Mosquitoes are the most important vectors of emerging infectious diseases. During the past decade, our understanding of the diversity of viruses they carry has greatly expanded. Most of these viruses are considered mosquito-specific but there is increasing evidence that these viruses may affect the vector competence of mosquitoes. Metagenomics approaches have focused on specific mosquito species for the identification of what is called the core virome. Despite the fact that, in most ecosystems, multiple species may participate in virus emergence and circulation, there is a lack of understanding of the virus-carrier/host network for both vector-borne and mosquito-specific viruses. Here, we studied the core virome of mosquitoes in a diverse local ecosystem that had 24 different mosquito species. Analysis of the viromes of these 24 mosquito species resulted in the identification of 34 viruses, which included 15 novel viruses, as determined according to the species demarcation criteria of the respective virus families. Most of the mosquito species had never been analysed previously and a comparison of the individual viromes of the 24 mosquito species revealed novel relationships among mosquito species and virus families. Groups of related viruses and mosquito species from multiple genera formed a complex web in the local ecosystem. Furthermore, analyses of the virome of mixed-species pools of mosquitoes from representative traps of the local ecosystem showed almost complete overlap with the individual-species viromes identified in the study. Quantitative analysis of viruses’ relative abundance revealed a linear relationship to the abundance of the respective carrier/host mosquito species, supporting the theory of a stable core virome in the most abundant species of the local ecosystem. Finally, our study highlights the importance of using a holistic approach to investigating mosquito viromes relationships in rich and diverse ecosystems.

Annual entomological surveillance programs aiming to monitor mosquito populations and record presence and absence of mosquito species have been performed in Greece. We report, in this study, new records and expansion of Aedes albopictus in the islands of Lesvos (region of North Aegean), Crete (region of Crete), and the regional units of Rodopi in East Macedonia-Thrace. Furthermore, Culex tritaeniorhynchus was recorded for the first time in Arta (region of Epirus) in northwestern Greece.

BackgroundMosquitoes are the most important vectors of emerging infectious diseases. During the past decade, our understanding of the diversity of viruses they carry has greatly expanded. Most of these viruses are considered mosquito-specific, while there is increasing evidence that these viruses may affect mosquito vector potential. Metagenomics approaches have focused on specific mosquito species for the identification of what is called core virome. However, in most ecosystems, multiple species may participate in virus emergence and circulation, while there is lack of understanding on the viruses-carrier/host network for both vector-borne and mosquito-specific viruses. Results Here, we studied the core mosquito virome in a diverse ecosystem comprised of 24 different mosquito species. Analysis of these 24 diverse viromes resulted in the discovery of 35 viruses with known genetic traits and 9 novel viruses. Comparison of the viromes of the 24 individual species revealed novel relationships between mosquito species and virus families, as most of the mosquito species had never been analysed in the past. Groups of related viruses and mosquito species from multiple genera formed a complex network in the ecosystem. Analyses of whole traps of mosquitoes of variable composition not only showed a stable core virome for each species but also a relationship between mosquito population and virome composition.ConclusionsOur study highlighted the importance of a holistic approach regarding mosquito viromes in rich and diverse ecosystems. Our data further supported the idea of a stable core virome, characteristic of each mosquito species. The remarkable stability of the core virome seemed to determine the composition of the total mosquito core virome of a habitat in the ecosystem.

This study reports the mosquito collections conducted from June to September of 2015 and 2016, in Regional Unit (R.U.) of Drama, East Macedonia-Thrace Region, in Northeastern Greece. A total of 923 specimens were examined based on their morphological characteristics and identified to the species level. Medically important taxa were recognized among the 15 mosquito species recorded belonging to seven genera. All data presented here comprise new distribution records due to lack of previous mosquito faunal surveys in the R.U. of Drama.

Biting midges (Culicoides) are vectors of arboviruses of both veterinary and medical importance. The surge of emerging and reemerging vector-borne diseases and their expansion in geographical areas affected by climate change has increased the importance of understanding their capacity to contribute to novel and emerging infectious diseases. The study of Culicoides virome is the first step in the assessment of this potential. In this study, we analyzed the RNA virome of 10 Culicoides species within the geographical area of Thrace in the southeastern part of Europe, a crossing point between Asia and Europe and important path of various arboviruses, utilizing the Ion Torrent next-generation sequencing (NGS) platform and a custom bioinformatics pipeline based on TRINITY assembler and alignment algorithms. The analysis of the RNA virome of 10 Culicoides species resulted in the identification of the genomic signatures of 14 novel RNA viruses, including three fully assembled viruses and four segmented viruses with at least one segment fully assembled, most of which were significantly divergent from previously identified related viruses from the Solemoviridae, Phasmaviridae, Phenuiviridae, Reoviridae, Chuviridae, Partitiviridae, Orthomyxoviridae, Rhabdoviridae, and Flaviviridae families. Each Culicoides species carried a species-specific set of viruses, some of which are related to viruses from other insect vectors in the same area, contributing to the idea of a virus-carrier web within the ecosystem. The identified viruses not only expand our current knowledge on the virome of Culicoides but also set the basis of the genetic diversity of such viruses in the area of southeastern Europe. Furthermore, our study highlights that such metagenomic approaches should include as many species as possible of the local virus-carrier web that interact and share the virome of a geographical area.