Was the 1918 flu avian in origin?

Abstract
Arising from: J. K. Taubenberger et al. Nature 437, 889–893 (2005); see also communication from Gibbs and Gibbs; Taubenberger et al. reply Taubenberger et al.1 claim that the 1918 influenza virus was derived from an avian source and adapted to humans shortly before the pandemic. However, we do not believe that this conclusion, which has been widely disseminated in the popular press and in scientific journals2,3,4, is supported by their phylogenetic evidence.