Phylogenetic trees for the NS and PB1 of avian influenza viruses from Eurasia. Phylogenetic relationships were determined with the paup program. The nucleotide tree of the NS gene is rooted to A/Equine/Prague/1/56 (H7N7). The PB1 tree is rooted to B/Lee/40. Nucleotides 39 to 842 (804 bp) of NS gene and nucleotides 25 to 2,237 (2,213 bp) of PB1 gene were used for the phylogenetic analysis. Only the terminal branches of the Eurasian avian lineage of the trees are shown. Virus names and abbreviations are listed in Table 1 or can be found in ref. 7 or GenBank by using the following accession numbers: AF036360, U49492, U49493, M17070, M60800, M55484, Z46440, Z26865, and AF036362. All viruses underlined are H9N2 influenza viruses.