Tuberculosis (TB) is a bacterial infection, spread by inhaling tiny droplets of saliva released through the cough or sneeze of an infected person. It affects the lungs primarily, but can spread to almost any part of the body. Before antibiotics, TB was a major problem and resulted in many deaths.
What causes it?
Tuberculosis is caused by a strain of bacteria called mycobacterium tuberculosis. It is spread when someone with an active infection in their lungs coughs or sneezes and another person inhales droplets of the saliva.
However, despite the fact that it is spread in the same way as Influenza (flu), TB is not as contagious, according to the NHS, and a person would usually need to spend a considerable amount of time in close contact with the patient before contracting it themselves.
It is therefore often spread between family members and others who live together. It is unlikely to get TB from sitting next to someone who is infected on the bus or train. The very young, elderly and those with pre-existing health conditions affecting their immune system (such as HIV/AIDS) are more likely to contract TB. The risk is also heightened for those who live in a community or have received visitors from a part of the world where TB is still commons.
There are three types of TB and three ways in which the body could react to the infection. The NHS outlines these:
- Your immune system kills the bacteria, and you experience no further symptoms. This is what happens in the majority of cases.
- Your immune system cannot kill the bacteria, but manages to build a defensive barrier around the infection. This means that you will not experience any symptoms, but the bacteria will remain in your body. This is known as latent TB but could develop into active TB at a later date if the immune system becomes weakened.
- Your immune system fails to kill or contain the infection and it slowly spreads to your lungs. This is known as active TB.
TB does not usually cause any symptoms until it reaches the lungs. As the bacteria are slow moving, it may take months or even years for any symptoms to surface. When they do, they commonly include, according to the BBC:
- A persistent cough, usually lasting longer than three weeks – it may be dry to start with but eventually bring up bloody mucus
- Night sweats for weeks or months
- Weight loss
- High temperature
In some cases, TB can spread from the lungs to other parts of the body (this is called extrapulmonary TB) causing a host of different symptoms:
- Lymph nodes – this causes the nodes to swell up and, over time, begin releasing fluid
- Genitourinary – this can cause groin pain and blood in the urine
- Gastrointestinal – this can cause abdominal pain, diarrhoea and bleeding from the rectum
- Skeletal – this leads to bone weakness and pain, loss of feeling and curving of the affected bone or joint
- Central nervous system – this can lead to headaches, vomiting, blurred vision and seizures
[adsense]How is it treated?
It is important to seek immediate medical advice if you suspect that you may have TB. The illness takes a long time to leave the body and is usually treated through a course of different antibiotics over 6 months.
A vaccine is available and recommended to those who are more at risk of being exposed to the bacteria – by living with someone who has the illness, for example, or travelling to a country where TB is still common.
Images: Wikimedia Commons and EOL