Abstract
Ross River virus (RRV) is the most medically significant mosquito-borne virus of Australia, in terms of human morbidity. RRV cases, characterised by febrile illness and potentially persistent arthralgia, have been reported from all Australian states and territories. RRV was the cause of a large-scale epidemic of multiple Pacific Island countries and territories (PICTs) from 1979 to 1980, involving at least 50,000 cases. Historical evidence of RRV seropositivity beyond Australia, in populations of Papua New Guinea (PNG), Indonesia and the Solomon Islands, has been documented. We describe the genomic characterisation and timescale analysis of the first isolate of RRV to be sampled from PNG to date. Our analysis indicates that RRV has evolved locally within PNG, independent of Australian lineages, over an approximate 40 year period. The mean time to most recent common ancestor (tMRCA) of the unique PNG clade coincides with the initiation of the PICTs epidemic in mid-1979. This may indicate that an ancestral variant of the PNG clade was seeded into the region during the epidemic, a period of high RRV transmission. Further epidemiological and molecular-based surveillance is required in PNG to better understand the molecular epidemiology of RRV in the general Australasian region.
Highlights
The geographical basis of River virus (RRV) lineage nomenclature was not supported in our recent, more comprehensive genome-scale RRV phylogenetic analysis, where we showed that virus isolates that clustered as distinct lineages were geographically dispersed and sampled Australia wide [10]
The unique clade is distinct from the genotype 4 (G4) viruses that were in wide Australian circulation at the time of the 1997 sampling of PNG3075
Phylogenetic analysis of the derived genome sequence and 104 available RRV full genome sequences revealed that the Papua New Guinea (PNG) isolate constitutes a unique genetic group, distinct from all other Australian RRV lineages
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In Australia, the most common mosquito-borne viral infection is caused by Ross. River virus (RRV), an alphavirus of the family Togaviridae [1]. Disease associated with RRV infection is characterised by potentially persistent and debilitating fatigue, myalgia, and arthralgia and/or arthritis. RRV cases have been reported from all Australian states and territories since it was first isolated from Aedes vigilax mosquitoes sampled in far-north
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