Comparative Evaluation of Human Norovirus Inactivation by Sodium Hypochlorite Using Zebrafish Embryos and iPSC-derived Human Intestinal Organoids

Changsun Choi, Chung-Ang University

Danbi Yoon1, Daseul Yeo1, Hyojin Kwon1, Seongwon Hwang1, Dong Jae Lim1, Songfeng Jin1 Changsun Choi1,* 1Department of Food and Nutrition, College of Biotechnology and Natural Resources, Chung-Ang University, 4726, Anseong, Gyeonggi-do 17546, Republic of Korea.

Food & Environmental Virology-I (Food)

Human norovirus (HuNoV) is a common global pathogen of acute gastroenteritis and a major public health issue, causing significant morbidity and mortality in all age groups. To control HuNoV outbreaks, sodium hypochlorite is the commonly used disinfectant in food safety and environmental hygiene. However, the virucidal efficacy of sodium hypochlorite against HuNoV may differ considerably depending on the cultivation model employed. This study aims to evaluate and compare the inactivation of GII.4[P16] strains by sodium hypochlorite using zebrafish embryo models and iPSC-derived human intestinal organoid (HIO). Viral inactivation was assessed via RT-qPCR through comparison of viral RNA levels at 3 and 72 hpi, to confirm replication in each cultivation model. In zebrafish embryo models, approximately 8 log gc/mL of GII.4[P16] virus was reduced to below the detection limit (LOD; 6 log gc/mL) by treatment at 50 ppm for 1 min. In contrast, in HIOs models, viral RNA levels were reduced below the detection limit (LOD; 4 log gc/mL) at 100 ppm for 1 min. However, treatment with 50 ppm allowed viral replication up to 4 log gc/mL. At high HuNoV titers, both cultivation models can be used to compare inactivation efficacy. According to our results, effective concentration of sodium hypochlorite is estimated to range from 100 to 150 ppm. Further studies are required to develop methods for assessing the efficacy of disinfectants against HuNoV at low viral titers.