Tuesday, September 01, 2015

NIOSH Video: Adventures In Toilet Plume Research




I ran across a video today from NIOSH which explores a topic we’ve looked at before, and one that just might have some relevance when it comes to the hospital spread of viruses such as MERS, Ebola, and Norovirus. 


The idea being that toilet flushes can aerosolize viruses in waste products, contaminate nearby surfaces, and potentially spread diseases.


Back in 2012, in Norovirus: The Gift That Keeps On Giving, we looked at an outbreak of norovirus that was believed due to just such an event, when a reusable open top grocery bag stored in a hotel bathroom became contaminated by one infected individual, and ended up spreading the virus to the other members of a girls soccer team.


A Point-Source Norovirus Outbreak Caused by Exposure to Fomites

Kimberly K. Repp1, and William E. Keene2

The authors describe the route of infection by saying:

Aerosolization of vomit and feces has been demonstrated to be of major importance in norovirus outbreaks [13]. Even viruses aerosolized from flushing a toilet can contaminate surfaces throughout a bathroom [14]. Once a fomes is contaminated, transfer to hands and other animate objects can readily occur [15]. The more confined the space (eg, most bathrooms), the more intense would be the “fallout” [13].

The authors also take notice of some of the lesser known hazards of reusable grocery bags (see my earlier blog It’s In The Bag).


It’s not a new idea, and in fact Mythbusters did a segment on this very early on in their series.  A couple of years ago, NIOSH and the University of Oklahoma produced a literature review on the topic.


Lifting the lid on toilet plume aerosol: a literature review with suggestions for future research.

Johnson-DL; Mead-KR; Lynch-RA; Hirst-DVL

Am J Infect Control 2013 Mar; 41(3):254-258


NIOSHTIC No. 20042357


BACKGROUND: The potential risks associated with "toilet plume" aerosols produced by flush toilets is a subject of continuing study. This review examines the evidence regarding toilet plume bioaerosol generation and infectious disease transmission.

METHODS: The peer-reviewed scientific literature was searched to identify articles related to aerosol production during toilet flushing, as well as epidemiologic studies examining the potential role of toilets in infectious disease outbreaks.

RESULTS: The studies demonstrate that potentially infectious aerosols may be produced in substantial quantities during flushing. Aerosolization can continue through multiple flushes to expose subsequent toilet users. Some of the aerosols desiccate to become droplet nuclei and remain adrift in the air currents. However, no studies have yet clearly demonstrated or refuted toilet plume-related disease transmission, and the significance of the risk remains largely uncharacterized.

CONCLUSION: Research suggests that toilet plume could play a contributory role in the transmission of infectious diseases. Additional research in multiple areas is warranted to assess the risks posed by toilet plume, especially within health care facilities.


The next obvious step was to construct an experiment that would test, and quantify, the effect.  And here again NIOSH and the University of Oklahoma came up with a `build’ that allowed them to test the amount of aerosols generated at different flush rates.


Credit NIOSH


Not only was this approach flushed with success, they showed that high powered flushing units – such as those commonly used in hospital settings – gave off more aerosols than standard toilets.  Something for nursing staff to think about the next time they are charged with emptying an emesis basin or bedpan from  a suspected norovirus patient.

Then entire 6 minute video is well worth watching, including briefly revisiting the soccer team story mentioned above, at the link below.



The hope being that this type of research will lead to engineering changes that can reduce the generation and spread of aerosolized viruses and bacteria.  Something that could prove very important during an epidemic or pandemic scenario.

For more on research into aerosolized viruses in hospital environments, you may wish to revisit:


CID Study: Airborne Norovirus In Healthcare Facilities

Influenza Transmission, PPEs & `Super Emitters’

Vomiting Larry And His Aerosolized Norovirus

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