Tuberculosis (TB): The most contagious killer?


Tuberculosis or commonly referred to as TB is a bacterial infection. TB is such that, most people have it but are unaware. This is because the immune system can contain the bacteria. However, about 10% of these people go on to have active TB. TB is said to kill more people than even HIV/AIDS or malaria. In 2019, about 10 million people had TB and 1.5 million passed on as a result of this infection. People who have TB have to take medications for months or sometimes years to get rid of this infection. Journey with us as we explore this disease.

Tuberculosis (TB)

TB is an infection caused by a bacterium. The reason why TB is dangerous is that it affects the lungs. The lung is the organ responsible for breathing and supplying oxygen to the blood which is sent to every part of the body. Can you imagine the consequences of this infection?

Classification of Tuberculosis (TB)

1. Latent TB: you have the bacteria but your immune system suppresses it so it does no harm and you show no symptoms. You cannot spread the bacteria to others.

2. Active TB: the bacteria cause infection, you can spread to others and it usually occurs when the immune system is down.

How it occurs

The cycle of TB infection

The bacteria responsible for this infection is called Mycobacterium tuberculosis. It is spread from person to person, thus making it contagious. It spreads when droplets containing this bacterium is inhaled. As a person inhales this bacterium, it gets into the lung together with the air breathed in. TB is contagious but it is not so easy to catch. You have to be with a person who has it to get it, hence it is spread usually among workers, relatives other than strangers.

In the lungs, immune cells called macrophages detect the foreigners(bacteria), rush to the bacteria, phagocytose(swallow) them and break them inside their cells. Usually, these cells are successful and can break down the bacteria in the lungs.

Other times, the immune system is not strong due to infections such as HIV/AIDS, diabetes, cancers or even surgery or other factors. When this happens, the macrophages (immune cells) will phagocytose(swallow) the bacteria but will not be able to kill it within. As a result, the bacteria can survive within the immune cell and divide profusely. This happens in other parts of the lungs and they form a colony (groups of macrophages with bacteria that is alive). It affects the different parts of the lungs.

The immune system does not stop there. It secretes enzymes to kill these lung cells (the individual’s lung cells) which have been infected with the bacteria. When this happens, the cells become damaged and this is when infected people begin to experience symptoms such as coughing blood, chest pain and so on.

As made mentioned, the lung is responsible for supplying the body or blood with oxygen to feed other organs and tissues. When the lungs become infected and their cells are damaged the workload increases because now, not every part of the lung can participate in supplying oxygen. Also, the oxygen demand becomes high and sometimes the lungs are not able to meet all the demand.

The importance of oxygen cannot be overrated. Just like living things such as leaves of plants and roots of plants, organs in our bodies are also living things and need oxygen to survive and function well. If you deprive a leaf of nutrients or oxygen, it begins to wrinkle and shrink and with time, it will eventually die: the same thing happens with our organs. Fortunately, the lungs will continue to work even if some parts are damaged, hence, organs and tissues will continue to receive oxygen but in smaller quantities.

If a person is diagnosed with tuberculosis, drugs will be given to get rid of the bacteria and allow the lung cells to heal, form new cells or recover.

One disadvantage of infection from tuberculosis is that it can travel to other regions of the body. This is because oxygen is supplied from the lung to the blood to be sent everywhere. Hence, the bacteria can get into this blood and travel to other parts such as the brain, kidneys, skeletal muscles, etc.

Symptoms of TB

· Cough for 3 weeks or more

· Cough blood or mucus

· Night sweats and chills

· Fatigue

· Chest pain

· Unintentional weight loss

· Fever

· Loss of appetite

These symptoms may be an indication of another disease other than TB. The best decision is to get tested when you experience these symptoms.

Complications of TB

TB can travel to other parts of the body. The part it affects will determine the severity of complications.

· Meningitis when it gets to the brain.

· Spinal pain when it reaches the spinal cord.

· Liver or kidney damages.

· Arthritis when it gets to the joint.

· Rarely, complications in the heart.


Tuberculosis (TB) dates way back into the past. Some archaeologists discovered 9000-year-old skeletons whose bones were infected with TB bacteria. Since that time, so much has been done to reduce and find a cure to this disease: From a German physician-Robert Koch identifying that bacterium causes TB to physicist Wilhelm Rontgen discovering x-ray to detect the infection in the body to 1921 when scientists eventually ended up with a TB vaccine- Bacillus Calmette-Guerin (BCG). The vaccine is usually effective and given at childbirth since TB is one of the six killer childhood diseases.

Now, there is a cure for TB- antibiotics.

However, infected people must take these drugs (antibiotics) for 6-9 months which sometimes comes with side effects. Sometimes, these people are unable to strictly take their drugs or stop along the way. This has caused the bacteria to evolve and become resistant to drugs. It is like beating an enemy but not going through with killing it. Hence, the enemy does not die. It now knows your strategies and finds new ways to hurt you and dodge your attacks. Currently, there are many drugs that the bacteria is resistant to. Below are a few:

· Mono-resistance: this happens when the bacteria is resistant to just the primary drug or first-line anti-TB drug.

· Poly-resistance: it occurs when the bacteria is resistant to more than one primary or first line of anti-TB drugs but not drugs such as isoniazid and rifampicin.

· Multi-resistance: this happens when the bacteria is resistant to the all the above including drugs such as isoniazid and rifampicin.

There are higher types of resistance such as

· Extensive drug resistance

· Rifampicin resistance

Bottom line is that we can help eradicate or reduce TB, if infected people decide to take their medications to the end. People who begin medications are not contagious after the first 2 weeks and can go back to normal life.

Our best bet is the immune system. We can only engage in activities that will keep us fit and good nutrition to strengthen the immune system to avoid getting active TB. For those who have the infection, taking medications as prescribed is the best way to get rid of the infection as well as isolating in the few weeks after infection to reduce transmission.


  1. WHO. Retrieved from

2.   Mayo clinic. Retrieved from



A young lady who is excited to influence the society and world with the knowledge she has acquired.