S-OIV strains (A/Taiwan/T1338/2009) were generously
supplied by the Taiwan Centers for Disease Control. After
two passages in MDCK cells, virus subtypes were identified
using real-time reverse transcription polymerase chain reaction.
Phylogenetic trees were constructed using a
neighbor-joining method based on a combination of Kimura
two-parameter distance matrix (1000 bootstrap replicates)
and MEGA 4.0 (Manufacturer: Megasoftware.net, Arizona,
USA) and PHYLIP 3.5c software packages25; details are
described in the study by Wang et al.11 MEGA was used to
construct neighbor-joining trees, and PHYLIP was used with
parsimony and maximum-likelihood methods to verify taxa