Reduced microbe abundance in an urban larval development container increases Aedes aegypti susceptibility to Zika virus

Aedes aegypti mosquitoes are a major vector of arboviruses that oviposit in both artificial containers (i.e., buckets, tires, cans) and natural containers (i.e., coconut husks, tree holes). These diverse container types will seed the larvae microbiome with differing bacterial communities. While the larval microbiome has been shown to alter adult susceptibility to arboviruses including dengue (DENV) and Zika virus (ZIKV), it is not known if exposure to different bacterial communities found between container types impacts adult Ae. aegypti interactions with arboviruses. To address this, rainwater was collected from an artificial container (plastic buckets) and a natural container (coconut husks) from three different collection sites and the microbiomes were preserved. Larval exposure to plastic bucket-derived microbiomes resulted in adults with increased susceptibility to ZIKV compared to larval exposure to coconut husk-derived microbiomes from all three collection sites, indicating that the container type, independent of collection environment, drives variation in adult susceptibility to ZIKV. 16S amplicon sequencing of larvae exposed to the preserved microbiomes revealed that bacterial community structure differed between plastic bucket and coconut husk derived communities at each collection site, but a conserved plastic- or coconut-derived bacterial community across collection sites was not identified. However, water from coconut husks had significantly more total bacterial abundance than water from plastic buckets. Normalization of bacterial loads between container types resulted in similar ZIKV infection rates. Together, these data suggest that larval exposure to specific container type-associated microbiomes alters adult susceptibility to ZIKV, largely driven by differences in total bacterial density between container types. Results from this study will help understand how the urbanization-driven expansion of Ae. aegypti into new/different oviposition sites might affect arbovirus susceptibility.