Virus isolations from sewage and from a stream receiving effluents of sewage treatment plants.

In order to detect viruses in sewage or streams, it is first necessary to concentrate the virus present in the fluid sample. Available methods are not readily manageable for concentrating virus from large volumes of fluid, and have not always yielded high recovery rates. In the study described in this paper, a method for concentration of viruses by adsorption on insoluble cross-linked maleic anhydride polyelectrolytes has been utilized to survey the viral flora of sewage and of a stream receiving sewage effluents, in a residential area of Houston, Texas. On a single day the virus flow at different points along the stream varied from 304 000 to 6 014 000 PFU/min. From 84 samples each of 1 US gal, 14 520 isolates were obtained, chiefly echovirus type 7 and polioviruses of all 3 types, some of them with characteristics of virulent wild strains. With virus isolation rates as high as those achieved, it is now possible to monitor virus in natural waters more effectively.