Fig. 1.

Infectious blood meals and intrathoracic injections of Ae. aegypti with ZIKV or ZIKV∆SF1 indicate that sfRNA1 determines virus transmission. (A) Schematic overview of the experimental setups. (B) ZIKV titers of the infectious blood meals used in the 3 replicate experiments were determined by end-point dilution assay (EPDA). Shown is the mean titer ± SEM. Statistics were performed by unpaired t test. (C) Female Ae. aegypti were fed with an infectious blood meal containing 3.0 × 10⁶ TCID₅₀/mL ZIKV or ZIKV∆SF1. Engorged females were incubated for 14 d at 28 °C, and infection and transmission rates were determined by infectivity assay on Vero cells. Shown are the mean infection and transmission rates ± SEM. Statistics were performed by Fisher’s exact test on cumulative data. (D) Viral titers in the bodies of mosquitoes with ZIKV-positive [Saliva (+)] and ZIKV-negative [Saliva (−)] saliva and titers of ZIKV-positive saliva samples were determined by EPDA. Shown are the median titers, and statistics were performed by Mann–Whitney U test. (E) Female Ae. aegypti were intrathoracically injected with ∼400 TCID₅₀ of ZIKV or ZIKV∆SF1. At 7 d postinjection, infection and transmission rates were determined. Statistics were performed by Fisher’s exact test on cumulative data. (F) Viral titers in the bodies of virus-positive bodies and saliva samples were determined by EPDA. Shown are the median titers, and statistics were performed by Mann–Whitney U test. Dotted lines indicate the EPDA detection limit. *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ns, not significant; WT, wild type.