A private doctor who had been to 10 homes for the elderly and the disabled during what proved to be his incubation period for the coronavirus was among 69 cases confirmed yesterday.
Chuang Shuk-kwan, head of communicable diseases at the Centre for Health Protection, said the doctor, 78, fell ill on Wednesday.
And during the infectious period - two days before the onset of symptoms - he worked at the Cheerful and Blissful homes for the disabled operated by St James' Settlement Rehabilitation Services at On Tai Estate Ancillary Facilities Block in Kwun Tong.
On July 22 he also visited the Cornwall home for the Elderly in Tai Po, the Wing On Home for the Aged (First Branch) in Ho Man Tin and the Kai King and Yau Chai homes for the aged in Sha Tin.
Two days later he went to the Chung Tao Elderly Home (First Branch) in Kwai Chung, the Loc Shun Elderly Home in Sham Shui Po, the Mu Lan Home for the Aged in Mong Kok and the Elderly Home of Love in Yau Ma Tei.
"We will test all the residents and staffers in these care homes," Chuang said.
Despite the Cornwall home having experienced clusters, she said the doctor was unlikely to have contracted the virus there as the first patient from the home fell sick one to two days after the doctor visited.
The doctor, who lives and works in Hong Tak Gardens in Tuen Mun, was not in a condition to help with tracing contacts, Chuang added.
Yesterday's new cases comprised 45 linked to local infections, 22 from unknown local sources and two imported, taking the tally to 4,119 with another three deaths of men aged 85-94 to make the fatality count 55.
Twenty preliminary positive cases are likely to be confirmed today.
Chuang also said four more Indonesian domestic helpers, 24 to 36, living at a boarding home at Apik Employment Agency at Kin On Commercial Building in Sheung Wan tested positive yesterday.
They were believed to be infected by a 39-year-old helper in the dormitory last month.
Two of the four stayed with a family in Tuen Mun for several days to help with cleaning and moving and a third lived at the home of a friend's employer in Hang Hau. Both families were being tested and quarantined.
On a cluster based on Kwai Chung Cargo Terminal, Chuang said a man, 58, was the eighth infected worker.
And a 48-year-old contract worker at the Hospital Authority's laundry center at Butterfly Beach in Tuen Mun has been infected.
He was responsible for putting clothes and blankets used by Covid-19 patients in washing machines, but Hospital Authority executive Linda Yu Wai-ling said the items were in dissolvable plastic bags and the worker wore protective gear.
"One of his family members also tested preliminary positive," Yu said.
She also said an internal medicine nurse, 31, at Caritas Medical Centre in Cheung Sha Wan was a preliminary positive case.
The nurse had not worked in an isolation ward in the past 14 days but on Sunday was coughing and had a loss of taste so she went to the emergency room.
Since she wore protection at work no patients have been listed as close contacts. But five colleagues who have eaten with her will be quarantined.