Fig. 4

The effect of mouse variables on sporozoite infectivity. a Luminescence of C57Bl/6 mice of different ages challenged with the same number of sporozoites. Mice challenged at 7 weeks of age were most susceptible to infection, and this susceptibility decreases with age, with statistical significance at days 12 and 15. b Luminescence data of C57Bl/6, BALB/c, and C3H mice infected with sporozoites. C57Bl/6 mice are the most susceptible of the three strains. c Comparison of infectivity of male and female C57Bl/6 mice. Female mice demonstrate higher susceptibility to infection than males. *p < 0.05; **p < 0.01; ***p < 0.0005, Mann–Whitney test. Dashed lines represent background bioluminescence levels obtained from uninfected mice injected with luciferin