Uncovering the genetic diversity within the Aedes notoscriptus virome and isolation of new viruses from this highly urbanised and invasive mosquito

Abstract

The Australian backyard mosquito, Aedes notoscriptus, is a highly urbanized pest species that has invaded New Zealand and the United States. Importantly, Ae. notoscriptus has been implicated as a vector of Ross River virus, a common and arthritogenic arbovirus in Australia, and is a laboratory vector of numerous other pathogenic viruses, including West Nile, yellow fever and Zika viruses. To further explore live viruses harboured by field populations of Ae. notoscriptus and, more specifically, assess the genetic diversity of its virome, we processed 495 pools, comprising a total of 6,674 female Ae. notoscriptus collected across fifteen suburbs in Brisbane, Australia, between January 2018 and May 2019. Nine virus isolates were recovered and characterised by metagenomic sequencing and phylogenetics. The principal viral family represented was Flaviviridae. Known viruses belonging to the genera Flavivirus, Orbivirus, Mesonivirus and Nelorpivirus were identified together with two novel virus species, including a divergent Thogoto-like orthomyxovirus and an insect-specific flavivirus. Among these, we recovered three Stratford virus (STRV) isolates and an isolate of Wongorr virus (WGRV), which for these viral species, is unprecedented for the geographical area of Brisbane. Thus, the documented geographical distribution of STRV and WGRV, both known for their respective medical and veterinary importance, has now been expanded to include this major urban centre. Phylogenies of the remaining five viruses, namely, Casuarina, Ngewotan, the novel Thogoto-like virus, and two new flavivirus species, suggested they are insect-specific viruses (ISVs). None of these viruses have been previously associated with Ae. notoscriptus or been reported in Brisbane. These findings exemplify the rich genetic diversity and viral abundance within the Ae. notoscriptus virome and further highlight this species as a vector of concern with the potential to transmit viruses impacting human or animal health. Considering it is a common pest and vector in residential areas, and is expanding its global distribution, ongoing surveillance, and ecological study of Ae. notoscriptus, together with mapping of its virome and phenotypic characterization of isolated viruses, is clearly warranted. Immanently, these initiatives are essential for future understanding of both the mosquito virome and the evolution of individual viral species.

Dissecting the Species-Specific Virome in Culicoides of Thrace

“…Hypotheses that attempt to explain such an observation include a central role of the insects in a "one-health" concept of vector-borne diseases of both plants and animals (Dietzgen et al, 2016) or contamination of insect samples with fungi (Cook et al, 2013;Chandler et al, 2015). Studies that include virome characterization after a cell culture on insect cells may support or confute the above hypotheses (Pyke et al, 2021). Submaritimus reo-like virus fell into the same phylogenetic clade with three other insect viruses, namely, Aedes camptorynhus reo-like virus, Atrato reo-like virus and Hubei reo-like virus.…”

Defining virus-carrier networks that shape the composition of the mosquito core virome of a local ecosystem

“…2021 ; C. Shi et al. 2020 ), through generations, and are recently of great interest as modulators of mosquito vector competency ( Öhlund, Lundén, and Blomström 2019 ; Pyke et al. 2021 ; Viglietta et al.…”

Australian terrestrial environments harbour extensive RNA virus diversity

“…Numerous novel RNA viruses have been identified in Australia's unique ecosystems (Geoghegan et al, 2021;Harvey et al, 2018;Le Lay et al, 2020;Mahar et al, 2020;Mu et al, 2018;Pyke et al, 2021;Chang et al, 2021;Van Brussel et al, 2022;Wille et al, 2018).…”