Comprehensive intra-host infection kinetics reveals high arbo-orthoflavivirus transmission potential by neglected vector species, Aedes scutellaris.

BACKGROUND: Dengue virus (DENV) and Zika virus (ZIKV) are primarily transmitted by Aedes mosquitoes. As most studies on vector competence have focused on Aedes aegypti and Aedes albopictus while neglecting other Aedes species, it is possible that the transmission risks might be underestimated. It is necessary to examine additional species that could potentially serve as competent vectors. This is particularly important considering the potential expansion of their geographical range due to climate change or species-specific vector reduction interventions. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we examined the infection kinetics and transmission potential of Aedes scutellaris from Thailand, comparing to Ae. aegypti and Ae. albopictus. Our findings demonstrated that Ae. scutellaris and Ae. albopictus had lower rates of midgut infection compared to Ae. aegypti due to smaller blood meal sizes during feeding. However, once the infection has established Ae. scutellaris exhibited efficient replication of ZIKV and DENV1-4 in the midguts, secondary organs, and salivary glands. Notably, Ae. scutellaris had a low salivary gland escape barrier, with comparable transmissibility as Ae. aegypti when inoculated with the same viral load. CONCLUSION: This study highlights the potential of Ae. scutellaris as a vector for DENV and ZIKV and emphasizes the importance of considering neglected mosquito species in arbovirus transmission and surveillance efforts.