Norovirus genotype diversity associated with gastroenteritis outbreaks in aged-care facilities

Abstract

Noroviruses are a major cause of gastroenteritis. Vaccine strategies against norovirus are currently under consideration but depend on a detailed knowledge of the capsid genotypes. This study examined the incidence of norovirus outbreaks in residential aged-care facilities in Victoria, Australia over one year (2013) and documented the (capsid) norovirus genotypes associated with these outbreaks. It was found that 65·0% of 206 outbreaks tested were associated with norovirus infection, thereby showing norovirus to be the major cause of viral gastroenteritis in residential aged-care facilities. Fifteen capsid (open reading frame 2) genotypes were identified as follows: GI.2 (0·9%), GI.3 (1·8%), GI.4 (3·7%), GI.6 (0·9%), GI.7 (0·9%), GI.8 (0·9%), GII.1 (0·9%), GII.2 (0·9%), GII.3 (1·8%), GII.4 (2009-like) (0·9%), GII.4 (2012) (48·6%), GII.4 (2012-like) (16·5%), GII.4 (unknown) (9·2%), GII.5 (2·8%), GII.6 (0·9%), GII.7 (0·9%), GII.13 (6·4%) and an as yet unclassified GII genotype (0·9%). Although GII.4 was the most common norovirus capsid genotype detected, the great diversity of norovirus genotypes in the elderly indicates vaccination strategies for this demographic are not straightforward.

A Unique Human Norovirus Lineage with a Distinct HBGA Binding Interface

“…Members of the GII.13/21 lineage revealed increased prevalence in the recent years. Surveillance indicates that the GII.13 and GII.21 huNoVs continue to cause outbreaks in the USA (CaliciNet http://www.cdc.gov/norovirus/reporting/calicinet/data.html ), Europe (NoroNet, http://www.rivm.nl/dsresource?objectid=rivmp:248062&type=org&disposition=inline ), and other countries [ 37 , 39 , 40 ], indicating that the GII.13/21 lineage is of clinical importance. It was also noted that, after being silent for the past decades, GII.17 NoVs became dominant in southern China in the past winter [ 41 ], overwhelmed GII.4 NoVs.…”

A norovirus intervariant GII.4 recombinant in Victoria, Australia, June 2016: the next epidemic variant?

“…The Victorian Infectious Diseases Reference Laboratory (VIDRL) is the main public health laboratory for viral identification in the State of Victoria, Australia. Faecal specimens collected from gastroenteritis outbreaks are routinely sent to VIDRL for norovirus testing [ 8 ]. An outbreak of gastroenteritis was defined as an incident, apparently associated with an event or location, in which four or more individuals had symptoms of gastroenteritis.…”

“…Faecal specimens were processed as described previously [ 8 ] and then tested by an ORF1 reverse transcription (RT)-PCR that detects both GI and GII norovirus [ 8 ]. Additionally, a GII ORF2 RT-PCR was also performed on one specimen from each gastroenteritis outbreak [ 8 ]. Where ORF1 and ORF2 testing provided different genotypes, an ORF1-ORF2 bridging PCR was performed to try and confirm recombination status [ 9 ].…”

Serum Immunoglobulin A Cross-Strain Blockade of Human Noroviruses

“…Although genogroup II (GII).4 NoV strains predominate worldwide, a large number of diverse NoV strains cocirculate at endemic levels. Genogroup I (GI) strain infections occur most frequently in children and the elderly [ 2 , 3 ]. Norovirus disease is usually self-limiting in healthy individuals, but it can be severe in the very young, elderly, and immunocompromised [ 3 – 5 ].…”