Tuberculosis (TB)

Overview

Tuberculosis (TB) is an infectious disease caused by the bacteria Mycobacterium tuberculosis. It primarily affects the lungs, although it can also spread to other parts of the body. While treatable and curable, TB remains a significant public health concern globally.

Disease epidemiology

Global

TB is the second leading infectious killer worldwide, after COVID-19, according to the World Health Organization (WHO). In 2022, an estimated 10.6 million people fell ill with TB, with 1.3 million deaths.

About a quarter of the global population is estimated to have been infected with TB bacteria, although not everyone develops the active TB disease.

Local

In 2023, there were 1,201 new cases of active TB disease among Singapore residents. This is lower than the 1,251 cases in 2022. The incidence rate was 28.9 cases per 100,000 population in 2023, compared to 30.4 cases per 100,000 in 2022.

TB is endemic in Singapore, and latent TB infection is not uncommon in our population.

For the latest updates, visit the Ministry of Health website.

Pathogen

Mycobacterium tuberculosis

Transmission

Transmission Route

TB is an air-borne disease and is transmitted through close and prolonged exposure to an infectious individual with untreated, active pulmonary (lung) TB disease. Not all individuals who are exposed to an infectious individual will get TB.

Infectious period: Individuals with active TB disease are infectious until they have completed effective treatment.

Incubation period: 2 to 8 weeks, but can be much longer (years).

Clinical features

Symptoms

• Persistent cough (two weeks or more)

• Fever

• Night sweats

• Weight loss

• Fatigue

• Loss of appetite

• Chest pain

Sequelae

• Untreated TB can lead to severe lung damage, disability, and death

• It can also spread to other parts of the body, causing serious complications

Risk factors

The risk of developing TB disease is higher for:

• Individuals with weakened immune systems, such as those with HIV/AIDS, diabetes, or suffering from malnutrition

• Individuals in close contact with someone with TB

• Individuals living in crowded or poorly ventilated conditions

• Individuals who abuse substances (including smoking)

• Individuals with certain medical conditions

• Children and the elderly who are more vulnerable

Diagnosis

Diagnosis of active TB disease involves various methods, including:

• Chest X-ray

• Sputum culture and microscopy

• Molecular tests (e.g., GeneXpert)

Diagnosis of latent TB infection (LTBI) may require an interferon-gamma release assay (IGRA) test or a tuberculin skin test (TST).

Treatment and management

TB is treated with a combination of antibiotics for several months. It is crucial to complete the full course of treatment to prevent drug resistance and ensure cure.

In some cases, hospitalisation and isolation measures may be necessary.

Precaution, prevention, and control

General advice

• Maintain good ventilation in living spaces

• Practice good cough etiquette (e.g., cover your cough or sneeze with a tissue)

• Frequent hand-washing soap and water

Advice for high-risk groups

• Individuals identified as having latent TB infection (LTBI) may be offered preventive treatment to reduce their risk of developing active TB disease

• People at high risk for TB exposure should be vigilant about symptoms and seek prompt medical evaluation if any concerns arise

Notification

TB is a notifiable disease in Singapore. Medical practitioners and laboratories are required to notify MOH of suspected or confirmed TB cases. Please refer to the Infectious Disease Notification for more information. 

Resources