Fig. 2
From: Mouse-adapted H9N2 avian influenza virus causes systemic infection in mice
Virulence of G1-MA, ZB-MA and wild-type viruses in mice. a and c Relative weight loss. Mice were intranasally inoculated with 10 5 pfu of each virus. The body weights of five inoculated mice were measured daily and are represented as the percentage of the weight on the day of inoculation (day 0). b and d Survival percentages of mice infected with 105 pfu of each virus. e Immunohistochemically-stained of the brains Groups of eight six-week-old BALB/c mice were inoculated intranasally with 105 pfu of each viruses. IHC examinations were performed on the cerebrum of mice inoculated with PBS, ZB or ZB-MA virus. Sections of brains of mice infected with indicated viruses at 5 dpi are shown. In the immunohistochemical-stained brain sections, the viral antigen-positive cells are marked by brown pigment. Arrows show that cell positive for influenza virus signals were detected in the brains of infected mice. Images were taken at × 400 magnification