Aerosolization of Ebola Virus Surrogates in Wastewater Systems

Abstract

Academic AbstractRecent studies have shown that Ebola virus can persist in wastewater, and the potential for the virus to be aerosolized and pose a risk of inhalation exposure has not been evaluated.We considered this risk for three wastewater systems: toilets, a lab-scale model of an aeration basin, and a lab-scale model of converging sewer pipes. We measured the aeroso l size distribution generated by each system, spiked Ebola virus surrogates into each system, and determined the emission rate of viruses into the air. While the number of aerosols released ranged from 10 5 to 10 7 per flush from the toilets or per minute from the lab-scale models, the total volume of aerosols generated by these systems was ~10 -8 to 10 -7 mL per flush or per minute in all cases. The Ebola virus surrogates MS2 and Phi6, spiked into toilets at an initial concentration of 10 7 PFU mL -1 , were not detected in air after flushing.Airborne concentrations of MS2 and Phi6 were ~20 PFU L -1 and ~0.1 PFU L -1 , respectively, associated with the aeration basin and sewer models. This corresponds to emission rates of 547 PFU min -1 and 3.8 PFU min -1 of MS2 and Phi6, respectively, for the aeration basin and 79 PFU min -1 and 0.3 PFU min -1 for the sewer model. Since informa tio n on the aerosolization of Ebola virus is quite limited, these emission rates can greatly help inform risk assessment of inhalation exposure to Ebola virus.iii

Wastewater-Based Epidemiology for Early Detection of Viral Outbreaks

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A pilot study on the disinfection efficacy of localized UV on the flushing-generated spread of pathogens

“…A single toilet flushing generates between hundreds of thousands and millions of aerosols, due to the force of water running down the surfaces of the bowl, and the turbulence caused by water mixing in the bowl [6,7]. When pathogenic organisms are shed along with fecal materials into the toilet bowl, numerous pathogen-laden droplets of aerosol are produced [8][9][10].…”

A Bayesian Belief Network Model Assessing the Risk to Wastewater Workers of Contracting Ebola Virus Disease During an Outbreak

“…As data on inhalation for wastewater workers are sparse, a study of aerosolized water inhalation during showering was used to estimate inhalation exposure volumes . Data from the experiment conducted at highest temperature and highest water velocity were used, resulting in the greatest volume of water inhaled, to be conservative relative to available literature on wastewater aerosolization . In addition, the inhaled volume value from the 10‐minute experiment was multiplied by 24 to determine the amount of water expected to be inhaled over a 4‐hour exposure.…”