Enterovirus Isolations from Sewage Comparison of Three Methods

A total of 108 sewage samples from 8 selected areas were prepared by 3 methods for inoculation into monkey kidney tissue culture. A total of 61 viruses were isolated: 55% by the unconcentrated and resin methods and 94% by the centrifuge method. Comparison of the methods showed that the centrifuge method yielded poliovirus and mixed isolates with the highest frequency. The methods differed in the efficacy with which they yielded isolates from samples known to contain virus. Twenty-four samples were positive by all 3 methods. From 16 samples found positive by the centrifuge method, only 10 were positive by the unconcentrated method, while the remaining 6 were positive by the resin method. Seventeen samples were found positive by the centrifuge method alone and 4 by the resin method alone.