Fig. 2. Pathogenesis of YFV-17D infection in mice using a high viral inoculum. (a) Survival of mice infected with 10⁷ p.f.u. YFV-17D. Mice (3–4 weeks old) were injected intramuscularly (IM) with 10⁷ p.f.u. YFV-17D and disease onset was monitored. Data are shown as the percentage without disease. Data were from 26 IFNAR^+/+ and 128 IFNAR^−/− mice. Statistically significant differences between IFNAR^+/+ and IFNAR^−/− pathogenesis were observed (P<0.0001, Mantel–Cox test). However, there was no statistically significant difference in survival for IFNAR^−/− mice injected intramuscularly with 10⁴ versus 10⁷ p.f.u. YFV-17D (P = 0.15, Mantel–Cox test). (b) Percentages of mice displaying no clinical signs of disease, neurotropic disease or viscerotropic disease.