Tuberculosis (TB) is an infectious disease, which mainly affects the lungs, but can also affect other parts of the body. It is caused by bacteria called Mycobacterium tuberculosis, discovered in 1882 by Robert Koch. Although TB is a serious condition, it can be treated and cured with antibiotics, usually taken for 6 months.
While in high-income countries TB may be seen as a disease of the past, it is still a leading cause of death globally, killing over 1.4 million people in 2019. It is one of the top 10 causes of death worldwide, according to the World Health Organization. This disease has been around for a very long time, with evidence of TB in people dating back as early as 7000 BC.
How is tuberculosis spread?
TB is spread when someone infected coughs or sneezes and releases millions of tiny droplets containing the bacteria into the air. If someone nearby inhales these expelled droplets, they may become infected.
If their immune system fails to kill the bacteria, the microbes spread within the lungs and within a few weeks or months, symptoms such as a cough develop. This is known as active TB.
Can you have tuberculosis without knowing it?
Some people who are infected may keep numbers of the bacteria under control, without eliminating them completely, a condition called latent TB. People with latent TB do not get sick and cannot spread the infection to others. Some may have latent TB all their lives, while others may get sick with active TB years later, when their immune system is weak from another condition, such as HIV.
What are the symptoms of tuberculosis?
The effects of TB can vary from person to person. Common symptoms include a high temperature, a persistent cough, weight loss, night sweats and fatigue. If the bacteria spread outside of the lungs, people may experience headaches, confusion and loss of appetite.
How is tuberculosis treated?
People with active TB are usually given a course of antibiotics for 6 months. After several weeks of treatment, people start to feel better and experience less symptoms, but it is essential they complete the whole 6-month course. Otherwise, some bacteria may remain that have developed resistance to the antibiotics. Cases of drug resistant TB are on the rise globally.
In places where TB is common, or in those who are at high risk, especially children, people can receive a vaccine – also known as the Bacillus Calmette-Guérin (BCG) vaccine. This contains a weakened strain of a related bacterium that causes TB in animals such as cows and badgers. This vaccine is 70 to 80 per cent effective at preventing serious forms of TB in children. It is less effective in adults, although younger adults may still be offered the jab if they are at high risk.