Highly pathogenic avian influenza A virus H5N1 non-structural protein 1 is associated with apoptotic activation of the intrinsic mitochondrial pathway

Bian, Qian; Lu, Jing; Zhang, Li; Chi, Ying; Li, Yan; Guo, Hongxiong

Avian influenza A (H5N1) virus is a highly pathogenic contagious agent that causes severe impairment in poultry and humans, particularly limited person-to-person transmission (1) . The cumulative number of confirmed human cases of H5N1 from 14 countries between November 2003 and July 2014 reached 667, 393 of which were fatal according to a report issued by the World Health Organization (2). In total, 47 individuals infected with H5N1 were identified in China and 30 (63.8%) succumbed to the H5N1 infection (2). H5N1 causes primary viral pneumonia with rapid progression to lung failure following invasion of epithelial cells in the upper and lower respiratory tracts (3) . However, the exact mechanism for elucidating the severity of human H5N1 infection remains unclear. Previously, apoptosis was not only observed in the alveolar epithelial cells of 2 patients who succumbed to H5N1 infection, but was also induced by H5N1 in numerous cell types in vivo and in vitro (4) (5) (6) . These results indicated that apoptosis may be important in H5N1 pathogenesis in the human body.