ABSTRACT
This chapter reviews some topics concerning viral depuration and relaying: the important human enteric viruses potentially present in fecally contaminated shellfish, the illnesses they cause and their sources, and the epidemiological evidence, especially in the US, that shellfish have caused viral illness. The topics also includes: the factors influencing viral persistence in shellfish habitats; the factors influencing viral uptake and persistence in shellfish; the factors influencing the subsequent elimination of viruses under depuration and relaying conditions. The chapter summarizes the state of knowledge and understanding of viral contamination of bivalve molluscan shellfish, the role of these seafoods in the transmission of enteric viral disease, and the control of viral contamination of shellfish by depuration and relaying. In addition to mollusks, crustaceans also accumulate viruses. Elimination of viruses and other microbial contaminants from shellfish appears to be a result of active elimination as a primary mechanism and physical inactivation of viruses as well.
