Parramatta River virus (PaRV) is an insect virus belonging to ''

Flaviviridae ''Flaviviridae'' is a family of enveloped positive-strand RNA viruses which mainly infect mammals and birds. They are primarily spread through arthropod vectors (mainly ticks and mosquitoes). The family gets its name from the yellow fever virus ...

'' and

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It was discovered in 2015. The virus was identified from the mosquito ''

Aedes vigilax ''Aedes'' is a genus of mosquitoes originally found in tropical and subtropical zones, but now found on all continents except perhaps Antarctica. Some species have been spread by human activity: ''Aedes albopictus'', a particularly invasive sp ...

'' collected from

Sydney Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...

under the joint research project by scientists at the

University of Queensland , mottoeng = By means of knowledge and hard work , established = , endowment = A$224.3 million , budget = A$2.1 billion , type = Public research university , chancellor = Peter Varghese , vice_chancellor = Deborah Terry , city = B ...

and the

University of Sydney The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's si ...

. In experimental infections, the virus is unable to grow in vertebrate cells, but only in ''Aedes''-derived mosquito cell lines. This suggests that the virus does not infect vertebrates. The name is given because it was discovered from

Silverwater Silverwater is a suburb in western Sydney, in the state of New South Wales, Australia. Silverwater is located 15 kilometres west of the Sydney central business district on the southern bank of the Parramatta River within the local governme ...

, a suburb of Sydney on the southern bank of the

Parramatta River The Parramatta River is an intermediate tide-dominated, drowned valley estuary located in Sydney, New South Wales, Australia. With an average depth of , the Parramatta River is the main tributary of Sydney Harbour, a branch of Port Jackson. Seco ...

. The mosquitoes from which the virus was isolated were actually collected in 2007, and had been preserved since then. The study commenced only after the development of the technique of viral detection in mosquitoes in the University of Queensland. The virus was identified as a result of investigation on the outbreak of '' Ross River virus'' in 2015. Both the viruses are transmitted by the same mosquitoes, but PaRV is not transmitted to humans, unlike RRV. According to one of the co-authors, Cameron Webb of the University of Sydney, this unique transmission of PaRV could hold a key "to vaccinate mosquitoes and stop their bites making thousands of Australians sick every summer." The reason, explained by Jody Hobson-Peters of the University of Queensland, is that if mosquitoes (vectors for human diseases) are infected with the PaRV, then they will no longer be able to carry other human-infectious viruses. The virus was identified from the whole genome sequence using

Sanger sequencing Sanger sequencing is a method of DNA sequencing that involves electrophoresis and is based on the random incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication. After first being developed by Frederi ...

. The viral genome consists of 10,893 nucleotides and encodes a polyprotein of 3384 amino acids. Comparison with the genomes of other viruses showed that its closest relatives are the Mediterranean Ochlerotatus flavivirus (MoFV) isolated from ''

Ochlerotatus ''Ochlerotatus'' is a genus of mosquito. Until 2000, it was ranked as a subgenus of ''Aedes'', but after Reinert's work, the clade was upgraded to the level of a genus. This change has resulted in the renaming of many subgenus species, and many a ...

'' mosquitoes in Spain, and the Hanko virus (HANKV) from ''Ochlerotatus'' mosquitoes in Finland (both identified in 2012). With MoFV its shares 72.7% nucleotide identity, and with HANKV the nucleotide similarity is 71.4%. The complete structure of the 3'UTR RNA of PaRV has been solved, revealing that that PaRV has evolved to produce multiple separate sfRNAs from its 3'UTR. Duplicated xrRNAs in PaRV and other insect-specific Flaviviruses appear to be evolutionarily selected for to provide functional redundancy allowing the production of sfRNAs if one structures is disabled by mutations.

References

{{taxonbar, from=Q28403396 Flaviviruses Insect viral diseases Diptera pests and diseases Nematocera