| Summary: | Hoff, J. C. and R. C. Becker (Northwestern Water Hygiene Lab., Rt. 4, Box 4129, Gig Harbor, Wash. 98335). The accumulation and elimination of crude and clarified poliovirus suspensions by shellfish. Amer. J. Epid. , 1969, 90: 53–61.— The accumulation and elimination of Escherichia coli and poliovirus type 1 (LSc2ab) by the Olympia oyster ( Ostrea lurida ), Pacific oyster [ Crassostrea gigas ), and Manila clam ( Tapes japonica ) were studied in a flowing seawater system. E coli and crude virus preparations containing cell debris were concentrated by all three species to much higher levels than were clarified virus suspensions from which the larger particulate matter had been removed. Virus accumulation ratios (concentration in shellfish/concentration in water) ranged from 10- to 900-fold with the use of crude virus and from 0.4- to 3.6-fold with clarified virus preparations. Both crude and clarified virus preparations were eliminated by the shellfish at similar rates. Virus concentrations declined rapidly during the first 24 hours, then continued to decline more slowly. Clarified virus was usually eliminated to indetectable levels within 48 hours whereas crude virus, originally accumulated to much higher levels, was frequently detectable after 72 or 96 hours. The results indicate that the state in which viruses exist in natural waters, i.e., whether they are present as free particles or attached to larger particulate matter, is an important consideration in assessing the potential of shellfish for the transmission of enteroviruses.
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