DOAG: Connecticut’s 2013 Vibrio Control Plan

This article appeared in the May 8, 2013 edition of the Ag Report

Connecticut’s 2013 Vibrio Control Plan

Steve Anderson, Office of the Commissioner, and Kristin DeRosia-Banick, Bureau of Aquaculture



On April 30, 2013, the Connecticut Department of Agriculture’s Bureau of Aquaculture hosted a meeting with Connecticut’s shellfish industry members at the Bridgeport Regional Aquaculture Science and Technology Education Center.  The purpose was to provide an update and opportunity for discussion of current regulatory issues facing the industry. 


Both state and federal shellfish regulators gave presentations on best management practices for Vibrio parahaemolyticus, a naturally occurring bacteria found in marine and estuarine waters.  Vibrio thrives in the brackish waters of Long Island Sound and is not associated with a pollution source.  Elevated levels are found in association with warm seawater temperatures. 


Vibrio can pose serious--even fatal--health risks to shellfish consumers if proper handling practices are not followed by harvesters and dealers.  Symptoms of Vibrio related illness can include gastrointestinal distress, abdominal cramping, nausea, vomiting, fever, and chills, all of which usually occur within 24 hours from ingestion.  According to the Centers for Disease Control and Prevention (CDC), the illness is usually self-limiting, typically lasts three days, and severe disease is rare (occurring more in those with weakened immune systems). 


While the CDC estimates that there may be as many as 4,500 cases of Vibrio related illness nationally,  it also states that the number of actual cases may be significantly higher because many go undetected and/or unreported. 


In 2012, according to the Foodborne Diseases and Active Surveillance Network, there were 193 cases of illness, 55 hospitalizations, and 6 deaths reported in the United States due to Vibrio.  The CDC reports that the incidence of laboratory-confirmed Vibrio infections has been on the rise since 1996. 


While there has been a rise nationally in the incidence rates for Vibrio related illnesses, the Connecticut Department of Agriculture’s proactive work with the FDA and state’s shellfish industry has limited confirmed illnesses here in Connecticut to one each year since 2009, staving off any outbreaks (defined as two or more persons from different households with illness)—even while they have occurred in neighboring states. 


An illness outbreak would require emergency shellfish bed closures and recalls of shellfish harvested from affected areas, which could potentially devastate Connecticut’s shellfish industry.


Why has Connecticut been so successful in these efforts?  Simply put, the state Department of Agriculture has been out in front every step of the way, bringing national recognition as a progressive leader in Vibrio management.


The agency’s shellfish program operates as part of the National Shellfish Sanitation Program, a cooperative effort of state, FDA, and industry partners who agree to accept and meet specific responsibilities in order to ensure public safety with regard to shellfish.


Among other requirements, this program requires the state to conduct an annual risk evaluation and, if necessary, implement a mandatory Vibrio parahaemolyticus control plan (VPCP).  


The risk evaluations are based upon the number of illnesses linked to oysters in the state, levels of Vibrio bacteria and pathogenic indicators in the growing areas, water and air temperatures, and the risk factors associated with harvest techniques practiced in Connecticut waters. 


Each Connecticut shellfish industry member must enter into a memorandum of agreement with the Connecticut Department of Agriculture committing to compliance with the 2013 VPCP.  The control plan includes the following:

1. Time/temperature requirements, including placement of oysters harvested for human consumption in a temperature-controlled storage area within five hours after the beginning of harvest during warmer summer months

2. Onboard vessel requirements, including product shading and cooling with seawater from a certified harvest area

3. Post-harvest temperature control measures

4. Specific recordkeeping requirements


The complete 2013 VPCP can be found on the Department of Agriculture’s website at


Success of these control measures is dependent upon the cooperation of Connecticut’s shellfish industry.  The Connecticut Department of Agriculture may shut down an operation for noncompliance with the VPCP if agency officials deem the violation presents a significant risk to public health and safety.


In conjunction with the VPCP for the commercial shellfish industry, the Connecticut Department of Agriculture conducts ongoing monitoring, including evaluation of harvester and dealer compliance, inspections, record reviews, and testing of shellstock for Vibrio levels, as well as outreach regarding the potential for Vibrio in the state via meetings, the agency’s website, and direct communications. 


Agency staff also has presented Vibrio guidance to municipal and regional public health officials and shellfish commission members so that they may educate recreational shellfish harvesters to prevent related illnesses among that population. 


The Department of Agriculture recognizes that even with their comprehensive efforts to ensure Connecticut’s shellfish are safe for human consumption, improvements can be made.  For example, the ability to measure Vibrio levels on a real-time basis at the agency’s laboratory in Milford using polymerase chain reaction technology, which would require an investment of approximately $70,000 in state funds for equipment, would prevent the need to send samples out of state for analysis. 

Should this acquisition be approved, the time saved and additional data gathered would enable the agency to conduct in-state studies and better manage Vibrio related risks, thus keeping more shellfish beds open on an ongoing basis. 


In the coming weeks and months, as water temperatures rise in Long Island Sound, the Connecticut Department of Agriculture will continue to assess its VPCP for both compliance and effectiveness.  The agency is committed to making any changes necessary to ensure that Connecticut’s shellfish remains safe, and that the industry continues to be a viable and productive part of the state’s economy. 


For more information about the Connecticut Department of Agriculture’s Bureau of Aquaculture and the state’s shellfish industry, visit