a, Schematic representation of the study design. AG6 mice were intraperitoneally infected with 1 × 106 p.f.u. of the DENV2 43 strain. Subsequently, 100 µl of a DENV2 NS1 antibody was intraperitoneally inoculated into the mice at 12 h post-infection. An equivalent quantity of untreated serum was inoculated as a mock control. After allowing 12 h for antibody dissemination, the infected mice were subjected to daily mosquito biting from day 1 to day 4 post mouse infection. The mouse-blood-fed mosquitoes were reared for an additional 8 days for DENV detection. b,c, DENV2 infection of AG6 mice. For measurement of DENV2 sNS1 concentration (b), mouse sera were used to determine the amounts of DENV2 sNS1 present from 0 to 5 days post-infection by ELISA. For detection of DENV2 viremia in the blood of infected AG6 mice (c), the presence of infectious viral particles in the blood plasma was assessed using a plaque assay. Data in b and c are representative of at least five infected AG6 mice. Values in the graph represent the mean ± s.e.m. A non-parametric Mann–Whitney test was used for statistical analysis. d–g, Immunoblockade of DENV2 sNS1 in the infected AG6 mice reduced the infection of fed A. aegypti (d,e) and A. albopictus (f,g). In d and f, the number of infected mosquitoes relative to total mosquitoes is shown at the top of each column. Each dot represents a mosquito. In b–g, the DENV2 43 strain was used for animal infections. In e and g, data are represented as the percentage of mosquito infection. Differences in mosquito infective ratios were assessed using Fisher's exact test. *P < 0.05, **P < 0.01, ***P < 0.001. Experiments reported in b–g were biologically reproduced at least three times. d.p.i., days post inoculation; NS, not significant.