You get TB, that is you contract TB, by breathing in the TB bacteria that cause TB and that are in the air. The bacteria get released into the air by someone who already has the TB bacteria in their body. TB is spread from one person to another through the air.
When a person with TB of the lungs or throat coughs, sneezes, sings or talks, droplets containing the bacteria are released into the air. That is why people who think they may be infectious, may often hold something over their mouth when they are near to other people. People working in a health clinic may also for this reason sometimes wear a mask.
People are not equally infectious. Generally it is only people with TB of the throat or lungs who are infectious. Also, the most important factor is whether someone is on effective TB treatment. TB treatment dramatically reduces the number of infectious droplets released by a person. The strength of a person’s cough can also affect the number of droplets released.
How you don’t get TB
- through food or water,
- or by kissing,
- or by skin contact such as shaking hands,
- or by touching a toilet seat,
- or by sharing a toothbrush,
- through clothing,
- or by giving an infected person a hug or a kiss.
Myths about how TB is spread
In many countries the public is not very well informed, and there are many myths about how TB is passed on. As a result many people believe that TB is hereditary or can be spread through food and water.
In developing countries a major effect of the resulting stigma and discrimination can be the social isolation of patients, both within and outside of the family. Within the family the patient may be forced to eat and sleep separately because of the fear of transmission. Patients may even isolate themselves to avoid infecting others. Education needs to be a major part of TB prevention.
One day I went to visit a family with my sister. While we were there I asked for water. The father gave me a glass of water, but my sister stopped me from drinking it. This confused me and really upset the man. We said nothing about it, but when we left my sister told me that people suspected he had TB, and touching the glass might have given me TB.
There are also myths about how TB can be cured. In 2019 the Chief Minister of Uttarakhand in India, said that living in close proximity to a cow could cure a person of TB,which of course it can't.1Press Trust of India, "Cows exhale oxygen, can cure Tuberculosis", 2019, https://www.firstpost.com/india/cows-exhale-oxygen-can-cure-tuberculosis-uttarakhand-cm-trivendra-rawats-bizarre-claims-spark-row-7063391.html
How do you stop the spread?
The spread of TB is stopped by firstly finding the adults who have TB. Particularly in countries with a high burden of TB, awareness of TB must be raised so that people with symptoms of TB know they should get help.
People with TB disease must then be provided with effective TB treatment which means that they will no longer be infectious and can no longer spread TB to other people. They will also usually then recover from being sick although the treatment for TB takes a long time.