Noroviruses are a leading cause of outbreaks of gastroenteritis. This study examined the incidence and molecular characteristics of norovirus outbreaks in Victoria, Australia in 2016. Norovirus was detected in 52.4% of gastroenteritis outbreaks surveyed and the year was notable in that there was no significant temporal peak in norovirus outbreaks. Norovirus Open Reading Frame (ORF)2 (capsid) genotypes were successfully identified in 84 of 110 norovirus outbreaks and included GI.3, GI.6, GI.9, GII.2, GII.3, GII.4, GII.6, and GII.17. Norovirus GII.4 was the most common ORF2 genotype detected (55.9%). Other relatively common ORF2 genotypes included GII.2 (19.0%), GII.17 (9.5%), GI.3 (7.1%) and GII.3 (4.8%). The GII.P4_NewOrleans_2009/GII.4_Sydney_2012 recombinant emerged as an important new GII.4 form. The study also confirmed the identity of three ORF1/ORF2 recombinant forms as follows: GII.P16/GII.2, GII.P16/GII.3 and GII.P16/GII.4. Statistical analysis indicated GII.4 (ORF2) was much more common in healthcare settings than in non-healthcare settings. The study indicates 2016 was a transition year in Victoria, Australia, in that the previous norovirus epidemic strain had diminished to the point where it was no longer dominant but as yet no replacement epidemic strain had become obvious.
This work is copyright. You may download, display, print and reproduce the whole or part of this work in unaltered form for your own personal use or, if you are part of an organisation, for internal use within your organisation, but only if you or your organisation do not use the reproduction for any commercial purpose and retain this copyright notice and all disclaimer notices as part of that reproduction. Apart from rights to use as permitted by the Copyright Act 1968 or allowed by this copyright notice, all other rights are reserved and you are not allowed to reproduce the whole or any part of this work in any way (electronic or otherwise) without first being given the specific written permission from the Commonwealth to do so. Requests and inquiries concerning reproduction and rights are to be sent to the Online, Services and External Relations Branch, Department of Health, GPO Box 9848, Canberra ACT 2601, or by email to copyright@health.gov.au.