Prognosis
Coronavirus in Vacant
Apartment Suggests Toilets’ Role in Spread
Apartment Suggests Toilets’ Role in Spread
By Jason Gale
August 26, 2020, 2:40 PM GMT+1
The discovery of coronavirus in the bathroom of an
unoccupied apartment in Guangzhou, China, suggests the airborne pathogen may
have wafted upwards through drain pipes, an echo of a large SARS outbreak in
Hong Kong 17 years ago.
unoccupied apartment in Guangzhou, China, suggests the airborne pathogen may
have wafted upwards through drain pipes, an echo of a large SARS outbreak in
Hong Kong 17 years ago.
Traces of SARS-CoV-2 were detected in February on the sink,
faucet and shower handle of a long-vacant apartment, researchers at the Chinese
Center for Disease Control and Prevention said in a study published this month
in Environment International. The contaminated bathroom was directly above the
home of five people confirmed a week earlier to have Covid-19.
faucet and shower handle of a long-vacant apartment, researchers at the Chinese
Center for Disease Control and Prevention said in a study published this month
in Environment International. The contaminated bathroom was directly above the
home of five people confirmed a week earlier to have Covid-19.
The scientists conducted “an on-site tracer simulation
experiment” to see whether the virus could be spread through waste pipes via
tiny airborne particles that can be created by the force of a toilet flush.
They found such particles, called aerosols, in bathrooms 10 and 12 levels above the Covid-19 cases. Two cases were
confirmed on each of those floors in early February, raising concern that
SARS-CoV-2-laden particles from stool had drifted into their homes via
plumbing.
experiment” to see whether the virus could be spread through waste pipes via
tiny airborne particles that can be created by the force of a toilet flush.
They found such particles, called aerosols, in bathrooms 10 and 12 levels above the Covid-19 cases. Two cases were
confirmed on each of those floors in early February, raising concern that
SARS-CoV-2-laden particles from stool had drifted into their homes via
plumbing.
The new report is reminiscent of a case at Hong Kong’s Amoy Gardens private
housing estate almost two decades ago, when 329 residents caught severe acute
respiratory syndrome, or SARS, in part because of faulty sewage pipelines.
Forty-two residents died, making it the most devastating community outbreak of
SARS, which is also caused by a coronavirus.
housing estate almost two decades ago, when 329 residents caught severe acute
respiratory syndrome, or SARS, in part because of faulty sewage pipelines.
Forty-two residents died, making it the most devastating community outbreak of
SARS, which is also caused by a coronavirus.
“Although transmission via the shared elevator cannot be
excluded, this event is consistent with the findings of the Amoy Gardens SARS
outbreak in Hong Kong in 2003,” Song Tang, a scientist with the China CDC Key
Laboratory of Environment and Population Health, and colleagues wrote in the
study, which cited unpublished data from China CDC.
excluded, this event is consistent with the findings of the Amoy Gardens SARS
outbreak in Hong Kong in 2003,” Song Tang, a scientist with the China CDC Key
Laboratory of Environment and Population Health, and colleagues wrote in the
study, which cited unpublished data from China CDC.
Apartments in multistory buildings may be linked via a
shared wastewater system, said Lidia Morawska, director of the International
Laboratory for Air Quality and Health at Australia’s Queensland University of
Technology. While solids and liquids descend the network, sewer gases -- often
detectable by their odor -- sometimes rise through pipes, said Morawska, who
wasn’t part of the research team.
shared wastewater system, said Lidia Morawska, director of the International
Laboratory for Air Quality and Health at Australia’s Queensland University of
Technology. While solids and liquids descend the network, sewer gases -- often
detectable by their odor -- sometimes rise through pipes, said Morawska, who
wasn’t part of the research team.
“If there’s smell,
it means that somehow air has been transported to where it shouldn’t go,”
Morawska said in an interview.
it means that somehow air has been transported to where it shouldn’t go,”
Morawska said in an interview.
Respiratory Droplets
SARS-CoV-2 spreads mainly through respiratory droplets --
spatters of saliva or discharge from the nose, according to the World Health
Organization. Since the first weeks of the pandemic, however, scientists in
China have said infectious SARS-CoV-2 virus in the stool of Covid-19 patients
may also play a role in transmission. A February study of 73 patients
hospitalized with the coronavirus in Guangdong province found more than half
tested positive for the virus in their stool.
spatters of saliva or discharge from the nose, according to the World Health
Organization. Since the first weeks of the pandemic, however, scientists in
China have said infectious SARS-CoV-2 virus in the stool of Covid-19 patients
may also play a role in transmission. A February study of 73 patients
hospitalized with the coronavirus in Guangdong province found more than half
tested positive for the virus in their stool.
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QuickTake
QuickTake
Previous research has shown that toilet flushes can generate
germ-laden aerosols from the excreta, the China CDC scientists said. Those
particles can remain in the air for long periods and be dispersed over
distances of more than 1 meter (3 feet), particularly in confined, poorly
ventilated spaces.
germ-laden aerosols from the excreta, the China CDC scientists said. Those
particles can remain in the air for long periods and be dispersed over
distances of more than 1 meter (3 feet), particularly in confined, poorly
ventilated spaces.
Fecal aerosolization occurred with SARS, and it’s possible
that it may rarely occur with SARS-CoV-2, depending on sewage systems, said
Malik Peiris, chair of virology at the University of Hong Kong’s School of
Public Health. The China CDC study found traces of virus, “which is not the
same thing as infectious virus,” he said. “But one has to keep the possibility
in mind.”
that it may rarely occur with SARS-CoV-2, depending on sewage systems, said
Malik Peiris, chair of virology at the University of Hong Kong’s School of
Public Health. The China CDC study found traces of virus, “which is not the
same thing as infectious virus,” he said. “But one has to keep the possibility
in mind.”
Fecal Plume
In the Amoy Gardens
case, warm, moist air from the bathroom of a SARS patient excreting “extremely
high concentrations” of virus in feces and urine established a plume in an air
shaft that spread the airborne virus to other apartments, research showed.
case, warm, moist air from the bathroom of a SARS patient excreting “extremely
high concentrations” of virus in feces and urine established a plume in an air
shaft that spread the airborne virus to other apartments, research showed.
Although toilets are a daily necessity, they “may promote
fecal-derived aerosol transmission if used improperly, particularly in
hospitals,” the China CDC researchers said. They cited a fluid-dynamics
simulation that showed a “massive upward transport of virus aerosol particles”
during flushing, leading to large-scale virus spread indoors.
fecal-derived aerosol transmission if used improperly, particularly in
hospitals,” the China CDC researchers said. They cited a fluid-dynamics
simulation that showed a “massive upward transport of virus aerosol particles”
during flushing, leading to large-scale virus spread indoors.
“The study finds high plausibility for airborne transmission
and outlines the evidence in great detail,” said Raina MacIntyre, professor of
global biosecurity at the University of New South Wales in Sydney, who was part
of an international team invited to collaborate with China CDC on the study.
and outlines the evidence in great detail,” said Raina MacIntyre, professor of
global biosecurity at the University of New South Wales in Sydney, who was part
of an international team invited to collaborate with China CDC on the study.
Previous investigations confirmed that SARS-CoV-2 genetic
material was found on toilets used by Covid-19 patients, in the air in hospital
nurses’ stations, on air outlet vents, and multiple other sites. The extent to
which fecal aerosol plumes are infecting people with the SARS-CoV-2 virus isn’t
known, said Queensland’s Morawska.
material was found on toilets used by Covid-19 patients, in the air in hospital
nurses’ stations, on air outlet vents, and multiple other sites. The extent to
which fecal aerosol plumes are infecting people with the SARS-CoV-2 virus isn’t
known, said Queensland’s Morawska.
“There are lots of situations where things happen and are
pretty unusual,” said Morawska, who was part of a team that investigated the
Amoy Gardens contagion. Scientists should investigate the “unusual situations”
because, by understanding them, they may find “they’re not that unusual.”
pretty unusual,” said Morawska, who was part of a team that investigated the
Amoy Gardens contagion. Scientists should investigate the “unusual situations”
because, by understanding them, they may find “they’re not that unusual.”
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