TB: The forgotten disease

PHOTO: TB: The forgotten disease

Tuberculosis (TB) is still a threat in SIngapore even if the numbers are low and other infectious diseases like Influenza A (H1N1) now garner headlines.

Doctors warn that the figures may rise again here, given the emergence of drug-resistant TB germs and the influx of foreign workers and visitors.

TB is a contagious disease that spreads by air, mainly via cough droplets. It is caused by the germ Mycobacterium tuberculosis.

The germs may remain latent in the body or become active, resulting in the disease.

When TB germs enter the body, the body's protective system usually contains them and the infected person may not know he has the latent form of the disease, said Professor Sonny Wang, the director of the TB Control Unit at Tan Tock Seng Hospital (TTSH).

Only about one in 10 among those infected will get the active form of the disease, with half of them falling ill within the first two years and the rest getting the disease within their lifetime, he added.

The symptoms include a chronic cough, unexplained weight loss, chest pain and blood in the sputum.

Since many of the symptoms are similar to those of other ailments, they are often overlooked.

Some TB diagnostic tests are also not always foolproof, said Dr Yeo Chor Tzien, a respiratory specialist at Gleaneagles Medical Centre.

For example, chest X-rays, the most common method, do not always show that someone has the germs.

Other methods include sputum tests and a special skin test to detect the presence of TB bacteria. More than one type of test may be needed to confirm the type of germ present and this can take up to two months.

Once TB is detected, treatment is in the form of a daily cocktail of pills for six to nine months. Some patients require injections at the start of their treatment.


Compliance problem

Compliance problem

Despite the need to adhere to this regimen, up to half of the patients fail to comply, Prof Wang said.

As a result, 'wayward' patients are put on Directly Observed Therapy (DOT).

This is where patients have to visit a polyclinic or the TB Control Unit daily to take the drugs in front of a nurse. Some patients are even compelled under the law to finish their treatment.

When patients do not comply, the disease can relapse and drug-resistant TB germs can develop, explained Dr K. Thomas Abraham, the chief of Singapore Anti-Tuberculosis Association CommHealth (Sata CommHealth).

This risk factor, plus the fact that no new TB drugs have been developed in at least a decade to tackle mutant strains, raise the chances for resistant TB germs to increase, added Dr Abraham.

The World Health Organisation (WHO) has warned of a rise in what is known as multi-drug-resistant TB (MDR-TB) cases, which cannot be treated with conventional first-line drugs.

In 2007, there were more than half a million new cases of MDR-TB worldwide, up from 424,000 cases in 2004. WHO estimates that 5 per cent of all TB cases are MDR-TB.

Here, the number of resistant cases have remained very low so far, with no more than four cases each in 2007 and 2008. However, this may change if more patients do not comply with their treatment, say doctors.


Symptoms of TB

The Symptoms

Sata CommHealth advises those with the following symptoms to seek medical attention:

  • Chronic cough of more than three weeks
  • Unexplained weight loss
  • Chest Pain
  • Lethargy
  • Intermittent fever and night sweats
  • Blood in sputum

Since it is difficult to prevent the disease from coming in, given the inflow of foreign visitors and workers, the only way to stop the number of cases from rising again is to keep transmission down.

Boosting the body's immune system with enough exercise, sleep and nutrition, so that the disease has less of a chance of turning active, can keep the disease at bay, said Dr Yeo.

Practising good hygiene, such as washing of hands and covering the mouth when coughing, can also limit the germs from spreading, he added.

Prof Wang said that support from the community and the workplace will also ensure that patients, especially those on DOT, do complete their treatment.

Dr Anita Menon, a paediatrician specialising in infectious diseases at the Singapore Baby and Child Clinic said that the compulsory BCG vaccination for infants and children here is relatively effective in preventing kids from contracting severe cases of TB. However, BCG's coverage for infection in adulthood varies, she said.

High risk groups

Dr Abraham said that those with symptoms such as a persistent cough or blood in the sputum should see a doctor at once, especially if they are in the higher risk groups.

These include those aged 40 and above; those who have chronic diseases such as diabetes, asthma or hypertension; or those who have lowered immunity as a result of chemotherapy or Aids.

Prof Wang said that as people are now living longer, more elderly people may contract the active form of TB as the latent TB they carry overcomes its waning immunity.

Dr Menon added that children under the age of five are also susceptible because of their low immunity.

If left untreated, one infected person can pass the germs to up to 15 others within a year.

The disease can lead to death as lung tissues are destroyed and the infection spreads. In 2008, 78 people here died from TB, accounting for one in 200 (0.5 per cent) of all deaths.

Prof Wang said: 'TB is an infectious disease that can spread and needs the support of the community to help enforce treatment.'

This article was first published on March 24, 2010 in Mind Your Body, The Straits Times.