Survival and Sodium Hypochlorite Disinfection of Potential Ebola Virus Surrogates MS2, PhiX-174, and Phi6 in a Conservative Matrix of Raw Hospital Sewage and Human Fecal Waste
Public Deposited- Last Modified
- February 27, 2019
- Creator
-
Strasser, Joseph
- Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
- Abstract
- Between March 2014 and January 2016, West Africa experienced the largest Ebola virus disease (EVD) outbreak in history. For the duration of the epidemic, a number of instances occurred where infected individuals were transported outside of West Africa to be treated in hospitals in more developed nations (i.e. United States). Fecal wastes produced from Ebola cases in health care facilities in the United States can be discharged directly into local sewage systems without pre-treatment in accordance to guidance from the US Centers for Disease Control and Prevention (CDC). There is a need for understanding how Ebola virus may persist in these wastes and to develop protocols for appropriate in situ disinfection pre-treatment of Ebola fecal wastes. Potential Ebola virus surrogates, MS2 coliphage, PhiX-174 coliphage, and Phi6 bacteriophage, were tested for survival at 22 and 37°C and disinfection with sodium hypochlorite in a conservative matrix of raw hospital sewage amended with human fecal waste. Phi6 required approximately nine days for a 5 log10 (99.999%) target reduction at the ambient condition (22°C) and, due to the presence of an outer lipid envelope layer, may conservatively represent the survivability of Ebola virus in a comparable fecal waste matrix. Target 5 log10 reductions of MS2 and PhiX-174 at 22 C required a predicted six and twelve weeks, respectively. All surrogate viruses were inactivated more rapidly at 37°C than at 22°C. Surrogates Phi6 and PhiX-174 were disinfected with sodium hypochlorite to a target 5 log10 (99.999%) reduction in 10 minutes at initial free chlorine concentrations of 2,800 and 3,500 mg/L, respectively. Free chlorine was rapidly consumed in the organic rich matrix, and therefore, high initial sodium hypochlorite concentrations were required to achieve significant reductions in viral titer. MS2 was extremely resistant to free chlorine disinfection and target reductions were not achieved with even the highest tested initial free chlorine concentrations. Disinfection kinetics were adequately described using the Selleck model, accounting for a first-order disinfectant decay rate. Enveloped surrogate persistence in raw sewage and fecal waste indicates precautionary pre-treatment with a high concentration of free chlorine may greatly reduce risk. Due to its nearly universal availability in health care settings, sodium hypochlorite (liquid bleach) is an appropriate chemical disinfectant for inactivating Ebola virus in a fecal waste matrix, but is not highly recommended because of the significant concentrations and volumes required to overcome the oxidizable organic content of such a matrix.
- Date of publication
- May 2017
- Keyword
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- Sobsey, Mark
- Reviewer
- Casanova, Lisa
- Stewart, Jill
- Sobsey, Mark
- Degree
- Master of Science in Public Health
- Academic concentration
- Environmental Chemistry and Biology
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 2017
- Language
- Deposit record
- 2177dff7-0371-4794-aaf1-8391f510885a
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