COMPARISON OF IMMUNOLOGICAL AND MOLECULAR HYBRIDIZATION DETECTION METHODS FOR THE DETECTION OF HEPATITIS-A VIRUS IN SEWAGE

Immune electron microscopy (IEM), radioimmunoassay (RIA) and molecular hybridization with a digoxigenin-labelled cDNA probe were compared fo r the detection of wild-type human hepatitis A virus (HAV) in raw and treated sewage. In the same experiments, classic tests for culturable enteroviruses were carried out. With the hybridization probes, HAV was detected in three of the 13 affluent samples (23%) and in eight out o f 13 effluent samples (61%). For four of the effluent samples, positiv ity revealed by IEM was confirmed by the cDNA probe. In contrast, two of the samples shown as positive by IEM were negative with the probes. Detection of HAV by RIA was negative in all cases. Demonstration of H AV was higher in effluent than in affluent. No particular relationship was established between demonstration of HAV, on the one hand, and th e various concentrations of enteroviruses observed in the same samples on the other. Overall, if all the results, irrespective of the type o f water (affluent or effluent), are taken together, 50% of the sewage samples tested were found to contain HAV by one or another method of d etection.