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.IMPORTANCEIn 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.

Characterizing viral species in mosquitoes (Culicidae) in the Colombian Orinoco: insights from a preliminary metagenomic study.

Mosquitoes (Diptera: Culicidae) are primary vectors of arthropod-borne viruses (arboviruses) that pose significant public health threats. Recent advances in sequencing technology emphasize the importance of understanding the arboviruses and insect-specific viruses (ISVs) hosted by mosquitoes, collectively called the "virome". Colombia, a tropical country with favorable conditions for the development and adaptation of multiple species of Culicidae, offers a favorable scenario for the transmission of epidemiologically important arboviruses. However, entomovirological surveillance studies are scarce in rural areas of the country, where humans, mosquitoes, and animals (both domestic and wild) coexist, leading to a higher risk of transmission of zoonotic diseases to humans. Thus, our study aimed to perform a preliminary metagenomic analysis of the mosquitoes of special relevance to public health belonging to the genera Ochlerotatus, Culex, Limatus, Mansonia, Psorophora, and Sabethes, within a rural savanna ecosystem in the Colombian Orinoco. We employed third-generation sequencing technology (Oxford Nanopore Technologies; ONT) to describe the virome of mosquitoes samples. Our results revealed that the virome was primarily shaped by insect-specific viruses (ISVs), with the Iflaviridae family being the most prevalent across all mosquito samples. Furthermore, we identified a group of ISVs that were common in all mosquito species tested, displaying the highest relative abundance concerning other groups of viruses. Notably, Hanko iflavirus-1 was especially prevalent in Culex eknomios (88.4%) and Ochlerotatus serratus (88.0%). Additionally, other ISVs, such as Guadalupe mosquito virus (GMV), Hubei mosquito virus1 (HMV1), Uxmal virus, Tanay virus, Cordoba virus, and Castlerea virus (all belonging to the Negevirus genus), were found as common viral species among the mosquitoes, although in lower proportions. These initial findings contribute to our understanding of ISVs within mosquito vectors of the Culicidae family in the Eastern Plains of Colombia. We recommend that future research explore deeper into ISV species shared among diverse vector species, and their potential interactions with arboviruses. In addition, we also showed the need for a thorough exploration of the influence of local rural habitat conditions on the shape of the virome in mosquito vectors.

Employing oxford nanopore technologies (ONT) for understanding the ecology and transmission dynamics of flaviviruses in mosquitoes (Diptera: Culicidae) from Eastern Colombia.

Studies focused on identifying the viral species of Flavivirus in vectors are scarce in Latin America and particularly in Colombia. Therefore, the frequency of infection of the Flavivirus genus and its feeding preferences were identified in the mosquito species circulating in the municipality of Puerto Carreño-Vichada, located in the Eastern Plains of Colombia. This was done by sequencing the viral NS5 and vertebrate 12S rRNA genes, respectively, using Oxford Nanopore Technologies (ONT). A total of 1,159 mosquitoes were captured, with the most abundant species being Aedes serratus at 73.6% (n = 853). All the mosquitoes were processed in 230 pools (2-6 individuals) and 51 individuals, where 37.01% (n = 104) were found to be infected with Flavivirus. In these samples, infection by arboviruses of epidemiological importance, such as dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), was ruled out by PCR. However, through sequencing, infection by different insect-specific viruses (ISFVs) and a medically important virus, West Nile virus (WNV), were identified in a mosquito of the Culex browni species. Additionally, the feeding patterns showed that most species present a generalist behavior. Given the above, conducting entomovirological surveillance studies is crucial, especially in areas of low anthropogenic intervention, due to the high probability that potentially pathogenic viruses could generate spillover events under deforestation scenarios.