Dengue-2 virus infection induces physiopathological changes of the ICR mice. Six-day-old ICR suckling mice were intracranially inoculated with DV2 (2.5×105 pfu/mouse). The (A) body weight (B) clinical score and (C) survival rate were monitored daily after inoculation. (D) The mice were sacrificed at day 5 p.i. The brain tissues were cryosectioned and DV2-NS1 expression in various regions of the mouse brain was detected with anti-DV NS1 antibody by IHC staining. Arrow points NS1 labeling. Disease symptoms were scored as follows: 0 for healthy; 1 for lightly sick (losing weight and ruffled hair); 2 for slow-moving and reduced mobility; 3 for moving with difficulty and anterior limb or posterior limb weakness; 4 for paralysis and mortally ill; 5 for death. Mock group was treated with 2% FBS/DMEM and iDV2 group was the virus subjected to heat treatment at 56°C for 30 min. The numbers of mice in each group were from 3 to 5. Data were analyzed using the Student’s t test. Significance was set at p < 0.05 (*), p < 0.01 (**), p < 0.05 (***).