Abstract
The WHO Consensus Document on the epidemiology of the SARS epidemic in 2003, included a report on a concentrated outbreak in one Hong Kong housing block which was considered a ‘super-spreading event’. The WHO report conjectured that the sanitary plumbing system was one transmission route for the virus. Empty U-traps allowed the aerosolised virus to enter households from the sewerage system. No biological evidence was presented. This research reports evidence that pathogens can be aerosolised and transported on airstreams within sanitary plumbing systems and enter buildings via empty U-traps. A sanitary plumbing system was built, representing two floors of a building, with simulated toilet flushes on the lower floor and a sterile chamber with extractor fan on the floor above. Cultures of a model organism, Pseudomonas putida at 106 - 109 cfu ml-1 in 0·85 % NaCl were flushed into the system in volumes of 6 to 20 litres to represent single or multiple toilet flushes. Air and surface samples were cultured on agar plates and assessed qualitatively and semi-quantitatively. Flushing from a toilet into a sanitary plumbing system generated enough turbulence to aerosolise pathogens. Typical sanitary plumbing system airflows (between 20-30 ls-1) were sufficient to carry aerosolised pathogens between different floors of a building. Empty U-traps allowed aerosolised pathogens to enter the chamber, encouraging cross-transmission. All parts of the system were found to be contaminated post-flush. Empty U-traps have been observed in many buildings and a risk assessment indicates the potential for high risk cross-transmission under defect conditions in buildings with high pathogen loading such as hospitals.
Under defective conditions (which are not uncommon) aerosolised pathogens can be carried on the airflows within sanitary plumbing systems. Our findings show that greater consideration should be given to this mode of pathogen transmission.
Under defective conditions (which are not uncommon) aerosolised pathogens can be carried on the airflows within sanitary plumbing systems. Our findings show that greater consideration should be given to this mode of pathogen transmission.
Original language | English |
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Article number | e0171556 |
Journal | PLoS ONE |
Volume | 12 |
Issue number | 2 |
DOIs | |
Publication status | Published - 10 Feb 2017 |
Keywords
- Building drainage system
- Pathogen
- Cross-transmission
- Pseudomonas putida
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Dive into the research topics of 'Pathogen Cross-Transmission via Building Sanitary Plumbing Systems in a full scale pilot test-rig'. Together they form a unique fingerprint.Profiles
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Michael Gormley
- School of Energy, Geoscience, Infrastructure and Society - Professor
- School of Energy, Geoscience, Infrastructure and Society, Institute for Sustainable Building Design - Professor
Person: Academic (Research & Teaching)
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David Kelly
- School of Energy, Geoscience, Infrastructure and Society - Associate Professor
- School of Energy, Geoscience, Infrastructure and Society, Institute for Sustainable Building Design - Associate Professor
Person: Academic (Research & Teaching)