Survival rates of the eight CC founder strains after infection with different doses of influenza A H3N2 virus infection. Eight to twelve weeks old female and male mice of the CC founder strains were infected intra-nasally with 1 × 101 (red and blue), 2 × 103 (orange and green) and 2 × 105 FFU (magenta and black) of the mouse-adapted influenza H3N2 virus (A/HK/01/68). Survival rates were monitored for 14 days p.i.. Mice that exhibited a weight loss of more than 30 % relative to their starting weight were euthanized and scored as dead. Significant sex-specific differences in survival curves were observed exclusively in NOD/ShiLtJ mice after infection with 1 × 101 FFU (**: p-value < 0.01, using log rank test). Colors for the CC founder strains have been chosen according to the CC strain RGB color code displayed at http://csbio.unc.edu/CCstatus/index.py.