Surrogate Testing Suggests That Chlorine Dioxide Gas Exposure Would Not Inactivate Ebola Virus Contained in Environmental Blood Contamination

Abstract

The ability to decontaminate a room potentially containing the Ebola virus is important to healthcare facilities in the United States. The Ebola virus remains viable in body fluids, a room that has housed a patient with Ebola virus disease must have all surfaces manually wiped with an approved disinfectant, which increases occupational exposure risk. This study evaluated the efficacy of gaseous chlorine dioxide inactivation of bacterial organisms in blood as the Ebola virus surrogates and as the organisms used by the Nebraska Biocontainment Unit to provide the margin of safety for decontamination. Bacillus anthracis, Escherichia coli, Enterococcus faecalis, and Mycobacterium smegmatis blood suspensions that were exposed to ClO₂ gas concentrations and exposure limits. The log reduction in Colony Forming Units (CFU) was determined for each bacterial blood suspension. Exposure parameters approximating industry practices for ClO₂ environmental decontamination (360 ppm concentration to 780 ppm-hr exposure, 65% relative humidity) as well as parameters exceeding current practice (1116 ppm concentration to 1400 ppm-hr exposure; 1342 ppm concentration to 1487 ppm-hr exposure) were evaluated. Complete inactivation was not achieved for any of the bacterial blood suspensions tested. Reductions were observed in concentrations of B. anthracis spores (1.3–3.76 log) and E. faecalis vegetative cells (1.3 log) whereas significant reductions in vegetative cell concentrations for E. coli and M. smegmatis blood suspensions were not achieved. Our results showed that bacteria in the presence of blood were not inactivated using gaseous ClO₂ decontamination. ClO₂ decontamination alone should not be used for the Ebola virus, but decontamination processes should first include manual wiping of potentially contaminated blood; especially for microorganisms as infectious as the Ebola virus.

Keywords:

• blood
• chlorine dioxide
• Ebola
• enterococcus
• escherichia
• mycobacterium