Local-scale virome depiction supports significant differences between Aedes aegypti and Aedes albopictus

Abstract

Aedes spp. comprise the primary group of mosquitoes that transmit arboviruses such as dengue, Zika, and chikungunya viruses to humans, and thus these insects pose a significant burden on public health worldwide. Advancements in next-generation sequencing and metagenomics have expanded our knowledge on the richness of RNA viruses harbored by arthropods such as Ae. aegypti and Ae. albopictus; increasing evidence suggests that vectorial competence can be modified by the microbiome (comprising both bacteriome and virome) of mosquitoes present in endemic zones. Using an RNA-seq-based metataxonomic approach, this study determined the virome structure of field-caught Ae. aegypti and Ae. albopictus mosquitoes in Medellin, Colombia, a municipality with a high incidence of mosquito-transmitted arboviruses. The two species are sympatric, but their core viromes differed considerably in richness, diversity, and abundance; the viromes were dominated by a few viruses. BLAST searches of assembled contigs suggested that at least 17 virus species (16 of which are insect-specific viruses [ISVs]) infect the Ae. aegypti population. Dengue virus 3 was detected in one sample. In Ae. albopictus, up to 11 ISVs and one plant virus were detected. Therefore, the virome composition was species-specific. The bacterial endosymbiont Wolbachia was identified in all Ae. albopictus samples and in some Ae. aegypti samples collected after 2017. The presence of Wolbachia sp. in Ae. aegypti was not related to significant changes in the richness, diversity, or abundance of this mosquitos virome, although it was related to an increase in the abundance of Aedes aegypti To virus 2 (unclassified). The mitochondrial diversity of these mosquitoes suggested that the Ae. aegypti population underwent a change that started in the second half of 2017, which coincides with the release of Wolbachia-infected mosquitoes in Medellin, indicating that the population of wMel-infected mosquitoes has expanded. However, additional studies are required on the dispersal speed and intergenerational stability of wMel in Medellin and nearby areas as well as on the introgression of genetic variants in the native mosquito population.