Chapter Twenty-Two - Methods for the Detection of Waterborne Viruses

Abstract

This chapter focusses on detection of waterborne viruses which is more complex than detection of other microorganisms because of difficulties in concentrating the sample and then in detecting the virus by cell culture or molecular biological means. With the exception of sewage, where the quantity of virus present may be sufficient to permit detection without further concentration, viruses in water are too dilute to be detected by direct analysis. The concentration techniques include adsorption, entrapment, hydroextraction, and ultra-centrifugation. The concentrate may be inoculated into cell cultures to detect infectious virus and if this is done in a quantitative fashion any virus present can be enumerated, the count being reported as plaque-forming units (pfu), tissue culture infectious doses (TCD50), or MPN units. Where necessary virus can be isolated and identified from the cell cultures. Viruses which do not produce an identifiable cytopathic effect in culture may nevertheless be detected by immunoperoxidase or immunofluorescence staining.