Polioviruses and other enteroviruses in urban sewage from Laval (Canada): presence of non-vaccinal strains of poliovirus.

During a 13-month period (August 1, 1977-August 31, 1978) 55 samples of 2-4 L of raw sewage from an urban residential area were collected and studied for the presence of human enteroviruses. Viruses were recovered from 47 (90.5%) of the samples. Of the 201 viral isolates propagated, 180 (89.5%) were identified by the serum neutralization test as poliovirus types 1,2, or 3; 16 (8%) were identified as coxsackie B viruses; and 5 (2.5%) could not be identified by the methods used. While all polioviruses, types 2 and 3 isolates, were vaccine-like (rct-/d-) or intermediate strains, 14 poliovires, type 1 out of 55 selected isolates, were found to be non-vaccine-like (rct+/d+), 8 were rct-/d-), and 33 were intermediate strains. Out of nine samples submitted to the serodifferentiation (McBride) test, six poliovires, type 1 rct+/d+ and three rct+/d-, were related to wild strains.