There has been concern about the transmission of the Sars virus through contaminated sewage systems and the use of contaminated toilets in the Amoy Gardens cluster of cases.
Now the WHO has confirmed that coronavirus can survive in human excrement for about four days and that convalescent patients shed the virus in their excrement for weeks. The experts have further warned that since the virus survives in sub-zero temperatures indefinitely, it might in all probability re-emerge next spring.
To most people, the term toilet transmission conjures up a scenario of finger-soiling and transferring the virus to food, but few are aware of the role of aerosol (droplets and airborne particles) churned up by flush systems.
There are currently two main toilet-flushing systems. One system uses water cascade and the other whirlpool.
The cascade system generates a lot of noise and a tremendous quantity of aerosol, as was proven by Japanese scientists four to five years ago.
The whirlpool system is quiet and generates much less aerosol - one should consider this when buying a toilet.
If an infected user contaminates a toilet bowl, the next user may get the virus through aerosol inhalation, whether he flushes before or after use. Closing the toilet lid may help, but note the lid is not airtight. The government advisory on this precaution notwithstanding, transmission through public toilets is very important in the prevention and containment of Sars and other respiratory viruses shed by patients in their urine or faeces during convalescence.