Virulence differences of closely related pandemic 2009 H1N1 isolates correlate with increased inflammatory responses in ferrets.

摘要: Several early pandemic H1N1 influenza isolates cause severe disease in different animals models, while most strains result mild clinical signs similar to seasonal influenza. In this study, the pathogenesis of virulent Mexican isolate A/Mexico/InDRE4487/2009 and a Canadian A/Canada-AB/RV1532/2009 was compared ferrets. These viruses differed at nine residues, none which has been previously identified as virulence factor. The caused more higher mortality, reached peak nasal wash titers. Both grew similarly respiratory tract, but only virus detected gut after day 3. During acute phase, both lung pathology, however induced inflammation even clearance. This also associated with rapid sustained induction inflammatory cytokines, indicating that dysregulation host response contributes importantly outcome.