A leading microbiologist is looking into how Covid-19 has spread in one of Hong Kong’s largest middle-class private estates, with the “chimney effect” possibly vertically transmitting the virus. Built in the early 1990s, Laguna City, in Lam Tin in Kwun Tong, is one of the city’s earliest large-scale private housing estates, consisting of 38 blocks and more than 8,000 residential units. Similar to Taikoo Shing, the estate is home to many middle-class families and professionals, overlooking Victoria Harbour. A partial evacuation order was issued for Block 5 on Monday after at least 10 cases had emerged in the building over the past two weeks, mostly in flat “E” across multiple floors. Two security guards at the estate have also been confirmed as carrying the virus, with one living on Reclamation Street in Yau Tsim Mong, which is also battling outbreaks. The district was home to 14 of the 73 new cases revealed by health authorities on Monday. Thirteen were discovered after more than 7,000 residents in one neighbourhood in Jordan were locked down and screened over the weekend. Leading microbiologist and government health adviser Professor Yuen Kwok-yung from the University of Hong Kong inspected the housing estate on Monday and said the security guard who lived on Reclamation Street might have brought in the virus. He also noted a family of four living in flat E on the 16th floor, all confirmed as infected, held a gathering on January 9 and at least one guest had been found to have the virus. The Department of Health has issued quarantine orders to all asymptomatic residents of E units and units combining with E units on all floors of Block 5, and is to transfer them to quarantine centres, while symptomatic residents would be sent to hospital. Hong Kong retail body predicts coronavirus-linked slump will continue Yuen said the virus might be spreading through vertical transmission as six cases were tied to households in the E units on the 15th, 16th, and 17th floor. Although he found no “obvious gross leakage” in the building’s drainage system, residents in every E flat in the block would have to be quarantined as a precaution. “We feel that there’s a need to evacuate the residents in order to protect them, because they may be now exposed to infected aerosol which might be going up by the chimney effect in the lightwells or in the pipes,” he said. The Post has contacted Citybase Property Management, which manages Laguna City, for comment. Meanwhile, a resident surnamed Wong, who lives in Block 28, said there were multiple notices plastered near lifts and entrances around his block. They range from the management’s disinfection measures to home quarantine guidelines. “So far no one in my block has got [the virus],” he said. “I’ll be more worried if someone living there gets it.” Of the city’s latest cases, 69 were locally transmitted, while 38 were untraceable, and the remaining four involved arrivals from the Philippines, Belarus, Pakistan and India. More than 60 people also tested preliminary-positive. Eight involved residents in Sham Shui Po, including six who live in an area placed under tighter mandatory testing conditions, whereby a single case in a building triggers screening for all residents. Testing was ordered for two buildings on Yu Chau Street. A resident of Kin Ling Elderly Home on Ferry Street in Jordan was also confirmed as infected, forcing about 20 residents and up to six staff members into quarantine. “There is only one case so far and she is wheelchair-bound, so she usually does not leave the residential care home except for follow-ups or admission to hospital,” said Dr Chuang Shuk-kwan, head of the Centre for Health Protection’s communicable disease branch. “The source of infection may be from other staff, other residents or even visitors, but we still need to investigate.” Also among the latest cases was a traditional Chinese medical practitioner who works in Smiling Shau Kei Wan Plaza. One patient, a doctor with the Department of Health, tested preliminary-positive. Health authorities revealed three nurses at Queen Elizabeth Hospital tested preliminary positive. Three wards at the hospital have been closed for cleaning, and nine other nurses have been listed as close contacts. “We appeal to the Hong Kong citizens to try to avoid going to the accident and emergency department of Queen Elizabeth Hospital because of minor symptoms,” Dr Lau Ka-hin, a chief manager at the Hospital Authority, said. Separately, adult patients at the AsiaWorld-Expo community treatment facility could choose to receive traditional Chinese medical treatment in addition to Western medical treatment starting on Tuesday, said Rowena Wong, chief of the Hospital Authority’s Chinese medicine department. “Based on our observations and studies we obtained from mainland China, we believe that Chinese medicine can help relieve some symptoms of Covid-19,” she said. Compulsory screening will also be required at Block 6 of Tung Fat Building in North Point after infections were reported in two flats. Hong Kong’s coronavirus tally stands at 10,158 cases, with 170 related deaths. The latest fatality was a 94-year-old female patient who died at Queen Elizabeth Hospital in the early morning. Additional reporting by Chan Ho-him and Thomas Shum