Why I don’t eat raw oysters: Norovirus genotypes implicated in two oyster-related illness outbreaks in Ireland

We investigated norovirus (NoV) concentrations and genotypes in oyster and faecal samples associated with two separate oyster-related outbreaks of gastroenteritis in Ireland. Quantitative analysis was performed using real-time quantitative reverse transcription polymerase chain reaction and phylogenetic analysis was conducted to establish the NoV genotypes present.

Raw oystersFor both outbreaks, the NoV concentration in oysters was >1000 genome copies/g digestive tissue and multiple genotypes were identified. In faecal samples, GII.13 was the only genotype detected for outbreak 1, whereas multiple genotypes were detected in outbreak 2 following the application of cloning procedures. While various genotypes were identified in oyster samples, not all were successful in causing infection in consumers. In outbreak 2 NoV GII.1 was identified in all four faecal samples analysed and NoV GII concentrations in faecal samples were >108 copies/g. This study demonstrates that a range of NoV genotypes can be present in highly contaminated oysters responsible for gastroenteritis outbreaks.

Epidemiology and Infection / Volume 142 / Issue 10 / October 2014, pp 2096-2104

P. RAJKO-NENOW, S. KEAVENEY, J. FLANNERY, A. McINTYR and W. DORÉ

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9320778&utm_source=Issue_Alert&utm_medium=RSS&utm_campaign=HYG&utm_reader=feedly