- On the basis of the phylogenetic relation of the nucleotide sequences of the partial S gene, 3 groups were identified (online Appendix Figure panel B).
- Group 1 comprised all recent Thai PEDV and the Chinese PEDV strains isolated in 2003–2004 (JS-2004-2 and LJB/03). Notably, a Thai isolate, 08NP04, was very similar to JS-2004-2.
- Group 2 comprised Br1/87 (LZC) and CV777.
- Group 3 consisted of the Korean isolates (Spk1 and Chinju99)