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Understanding Tuberculosis

  • 02 Feb 2024
  • 3mins

In January 2024, the Ministry of Health announced that around 3,000 people in the Jalan Bukit Merah area of Singapore were set to go for a mandatory tuberculosis (TB) screening. It is a precautionary move that came after 10 cases of TB were linked to the area.

Despite the TB cluster, infectious disease specialist Dr. Loh Jiashen asserts this is nothing to be alarmed about. Dr. Loh spoke in an interview with CNA’s Asia First where he shared more about the current prevalence of TB in Singapore, how concerned you should be about it, and what you can do to lower your risk of TB.

What is Tuberculosis

Tuberculosis, otherwise known as TB, is an air-borne virus caused by Mycobacterium Tuberculosis. The mycobacteria usually attack the lungs, which results in pulmonary tuberculosis, but they can spread to other parts of the body, such as the brain, lymph nodes, kidneys, bones, and joints, resulting in extrapulmonary tuberculosis.

Symptoms of TB

There are three stages of TB:

Primary Infection

This happens when your immune system is able to capture and kill the tuberculosis mycobacteria; however, some mycobacteria still managed to survive and multiply. People suffering from a primary infection tend to exhibit flu-like symptoms such as a low fever, fatigue and coughing.

Latent Infection

Primary infection is typically followed by latent infection, where the infected person will exhibit symptoms of TB but it has not yet developed into active TB. One way to know if you are down with TB during a latent infection is through positive results on a TB blood test or tuberculin skin test. The latent TB germs cannot be spread to others. However, the TB mycobacteria can become active and turn into the TB disease.

Active Infection

An active TB infection happens when the immune system is unable to control the infection from multiplying and spreading throughout the lungs or other parts of the body. People suffering from an active infection can spread the disease to others. Symptoms of an active TB infection include coughing up blood or mucus, chest pains, pain when breathing or coughing, night sweats and a loss of appetite.

According to Dr. Loh, if you have been suffering from a chronic cough for more than one to two months, it is worth getting it checked out by your doctor to try and diagnose what’s wrong.

“Fatigue and unexplained weight loss, these are all also red flags for a person to seek medical attention,” Dr. Loh adds.

How it spreads

TB is spread through the air from one person to another. The droplets containing the TB mycobacteria must be inhaled by the other person for it to spread. This means being near someone infected with TB when they cough, speak or sing will put you at risk of contracting the disease.

This also means sharing utensils with the infected person, as well as kissing or shaking hands with them, does not spread the disease. However, being in close contact with someone who has TB over a period of time will increase your risk of catching the disease from breathing air that has been saturated with the TB mycobacteria.

TB in Singapore

According to Dr. Loh, Singapore has had a long history with TB.

The disease was prevalent in the 1950s, with a mortality rate of 72 per 100,000 men and 31 per 100,000 women. An immunization programme was later introduced for newborn babies. Since then, the rate of TB in Singapore has been on the decline, and it has become endemic in Singapore, with latent TB infection not being uncommon in our population. In 2022, there were 1,251 new cases of TB recorded, a decrease from the 1,300 cases recorded in 2021.

Currently, there are about 30 to 35 new and active cases per 100,000 in the population per year. Thus, Singapore is considered to have a moderate incidence rate of TB, with a high incidence rate ranging around 50 to 100.

“So, we are in [the moderate] range, and it seems to have plateaued over the last few decades, or stabilised over the last few decades,” Dr. Loh stated. “Most of the cases here are sensitive to oral treatment. We have like less than 1% of very, very resistant tuberculosis.”

Lowering your risk of TB

Although TB is not a big concern in Singapore, you can still take steps to lower your risk of being infected with a few simple precautions:

  • Have good ventilation in your room, as TB can remain suspended in the air for a long period of time with no ventilation
  • Have natural light, as UV light kills off the TB mycobacteria
  • Practice good hygiene; wear a mask to prevent inhaling air droplets infected with TB, or if you are infected, wear a mask or cover your mouth and nose when coughing or sneezing.
  • Have a healthy immune system
Contributed by

Dr. Loh Jiashen
Infectious Disease Specialist
Farrer Park Hospital