Relevance of F-Specific RNA Bacteriophages in Assessing Human Norovirus Risk in Shellfish and Environmental Waters

Area of Science:

• Environmental microbiology
• Virology
• Food safety

Background:

• Human noroviruses (HuNoVs) are a primary cause of gastroenteritis from shellfish consumption.
• Detecting infectious HuNoVs is challenging, leading to reliance on genome detection with interpretation difficulties.
• F-specific RNA bacteriophages (FRNAPH) are explored as indicators of fecal and viral contamination in shellfish and water.

Purpose of the Study:

• To investigate the utility of FRNAPH as indicators of fecal and viral contamination in shellfish and water.
• To assess FRNAPH as microbial source tracking tools.
• To evaluate the relationship between FRNAPH and HuNoV presence in shellfish.

Main Methods:

• Investigated FRNAPH as indicators in shellfish and water samples from a local harvesting area.
• Compared FRNAPH detection with Escherichia coli for fecal pollution indication.
• Analyzed seasonal trends and bioaccumulation of FRNAPH in shellfish.
• Examined the correlation between HuNoV genomes and human-specific FRNAPH subgroup II (FRNAPH-II) in European shellfish.

Main Results:

• Detection limits posed challenges, with infectious FRNAPH found without genomes and vice versa, suggesting genome detection alone is insufficient for risk assessment.
• FRNAPH showed no advantage over E. coli in water but exhibited seasonal trends and higher concentrations in shellfish, indicating bioaccumulation.
• A correlation was observed between HuNoV genomes and FRNAPH-II in shellfish across Europe.

Conclusions:

• Genome-based detection of HuNoVs may not accurately reflect infectious risk.
• Infectious FRNAPH-II shows potential as a specific indicator for infectious HuNoVs in shellfish.
• Further research is needed to validate FRNAPH-II as a reliable marker for HuNoV risk in shellfish, particularly by analyzing shellfish from HuNoV outbreak cases.