Joanne Macdonald¹, Michael Poidinger¹, John S. Mackenzie¹, Richard C. Russell², Stephen Doggett², Annette K. Broom³, Debra Phillips⁴, Joseph Potamski⁴, Geoff Gard⁵, Peter Whelan⁶, Richard Weir⁵, Paul R. Young¹, Debra Gendle¹, Sheryl Maher¹, Ross T. Barnard¹ and Roy A. Hall¹

¹Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Qld. 4072, Australia. ²Department of Medical Entomology, The University of Sydney, Westmead Hospital, Westmead, NSW, 2145, Australia. ³Discipline of Microbiology and Immunology, School of Biomedical, Biomolecular, and Chemical Sciences, The University of Western Australia, Nedlands, Western Australia 6009, Australia. ⁴Public Health Virology, Queensland Health Forensic and Scientific Services, Coopers Plains, Qld. 22222, Australia. ⁵A.L. Rose Laboratory, Berrimah Veterinary Laboratories, Berrimah Farm, Berrimah, NT. 0828, Australia. ⁶Medical Entomology, Centre for Disease Control, NT Department of Health and Families, Darwin, NT. 0811, Australia.  

Abstract

Edge Hill virus (EHV) is a mosquito-borne flavivirus isolated throughout Australia during mosquito surveillance programs. While not posing an immediate threat to the human population, EHV is a taxonomically interesting flavivirus since it remains the only member of the yellow fever virus (YFV) sub-group to be detected within Australia. Here we present both an antigenic and genetic investigation of collected isolates, and confirm taxonomic classification of the virus within the YFV-group. Isolates were not clustered based on geographical origin or time of isolation, suggesting that minimal genetic evolution of EHV has occurred over geographic distance or time within the EHV cluster. However, two isolates showed significant differences in antigenic reactivity patterns, and had a much larger divergence from the EHV prototype (19% nucleotide and 6% amino acid divergence), indicating a distinct subtype or variant within the EHV subgroup.