Characterization of Viral Communities of Biting Midges and Identification of Novel Thogotovirus Species and Rhabdovirus Genus

Abstract

More than two thirds of emerging viruses are of zoonotic origin, and among them RNA viruses represent the majority. Ceratopogonidae (genus Culicoides) are well-known vectors of several viruses responsible for epizooties (bluetongue, epizootic haemorrhagic disease, etc.). They are also vectors of the only known virus infecting humans: the Oropouche virus. Female midges usually feed on a variety of hosts, leading to possible transmission of emerging viruses from animals to humans. In this context, we report here the analysis of RNA viral communities of Senegalese biting midges using next-generation sequencing techniques as a preliminary step toward the identification of potential viral biohazards. Sequencing of the RNA virome of three pools of Culicoides revealed the presence of a significant diversity of viruses infecting plants, insects and mammals. Several novel viruses were detected, including a novel Thogotovirus species, related but genetically distant from previously described tick-borne thogotoviruses. Novel rhabdoviruses were also detected, possibly constituting a novel Rhabdoviridae genus, and putatively restricted to insects. Sequences related to the major viruses transmitted by Culicoides, i.e., African horse sickness, bluetongue and epizootic haemorrhagic disease viruses were also detected. This study highlights the interest in monitoring the emergence and circulation of zoonoses and epizooties using their arthropod vectors.

Sinu virus, a novel and divergent orthomyxovirus related to members of the genus Thogotovirus isolated from mosquitoes in Colombia

“…Although the current International Committee on Taxonomy of Viruses (2015) (ICTV) (www.ictvonline.org/virustaxonomy.asp) only lists two species within the genus Thogotovirus , there are now actually eight viruses within the genus: Thogoto (THOV), Dhori (DHOV), Batken (BKNV), Upolu (UPOV), Aransas Bay (ABV), Jos (JOSV), Bourbon (BRBV) and Dielmo orthomyxovirus (DOV) (Allison et al, 2015, Bussetti et al, 2014, Lvov et al, 2015, Briese et al, 2014, Lambert et al, 2015, Temmam et al, 2016). The addition of SINUV to the genus will bring the total number of thogotoviruses to nine.…”

“…The addition of SINUV to the genus will bring the total number of thogotoviruses to nine. Most of the thogotoviruses have been associated with ticks, although Batken virus has been isolated from both ticks and mosquitoes (Lvov et al, 1974), Sinu virus was isolated from mosquitoes and Dielmo orthomyxovirus was found in Culicoides midges (Temmam et al, 2016). …”

“…With the exception of DOV, all of the other eight thogotoviruses were initially detected by culture ( in vitro ) in vertebrate or insect cell lines or by inoculation of newborn mice. However, given the tremendous number and diversity of arthropods on Earth and the increasing use of metagenomics to search for novel virus genomes in all life forms (Li et al 2015, Temman et al 2016, Shi et al 2016, Paez-Espino et al 2016) one can assume that other new thogotoviruses (and quaranjaviruses) will be discovered in non-hematophagous arthropods and other vertebrates.…”

Novel viruses in salivary glands of mosquitoes from sylvatic Cerrado, Midwestern Brazil

“…These partial genomic sequences belong to the same novel virus, which we named Lobeira virus (LOBV) ( Table 2 ). According to our phylogenetic tree based on L protein, this virus clustered with high node values with RISV, NOCRV and Tongilchon virus 1 forming clade I of the recently proposed Dielmovirus genus, dimarhabdovirus supergroup (dipteran-mammal-associated rhabdovirus) [ 36 ]. Together with clade II, clade I behaves as a basally rooted lineage of dimarhabdovirus supergroup ( Fig 2 ).…”

Viral Metagenomics on Blood-Feeding Arthropods as a Tool for Human Disease Surveillance

“…Female midges feed on a variety of hosts, and therefore a diversity of plant, animal and human viruses can be identified in the virome [50]. They transmit various culicoides-borne arboviruses, e.g., Schmallenberg virus in European ruminants, Bluetongue virus, Oropouche virus and African horse sickness virus [51,52,53].…”