March 24: World Tuberculosis Day

Edward Johnson, hi-tech and engineering expert, March 24, 2025

What is tuberculosis?

Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis, also known as Koch's bacillus, discovered by Robert Koch in 1882. It usually affects the lungs (pulmonary tuberculosis), causing a persistent cough with bloody sputum, rapid weight loss, fever and night sweats. However, it can also affect other organs, such as the kidneys, brain or spine (extrapulmonary form).

Available treatments

Standard treatment includes four antibiotics: isoniazid, rifampicin, ethambutol and pyrazinamide, taken daily during the first two months, followed by a maintenance phase with isoniazid and rifampicin for four additional months. However, given the emergence of drug-resistant strains, particularly in Russia, China and South Africa, more powerful drugs such as bedaquiline or delamanid are now being used.

Tuberculosis around the world

Nearly 10.6 million new cases were recorded in 2022, according to the World Health Organization (WHO). More than 95% of them occur in developing countries such as India (around 2.8 million cases), Indonesia (around 969,000 cases), China, Nigeria and Pakistan. In sub-Saharan Africa, the situation is particularly worrying due to the association of tuberculosis with HIV, particularly in South Africa, where the co-infection rate reaches 50 to 60%. This double threat is responsible for a large share of the 1.3 million deaths linked to the disease each year.

How is tuberculosis transmitted?

Tuberculosis is transmitted through the air when an infected person releases contaminated microdroplets by coughing, sneezing or simply talking. A single contagious person can infect on average between 10 and 15 other people per year in poorly ventilated environments, such as public transport, schools, or overcrowded housing in large cities like Lagos, Mumbai or Manila. The risk of infection depends particularly on the duration of exposure to the bacterium, physical proximity to the sick person, and the immune status of the exposed individual. For example, immunocompromised people, particularly those infected with HIV, face an increased risk of developing the disease after being exposed to Koch's bacillus.