Processing and Control of Human Norovirus and Surrogates in Engineered Water Reuse Systems

human norovirus;virus purification;disinfection;wastewater;leafy greens;murine norovirus;Environmental Health & Engineering

Dunkin, NathanShiff, Clive J ;

Johns Hopkins University

关键词: human norovirus;    virus purification;    disinfection;    wastewater;    leafy greens;    murine norovirus;    Environmental Health & Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/60862/DUNKIN-DISSERTATION-2017.pdf?sequence=1&isAllowed=n

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Human noroviruses (hNoVs) are the number one cause of acute gastroenteritis outbreaks globally across all age groups. However, our knowledge of the environmental persistence of hNoVs has been hampered by the lack of cell culture model suitable for environmental studies. As a result, researchers have relied primarily on hNoV reverse-transcription quantitative PCR (RT-qPCR) signals or infectivity of cultivable surrogate viruses such as murine norovirus (MNV) as estimates of hNoV infectivity. Furthermore, investigators have historically studied hNoVs and surrogate viruses in their native matrices (diluted stool and growth media, respectively) despite the fact that these matrices possess high organic loads that could bias viral persistence outcomes. The objective of this dissertation research was to characterize and select optimal methods for virus preparation, and to apply these methods to study the efficacy of existing and novel disinfectants to reduce hNoVs and surrogates in municipal wastewater and industrial leafy green wash water. Results indicate that advanced purification of hNoVs and mammalian surrogates by sucrose cushion purification (or related density-based separation approach) is warranted prior to seeding in order to reduce 15-second chlorine demands by 99% and total organic carbon by 93% in experimental water matrices. In wastewater, viral RT-qPCR reductions by monochloramine and peracetic acid (PAA) were less than 0.5 log10 for hNoVs and surrogates at concentrationtime (CT) values up to 450 mg-min/L except for hNoV GI, where 1 log10 reduction was observed at CT values of less than 50 mg-min/L for monochloramine and 200 mg-min/L for PAA. In leafy green wash water, free chlorine CT values for 2 log10 molecular reduction of hNoV GI in whole leaf and chopped romaine wash waters were 1.5 and 0.9 mg-min/L, respectively. For hNoV GII, CT values were 13.0 and 7.5 mg-min/L, respectively. These results indicate that hNoVs likely exhibit genogroup dependent resistance and that disinfection practices targeting hNoV GII will likely be protective for hNoV GI. The data generated in this dissertation will help researchers limit bias in future studies on viral persistence and will inform regulators and engineers on wastewater and industrial leafy green operational practices necessary to inactivate hNoVs and protect human health.