Comparison of poliovirus detection in sewage and stool samples; a study in a crèche in the third week after vaccination.

In a model experiment conducted in a Prague crèche, the detection rate for polioviruses in partially purified, non-concentrated sewage as sampled by means of gauze pads (Moore's method) was compared with that for individual stool samples. In the third week after the vaccination of children with live attenuated type 1 poliovirus (March 1975) and at an equal interval after their vaccination with a combination of types 2 and 3 (May 1975), corresponding poliovirus types were detected both in individual stool samples and sewage. The mean amount of sewage virus recovered during one week was directly proportional to the percentage of positive stool samples. After combined type 2 and 3 poliovirus administration, however, both types were only detected in one sewage sample, while in two samples type 3 only, and in one sample type 2 only, were identified. The results of the study indicate that poliovirus is detectable in sewage by the method employed if it is excreted by approximately one per cent of persons in the sewer catchment area of a small community. If a number of antigenic types are simultaneously present, their identification requires systematic examination of the sewage.