FIG. 1.

Replication of the H7N7 NL/03 ca virus in mice. Shown are levels of replication of wt and ca viruses in mice following i.n. inoculation with 10⁶ TCID₅₀/mouse of the H7N7 NL/03 wt (•), H7N7 NL/03 ca (▪), AA wt (▴), and AA ca (⧫) viruses. Virus titers in the nasal turbinates (A) and lungs (B) of four mice per group sacrificed on 2, 3, or 4 dpi, respectively, are expressed as log₁₀ TCID₅₀/g of tissue. The solid line represents the mean for the group. The lower limit of detection is indicated by the dashed horizontal line. An asterisk indicates a statistically significant (P < 0.05) reduction in virus titers compared to the corresponding wt virus.