Metagenomic Virome Analysis of Culex Mosquitoes from Kenya and China

Abstract

Many blood-feeding arthropods are known vectors of viruses that are a source of unprecedented global health concern. Mosquitoes are an integral part of these arthropod vectors. Advancements in next-generation sequencing and bioinformatics has expanded our knowledge on the richness of viruses harbored by arthropods. In the present study, we applied a metagenomic approach to determine the intercontinental virome diversity of Culex quinquefasciatus and Culex tritaeniorhynchus in Kwale, Kenya and provinces of Hubei and Yunnan in China. Our results showed that viromes from the three locations were strikingly diverse and comprised 30 virus families specific to vertebrates, invertebrates, plants, and protozoa as well as unclassified group of viruses. Though sampled at different times, both Kwale and Hubei mosquito viromes were dominated by vertebrate viruses, in contrast to the Yunnan mosquito virome, which was dominated by insect-specific viruses. However, each virome was unique in terms of virus proportions partly influenced by type of ingested meals (blood, nectar, plant sap, environment substrates). The dominant vertebrate virus family in the Kwale virome was Papillomaviridae (57%) while in Hubei it was Herpesviridae (30%) and the Yunnan virome was dominated by an unclassified viruses group (27%). Given that insect-specific viruses occur naturally in their hosts, they should be the basis for defining the viromes. Hence, the dominant insect-specific viruses in Kwale, Hubei, and Yunnan were Baculoviridae, Nimaviridae and Iflaviridae, respectively. Our study is preliminary but contributes to growing and much needed knowledge, as mosquito viromes could be manipulated to prevent and control pathogenic arboviruses.

Rapid detection of Banna virus by reverse transcription-loop-mediated isothermal amplification (RT-LAMP)

“…Our result shows that the assay could detect representative BAV isolates either from group A, B or C with no cross-reactivity with other tested mosquito-borne viruses such as DENV, CHIKV, YFV, WNV and JEV. At the same time, the result for the RT-LAMP assay for field-collected mosquito samples was consistent with RT-PCR and previously reported metagenomic analysis data, the mosquito samples with abundant BAV reads in metagenomic analysis were detected positively by RT-LAMP (Atoni et al, 2018;Xia et al, 2018b). In addition, this assay is fast and convenient.…”

De novo profiling of RNA viruses inAnophelesmalaria vector mosquitoes from forest ecological zones in Senegal and Cambodia

“…The presence in this study of such a large number of novel and unclassified virus assemblies highlights the fact that the malaria vector virome is understudied. The same observation has been made during metagenomics surveys in Drosophila , Aedes and Culex [24, 35, 36] among other arthropods, indicating that the vast majority of insect viruses are not yet discovered.…”

Viromics on Honey-Baited FTA Cards as a New Tool for the Detection of Circulating Viruses in Mosquitoes

“…Since we could not sequence the honey used to impregnate the FTA cards as sugar bait, we cannot discard the possibility that these sequences might have come from it. However, recent virome studies have described these two families as the most abundant in culicid mosquitoes from the Yunnan province in China, and Zambezi province in Mozambique [49,50]. The additional description of honeybee-infecting virus Rhopalosiphum padi virus (Dicistroviridae, genus Cripavirus) in mosquito species from Hubei, China [51] and in Culex mosquitoes from California [41], together with the assembly of sequences linked to chronic bee paralysis virus (CBPV) (unclassified ssRNA+ virus) and Apis mellifera filamentous virus (dsDNA Hytrosaviridae family) from French Anopheles maculipennis [52] and from Culex mosquitoes from California [41] respectively, suggested that these viral families could be associated to mosquitoes as well.…”

“…Besides invertebrate-related viruses, it was not surprising to find viral families usually detected in plants, fungi and algae (e.g., Tymoviridae, Totiviridae, Partitiviridae, Endornaviridae or Virgaviridae) as part of the viral diversity associated to honey-baited FTA cards ( Figure 1B). Since, in Culex mosquitoes, sequences related to Totiviridae-like viruses have been found in Guadeloupe [46], Australia [25], China [49] and California [41]; Partitiviridae-like viruses have been detected in Sweden [45,48], Australia [25], Kenya [49] and California [41]; Endornaviridae-like viruses in Australia [25] and Tymoviridae-like viruses have been identified in Guadeloupe [46], Kenya [49], California [41], China [53], and Sweden [48]. Moreover, a Culex Tymoviridae-like virus (CuTLV) that was isolated from a Culex spp.…”