Poster Presentation 8th Australasian Virology Society Meeting and 11th Annual Meeting of the Australian Centre for Hepatitis & HIV Virology Meeting 2015

Discovery of a highly divergent bunyavirus in Culex mosquitoes from Papua New Guinea and Australia (#146)

Jody Hobson-Peters 1 , David Warrilow 2 , Breeanna McLean 1 , Daniel Watterson 1 , Agathe Colmant 1 , Andrew F van den Hurk 2 , Sonja Hall-Mendelin 2 , Marcus Hastie 3 , Jeffrey J Gorman 3 , Jessica J Harrison 1 , Natalie Prow 1 , Ross Barnard 1 , Richard Allcock 4 5 , Cheryl Johansen 6 , Roy Hall 1
  1. Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Qld, Australia
  2. Public Health Virology Laboratory, Forensic and Scientific Services, Department of Health, Coopers Plains, Qld, Australia
  3. Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, Qld, Australia
  4. Lottery West State Biomedical Facility - Genomics, School of Pathology and Laboratory Medicine, University of Western Australia, Perth, WA, Australia
  5. Department of Clinical Immunology, Pathwest Laboratory Medicine Western Australia, Royal Perth Hospital, Perth, WA, Australia
  6. School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia

The Bunyaviridae includes significant human and veterinary pathogens, such as Rift Valley fever, Schmallenberg and Akabane viruses, with virulent strains continually emerging and expanding their geographic range.

During outbreaks of Japanese encephalitis virus (JEV) in the Australasian region in 2003, mosquitoes were collected on Badu Island in the Torres Strait to monitor the spread and transmission of the virus.  When these mosquito samples were recently re-examined for the presence for novel mosquito-borne viruses, we isolated a new bunyavirus (Badu virus – BADUV) from a pool of Culex sitiens. BADUV is unable to replicate in vertebrate cells, but grows readily in a variety of mosquito cell lines. Genetically, BADUV is divergent from all sequenced bunyavirus isolates to date, but phylogenetically clustered most closely with recently discovered, insect-specific bunyaviruses in the newly proposed Goukovirus genus. Further analysis of the genomic structure and gene products of BADUV indicate the virus may have important ancestral links with members of the Phlebovirus genus. The detection of a functional furin cleavage motif upstream of the two glycoproteins in the M segment-encoded polyprotein, and mass spec data supporting cleavage at this site, further suggests that BADUV may employ a unique strategy to process the virion glycoproteins.

The production of BADUV-specific monoclonal antibodies and RT-PCR primers further facilitated the detection of the virus in mosquitoes collected in PNG in 1997/1998 and from Cape York Peninsula in 2004. These findings support a previous hypothesis that wind-borne mosquitoes disperse viruses from PNG to the islands of the Torres Strait and Australian mainland, as proposed for incursions of JEV.

BADUV represents the first insect-specific bunyavirus to be detected in the Australasian region and provides a unique opportunity to study the mechanism of its maintenance and spread, the evolution of bunyaviruses, and its effect on the transmission of significant arboviruses such as JEV.