Scientists now think coronavirus may travel through plumbing pipes, after three families living in a high-rise building in China tested positive for the virus despite never coming into contact with each other and living 12 floors apart.
Four members of one family living on the 15th floor of the high-rise in Guangzhou, China, had recently returned home from Wuhan. They became the centre of a small localised outbreak. Investigations found the virus in their apartment.
Their upstairs neighbours, two middle-aged couples on the 25th and 27th floors, also started feeling unwell.
Security footage showed the groups never shared a lift during the time they were infected, and scientists found no traces of coronavirus on the lift buttons.
Positive virus samples were found in both of the higher apartments.
Now a study cited in the Mail Online has suggested the virus could have travelled through the building’s plumbing, in airborne particles called “bio aerosols” moving upward as a result of the “chimney effect”.
In the study, scientists released ethane gas into the family’s toilet and monitored for the gas in apartments above.
It was found in the two middle-aged couple’s apartments as well as two others on higher floors.
Those couples who became infected may have inhaled the coronavirus particles directly or touched the surfaces where they landed.
Coronavirus usually spreads in droplets when an infected person coughs, sneezes or speaks.
Bio aerosols can linger in the air for 30 minutes or more after a toilet is flushed, according to a 2018 study.
And researchers found certain environments make airborne transmission more common, including poorly ventilated rooms.
The middle-aged couples both said they never opened their bathroom windows, so providing an environment ripe for infection.
This is not the only known incidence of coronavirus appearing to travel through a building’s plumbing.
Reports suggest that in March a couple on the 32nd floor of an apartment block in Hong Kong seem to have passed the virus on to a man living two floors above them.