Measurement of the virolysis of human GII.4 norovirus in response to disinfectants and sanitisers

The aim of this study was to develop a method for investigating the stability of the human NoV capsid in response to disinfectants and sanitisers (virucides) as an indirect method for determining virus infectivity. Capsid destruction or “virolysis” was measured using the reverse transcribed quantitative PCR (RT-QPCR) reaction in conjunction with RNase treatment (in order to destroy any exposed RNA). Two commercially available alcohol based handwashes, alcohols (75% (v/v) ethanol or isopropanol), quaternary ammonium compounds (0.14% BAC or 0.07% DIDAC), and chlorine dioxide (200 ppm) were all ineffective at promoting virolysis of human norovirus present in dilute clinical samples at the concentrations tested. GII.4 NoVs were sensitive to a combination of heat and alkali. These data show that NoVs present in dilute stool samples are resistant to virolysis using virucides that are used commonly.