Submitted to: Food and Environmental Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2017
Publication Date: 8/22/2017
Citation: Kingsley, D.H., Chen, H., Meade, G.K. 2017. Persistence of MS-2 bacteriophage within Eastern Oysters. Food and Environmental Virology. 10:83-88.
Interpretive Summary: Bacteriophage is now being used on a limited basis as an indicator of sewage exposure and pollution for shellfish. For example the US National Shellfish Sanitation Program now requires a three week closure of shellfish harvest areas after suspected sewage release events. However if male-specific coliphage levels are below the standard, shellfish beds may be reopened for harvest. Recently the State of NJ used elevated phage levels as a justification for specific closure of shellfish beds after hurricane Sandy until the following spring. This work was initiated to evaluate and characterize the effect of water temperature on the temporal persistence of bacteriophage within shellfish meats. Results conclusively demonstrate that water temperature dramatically affects male-specific coliphage persistence.
Technical Abstract: Male-specific bacteriophage have been proposed as human enteric virus indicators for shellfish. In this study, Eastern oysters (Crassostrea virginica) were individually exposed to 56000000000 plaque forming units of MS-2 for 48 hrs at 15 degrees Celcius followed by collective maintenance in continuously UV-sterilized seawater for 0-6 weeks at either 7, 15, or 24 degrees Celcius. Assessment of weekly declines of viable MS-2 indicated that cooler temperatures dramatically enhanced persistence of MS-2 within oyster tissues. At three weeks, the average log PFU reductions for MS-2 within oysters were 2.28, 2.90, and 4.57 for oysters held at 7, 15, and 24 degrees Celcius, respectively. Fitting temporal survival data with linear and the non-linear Weibull models indicated that the Weibull model best fit observed reductions. In total, this data can serve as a guideline for regulatory agencies regarding the influence of water temperature on indicator phage after episodic sewage exposure.