Understanding and Preventing Tuberculosis

Dr Leong Hoe Nam, an infectious diseases specialist at Mount Elizabeth Novena Hospital, sheds light on tuberculosis and how we can prevent its spread.

What are the symptoms of tuberculosis (TB)?

The usual symptoms are fever, cough, weight loss, and loss of appetite. If you feel unwell, go and see a doctor. Unfortunately these symptoms are very non-specific. To complicate matters, many individuals may have the active disease and yet not manifest any symptoms.

Is TB treatable?

TB is very easily treated. The patient has to undergo a treatment regime which may last 6 – 9 months or more. In some cases, treatment may persist for as long as 18 months. The treatment usually entails oral medications, and sometimes injection therapy too.

Is there a danger of TB spreading in Singapore? How do we protect ourselves from it?

The nature of TB is to grow innocuously for months. The lack of a sudden deterioration lulls the patient to complacency, and we may not know about it. During this time, the infection may spread between loved ones living in the same household. In other words, the exposure would have passed on before the condition is diagnosed.

If you visit someone with TB, you should wear an N95 mask. If you have already been exposed to the individual (eg. a family member living with you gets diagnosed with the illness), there is no longer a need to wear a mask. Should you be diagnosed with tuberculosis, you can wear a regular surgical mask to prevent its spread. You should also refrain from going out of the house.

What are the dangers of TB that we should be aware of?

TB is an infection caused by a bacteria. It is an infective organism that has been around since Egyptian mummies and beyond. It can infect literally any organ from the lungs to the brain, skin, the urinary tract, the gut and even the reproductive organs. No one is spared of this infection, and you can get this infection again and again.

The long incubation period of TB makes it difficult for people to suspect its presence and diagnose it. In fact, TB is often called a 'masquerader of diseases'. It mimics cancer, but it obviously carries a much better diagnosis than cancer.

TB is usually transmitted through inhaling the bacteria from an infected person. The germs travel to the lungs and take root there, or spread further through the blood stream to the rest of the body. For those who have a strong immunity system, the bacteria can be walled off. It goes into latency or otherwise known as 'latent tuberculosis'. For those with a poor immunity system, it rapidly progresses into disease in the places it takes root. The result is TB in the lungs, brain, gut, urinary tract, etc.

Most patients (about 90%) with latent TB will not develop the disease. The remaining 10% will develop the disease some time in their lifetime. This could even be 30 – 40 years later. However, should the patient have diabetes mellitus, this risk rises to 30% and for those with HIV, it rises to 60%. In other words, the risk of the disease developing depends on the immunity system of the infected person.

I would thus recommend everyone to keep fit and stay healthy.

What is the state of TB in Singapore now? How did it resurface?

In Singapore, an estimated 3,000 new cases are diagnosed every year. We are seeing a similar number of cases yearly. The bulk of the cases (about 90% of patients) has the disease infecting the respiratory system. Many patients have a history of being immunocompromised, ie. having a weakened immune system for a period of time, but the infection also happens to very healthy individuals like you and I.

TB is a disease that has a tendency to resurface in the population. With many more people living much longer now, and some having immunocompromised health conditions (eg. diabetes mellitus, transplanted individuals, chronic renal failure and even AIDS), we are seeing a resurgence of the disease. This is a phenomenon observed all over the world.

The world is also increasingly connected. And individuals may travel to countries of high TB prevalence, bringing back the disease to their home countries.