ENTERIC VIRUSES IS SHELLFISH – WHAT, HOW, WHERE?

Kata Farkas¹, Vanessa Kienmoser², Shelagh K Malham²

¹School of Environment Natural Resources and Geography, Bangor University, Deiniol Road, Bangor, Gwynedd, LL57 2UW

²School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5TH

e-mail: k.farkas@bangor.ac.uk

Enteric viruses are frequently found in shellfish and often associated with shellfish-borne outbreaks. Noroviruses and hepatitis A virus are the lead cause of such outbreaks, however recently emerging viruses, such as hepatitis E virus and sapovirus, are associated with shellfish-borne illnesses. For safety controls, coliform bacteria are used as indicators for the level of faecal contamination of shellfish. Nonetheless, bacteria concentrations may not correlate with the titre of enteric viruses and hence viruses should be directly monitored.

For the detection and quantification of enteric viruses in shellfish, the ISO/TS 15216-1:2013 standard is commonly used, however, that involves a proteinase K treatment that may cause the degradation of the virus capsid and hence viral infectivity cannot be investigated. Therefore we investigated the usefulness of other elution methods for the recovery of common RNA enteric viruses (norovirus and hepatitis A virus) and a process control, mengovirus. The recovery of a common viral indicator, adenovirus, which is an enteric virus usually asymptomatic in healthy individuals and found in wastewater in high concentrations, was also assessed.

Our results indicated that the recovery of viruses is highly strain-dependent, which may leads to false negative results. However, adenoviruses could be recovered regardless of the method used. These results suggest that a surveillance system that includes the monitor of input (viral flow from wastewater) and the direct detection of reliable indicators, e.g. adenoviruses, may be useful in order to manage the risks associated with shellfish-consumption.