Accumulation of sediment-associated viruses in shellfish

Area of Science:

• Environmental microbiology
• Aquatic toxicology
• Food safety

Background:

• Contaminated sediments are a potential reservoir for human viruses in marine environments.
• Shellfish can accumulate viruses from their surroundings, posing a risk to human health.
• Understanding virus transfer from sediments to shellfish is critical for public health protection.

Purpose of the Study:

• To investigate the role of contaminated sediments in the bioaccumulation of poliovirus by oysters and clams.
• To compare virus accumulation from resuspended versus undisturbed contaminated sediments.
• To evaluate the significance of sediment-bound viruses in shellfish for public health.

Main Methods:

• Oysters (Crassostrea virginica) and clams (Mercenaria mercenaria) were exposed to sediments containing bound poliovirus type 1.
• Sediments were either resuspended or left undisturbed.
• Shellfish tissues were analyzed for the presence of accumulated viruses.

Main Results:

• Oysters consistently bioaccumulated viruses when sediment-bound viruses were in the water column (4/5 trials).
• Virus accumulation in clams from undisturbed sediments was observed in 2/5 trials and considered marginal.
• Higher incidence of bioaccumulation occurred with resuspended sediments, but concentrations were not significantly different from undisturbed sediments.

Conclusions:

• Shellfish bioaccumulation of viruses from sediments is most significant when sediments are disturbed and suspended in the water column.
• Undisturbed contaminated sediments pose a marginal risk for virus accumulation in shellfish.
• Water-column sampling at the water-sediment interface is recommended for accurate assessment of shellfish harvesting water quality.