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.

Keywords: Culex quinquefasciatus; Culex tritaeniorhynchus; emerging infectious diseases; insect-specific viruses; metagenomics; mosquito microbiome; virome.

Figure 1

World geographical map outlining the geo-location of Kenya and China. Kenya is outlined in orange in the African continent while China is outlined in green in the Asian continent. The red stars represent sampling sites.

Figure 2

Percentage proportions of viruses in different host groups from mosquitos in Kwale, Kenya, and the Hubei and Yunnan provinces of China.

Figure 3

Stacked bar graph of all virus families (color coded) identified in the viromes of the Culex mosquito in Kwale county, Kenya and provinces of Hubei and Yunnan, China, 2014–2017. Only virus families with reads more than 30 were included in the figure.

Figure 4

Abundance of the 10 most common virus species in Culex mosquito viromes in Kwale, Hubei, and Yunnan.