The impact of the HA2-47 residue on wt H1N1pdm infectivity in ferrets.

Groups of ferrets were inoculated with the indicated amount of wt A/California/7/09 (Cal/09 HA2-E47), the E47K mutant (Cal/09 HA2-K47), wt A/Brisbane/10/2010 (Bris/10 HA2-K47) or the K47E mutant (Bris/10 HA2-E47). The number of infected ferrets in each group (N = 4 or 7) and geometric mean titers of the nasal wash samples from the infected ferrets at day 3 post-infection determined by TCID50 are indicated. PFU: plaque forming units. FID50: 50% ferret infection dose; SD: standard deviation.