betty July 3, 2022

SINGAPORE – The Ministry of Health (MOH) announced on June 24 that about 170 people at 2 Jalan Bukit Merah tested positive for tuberculosis (TB). The tests were offered to residents and workers at the block after seven people there were diagnosed with the disease between February 2021 and March this year.

The Straits Times answers some of your questions about the disease.

Q: What is TB and how does it spread?

A: TB is an infectious disease caused by a bacteria called Mycobacterium tuberculosis. The air-borne disease spreads when an infected person coughs, sneezes or breathes, and a person nearby inhales the expelled infected droplets in the air.

Transmission of TB often requires close and prolonged contact with an infected individual. TB does not spread via contact with items or surfaces touched by an infected person – unlike Covid-19.

People living in the same household and close workplace colleagues are at a higher risk of being exposed to TB and getting infected.

Q: What are the types of TB?

A: There are two types – latent and active.

For some people, the body’s immune system naturally kills the TB bacteria when it enters the body and they are unaffected.

In others, the immune system might be unable to kill the bacteria but is able to prevent it from spreading in the body. This is known as latent TB, where the bacteria is suppressed but “asleep” in the body.

Those with latent TB are not ill, will not have any symptoms and are not infectious to others.

However, latent TB can later become active TB when immunity wanes – with the United States Centres for Disease Control and Prevention (CDC) estimating that, without treatment, 5-10 per cent of infected people will develop active TB at some point in their lives.

Active TB, also known as TB disease, is when the body fails to kill or contain the bacteria, making the person ill. An individual with active TB will have symptoms and can potentially spread the disease to others.

About half of the people who develop active TB will do so within the first two to three years of being infected.