Residents of Block 325A Sumang Walk will undergo mandatory Covid-19 tests after eight cases were found in three different households in the block.
In an update last night, the Ministry of Health (MOH) said it will be conducting polymerase chain reaction (PCR) tests for all residents of the block to prevent any possible spread in the community.
Testing will be conducted at the pavilion at Block 324 Sumang Walk between 9am and 4pm today and tomorrow.
Residents have been informed via leaflets and SMS notifications.
Visitors who were at Block 325A between May 10 and last Saturday are also encouraged to undergo testing.
The latest case at the Punggol block was a 13-year-old girl who is a student at Paya Lebar Methodist Girls' School. Her case, which is currently unlinked, was confirmed by MOH on Sunday.
She developed anosmia - loss of the sense of smell - on May 29 and did not seek medical treatment until last Friday, when she visited a general practitioner's clinic and was tested for Covid-19.
Earlier cases at the Punggol block were from two separate households: One with four cases, and another with three.
The infections in the household with four cases were confirmed on May 17 and 20, while those in the household with three cases were confirmed on May 21 and 22.
Investigations are ongoing to determine links and the source of transmission, said MOH.
In the event that a positive Covid-19 case is detected during the testing operation today and tomorrow, MOH said it will isolate the case, identify all close contacts, and test and quarantine them to protect the community from further transmission.
Those who are awaiting their PCR test results are advised to minimise social interactions as much as possible.
Residents are also advised to monitor their health closely and consult a doctor immediately if they feel unwell.
Last night, the ministry also said that mandatory testing for the 1,413 residents of Block 506 Hougang Avenue 8 and staff working in neighbouring blocks has ended, with no cases reported.
Another group of more than 3,500 people who live in or work at blocks near Block 506, or who had visited people there, have tested negative for Covid-19.
A total of 3,778 people have voluntarily been tested. Of these, 3,531 were found to be negative, with 247 results pending.
The neighbouring blocks comprise Block 511 Hougang Avenue 10; Blocks 681, 683 and 684 Hougang Avenue 8; Block 682 Hougang Avenue 4; and Blocks 685 and 698 Hougang Street 61.
Compulsory swabbing for this group began last Friday after 13 cases were linked to a cluster at Block 506.