'Lockdown Order Not Suitable For Richland Gardens'

Infectious disease expert Leung Chi-chiu said on Friday that a stay-home order would not be suitable for residents of a Kowloon Bay housing block despite a number of Covid-19 cases there, because the virus could have been spreading through the building's sewage pipes.

Leung added that Block 6 of Richland Gardens is not at risk of a large cluster of infections, as rapid antigen tests conducted on residents only identified one new preliminary case so far.

“On the testing of a large number of residents living in that block, we did not find a high incidence of any secondary infection at this moment,” he said.

“Although the antigen test is not so sensitive, if all the others were negative, the chance of a large outbreak will be low. We may be seeing one or several more possible cases on nucleic acid testing, but still the outbreak may not be excessive at the moment.”

Residents of Block 6, as well as those living in units E of Block 4 and units D of Block 18, where there are also confirmed cases, have been ordered to take traditional nucleic acid tests and rapid antigen tests.

But Leung said it's unsuitable to impose a lockdown in any residential block where it's likely that the coronavirus could be spreading through a faulty sewage system.

University of Hong Kong microbiologist and government adviser Yuen Kwok-yung had earlier said that the virus might have spread through Block 6's sewage pipes, as all those infected live in units facing the same direction and linked to the same sewage system.

Leung said the authorities should quickly check the sewage pipes of other blocks on the estate, adding that a faulty U-trap could help transmit viruses in the building.

Meanwhile, the Hong Kong Toilet Association said 95 percent of buildings in Hong Kong use the same sewage system as Block 6 of Richland Gardens, in which all the drains from a unit's toilet, bathroom and kitchen go into the same pipe.

The association's vice chairman, Henry Hung, warned that it could be a huge concern if the U-traps are not in good condition and not filled with water regularly.

“The general practice now is that we do not use water to wash the floor in the bathroom, do you? So when water is not used on the floor, then the water seal trap or the floor drain will be dried up. This is exactly the similar occasion [in] Amoy Gardens back [in] 2003,” he said, referring to the cause of the most serious community Sars outbreak in the territory.