A coronavirus cluster in a high-rise apartment building may have spread through ‘faecal fumes’ that travelled through a drain pipe from an infected neighbour, a study claims.
Residents living in flats in the housing block in Guangzhou, China, became the centre of the study carried out by the Annals of Internal Medicine after nine people from three families tested positive for coronavirus.
All 193 residents and 24 workers at the building were tested and all nine positive cases were found to be neighbours who lived above each other.
Nick Talley MD, editor-in-chief of Medical Journal Australia, said he found the study results ‘speculative’.
The physician-scientist tweeted: “Interesting but speculative. Probable Evidence of Fecal Aerosol Transmission of SARS-CoV-2 in a High-Rise Building | Annals of Internal Medicine”.
According to the study, the family living in the bottom apartment, identified in the study as ‘Family A’, had travelled to Wuhan, the epicentre of the outbreak, in early January, but families B and C had no travel history.
Five members of family A returned home from their trip on January 24.
A week later, the middle-aged couple of family B showed symptoms of the virus.
The members of both families did not know each other and had not shared the same lifts during the infectious period.
Researchers used ethane as a tracer gas to test the pipes to the three flats and found they were all connected by drainage stacks all with a vent in the master bathrooms on each floor.
When researchers continuously released ethane in family A’s master bathroom, concentrations of the gas were detected in all the other flats, demonstrating the pipes could serve as a “transport route”, the study claims.
Researchers said it was likely that the infection in the building stemmed from three young members of family A who used and flushed the the toilet which caused the virus-laden particles to leak into the neighbours’ flat via the drainage system.
If residents of the two flats above family A happened to be in their bathroom at the same time that the toilet was flushed, researchers believe that they may have inhaled the fumes and contracted the virus.
The study found: “The bioaerosolization of wastewater mixed with urine, feces, and exhaled mucus originating from index patients is suggested to be the source of infectious bioaerosols in this outbreak.
“Thus, the COVID-19 outbreak in block X may have been caused by fecal aerosol transmission, on the basis of circumstantial evidence.”
A study carried in June has also claimed ‘faecal fumes’ may spread coronavirus.
The research, published in the journal Physics of Fluids, said coronavirus can be passed not only through respiratory droplets but through virus-laden faeces.
The study claimed viable virus particles were found in the faeces of coronavirus patients as well as traces of viral RNA on toilet bwls and sinks in their hospital isolation rooms, New York Times reported.
Joshua L. Santarpia, a professor of pathology and microbiology at the University of Nebraska Medical Center who was not involved in the Physics of Fluids research, said: “The aerosols generated by toilets are something that we’ve kind of known about for a while, but many people have taken for granted.
“This study adds a lot of the evidence that everyone needs in order to take better action.”