Metcalf, T. G. and W. C. Stiles (Univ. of New Hampshire, Durham, N. H. 03824). Enteroviruses within an estuarine environment. Amer. J. Epid., 1968, 88: 379–391—A 4 year study of virus isolates recovered in cell cultures from sewage effluents, seawater and shellfish showed enteroviruses discharged in sewage effluent to pass into shellfish growing waters via tributary rivers. The occurrence of potentially pathogenic human viruses in oysters followed dissemination of virus pollution into estuary waters. Virus uptake by oysters occurred quickly following the appearance of virus in environmental seawater. A true picture of enterovirus prevalence in the estuary was obtained only by examination of both oysters and seawater. Virus-free oysters remained free from enterovirus when placed in virus polluted waters at temperatures below 7 C. Virus-carrying oysters immersed in estuary waters with temperatures less than 7 C retained fully infectious enterovirus for at least 4 months during the winter season.