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Protozoan Contaminants in Shellfish

Investigators
Ortega, Ynes
Institutions
University of Georgia
Start date
2003
End date
2006
Objective
It is proposed to evaluate microscopy based and PCR methods to determine the most sensitive technique for detecting parasites in laboratory contaminated shellfish and further compared using samples collected through surveys of the US East coast areas where protozoan contamination of oysters was previously reported. Surveys will also be performed in Peru, a Latin American country that exports shellfish and crustaceans into the U.S.
More information
Outbreaks of shellfish-associated infection have been reported for more than a century. Oysters contaminated with protozoan parasites have been reported from the Eastern coast of the U.S. representing a potential public health concern but also the potential of using shellfish as biological markers of water contamination. It is proposed to evaluate microscopy based and PCR methods to determine the most sensitive technique for detecting parasites in laboratory contaminated shellfish and further compared using samples collected through surveys of the US East coast areas where protozoan contamination of oysters was previously reported. Surveys will also be performed in Peru, a Latin American country that exports shellfish and crustaceans into the U.S. These surveys will include the assessment of several environmental variables as predictors or indicators of contamination, such as season of the year, average monthly temperature and precipitation, ocean temperature and water salinity and turbidity. Inactivation of protozoan parasites will be evaluated using three shellfish sanitation procedures and disseminate the information with members of the shellfish industry and food safety community via workshops printed material and seminars.

This study will address several environmental variables as predictors or indicators of contamination of shellfish by protozoan parasites. Inactivation methodologies will be evaluated and outreach efforts for shellfish farmers and harvesters will be implemented.

The objectives of this project will be accomplished by:
Evaluation of current isolation and detection methods of Cryptosporidium, Giardia, Toxoplasma, and Cyclospora in laboratory contaminated oysters.
To determine the viability for Cryptosporidium and Giardia will be determined by RT-PCR, and Cyclospora by sporulation.
Survey shellfish at the points of harvest and sale to assess the presence of parasites and their viability.
Validate the most efficient isolation and detection methods using samples collected from surveys of the Chesapeake Bay and the Georgia coast, and overseas.
Evaluation of sanitation methods for reducing microbial loads in shellfish at high and low temperatures. Information gathered in this investigation will be disseminated through a yearly summer workshop to educate food safety professionals, shellfish producers or students to be held at the Center for Food Safety, University of Georgia.
Establish an outreach program to disseminate information to producers and harvesters of shellfish on parasites associated to shellfish contamination and establish a training program for visiting scientists. A bilingual web site will be implemented with practical information about parasites in oysters.

This project will provide an estimate of the presence of parasites in shellfish commercialized for human consumption and its association to the risk of acquiring the infection. Shellfish are also being used as indicators to determine the coastal water contamination by animal and human waste.

Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
View this project
Project number
GEO-2003-04314
Accession number
196885
Categories
Parasites
Natural Toxins
Viruses and Prions
Bacterial Pathogens
Chemical Contaminants
Education and Training
Cryptosporidium
Commodities
Seafood