A New Species of Mesonivirus from the Northern Territory, Australia

<div><p>Here we describe Casuarina virus (CASV), a new virus in the family <i>Mesoniviridae</i>. 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 <i>Coquillettidia xanthogaster</i> 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 <i>Alphamesonivirus 1</i>, 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.</p></div>