The overarching goal of the proposed project is to adapt and validate effective methods for detection of (viable) shellfish-borne protozoan pathogens, and construct a risk-based model for identifying key steps in the management, production, distribution, and preparation of shellfish to minimize illness in consumers.Towards this goal, four specific objectives will be completed:Objective 1. Adapt and validate sensitive molecular detection methods for simultaneous detection of foodborne protozoan pathogens, including Cryptosporidium, Giardia, Toxoplasma, and Cyclospora in oysters and water.Objective 2. Adapt and validate quantitative molecular detection methods that differentiate viable from nonviable foodborne protozoan pathogens, including Cryptosporidium, Giardia, Toxoplasma, and Cyclospora in oysters and water.Objective 3. Optimize and validate a sampling approach for sensitive detection of protozoan pathogens by evaluating presence and depuration of parasites in different oyster tissues.Objective 4. Develop a risk-based approach to evaluate or develop economical and adoptable control strategies aimed at reducing the incidence of shellfish-borne illness during production, harvest, post-harvest storage, distribution, and preparation.