Fig. 2

Infection of Irf3/7^−/− mice. A CHIKV-fed mosquitoes were allowed to feed on three Irf3/7^−/− mice, and transmission of virus from mosquitoes to mice was assessed by viraemia determinations using CCID₅₀ assays of serum samples. The viraemia for each individual mouse (#1, #2 and #3) is plotted. †Mice reached ethically defined endpoints for euthanasia. See Table 3 for details. B VLA1553-fed mosquitoes were allowed to feed on Irf3/7^−/− mice, and transmission was assessed by viraemia determinations using serum from Irf3/7^−/− mice and CCID₅₀ assays. ND, not detected; limit of detection was ~ 2 log₁₀CCID₅₀/ml. See Table 3 for details. C To confirm that Irf3/7^−/− mice can be infected with VLA1553, three mice were inoculated via the intraperitoneal route with 4 log₁₀CCID₅₀ of VLA1553 and individual viraemia determined by CCID₅₀ assays as for A