Abstract
The discovery and characterisation of new mosquito-borne viruses provides valuable information on the biodiversity of vector-borne viruses and important insights into their evolution. In this study, a broad-spectrum virus screening system, based on the detection of long double-stranded RNA in inoculated cell cultures, was used to investigate the presence of novel viruses in mosquito populations of northern Australia. We detected and isolated a new virus (tentatively named Parry’s Lagoon virus, PLV) from Culex annulirostris, Culex pullus, Mansonia uniformis and Aedes normanensis mosquitoes that shares genomic sequence similarities to Corriparta virus (CORV), a member of the Orbivirus genus of the family Reoviridae. Despite moderate to high (72.2% to 92.2%) amino acid identity across all proteins when compared to CORV, and demonstration of antigenic relatedness, PLV did not replicate in several vertebrate cell lines that were permissive to CORV. This striking phenotypic difference suggests that PLV has evolved to have a very restricted host range, indicative of a mosquito-only life cycle.
Highlights
Viruses of the Reoviridae family are icosahedral, non-enveloped and consist of a 9–12 segmented double-stranded RNA genome [1]
Culex annulirostris mosquito pools that were negative for flaviviruses and alphaviruses and did not cause cytopathic effect (CPE) in vertebrate cells negative for flaviviruses and alphaviruses and did not cause cytopathic effect (CPE) in vertebrate (n = 138) were examined for the presence of insect-specific viruses
During an investigation to determine the prevalence and biodiversity of insect-specific viruses in mosquitoes of northern Western Australia, a novel orbivirus was identified in pools of Culex annulirostris, Culex pullus, Mansonia uniformis and Aedes normanensis mosquitoes collected in 2010 and 2011 that had previously been screened for vertebrate-infecting viruses
Summary
Viruses of the Reoviridae family are icosahedral, non-enveloped and consist of a 9–12 segmented double-stranded RNA (dsRNA) genome [1]. The family consists of two clear subfamilies, the Spinareovirinae (“spiked” core particles) and the Sedoreovirinae (“spikes” absent on core particles). Reoviruses are separated into 16 distinct genera [1]. The genus Orbivirus (subfamily: Sedoreovirinae), characterised by the presence of a 10-segment RNA genome, is the largest of the Reoviridae genera and contains 22 distinct virus species [1]. Bluetongue virus, African horse sickness virus and epizootic haemorrhagic disease virus are regarded as the most economically important viruses within this genus, due to direct economic losses associated with herd morbidity and mortality as well as a significant loss through restriction on animal movement [2]
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