Evaluating Efficacy of Field-Generated Electrochemical Oxidants on Disinfection of Fomites Using Bacteriophage MS2 and Mouse Norovirus MNV-1 as Pathogenic Virus Surrogates

Abstract

Surface disinfection, as part of environmental hygiene practices, is an efficient barrier to gastroenteritis transmission. However, surface disinfectants may be difficult to obtain in remote, resource-limited, or disaster relief settings. Electrochemical oxidants (ECO) are chlorine-based disinfectants that can be generated using battery power to electrolyze brine (NaCl) solutions. Electrolysis generates a mixed-oxidant solution that contains both chlorine (HOCl, OCl(-)) and reactive oxygen species (e.g., ·OH, O3, H2O2, and ·O2-) capable of inactivating pathogens. One onsite generator of ECO is the Smart Electrochlorinator 200 (SE-200, Cascade Designs, Inc.). In a laboratory study, we assessed ECO surface disinfection efficacy for two gastrointestinal virus surrogates: bacteriophage MS2 and murine norovirus MNV-1. We quantified both infectivity and nucleic acid inactivation using culture-dependent and independent assays. At free available chlorine concentrations of 2,500ppm and a contact time of 30s, ECO inactivation of infective MS2 bacteriophage exceeded 7 log10 compared to MNV-1 disinfection of approximately 2 log10. Genomic RNA inactivation was less than infective virus inactivation: MS2 RNA inactivation was approximately 5 log10 compared to MNV-1 RNA inactivation of approximately 1.5 log10. The results are similar to inactivation efficacy of household bleach when used at similar free available chlorine concentrations. Our work demonstrates the potential of ECO solutions, generated onsite, to be used for surface disinfection.