The Diversity and Distribution of Viruses Associated with Culex annulirostris Mosquitoes from the Kimberley Region of Western Australia.

Simon H Williams,Peter J Neville,John S Mackenzie,Michael D A Lindsay,Jay Nicholson,Nilusha Somaweera,Avram Levy,Rachel A Yates,Komal Jain,W Ian Lipkin,Allison Imrie,David W Smith

doi:10.3390/v12070717

Abstract

Metagenomics revealed an impressive breadth of previously unrecognized viruses. Here, we report the virome of the Culex annulirostris Skuse mosquito, an important vector of pathogenic arboviruses in Australia. Mosquitoes were collected from three sites in the Kimberley region of Western Australia. Unbiased high-throughput sequencing (HTS) revealed the presence of 16 novel viral sequences that share less than 90% identity with known viruses. None were closely related to pathogenic arboviruses. Viruses were distributed unevenly across sites, indicating a heterogeneous Cx. annulirostris virome. Polymerase chain reaction assays confirmed HTS data and identified marked variation between the virus prevalence identified at each site.

Highlights

Mosquito-borne viral diseases pose a persistent challenge to global public health
We describe the virome of Culex annulirostris mosquitoes collected from three sites located in the Kimberley region in the far north of Western Australia (WA) that are representative of locations where Murray Valley encephalitis virus (MVEV) and WNV (Kunjin) are most regularly detected in surveillance programs and where human cases are most frequent [15]
The use of suckling mice in the 1970s and 1980s led to the first wave of arbovirus discovery, including the isolation of Kununurra and Kimberley viruses from the northwest of WA [41]

Summary

Introduction

Mosquito-borne viral diseases pose a persistent challenge to global public health. Flaviviruses, such as yellow fever, dengue, Zika, Japanese encephalitis, and West Nile (WNV), and alphaviruses including Ross River and chikungunya cause significant morbidity and mortality in humans [1,2,3].Each of these viruses was discovered through classical methods, including culture, electron microscopy, and serology [4]; recent metagenomic studies suggest they represent just a fraction of the complete mosquito virome [5,6,7,8].Comprehensive arboviral surveillance was conducted in Western Australia (WA) since 1972 [9].Field-caught mosquitoes are transported by cold chain from across WA to a centralized laboratory to be sorted [10], pooled, and processed for inoculation onto invertebrate and vertebrate cells [11].Viral supernatant is collected from cultures displaying a cytopathic effect and characterized by Viruses 2020, 12, 717; doi:10.3390/v12070717 www.mdpi.com/journal/viruses. Mosquito-borne viral diseases pose a persistent challenge to global public health Flaviviruses, such as yellow fever, dengue, Zika, Japanese encephalitis, and West Nile (WNV), and alphaviruses including Ross River and chikungunya cause significant morbidity and mortality in humans [1,2,3]. Each of these viruses was discovered through classical methods, including culture, electron microscopy, and serology [4]; recent metagenomic studies suggest they represent just a fraction of the complete mosquito virome [5,6,7,8].

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Conclusion