Fig. 1.

Phylogenetic tree of the HA gene of A/environment/Mexico/CPA-04740/2011 (H4N2) [■] Influenza A virus isolated from a wetland. The phylogenetic tree was constructed with the Neighbor-Joining method. The percentages of replicate trees in which the associated taxa clustered together in a bootstrap test (1,000 replicates) are shown next to the branches. The evolutionary distances were computed using the Kimura 2-parameter method. The analysis involved 45 nucleotide sequences. Evolutionary analyses were conducted in MEGA5.05.