No abstract

No abstract

A collaborative virological survey of drinking water was initiated in three major Canadian urban areas, Montreal, Ottawa, and Toronto. In each selected area, three water purification plants were sampled monthly for up to 18 months. The total population served by all nine plants was about 1 500 000. Samples of raw (100 L) and treated (1000 L) water were examined by virus concentration procedures based on adsorption-elution. Sample concentrates were assayed for cytopathic viruses on BS-C-1 cells and the results were expressed as the most probable number of cytopathic units (MPNCU). Viruses were detected in 57% (0-15.35 MPNCU/L) of the raw water samples from Montreal, 37% (0-46.0 MPNCU/L) in Ottawa, and 33% (0-4.91 MPNCU/L) in Toronto. The majority of isolates were reoviruses, but picornaviruses were also found. All finished waters (177 samples) met bacteriological, turbidity, and residual chlorine standards and were free of detectable viruses.

No abstract

Reference antisera to established prototype enterovirus strains failed to neutralize three enterovirus isolates which were recovered from clinical specimens. Hyperimmune rabbit serum to one of the isolates neutralized the prototype coxsackie B6 strain as well as t~he three isolates. Kinetic neutralization tests confirmed the one-way cross reaction and it was concluded that the isolates are prime strains of eoxsackie B6 virus, a virus for which antigenic variants have not been reported so far. Since the co~saekie B 6 serotype has never been encountered in Ontario, the prevalence of antibodies to the isolate was studied by e~amining 382 human sera from our collection of patients' sera. Approximately 10 per cent of the sera contained antibodies to the isolate but cross reactivity with the prototype strain was seen only when the titre against the prime strain was very high.