Viral metagenomics characterizes known and identifies unknown viruses
based on sequence similarities to any previously sequenced viral genomes. A
metagenomics approach was used to identify virus sequences in Australian
mosquitoes causing cytopathic effects in inoculated mammalian cell cultures.
Sequence comparisons revealed strains of Liao Ning virus
(Reovirus, Seadornavirus), previously
detected only in China, livestock-infecting Stretch Lagoon virus
(Reovirus, Orbivirus), two novel
dimarhabdoviruses, named Beaumont and North Creek viruses, and two novel
orthobunyaviruses, named Murrumbidgee and Salt Ash viruses. The novel virus
proteomes diverged by ≥50% relative to their closest previously
genetically characterized viral relatives. Deep sequencing also generated
genomes of Warrego and Wallal viruses, orbiviruses linked to kangaroo blindness,
whose genomes had not been fully characterized. This study highlights viral
metagenomics in concert with traditional arbovirus surveillance to characterize
known and new arboviruses in field-collected mosquitoes. Follow-up
epidemiological studies are required to determine whether the novel viruses
infect humans.