Morbidity and mortality from influenza A virus (IAV) infection in gonadally-intact male and female C57BL/6 mice. Average (± SEM) change in body mass (a) and rectal temperature (b) from baseline (that is, day 0) following inoculation with 102 50% tissue culture infective dose (TCID50) of mouse-adapted IAV, A/Puerto Rico/8/1934 (PR8). The proportion of wild-type (WT) male and female mice surviving PR8 infection during the 21 days post inoculation is shown in (c). Each group consisted of ten mice run in a series of two replications. *Significantly different at P < 0.05.