Fig 6. Infection and transmission rates of Ae. aegypti intrathoracically injected with ZIKV, CHIKV, or both viruses.

Mosquitoes were infected through intrathoracic injections with a dose of 2.8 × 10³ TCID₅₀ units of ZIKV^SUR, CHIKV³⁷⁹⁹⁷, or both. (A) Infection and (B) transmission rates of Ae. aegypti mosquitoes at 7 dpi presented as percentage of the total number of injected mosquitoes. The percentage of co-infected mosquito bodies and saliva samples is indicated by the dashed line. Shown are the mean percentages from three independent replicates. Error bars show the standard error of the mean. Sample size ranged between 48–49 female mosquitoes per treatment. Results were evaluated with Chi-squared tests, and corrected for multiple comparisons with the Bonferroni correction. Significant differences between treatments (P < 0.05) are indicated by different letters.(C-D). Virus titers of CHIKV and ZIKV mosquito (C) bodies and (D) saliva. Each dot represents one mosquito body, and the horizontal bars indicate median titers. The detection limit of the EPDA is indicated by a dashed line. Results were evaluated with a Kruskal-Wallis test, and Dunn’s test for multiple comparisons, corrected with the Bonferroni correction. Significant differences between treatments (P < 0.05) are indicated by different letters.