Friday, 17 June 2016

Tuberculosis in Ang Mo Kio: Precautionary screening for residents after 6 TB cases found

Screening for residents of Ang Mo Kio block after 6 TB cases found
Six neighbours have same drug-resistant strain of the disease over four-year period
By Linette Lai, The Straits Times, 16 Jun 2016

The residents of a block of flats in Ang Mo Kio Avenue 3 are being urged to undergo screening for tuberculosis (TB), after six of their neighbours were diagnosed with the same drug-resistant strain of the disease over a four-year period.

Last night, grassroots volunteers, officers from the Ministry of Health (MOH) and Ang Mo Kio GRC MP Koh Poh Koon knocked on the doors of the 160 units of Block 203 to inform residents of the situation, which MOH described as "highly unusual".

Three of the six TB patients lived in the same unit but the other three were from different households. All four households said they did not know and had not interacted with one another.

This stumped investigating doctors as TB is typically spread through "close and prolonged contact", said Associate Professor Benjamin Ong, director of medical services at MOH.

Even among members of the same household, transmission could take days or weeks to occur.

"It is unusual for TB to be spread by casual, brief exposure," Prof Ong told reporters yesterday. The ministry has been unable to find out how the same strain of TB could have spread among the six.

The cluster came to light when a sharp-eyed doctor at Tan Tock Seng Hospital's TB Control Unit noticed that a patient diagnosed with multi-drug resistant TB lived in the same block as earlier cases and alerted the ministry.

The first patient was diagnosed with the disease in February 2012. The last was diagnosed last month.

The group comprises five men and one woman aged between their early 20s and 70. They are no longer infectious and cannot spread the disease, said Dr Jeffery Cutter, director of MOH's communicable diseases division.

Three have completed treatment, and the other three are undergoing treatment in hospital.

Screening of their close contacts, such as family members and colleagues, has also been carried out. MOH said, without specifying the number, that some were found to have the latent form of the disease, which cannot be spread.

TB is caused by bacteria that usually attack the lungs. It is spread via droplets in the air when someone with an active infection coughs.

Of those who are infected, only one in 10 will actually develop an active infection. The vast majority have latent infections without symptoms, and will not spread the disease.

Normal TB infections can be completely cured within six to nine months, but the use of antibiotics has led to the rise of drug-resistant strains that are harder to treat.

MOH is providing voluntary free screening for residents at the void deck of the 11-storey block from today until Sunday as a precautionary measure, to pick up any undiagnosed or latent TB infections.

Told of the situation last night, some residents expressed concern while others said they were not worried as they did not interact much with their neighbours.

When approached by reporters, Dr Koh, who is also Minister of State for Trade and Industry and National Development, said he would comment on the issue later.

Results Of On-Site Tuberculosis Screening: Two more TB cases found in Ang Mo Kio
MOH to conduct DNA tests to see if these are related to cluster of six cases in same block
By Linette Lai, The Straits Times, 5 Jul 2016

Two more people are feared to have contracted tuberculosis in an Ang Mo Kio block where six drug-resistant cases have already been identified.

The Ministry of Health (MOH) said yesterday that the two suspected active cases, which are potentially infectious, are currently "being followed up for treatment, monitoring, and contact tracing".

The ministry will also carry out DNA tests to see if they are related to the cluster of six cases, although "this may take some time".

In what it described as a "highly unusual occurrence", six people in Block 203, Ang Mo Kio Avenue 3, were diagnosed with the same strain of multi-drug-resistant TB over a four-year period.

The four households involved said they did not know each other and had not interacted. The disease typically requires "close and prolonged contact" to spread.

The discovery triggered a four- day precautionary screening exercise at the foot of the block to pick up undiagnosed cases. This ended on June 19, though a second round of house visits to encourage more people to get tested was held last Saturday. During the visits, MOH officers offered to collect blood samples to make testing more convenient for residents.

A total of 223 residents and former residents were tested in the first round. An estimated 350 people live in the block.

In addition to the two new suspected cases, another 45 people were found to potentially have a latent form of the disease. This means that they have no symptoms and cannot spread TB.

Tests also picked up three people who previously had TB, but had already completed treatment. These were not related to the drug-resistant cluster, MOH said. The ministry is following up with nine people who completed only part of the screening, which involves both an X-ray and a blood test.

MOH added yesterday that those who may have latent TB have been advised to monitor themselves for symptoms. Tan Tock Seng Hospital's TB Control Unit will check up on them every six months for the next two years.

"Treatment may be offered on a case-by-case basis after assessment by the TB Control Unit," it said, adding that four people in this group have started treatment.

Latent TB is not uncommon among Singaporeans. It affects only 2 per cent of people aged 18 to 29, but nearly 30 per cent of those aged between 70 and 79.

MOH said the baseline prevalence of TB in the affected block is expected to be up to 23 per cent, after considering factors such as its demographic profile. "The rate of latent TB among those who were screened on-site... is about 22 per cent, within the upper end of the expected baseline prevalence range."

Screening results from another 12 people who got their tests done at Sata CommHealth clinics, as well as those who were screened last Saturday, are still pending.

Screening ends at block where TB cases were found
By Linette Lai, The Straits Times, 20 Jun 2016

About 230 people have been screened for tuberculosis at an Ang Mo Kio block where a cluster of multi-drug-resistant TB cases was identified recently.

The Ministry of Health (MOH), giving an update at the end of its on-site TB screening at the void deck, said that the residents and former residents had been tested at Block 203, in Ang Mo Kio Avenue 3, since screening started last Thursday.

Of these, nine said they had a cough for more than three weeks, and were referred to Tan Tock Seng Hospital's TB Control Unit for further tests. Another 13 aged five and below were given screening appointments at the unit as the tests are different for young children.

About 350 people live in the block.

MOH said that it expects to detect some cases of latent TB - when a person has TB bacteria in his body but there are no symptoms, as such infections are not uncommon in the general population.

These may not be related to the cluster.

In what the ministry said was a "highly unusual occurrence", six residents in the block were diagnosed with the same strain of multi-drug-resistant TB over a four-year period.

MOH added that its officers and grassroots volunteers had reached out to more than 80 per cent of households in the 160-unit block by going door to door. Those tested will get their screening results within two weeks.

The ministry added that it has made arrangements for residents and former residents who lived in the block from July 2011 to be screened free of charge at any Sata CommHealth clinic until the end of the month. After June 30, they may make an appointment to be screened at the Tan Tock Seng Hospital's TB Control Unit.

Doctor connected six cases over four-year period
By Linette Lai, The Straits Times, 17 Jun 2016

It was in October last year that the red flags were first raised.

Dr Cynthia Chee, a senior consultant at Tan Tock Seng Hospital's TB Control Unit, and her team realised that a patient diagnosed that month lived in a block of flats where several others had been diagnosed before with the same strain of multi-drug resistant tuberculosis.

When another case surfaced last month, she knew it was time to act.

"The significance was not clear to us at that time," said Dr Chee, about last October's discovery. "Then another case surfaced, and I just felt that it was something that MOH (Ministry of Health) should know about."

After more digging, it came to light that, altogether, six people in Block 203, Ang Mo Kio Avenue 3, had fallen prey to that particular strain of bacteria over a four-year period.

How this happened is still puzzling doctors as the patients came from four different households. Aside from three who were from the same household, the patients said they did not know or interact with one another.

The TB bacteria typically require close contact over a long period of time to spread.

Dr Koh Poh Koon, an MP for Ang Mo Kio GRC and a medical doctor, told reporters yesterday that Dr Chee was "very astute" to have noticed the pattern. "All of us see many patients on a daily basis, and the amazing thing is how she connected six patients over a four-year period."

Doctors were able to ascertain the cases were linked as the DNA fingerprints of TB cases in Singapore are recorded.

If the strains of two people match - as they did in the Ang Mo Kio case - then it is likely that they have been in close contact.

Fingerprinting makes it easier to track the spread of TB than the traditional method of contact tracing, or asking an infected person who he has been in contact with.

"It's very, very challenging," Dr Chee said. "People don't want to tell us about where they have been because there is a fear of stigmatisation from family or friends. Some are afraid they will lose their jobs."

Mystery over how 6 patients ended up with same TB strain
Other than the three from the same household, they did not know one another
By Linette Lai, The Straits Times, 16 Jun 2016

How six people from four different households managed to pick up the same strain of multi-drug resistant tuberculosis (TB) is a mystery.

The six patients told Health Ministry officials that apart from the three from the same household, they did not know or interact with one another and had not congregated at common areas. They ranged in age from early 20s to 70.

The index case was a man who was first diagnosed with drug-resistant TB in February 2012. Another member of his household was diagnosed with the same strain three months later. That year, a woman living in the same unit was also diagnosed with a latent form of TB. This meant she would have shown no symptoms of the disease. However, in October last year, she too developed an active infection.

In May 2014, one of their neighbours was diagnosed with the same strain of TB. A fifth person was diagnosed in October last year.

When a sixth case came to the attention of a doctor at Tan Tock Seng Hospital's (TTSH) TB Control Unit, she noticed it was the same TB strain as that of another patient living in the same block, and notified the Ministry of Health (MOH).

The authorities declined to provide many details about the six, to maintain their privacy. However, they confirmed that two households were located on the same floor, with the other two some distance away.

Dr Jeffery Cutter, director of the communicable diseases division at MOH, said it was highly unlikely the patients could have caught TB by sharing the same lift, for example.

"It's possible, but we think that the likelihood is low," he said. "TB transmission requires close and prolonged contact." Even among members of the same household, the TB bacterium may take days or weeks to spread. It cannot be caught by touching a surface that an infected person has coughed on.

Professor Sonny Wang, director of the TB Control Unit at TTSH, said he believed there might have been contact between the six people which doctors could not identify. "We had some difficulty in getting people to divulge their daily activities to us, and they would tell us only the obvious things, like they went to work... and so on," he said.

"Maybe they were indeed not close contacts, and they were casual contacts, in which case we think that this is a very unusual situation because this is not the way TB ordinarily spreads."

What you need to know about TB
The Straits Times, 16 Jun 2016

Q What is tuberculosis? A Tuberculosis, or TB, is a mycobacterial disease that usually affects the lungs.

It can also affect other parts of the body, including the brain, lymph nodes, kidneys, bones and joints.

It can be fatal if not treated properly, and the disease is a major cause of death and disability in many parts of the world.

Initial infection usually goes unnoticed as a condition known as latent TB infection (LTBI).

About a tenth of adults with healthy immune systems who have LTBI will eventually develop TB.

Q How is TB spread?

A The airborne disease is spread through fine respiratory droplets from an infected person.

Those who have TB are most likely to spread it to people with whom they have close and prolonged contact, such as family members, friends and co-workers.

One cannot contract TB from sharing eating utensils, food, cigarettes, or kissing or shaking hands.

Q How is TB treated?

A The disease is curable and treatment usually involves a combination of several drugs taken for six to nine months. More than 95 per cent of patients are cured if they take the prescribed medication. Multi- drug-resistant TB requires 20 to 24 months of treatment.

Q How prevalent is TB here?

A There were 1,498 new cases among Singapore citizens and permanent residents last year, bringing the incidence rate to 38.4 per 100,000 resident population. Singapore has the second-lowest incidence of TB in Asia, after Japan. Based on reported cases, it is more prevalent among older men.


Worried residents say they'll get screened
By Yeo Sam Jo, The Straits Times, 16 Jun 2016

Some residents were very worried, others much less so, after being told last night that six of their neighbours had been diagnosed with the same drug-resistant strain of tuberculosis (TB).

They were informed by representatives from the Ministry of Health (MOH), grassroots volunteers and Ang Mo Kio GRC MP Koh Poh Koon. Split into teams, the group of about 10 went from door to door at Block 203, Ang Mo Kio Avenue 3, encouraging residents to go for a free TB screening that will be provided at their void deck from today till Sunday.

"Of course, I'm scared, and I'm worried for my family," said 34-year-old delivery attendant Fazli Sahat, who lives with his wife and two teenage sons on the ninth storey of the block of two-room rental flats. "I've told them we must all go for the check-up and get any medical treatment if we need to."

One floor up lives telemarketer Mumtaz Begum Syed Yusope, 42, her elderly mother and uncle.

"It's weird that something like this can happen," she said, referring to how six people in the same block got the disease over four years. The first patient was diagnosed in 2012, and the last in May this year. "But I'm glad that they are giving us free check-ups - especially for the elderly folk who are more vulnerable," added Ms Mumtaz.

The screening, which takes about 15 minutes and includes a blood test and a chest X-ray, is being provided free, along with any subsequent treatment if necessary.

When The Straits Times visited the block at around 8pm, grassroots volunteers and MOH officers were setting up tables and chairs at the void deck for the screenings. Dr Koh was chatting with residents in their homes. He said he would speak to the media only later.

Letters in four languages containing information on the free screening and frequently asked questions about the disease were also distributed to residents.

Madam Joanne Yeo, who lives with her sister and son on the eighth floor of the 11-storey block, was not too concerned. The 53-year-old, who is unemployed, said her family does not interact with their neighbours very much.

"If I am coughing badly, I'll just go straight to the doctor," she added.

But others said they would rather be safe than sorry. Part-time cleaner Phua Geok Lian, 68, who lives on the fifth floor with her husband, said: "It's no use worrying too much. But we will go for the check-up just for peace of mind."

The screening will be available from 9am to 9pm. Those unable to have it done at Block 203 can walk into any Sata CommHealth clinic from June 20 to 30. Parents with children under five are encouraged to take them to Tan Tock Seng Hospital for a skin test.

Former residents who lived in the block from July 2011 can also go for screening at any Sata clinic until June 30. After that, residents and former residents can make an appointment at the TB Control Unit.

• For more information, residents can call 6325 9220 or e-mail

TB screening station set up at Ang Mo Kio block
About 70 current and former residents of affected block undergo tests after outbreak
By Linette Lai, The Straits Times, 17 Jun 2016

A tuberculosis screening station was set up yesterday at the Ang Mo Kio housing block where a "highly unusual" outbreak of the disease was revealed earlier this week.

Around 70 people - both residents and former residents of the block - were tested for the disease.

The screening took place at the affected block in Ang Mo Kio Avenue 3, which houses around 350 people. Results from blood tests and X-rays will be made available to residents within two weeks.

Many living in Block 203 said they were going as a precaution.

The Ministry of Health (MOH) revealed on Wednesday how six residents of the block were diagnosed with the same drug-resistant strain of the disease between February 2012 and last month.

The four households involved said they did not know one another and had not interacted. However, TB transmission typically requires "close and prolonged contact".

The Straits Times understands that the first patient in this cluster, who was diagnosed in February 2012, is linked to another drug-resistant TB outbreak, reported in 2013, which was traced to three cybercafes in Parklane shopping mall.

The ministry informed the block's residents about the situation on Wednesday night and started screening at 9am yesterday.

Residents were asked questions such as if they or their family members had a history of TB, as well as whether they had been coughing.

"My neighbour coughs a lot - I can hear him at home and it's been going on for a few months," said retiree Khoo Bah Tee, 73. "But I'm not worried (as) we don't talk to each other."

Madam Tew Sui Hong, 74, did not go for screening, saying she felt well. "If you feel sick, you'd know it - you'll be coughing and feeling weak. I feel perfectly healthy, so I don't see a need to go down," she said.

Dr Koh Poh Koon, who is an MP for Ang Mo Kio GRC, visited the screening station yesterday to speak with residents. "It's important that they understand what TB is all about, and to allay their anxiety," he said.

Dr Koh joined MOH officers and grassroots volunteers on Wednesday night to explain the situation and distribute leaflets to residents.

They will continue to do so for the next few nights. "Some might be overseas, some may not be at home at the time we visit, but we will make sure that the information is put under their doors," Dr Koh said.

Resident Siti Hasmah Nordin, 30, a housewife, said: "I was shocked when I heard about it and I want to know more because I'm worried for my (eight-year-old) daughter."

Additional reporting by Cheryl Lin

TB cases in Ang Mo Kio: Risk of an epidemic low, no cause for panic, say experts
By Clement Yong, The Straits Times, 17 Jun 2016

A "highly unusual" outbreak of six tuberculosis cases within a period of four years at Block 203 in Ang Mo Kio has brought a forgotten disease back into the spotlight.

Even as the block's residents queued up for TB screenings yesterday, the Government and healthcare experts have assured the public that the risk of an epidemic is low.

TB, especially its multi-drug resistant strain, is not that common. According to statistics released by the Ministry of Health (MOH), the incidence of TB among Singaporeans and permanent residents last year was 38.4 per 100,000 - the second lowest in Asia after Japan.

Multi-drug resistant TB, which the six Ang Mo Kio residents were diagnosed with, makes up just a small fraction of total cases.

Dr Jeffrey Cutter, director of the MOH's communicable diseases division, puts its incidence rate at less than 1 per cent of total TB diagnoses. Last year, Singapore saw fewer than 10 such cases out of almost 1,500 TB cases observed.

TB is spread through fine respiratory droplets from an infected person. Those with TB are most likely to spread it to people in close and prolonged contact, such as family members, friends and co-workers.

While TB can be fatal - there were 55 TB deaths in 2014 - doctors The Straits Times spoke to emphasised that it can be treated.

"Unlike HIV or diabetes, which are chronic diseases, TB is gone once the patient completes his medication regimen," said Dr Leong Hoe Nam, an infectious diseases specialist at Mount Elizabeth Novena Hospital.

Dr Wong Wei Mon, deputy medical director of Raffles Medical, said regular TB typically requires six to nine months of treatment involving a cocktail of drugs; patients with multi-drug resistant TB are given less common second-line drugs for a longer period of "up to 18 months".

Regular TB patients can return to work or school after two weeks of treatment as they become non-infectious. Those with the more resistant strain have to stay in hospital longer so doctors can ascertain suitable drugs to prescribe.

Dr Ong Kian Chung, a respiratory specialist at Mount Elizabeth Hospital, said most TB patients undergo treatment where medication-taking is supervised to facilitate adherence, in line with international practices.

Dr Cutter encouraged Singaporeans not to shy away from TB screenings. "Early detection is key. Almost all TB cases are eventually treated... There is no cause for panic."

Remove TB stigma to better fight the disease
Tuberculosis, or TB for short, is an ancient disease of man caused by the bacterium Mycobacterium tuberculosis, first discovered in 1882 by the celebrated German microbiologist Robert Koch.
By Hsu Li Yang, Published The Straits Times, 17 Jun 2016

Tuberculosis, or TB for short, is an ancient disease of man caused by the bacterium Mycobacterium tuberculosis, first discovered in 1882 by the celebrated German microbiologist Robert Koch.

It is in many ways a slow infection. TB is typically spread by prolonged and close contact with a person with active pulmonary (lung) TB. The majority of infected persons clear the bacterium spontaneously, while a minority contain it without any outward manifestation of the disease. This is termed latent TB, which is non-infectious.

Only a minority of persons with latent TB progress to develop active symptomatic TB in their lifetime, usually months to years after the original exposure. Because the most common presenting symptom of active TB - coughing - is shared by many other viral and bacterial infections, the disease is often diagnosed late, giving the bacterium further opportunity to spread despite its relative inefficiency at doing so.

Singapore has been a model for TB control, reducing the incidence of this contagious airborne disease almost tenfold between 1960 and the mid-2000s. However, the local burden of disease remains significant, with 1,498 newly diagnosed cases of active TB among Singapore residents last year. The challenges of maintaining and improving on past results are manifold, and include ensuring that persons with active TB complete a protracted (usually six months) course of a cocktail of anti-TB drugs, as well as improving on contact investigations - a process to identify persons who have been exposed to the TB germ and are at high risk of infection.

Comprehensive contact investigation helps prevent further spread of TB by offering a window of opportunity for preventive treatment of infected individuals prior to the development of active contagious TB. However, the public fear and stigma of TB in Singapore has not fallen to the extent that persons with active TB infection will divulge their close contacts or voluntarily ask these people to go for TB screening for fear of being identified and stigmatised.

Multidrug-resistant TB (MDR-TB) is a term used to describe a drug-resistant form of the infection where the two "backbone" drugs of the anti-TB cocktail - isoniazid and rifampicin - are no longer effective against the bacterium. The phenomenon of MDR-TB did not arise spontaneously, but is a consequence of numerous instances of incomplete adherence to TB treatment, facilitated in several parts of the world by the rising HIV epidemic in the 1980s to 90s.

MDR-TB compounds the challenges of TB control drastically. Treatment of active MDR-TB infection results in lower success rates compared with drug-susceptible TB despite a treatment regimen that is more toxic, costly and which takes twice as long to complete. For persons with latent MDR-TB infection, there is also insufficient evidence that preventive treatment is effective. Singapore is fortunate in that our MDR-TB rates have remained low, at less than 1 per cent of all TB cases last year. The majority of our MDR-TB cases are imported, with no reported subsequent secondary infections locally.

Given what we know of TB, the recent cluster of cases at a Housing Board block in Ang Mo Kio is unique for several reasons. Firstly, it is MDR-TB, which escalates the stakes for prevention of further transmission. Secondly, the infected persons appear not to have any focal point of prolonged close proximity usually necessary for the transmission of TB.

Many would presume that the TB transmission occurred in common lifts or because of the "crowded" living conditions in an HDB block. However, if such assumptions are true, we would have seen more reported TB case clusters in apartment blocks previously. Yet, according to the Singapore Tuberculosis Elimination Programme's registry, with the exception of case clusters within a single household, less than 2 per cent of TB clusters (defined via molecular fingerprinting of the bacterium) over the past 10 years actually share identical housing block addresses. That living in the same apartment block is not a risk factor for the spread of TB is also borne out by international experience.

Moving forward, the unique features of this Ang Mo Kio MDR-TB cluster warrant more detailed and extensive investigation in order to determine how it has occurred as well as to identify others who may have been infected.

We need better public education and communication to increase awareness of TB, and remove the stigma from TB, which in turn will lead to better contact investigations and reduction of the spread of the bacterium. Better community support, especially from employers, will be welcome and will help improve treatment adherence of patients on anti-TB therapy, which will reduce the risk of the emergence of drug resistance.

The writer is an associate professor and programme leader of the Anti-microbial Resistance Programme, NUS Saw Swee Hock School of Public Health.

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