Figure 4.

Quantification of H3N2 virus in respiratory tissues of infected ferrets. Ferrets were intranasally infected with 10⁶ TCID₅₀ in 0.5 mL of rPerth WT (black circles) or rPerth mutant (red circles) and were sacrificed on day 3 post-infection. NW—nasal wash, NT—nasal turbinate, SP—soft palate. (A) RNA was isolated from the indicated respiratory tract organ homogenates and qPCR for a region of the M segment was performed to quantify the relative amounts of influenza virus, normalized to RNA isolated from a virus stock with a known titer. (B) Titration of tissue homogenates to quantify infectious viral titers. Each dot represents a single animal and mean line ±SEM is depicted.