A New Species of Mesonivirus from the Northern Territory, Australia

Abstract

Here we describe Casuarina virus (CASV), a new virus in the family Mesoniviridae. This is the first report of a mesonivirus in Australia, which extends the geographical range of this virus family to 3 continents. The virus was isolated in 2010 from Coquillettidia xanthogaster mosquitoes during surveillance in the suburbs of Darwin, the capital of the Northern Territory. Cryo-electron microscopy of the CASV virions revealed spherical particles of 65 nm in size with large club-shaped projections of approximately 15 nm in length. The new virus was most closely related to Alphamesonivirus 1, the only currently recognized species in the family. In 2013 a further 5 putative new mesonivirus species were described: Hana, Méno, Nsé, Moumo and Dak Nong viruses. The evolutionary distance between CASV and two of its closest relatives, Cavally and Hana viruses (Jones-Taylor-Thornton distance of 0.151 and 0.224, respectively), along with its isolation from a different genus of mosquitoes captured on a separate continent indicate that CASV is a new species.

Insect-Specific Viruses

“…Alphamesonivirus-6 is also an independent isolate from Indonesia called Karang Sari virus (KSaV), while Alphamesonivirus-7 was isolated in Thailand and has been described as Kamphaeng Phet virus (KPhV) (Vasilakis and Tesh, 2015;Vasilakis et al, 2014). Currently, three known ISVs have yet to be assigned to species; the unculturable MoumoV, a presumed serotype of Alphamesonivirus-1 isolated in Vietnam called Dak Nong virus (DKNV) (Kuwata et al, 2013), and finally an isolate known as Casuarina virus (CASV) (Warrilow et al, 2014). CASV was isolated in 2010 during mosquito surveillance in Northern Australia, in the Darwin suburb known as Casuarina from a pool of Coquillettidia xanthogaster.…”

Proteolytic processing of mesonivirus replicase polyproteins by the viral 3C-like protease

“…The heptanucleotide sequence is conserved among mesoniviruses (Fig. 3a) and located upstream of a putative RNA structural element (Nga et al, 2011;Vasilakis et al, 2014;Warrilow et al, 2014;Zirkel et al, 2011Zirkel et al, , 2013. To provide direct experimental evidence for the presumed functional role of this sequence, we expressed fusion protein constructs containing the CavV ORF1a/1b overlap region.…”

Negeviruses found in multiple species of mosquitoes from southern Portugal: Isolation, genetic diversity, and replication in insect cell culture

“…Despite the limited sensitivity/specificity these experimental approaches entail, they have allowed the identification and/or characterization of multiple viruses over time, many of which have been shown to replicate exclusively in insect cells. Examples include the first insect-specific bunyavirus, Gouléako virus (Marklewitz et al, 2011), and alphavirus, Eilat virus (Nasar et al, 2012), numerous flaviviruses , and nidoviruses from Asia, Africa, and Australia (Lauber et al, 2012;Zirkel et al, 2013;Warrilow et al, 2014), the latter constituting a new viral family (Mesoniviridae).…”