Weight loss and survival curve of AG6 mice after infection with DENV-2 8H2-7-LP and DENV-2 1D4-5-SP. AG6 mice between 6–8 weeks old were infected with two viral variants and the parental isolate through s.c. injection. Three different dose of viruses, 103 PFU (A, D; n = 3), 104 PFU (B, E; n = 3), and 105 PFU (C, F; LP and SP n = 4, Parental n = 3), were inoculated into mice. Mice injected with PBS were included within each panel for control (CT, n = 6). Weight change was recorded and presented as a ratio to the initial weight on day 0. Moribund mice with weight loss over 20% were euthanatized and recorded as death. Two-way ANOVA was used in statistical analysis of differences among groups, *P < 0.05, **P < 0.01, ***P < 0.001,****P < 0.0001, n.s., not significant.