Inactivation mechanisms of human norovirus surrogate Tulane virus by peracetic acid at different pHs

Many illnesses caused by viruses are spread by water and fresh products, hence it is critical to inactivate viruses in the water disinfection and food sanitation process. To apply a novel disinfectant requires studies to fully explore the inactivation efficacy and mechanisms of that new disinfectant. In this study, we determined the inactivation kinetics and mechanisms of a potential disinfectant named peracetic acid (PAA) on Tulane virus (TV), a surrogate for human norovirus, at pH 7.8, 5.4 and 4.5. No significant difference was observed between the inactivation kinetics under different concentrations and pHs. A 2.5-log10 reduction in TV infectivity was achieved after 10 min exposure at 10 mg/L PAA or 5 mg/L after 20 min exposure. The efficacy is partly impacted by the significant aggregation of TV under these studied pHs. We explored whether the inactivation was caused by the damage of the genome or the protein capsid or both. The genome damage was revealed by quantifying the viral intact genome using the reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR). The capsid proteins degradation is determined by quantifying the viruses with the attachment using a binding assay with designed porcine gastric mucin conjugated with magnetic beads (PGM-MBs). Based on our results, only less than 10% of PAA-exposure TV lost the ability to bind to PGM- MBs. A linear correlation between the reduction of TV and TV NSP1 genes suggested that genome damage is only responsible for approximately 10% of TV inactivation. These results indicated that the combination of the genome and spike protein damage did not fully explain inactivation. The findings in this study would contribute to the design of the conditions for PAA applying in the drinking water and wastewater treatment plant and the food industries.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste

Dry Heat as a Decontamination Method for N95 Respirator Reuse

A pandemic such as COVID-19 can cause a sudden depletion in the worldwide supply of respirators, forcing healthcare providers to reuse them. In this study, we systematically evaluated dry heat treatment as a viable option for the safe decontamination of N95 respirators (1860, 3M) before its reuse. We found that the dry heat generated by an electric cooker (100°C, 5% relative humidity, 50 min) effectively inactivated Tulane virus (>5.2-log10 reduction), rotavirus (>6.6-log10 reduction), adenovirus (>4.0-log10 reduction), and transmissible gastroenteritis virus (>4.7-log10 reduction). The respirator integrity (determined based on the particle filtration efficiency and quantitative fit testing) was not compromised after 20 cycles of 50-min dry heat treatment. Based on these results, we propose dry heat decontamination generated by an electric cooker (e.g., rice cookers, instant pots, ovens) to be an effective and accessible decontamination method for the safe reuse of N95 respirators. </div