Oysters and norovirus: something special?

Area of Science:

• Foodborne pathogens
• Virology
• Public health

Background:

• Shellfish consumption is a known risk factor for human pathogen transmission.
• Despite regulations targeting enteric bacteria, viral outbreaks linked to shellfish persist.
• Noroviruses are the leading cause of viral gastroenteritis outbreaks associated with shellfish, especially oysters.

Purpose of the Study:

• To investigate the reasons behind the prevalence of specific norovirus genogroups in shellfish-related outbreaks.
• To explore the potential for selective accumulation of norovirus strains by oysters.
• To understand the mechanisms contributing to the observed genogroup I/II bias in shellfish outbreaks.

Main Methods:

• Analysis of global shellfish-related outbreak data.
• Review of in vitro, in vivo, and environmental studies on norovirus-oyster interactions.
• Examination of oyster's capacity for selective norovirus accumulation based on human-shared carbohydrate ligands.

Main Results:

• Norovirus genogroup I strains are disproportionately represented in shellfish-related outbreaks compared to other transmission routes.
• Oysters demonstrate selective accumulation of norovirus strains.
• This selective accumulation is influenced by virus-host carbohydrate ligand interactions.

Conclusions:

• Oysters are not merely passive filters but actively influence norovirus strain prevalence.
• Selective norovirus accumulation by oysters, mediated by ligand interactions, may explain the observed genogroup bias in outbreaks.
• Findings highlight the need to consider specific viral-host interactions in shellfish safety regulations.