FIG 5.
Replication of TY165 and TY165-PA-K185R viruses in mice. Nine mice per group were intranasally inoculated with 102 PFU of TY165 and TY165-PA-K185R viruses. Three mice were euthanized on days 2, 4, and 6 postinfection. Lungs, nasal turbinates, spleens, kidneys, brains, and nasal washes were collected and virus titers were determined by means of plaque assays in MDCK cells. Data shown are the mean virus titers with standard deviations. The P values were calculated by using Student's t test, comparing the virus titers between the wild-type and mutant viruses detected in the indicated organs. **, P < 0.001; *, P < 0.05.