all the available data from phylogenetic, sequence, serological and historical analysis, combined with what is known of influenza A virus biology1,2,3,4. However, Gibbs and Gibbs5 and Antonovics et al.6 question our inferred origin of the 1918 influenza virus.