[Importance of the results of a virological examination of sewage. A quantitative evaluation of the finding of enteroviruses in sewage].

In order to evaluate quantitatively the effectiveness of virological examinations of sewage, a labeled virus in a dose of 7.5X10(9) PFU was introduced into the canalization system of a community. Such an amount of virus could be found in the canalization system if 5--10% of the residents would excrete it simultaneously. The labeled virus was selectively detected in the community sewage. This procedure has demonstrated that the routine methods for sewage collection, specimen treatment, and virus isolation permit virus detection when 5--10% of this virus excretors are available. The labeled virus entered the canalization system most actively within the first 2 hours after administration, then its amount declined, and within 24 hours ceased. The labeled virus was found on all swabs which were in the sewage flow since the time of administration to the 7th day. The maximum amount of virus was found on the swab which was in the sewage flow for the first 2 hours after virus administration. By 7 days the amount of labeled virus on swabs decreased 10-fold. Under experimental conditions, in sewage kept at 25 degrees C enteroviruses of the group of poliomyelitis, ECHO, and Coxsackie had approximately similar inactivation rate (0.16--0.22 Ig TCD50 per day) and the half-life period (1.3 days), that is, in 7 days the virus titer on a swab should decline by 1.0--1.5 Ig TCD50.