Evaluation of ultraviolet irradiation at 254 nm and 222 nm in inactivating human noroviruses on surfaces

Human norovirus (hNoV), the main cause of foodborne illness and non-bacterial gastroenteritis, can be transmitted through human-to-human contact. Indirectly, food or food-related surfaces are readily contaminated by hNoV, completing the transmission route. So far, no standard cultivation tool is available for detecting viable hNoV, resulting in the challenges of evaluating inactivation effectiveness of various disinfection technologies, including UV 222 treatments. The significance of our study lies in attempts to quantify hNoV infectivity loss of four strains using zebrafish model during UV 222 and UV 254 treatments, together with the underlying antiviral mechanisms indicated by three different types of reverse transcription qPCR methods. In addition, the concerns over the possible emergence of variants were subdued by genome-wide sequencing results after consecutive UV exposures and passaging in vivo zebrafish model.