Fig 3.
Clinical symptoms and viral shedding in TIV-immunized and control ferrets following 1918 virus challenge. (A) Mean weight loss observed among vaccinated (open circles) and PBS control (filled circles) ferrets following challenge with 106 PFU of the 1918 virus. Nasal washes (B) and tissues (C) at 3 (left) and 5 (right) days p.c. were collected and viruses titrated in a standard plaque assay. Gray-shaded bars represent results for unimmunized (PBS) control ferrets, and open bars represent results for TIV-immunized ferrets. The data shown are mean values plus standard deviations (error bars) for 5 ferrets per group (A and B) and for 3 ferrets per group for each time period (C). Differences in viral titers between groups were analyzed by Student's t test (*, P ≤ 0.04; **, P ≤ 0.005; ***, P ≤ 3E-06).