Current and former residents of Block 174D Hougang Avenue 1 will be offered voluntary screening for tuberculosis (TB) following the detection of a cluster of cases in the block, said the Ministry of Health (MOH) yesterday.
MOH described the move as a precautionary measure after four individuals residing in four different units at the block were diagnosed with the disease.
The screening will be conducted free of charge at the Tuberculosis Control Unit in Moulmein Road from tomorrow.
MOH was notified on Oct 10 of the four cases, who were diagnosed between January 2018 and June this year.
The ministry noted that all four immediately started treatment following diagnosis. Two have completed treatment, while the other two are currently undergoing treatment and are no longer infectious.
"As individuals diagnosed with tuberculosis will rapidly become non-infectious once treatment starts, the cases are not an ongoing public health risk," MOH said.
Contact investigations were initiated upon notification of the cases and close contacts have already been identified and contacted for screening. Investigations into the four cases at the time of diagnosis did not identify them as close contacts, MOH said.
"The cluster was subsequently determined due to the results of the genetic sequencing performed in October as part of retrospective testing of tuberculosis cases to determine possible linkages," the ministry added.
"This revealed that all four cases have similar genetic make-up. Investigations into the cases did not reveal any common links, other than that they live in the same block.
"They did not know or interact with one another, or congregate at the same common areas, and had also not identified each other as close contacts. The cluster therefore does not fit the usual pattern of tuberculosis spread."
MOH noted that TB is typically spread through close and prolonged contact with an infectious individual, and not by contact with items or surfaces touched by an infected person.
Those contacted and screened typically are family members, close workplace colleagues and acquaintances from common social activities with close, regular interaction.
"The expanded tuberculosis screening offered by MOH is a precautionary measure to assure and protect residents living in the same block. The exercise could help detect any undiagnosed cases."
The screening is not compulsory but is strongly encouraged.
Those with active TB will be treated immediately and those with latent non-infectious TB will be monitored and treated if necessary.
MOH also noted that the risk of transmission to people who are not close contacts of a case is very low, which means screening is also not necessary for individuals who had occasionally visited the block or vicinity.
Officers from the Tuberculosis Control Unit and the National Centre for Infectious Diseases will also be conducting house visits to all units at the affected block between today and Tuesday.
Residents will be able to make appointments for the screening during the house visits.
They can also call the Tuberculosis Control Unit to make an appointment for screening.
Former residents who lived in the block from February this year and wish to be screened may call the Tuberculosis Control Unit hotline on 6258-4430 .
