The PB1-F2 protein of the strain A / Duck / VietNam / QT801/2011 (H5N1) was truncated and has only 9 amino acids.
Protein PB 1 - F 2 của chủng A / Duck / VietNam / QT 8 01/2011 (H 5 N 1) clade 2.3.2.1 chỉ chứa 9 amino acid.