Reducing the Extent of Permanently Closed Shellfish Growing Areas through Regulatory Modernization: Enteric Virus Contamination and Mitigation Strategies (NSI)

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Project Type: 
Research
Project Number: 
RI/SSS-6
Inception Date: 
2012
Completion Date: 
2014

Participants:

William Burkhardt III U.S. Food and Drug Administration Co-Principal Investigator
Michael Hickey Massachusetts Division of Marine Fisheries Co-Principal Investigator
Jeff Kennedy Massachusetts Division of Marine Fisheries Partner
Kohl Kanwit Maine Department of Marine Resources Partner
Lori Howell Spinney Creek Shellfish, Inc. Co-Principal Investigator
Laura Stadig Spinney Creek Shellfish, Inc. Technician
Jayme Gough Spinney Creek Shellfish, Inc. Technician
Robert Moyer Spinney Creek Shellfish, Inc. Technician
Joey Marchants FDA Gulf Coast Seafood Laboratory Technician
Kristin DeRosia-Banick Connecticut Department of Agriculture Partner
David Carey Connecticut Department of Agriculture Partner
Ken Moore Interstate Shellfish Sanitation Conference Partner
Stephen Jones N.H. Sea Grant Principal Investigator
Michael Chambers N.H. Sea Grant Co-Principal Investigator
Tom Howell Spinney Creek Shellfish, Inc. Co-Principal Investigator

Students Involved:

Meghan Hartwick UNH - Department of Molecular, Cellular & Biomedical Sciences
Abstract: 

In the Northeastern United States, many acres of productive shellfish growing waters are permanently closed to aquaculture and harvesting activities due to concerns associated with human fecal pollution from municipal wastewater treatment plant outfalls. Often, these potential aquaculture sites are highly productive, sheltered, near-shore locations with good commercial access. The main outcome for this project is to increase coastal areas that are permitted for shellfish growing and harvesting. The size of these areas is based in part on fecal coliform levels, yet scientific investigations have demonstrated that fecal coliform levels are often unrelated to enteric virus occurrence and are misleading with respect to virus contamination. Norovirus (NoV) is responsible for the majority of shellfish consumption related viral disease worldwide with significant health costs in the U.S. Male-specific coliphage (MSC), a bacteriophage of E. coli bacteria and a small, round, RNA virus like NoV, has been proposed as a specialty viral indicator organism that better reflects the persistence of viruses in molluscan shellfish meats impacted by wastewater. The proposed approach is a well-defined, comprehensive approach to determining the feasibility of expanding aquaculture and harvest of hard clams and oysters in the Northeast U.S. The approach involves determining seasonal environmental conditions for minimal enteric virus contamination, and the effectiveness of seasonal MSC relay and depuration for purging of low-level microbial contamination. Highly similar previous studies in Maine with soft-shelled clams led to successful re-opening of closed, highly productive areas with significant local economic benefits. This project has a high probability of success in leading to changes in the National Shellfish Sanitation Program and increasing available growing areas in New England and nationally. The project will also positively impact aquaculture development, quality assurance processes, and ultimately consumer confidence, thus successfully achieving our overall outcome.

Objectives: 

The overall project goal is to open currently closed, yet highly productive, shellfish beds for aquaculture and harvest based on solid scientific evidence ensuring shellfish safety. The primary research objective is to determine the efficacy of using male-specific coliphage (MSC) as a model indicator of enteric viral contamination for Eastern oysters and hard-shelled clams (quahogs) and for assessing relay and depuration viral removal kinetics. The specific objectives are as follows:

1. Determine the relationships between water temperature-influenced seasonal levels of norovirus (NoV), MSC and fecal coliforms (FC) in Eastern oysters (Crassostrea virginica) and hard-shelled clams (Mercenaria mercenaria) harvested from a mid/southerly New England estuarine system such as the Taunton River-Mount Hope Bay estuarine system, Mass.;

2. Determine relative NoV, MSC and FC elimination (reduction) kinetics during relay and depuration as they relate to water temperature and season.

Methodology: 

Seasonal levels of MSC and NoV will be determined in hard-shelled clams and Eastern oysters from southern New England waters, and the elimination rates of MSC and NoV from the shellfish will be determined under seasonal environmental conditions using relay and depuration. A Single Lab Validation for detecting MSC levels in hard-shelled clams will be conducted and submitted to the ISSC for review and adoption to alleviate a barrier and allow the method to be used in regulatory and private labs. Field experiments will involve monthly collection and analysis of hard-shelled clams and oysters from selected areas near the WWTP outfall in the Taunton River, MA. Shellfish will be analyzed for MSC, fecal coliforms (FC) and NoV. Three relay and depuration experiments will be conducted in June-August. Shellfish will be relayed to approved shellfish growing areas in Mt. Hope Bay for 2 weeks, and depuration will take place in tanks at Spinney Creek Shellfish (SCS) using disinfected, natural seawater at ambient temperatures for 2 to 30 days, depending on temperature and initial MSC levels. All relay and depuration samples will be analyzed for MSC, FC and NoV. Maps of candidate areas for strategic openings and educational materials on the study and public health issues will be developed for use in outreach and presentations.

Accomplishments: 

2015

N.H. Sea Grant researchers help state of Connecticut re-open shellfish beds more quickly after viral contamination

N.H. Sea Grant researchers facilitated the duplication of lab analyses in 2015 that helped the state of Connecticut to re-open shellfish growing areas more quickly after viral contamination, thus allowing for faster economic rebound within the state's aquaculture industry.
Relevance: N.H. Sea Grant research determined that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish located near wastewater treatment plants. In 2015, a series of small leaks and breaks in multiple sewage collection systems in Connecticut forced the closure of a large part of the state's shellfish growing areas, thus impacting the Connecticut aquaculture industry. The state's shellfish program tried to re-open areas using MSC sample analyses, but elevated MSC levels were apparent in the first round of laboratory analyses.
Response: N.H. Sea Grant researchers funded by a NOAA Sea Grant Aquaculture Research National Strategic Investment facilitated the duplication of sampling efforts in 2015 to see if a different certified lab using MSC analyses found the same elevated results.
Results: The second lab results indicated low MSC levels at all sampling sites, and a review of the Conn. laboratory data suggested a subtle cross contamination problem that biased the first lab's results. The result of this investigation allowed the state of Connecticut to re-open the shellfish growing areas and get the industry back in business in fewer than 21 days.

N.H. research leads to integration of viral indicator into national shellfish sanitation guide

In 2015, based on their determination that male-specific coliphage is an effective indicator of viruses in shellfish beds located near wastewater treatment plants, N.H. Sea Grant researchers worked with a working group from the Interstate Shellfish Sanitation Conference to integrate male-specific coliphage into the National Shellfish Sanitation Program Guide.
Relevance: N.H. Sea Grant researchers funded by a NOAA Sea Grant Aquaculture Research National Strategic Investment determined that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish beds located near wastewater treatment plants. The Interstate Shellfish Sanitation Conference held an informational meeting about MSC that was based on the results of this study.
Response: In 2015, the MSC working group from the Interstate Shellfish Sanitation Conference Growing Area Committee worked out the details to effectively integrate MSC into the National Shellfish Sanitation Program Guide, particularly in Chapter IV (Growing Areas) and Chapter V (Relay), with additional work ongoing to incorporate the findings into Chapter XV (Depuration). The researchers and partners spent a substantial time in conference calls and attending the conference meeting in October 2015 working through the results of the research project.
Results: The incorporation of MSC research results into the National Shellfish Sanitation Program Guide indicates its acceptance as an assessment tool for wastewater treatment plants and their potential impact on nearby shellfish beds. This research is helping to frame policy changes that will better protect human health.

N.H. Sea Grant researchers determine UV treatment decreases contamination in oyster beds near wastewater treatment plant

In 2015, N.H. Sea Grant researchers funded by a NOAA Sea Grant Aquaculture Research National Strategic Investment used bacterial indicators to determine that a UV treatment system installed in a Connecticut wastewater treatment facility helps to control viral contamination from entering nearby oyster beds, thus protecting human health and the aquaculture industry
Relevance: The Stratford Water Pollution Control Facility (WPCF) has an outfall that is located adjacent to Connecticut's Housatonic River. There has been concern over possible viral contamination of oysters located in beds near this outfall.
Response: The Stratford WPCF recently installed an ultraviolet treatment system to improve water quality treatment and decrease risk of viral contamination in shellfish near the outfall. In 2015, N.H. Sea Grant researchers funded by a NOAA Sea Grant Aquaculture Research National Strategic Investment tested the oysters near the Stratford WPCF outfall using male-specific coliphage (MSC), an indicator for viral contamination.
Results: Researchers found that MSC levels were very low in oysters near the Stratford WPCF, indicating that the newly installed UV treatment systems are doing a good job of controlling viral contamination in nearby oyster beds. This information provides a better understanding of pollution treatments that will reduce the likelihood of shellfish bed closures and human illness.

2014

N.H. research informs decisions to use viral indicator as shellfish assessment tool to protect human health
N.H. Sea Grant research informed policy decisions about using male-specific coliphage, a viral indicator, as an assessment tool for wastewater treatment plants and their potential impact on nearby shellfish beds. These policies help to protect human health.
RELEVANCE: In the Northeastern U.S., many acres of productive shellfish growing waters are permanently closed to aquaculture and harvesting activities due to concerns associated with human fecal pollution from municipal wastewater treatment plant outfalls.
RESPONSE: N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative determined that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish beds located near wastewater treatment plants. The Interstate Shellfish Sanitation Conference (ISSC) held an informational meeting in 2014 about MSC that was based on the results of this study.
RESULTS: As a result of this meeting, the ISSC Growing Area Classification Committee agreed that MSC should continue to be used as an assessment tool for evaluating the impacts of raw untreated sewage discharged from large community sewage collection systems or wastewater treatment plant failures. They support the usage of MSC sampling data to determine viral wastewater treatment plant performance, recognizing that it could also be used to verify viral persistence in shellfish meats harvested from growing areas adjacent to waste treatment facilities for depuration and relay harvesting. Lastly, the Committee also supported the usage of MSC in conjunction with fecal coliform in effectiveness studies and process controls for relaying, container relaying and depuration facilities.

Research on shellfish viral indicator allows companies to expand shellfish harvest areas and increase job opportunities
N.H. Sea Grant researchers helped to inform the development of a container relay post-harvest treatment approach that allows shellfish depuration companies to harvest clams, leading to increased economic benefits for companies and job opportunities for clam diggers.
RELEVANCE: In the Northeastern U.S., many acres of productive shellfish growing waters are permanently closed to aquaculture and harvesting activities due to concerns associated with human fecal pollution from municipal wastewater treatment plant outfalls.
RESPONSE: N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative studied methods of detecting viruses in shellfish beds to protect human health. Their research indicates that male-specific coliphage (MSC) can serve as an effective indicator for shellfish viruses, particularly in areas near wastewater treatment facilities.
RESULTS: The NHSG research informed the decision by the Maine Department of Marine Resources to open the Presumpscot River for soft-shell clam harvesting in 2014 with the use of a MSC-based program that includes post-harvest shellfish purification. This has allowed harvesters with access to depuration facilities, including Spinney Creek Shellfish Company in Eliot, Maine, to harvest clams in previously closed areas, sustaining 20 jobs and two businesses, and creating nine new harvester positions and one business. Overall, 4000 bushels of clams were harvested valued at $480,000.

N.H. researchers find low levels of shellfish viral indicator in areas prohibited for harvesting
Previous research indicates that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish located near wastewater treatment plants. In 2014, N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative found that MSC levels in shellfish are low in three areas of Mass. and Conn. that are currently classified as prohibited for shellfish harvesting. These areas were previously observed to have elevated levels of fecal-borne bacterial contamination, but recent upgrades to wastewater treatment facilities may have led to decreased discharge of MSC. This research will help shellfish managers improve their ability to assess shellfish beds for potential contaminants, allowing for seasonal harvesting with post-harvest processing in previously closed areas.

N.H. research leads to collaboration on single lab validation to detect shellfish viral indicator in wastewater
N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative studied male-specific coliphage (MSC) and its impact on shellfish beds in New England. Based on this research, the U.S. FDA and Spinney Creek Shellfish Company began collaborating in 2014 to conduct a single lab validation of a method to detect MSC in wastewater. This method will help scientists to evaluate differential wastewater samples from influent and effluent to determine the de-activation rate of viruses through a specific wastewater treatment facility. This MSC method for wastewater has far-reaching potential to improve water quality adjacent to wastewater treatment facility outfalls, leading to implications for shellfish, swimming beaches and public health.

N.H. research offers basis for meeting to discuss shellfish viral indicators
N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative studied male-specific coliphage (MSC) and its impact on shellfish beds in New England. The Interstate Shellfish Sanitation Conference (ISSC) held an MSC informational meeting in 2014 that was based primarily on the results from this study. The meeting offered the opportunity for MSC experts, academics, and scientists to present current information and science on MSC and to develop recommendations for the Growing Area Classification Committee. This research will help experts to determine the best assessment tool to detect viruses in shellfish beds.

N.H. researchers collaborate with Connecticut Bureau of Aquaculture to advance shellfish management techniques
Research funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative indicates that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish located near wastewater treatment plants. N.H. researchers discussed their results and methods with state agencies in Connecticut to help improve their understanding of using MSC as a shellfish harvest management tool. In 2014, researchers began working with the Conn. Bureau of Aquaculture to determine the potential for using MSC studies to demonstrate the feasibility of relaying oysters for eliminating risks from viral contaminants under specific environmental conditions in portions of the lower Housatonic River. These interstate coordination efforts will help advance the spread of new management techniques to help reduce the extent of permanently closed shellfish growing areas due to proximity to wastewater treatment facility discharges.

N.H. research improves understanding of microorganism bio-accumulation in four shellfish species
N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative studied male-specific coliphage (MSC) and its impact on shellfish beds in New England. In 2014, researchers detected differences in MSC levels compared to fecal coliform levels in four shellfish species: soft-shelled clams, quahogs, American oysters and European oysters. Their results indicate that quahogs and European oysters bio-accumulated both fecal coliform and MSC to levels comparable to soft-shelled clams. However, American oysters do not bio-accumulate MSC as readily as soft-shelled clams or quahogs under similar conditions. This research will help scientists and shellfish managers to improve their understanding of how shellfish accumulate microorganisms in comparison to one another during similar environmental conditions.

2013

Research leads to changes in policies for increasing shellfish aquaculture opportunities
The Interstate Shellfish Sanitation Conference is changing policies for using male-specific coliphage to manage shellfish growing areas and harvesting of shellfish near wastewater treatment plant discharge.

RELEVANCE: Many acres of shellfish beds remain permanently closed in the Northeastern U.S. due to concerns about the reliability of male-specific coliphage (MSC) as an indicator of virus contamination in shellfish near wastewater treatment plant effluent.

RESPONSE: With funding provided by the NOAA Sea Grant Aquaculture Research National Strategic Initiative (NSI), N.H. Sea Grant researchers conducted studies to determine the efficacy of using MSC as an indicator of virus contamination in shellfish near wastewater treatment plant discharge. Their results showed that MSC is a more appropriate indicator for this than fecal coliform levels, the previous method used to determine the presence of viruses in shellfish meat.

RESULTS: Based on data results from this research, the Interstate Shellfish Sanitation Conference (ISSC) adopted and integrated a method for detecting MSC in quahogs into the National Shellfish Sanitation Program (NSSP) guidance document. Research results are also serving as the basis for four more MSC-related proposed policy changes that are currently being considered.

Approval of shellfish virus indicator based on N.H. Sea Grant research leads to increased employment opportunities
N.H. Sea Grant-funded research on shellfish virus indicators has led to increased employment opportunities for shellfish harvesters and laboratory technicians trained to run detection tests that ensure shellfish safety.

RELEVANCE: Male-specific coliphage (MSC) has been previously approved for use in detecting virus contamination in American oysters and softshell clams. However, MSC was not approved as a viral indicator in quahogs, a commercially and recreationally important species in the Northeast U.S.

RESPONSE: Based on N.H. Sea Grant research, the Interstate Shellfish Sanitation Conference adopted a proposal regarding the usage of MSC as an indicator for viruses in quahogs, approving MSC for limited use in microbiological testing.

RESULTS: Spinney Creek Shellfish Inc. has been able to harvest shellfish in more areas as a result of this research, thus increasing the employment opportunities for lab technicians and additional shellfish harvesters.

Research identifies more accurate indicator of shellfish viral contamination near wastewater treatment facilities
In the Northeastern U.S., many acres of productive shellfish growing waters are permanently closed to aquaculture and harvesting activities due to concerns associated with human fecal pollution from municipal wastewater treatment plant outfalls. Fecal coliform (FC) levels often dictate the size of shellfish growing and harvesting areas, yet research has previously demonstrated that FC levels are often unrelated to and not indicative of virus contamination in shellfish. With funding provided by the NOAA Sea Grant Aquaculture Research National Strategic Initiative, N.H. researchers examined the relationship between seasonal levels of FC, norovirus and male-specific coliphage (MSC) in oysters and hard-shelled clams harvested from mid/southern New England estuaries affected by wastewater treatment plant effluent. The 2013 results indicate that MSC is a more accurate indicator of viral contamination in shellfish than FC. This research will help shellfish managers to better understand seasonal impacts on shellfish virus contamination and effectiveness of various viral indicators, and thus potentially lead to the re-opening of previously closed, highly productive shellfish growing areas near wastewater effluent discharges.

N.H. researchers collaborate with state agencies to advance shellfish management techniques
Despite previous uncertainties, research funded by a NOAA Sea Grant Aquaculture Research National Strategic Initiative indicates that male-specific coliphage (MSC) is an effective indicator of viruses in shellfish located near wastewater treatment plants. In 2013, N.H. researchers discussed their results and methods with state agencies in N.J., R.I., Conn. and Wash. to help improve their understanding of using MSC as a shellfish harvest management tool. Although the main focus was on Taunton River and Salem Sound in Mass., researchers also consulted with the state of Conn. on their plans to use MSC as a viral indicator of sewage contamination to reclassify sections of the Housatonic River, a historically productive shellfish growing area, from “prohibited” harvest to “restricted for relay.” Researchers are also working with the N.H. Department of Environmental Services shellfish program to test blue mussels in aquaculture and relay sites for MSC and viruses. These inter- and intra-state coordination efforts will help advance the spread of new management techniques to help reduce the extent of permanently closed shellfish growing areas due to proximity to wastewater treatment facility discharges.

N.H. researchers expand study areas and species to improve understanding of viral accumulation in shellfish
Many of the highly productive shellfish beds in the Northeastern U.S. remain closed to harvest due to concerns about the impacts of nearby wastewater treatment plant effluent. Research funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative focused on the efficacy of various indicators to more accurately assess virus contamination and mitigation strategies in shellfish. In 2013, N.H. researchers expanded their study area to include two new sites in Mass. and on the border of N.H./Maine. They have also expanded the number of species they are studying by two to include European oysters and soft-shelled clams. These additions to the study areas and species will help resource managers gain a clearer understanding of the dynamic nature of viral accumulation and depuration in shellfish growing in areas near wastewater treatment plant effluent.

N.H. Sea Grant research indicates cold water impacts on shellfish species’ ability to bioaccumulate viruses
In 2013, N.H. Sea Grant researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative studied the effects of seasons on the ability of various shellfish species to depurate virus contamination from wastewater treatment plant effluent. Their research indicated that different shellfish species have different behavior relative to bioaccumulation and depuration of MSC and viruses during cold (

N.H. Sea Grant research leads to review of shellfish aquaculture policies to expand harvest opportunities
The Interstate Shellfish Sanitation Conference (ISSC) is currently reviewing shellfish aquaculture policies to determine what changes need to be made to improve virus detection in shellfish beds. Fecal coliform levels have historically been used to set permitted areas for shellfish growing and harvesting, but 2013 N.H. Sea Grant research has shown that male-specific coliphage (MSC) is a better indicator for shellfish virus contamination in areas affected by wastewater treatment facility effluent. Using research findings from this project to inform their decisions, the ISSC is currently reviewing several key policies that relate to the use of MSC for expanding areas and time for shellfish harvest opportunities. By furthering the progress of key shellfish aquaculture policies that are under consideration, NHSG research will have a positive impact on aquaculture development, quality assurance processes and consumer confidence related to shellfish in the U.S.

New working group and summit to address shellfish virus detection based on N.H. research
In 2013, N.H. Sea Grant-funded research focused on the use of male-specific coliphage (MSC) to detect viruses in shellfish and addressed previous uncertainties surrounding its usage as an indicator. Their study findings have provided a significant basis for the development of a MSC Summit organized by the Interstate Shellfish Sanitation Conference (ISSC) to review all scientific knowledge and potential applications of MSC related to shellfish viruses. The researchers have been asked to participate in a related expert working group regarding MSC as well. The summit and working group will lead to improved discussion surrounding methodologies for virus detection and change present policies to reduce the extent of permanently closed shellfish growing areas in U.S. waters.

N.H. Sea Grant research helps FDA assess wastewater treatment plant performance with respect to shellfish viruses
Many acres of productive shellfish growing waters are permanently closed to harvesting and aquaculture activities due to concerns over their proximity to human fecal pollution from wastewater treatment plants outfalls. Although fecal coliform levels have been previously used to set these closure area boundaries, NHSG-funded research has determined that male-specific coliphage (MSC) is a more accurate indicator for the presence of viral contamination in shellfish. These 2013 research findings have helped provide the FDA with the scientific knowledge to further their development of using MSC as a modeling organism to determine wastewater treatment plant performance with respect to viruses. The study findings will also support discussions between the FDA and the EPA pertaining to improving wastewater treatment plant performance, and thus potentially improve water quality and shellfish safety in proximity to these treatment plants nationwide.

N.H. Sea Grant research results used by FDA to address shellfish harvest near wastewater treatment plants
In 2013, N.H. researchers funded by the NOAA Sea Grant Aquaculture Research National Strategic Initiative found that male-specific coliphage (MSC) is a reliable indicator for virus contamination in shellfish grown near wastewater treatment plant outfalls. These results were used by the FDA to aid in the development of using MSC to determine wastewater treatment plant performance. This research also inspired state agencies in Mass. and R.I. to partner with the FDA and begin dilution studies in two wastewater treatment plants in their own states. Their results, coupled with N.H. research, may allow states to re-classify a shellfish bed from “prohibited” from harvest to a classification that allows seasonal harvesting near treatment plants.