Influence of dengue virus serotypes on the abundance of Aedes aegypti insect-specific viruses (ISVs)

A comprehensive understanding of the virome in mosquito vectors is crucial for assessing the potential transmission of viral agents, designing effective vector control strategies, and advancing our knowledge of insect-specific viruses (ISVs). In this study, we utilized Oxford Nanopore Technologies metagenomics to characterize the virome of Aedes aegypti mosquitoes collected in various regions of Colombia, a country hyperendemic for dengue virus (DENV). Analyses were conducted on groups of insects with previous natural DENV infection (DENV-1 and DENV-2 serotypes), as well as mosquito samples that tested negative for virus infection (DENV-negative). Our findings indicate that the Ae. aegypti virome exhibits a similar viral composition at the ISV family and species levels in both DENV-positive and DENV-negative samples across all study sites. However, differences were observed in the relative abundance of viral families such as Phenuiviridae, Partitiviridae, Flaviviridae, Rhabdoviridae, Picornaviridae, Bromoviridae, and Virgaviridae, depending on the serotype of DENV-1 and DENV-2. In addition, ISVs are frequently found in the core virome of Ae. aegypti, such as Phasi Charoen-like phasivirus (PCLV), which was the most prevalent and showed variable abundance in relation to the presence of specific DENV serotypes. Phylogenetic analyses of the L, M, and S segments of the PCLV genome are associated with sequences from different regions of the world but show close clustering with sequences from Brazil and Guadeloupe, indicating a shared evolutionary relationship. The profiling of the Ae. aegypti virome in Colombia presented here improves our understanding of viral diversity within mosquito vectors and provides information that opens the way to possible connections between ISVs and arboviruses. Future studies aimed at deepening our understanding of the mechanisms underlying the interactions between ISVs and DENV serotypes in Ae. aegypti could provide valuable information for the design of effective vector-borne viral disease control and prevention strategies. IMPORTANCE In this study, we employed a metagenomic approach to characterize the virome of Aedes aegypti mosquitoes, with and without natural DENV infection, in several regions of Colombia. Our findings indicate that the mosquito virome is predominantly composed of insect-specific viruses (ISVs) and that infection with different DENV serotypes (DENV-1 and DENV-2) could lead to alterations in the relative abundance of viral families and species constituting the core virome in Aedes spp. The study also sheds light on the identification of the genome and evolutionary relationships of the Phasi Charoen-like phasivirus in Ae. aegypti in Colombia, a widespread ISV in areas with high DENV incidence.

Automated summary

A comprehensive understanding of the virome in mosquito vectors, especially Aedes aegypti, is important for assessing viral transmission potential, designing effective vector control strategies, and deepening our knowledge of insect-specific viruses (ISVs). This study used metagenomics to characterize the virome of Ae. aegypti mosquitoes in Colombia, a country with high dengue virus (DENV) incidence. The results showed that the virome composition of Ae. aegypti is similar in both DENV-positive and DENV-negative samples, but the relative abundance of certain viral families differs depending on the DENV serotype. Additionally, ISVs, such as Phasi Charoen-like phasivirus (PCLV), were frequently found in the core virome of Ae. aegypti, with variable abundance associated with specific DENV serotypes. Phylogenetic analyses revealed a shared evolutionary relationship between PCLV sequences from Colombia, Brazil, and Guadeloupe. This study improves our understanding of viral diversity in mosquito vectors and suggests possible connections between ISVs and arboviruses.