She tested positive for the virus on Tuesday after she began showing symptoms on May 29. She is currently unlinked to other cases.
The Ministry of Health (MOH) confirmed 569 new coronarivus cases on Wednesday, bringing the total in Singapore to 36,405. Of the new cases, 562 are foreign workers living in dormitories.
There were no imported cases, and 99 per cent of the new cases are linked to known clusters.
The remaining community cases comprise six work pass holders, of which five are Indian nationals who are men and one is a Chinese national who is a woman. Their ages range from 23 to 40. All six are linked to previously announced cases and are asymptomatic.
MOH also said that 12 of the 14 pre-school staff who tested positive for the virus were likely to be past infections, based on epidemiological investigations, including their positive serological test results. One more serological test came back positive on Wednesday, indicating a likely past infection.
In all, more than 39,000 preschool staff have been tested, and only one case was likely to be a current infection at the point of screening, as announced on May 29.
Two new clusters were also confirmed on Wednesday, both of them are dormitories. They are at 12 Kwong Min Road and 8 Tuas South Lane.
MOH also said the cluster at 1 North Coast Drive has been closed as it has not had new cases linked to them for two incubation periods, or 28 days.
The ministry did not add to its list of public places visited by community cases while they were infectious.
The places visited by community cases while they were infected include wet markets, supermarkets, hawker centres, and malls such as Parkway Parade, Jurong Point, Bukit Panjang Plaza, Jem and Junction 8.
The full list of places, along with the dates and times when the locations were visited by the patients, can be found on the ministry's website.
MOH said there is no need to avoid the listed places and the National Environment Agency will engage the management of these premises to give guidance on cleaning and disinfection.
Those who have gone to these places should monitor their health closely for 14 days from the date they visited, said MOH, adding that they should visit a doctor promptly if they develop fever, respiratory symptoms or loss of taste or smell.
Those who were identified as close contacts of confirmed cases would already have been notified by MOH, said the ministry.
When asked if information from digital check-in SafeEntry - which has been utilised in places such as malls, supermarkets, and workplaces - is being used to inform those who have been at these locations at the same time as confirmed Covid-19 cases, MOH said it does not use SafeEntry information to identify others who had gone to places visited by confirmed Covid-19 cases.
The data collected by SafeEntry is used by contact tracers when interviewing patients to help them remember where they have been and map out these places, said MOH.
"A robust activity map allows accurate and efficient identification and quarantine of close contacts to contain further transmission of the disease," the ministry said.
It added: "We will continue to leverage technology to supplement our contact tracing efforts." The daily average for new community cases has decreased to four in the past week from six the week before, said MOH. Across the same periods, the number of unlinked cases has remained stable at an average of two per day.
The MOH also said 407 more patients were discharged, bringing the total number of recovered patients to 23, 573.
Currently, 334 confirmed cases are in hospital, with five in critical condition in intensive care.
Another 12,465 are isolated and cared for at community facilities, which are for those with mild symptoms or who are clinically well but still tested positive for Covid-19.
Twenty-four have died from Covid-19 complications, while nine who tested positive for Covid-19 have died of other causes.
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