Transmission of Severe Acute Respiratory Syndrome (SARS) by
airborne, waterborne route and infected dust aerosols have been
examined and ruled out by epidemiological picture and laboratory
results.
Such was the conclusion by the report compiled jointly by the Hong
Kong Special Administrative Region (HKSAR) Department of Health and
other government agencies on the outbreak of SARS, that occurred
among residents of Amoy Gardens in Kowloon Bay in Kowloon towards
the end of March 2003.
The report, which was made public Thursday, is the result of a
detailed investigation covering epidemiological, environmental
public hygiene, building design and utilities considerations of the
housing estate.
However, tiny water droplets containing viruses from the
contaminated sewage of the bathroom floor drains and dried-up
U-trap of the toilet bowl were found to provide a pathway through
which the residents came into contact with the small droplets, the
report said.
"These droplets entered the bathroom floor drain through negative
pressure generated by exhaust fans when the bathroom was being used
with the door closed. Water vapor generated during a shower and the
moist conditions of the bathroom could also have facilitated the
formation of water droplets.
"Contaminated droplets could then have deposited virus on various
surfaces, such as floor mats, towels, toiletries and other bathroom
equipment," it said.
The report suggests that for the U-trap preventive mechanism to
function properly, the water traps must be sufficiently filled with
water all times, it said.
The HKSAR Food And Environmental Department has given advice to
residents of various blocks in Amoy Gardens to disinfect their
flats as precautionary measures, particularly sinks, bathtubs, wash
hand basins, toilet bowls and floor drains in the toilets and
kitchens, it said.
The administration has published a set of guidelines to draw the
public's attention to the proper maintenance and repair of the
drainage system and sanitary facilities.
(Xinhua News Agency April 18, 2003)