Tuberculosis is a contagious disease that usually affects the lungs, but sometimes also other parts of the body such as kidneys, lymph nodes, and bones. In the past, tuberculosis was often fatal and was referred to as ‘consumption’. Today it can be cured with antibiotics.
For most healthy people, the risk of contracting tuberculosis is low. According to the CDC In 2018, a total of 9,025 TB cases were reported in the US. This is significantly less than in the early 20th century, when tuberculosis was one of the leading causes of death in the country. Although less common than before, the disease remains a serious public health problem in many parts of the world, killing 1.5 million people in 2018.
On 24 March 1882, the German physician Robert Koch isolated Koch’s bacillus (or mycobacterium tuberculosis), the bacterium that causes tuberculosis and that coexisted with humans for thousands of years. This discovery earned him the Nobel Prize for Medicine or Physiology in 1905. The World Health Organisation (WHO) declared 24 March World Tuberculosis Day.
Types of tuberculosis infections:
- Tuberculosis or phthisis. This is the most common form of tuberculosis (about 70% of cases). Bacteria destroy lung tissue, creating cavities. The disease stays in the lungs.
- Extrapulmonary tuberculosis. In this case, the bacteria attack other parts of the body, such as bones, kidneys, lymph nodes, meninges or the central nervous system. Extrapulmonary tuberculosis may or may not be accompanied by pulmonary tuberculosis.
- Disseminated or miliary tuberculosis. (Chest x-ray have a millet-seed-like appearance). The bacteria spread through the bloodstream and attack the entire body. It is therefore pulmonary and extrapulmonary tuberculosis.
How TB is Spread?
Some facts about the transmission of tuberculosis:
- The TB bacillus is spread by droplets of saliva that float in the air when a person coughs, sneezes, sings or plays a wind instrument, not touching an infected person;
- Repeated or prolonged contact with an infected person is usually necessary to become infected;
- Only people with symptoms are contagious;
- A contagious person taking medication is no longer contagious after two or three weeks of treatment
latent vs active tuberculosis
A distinction should be made between Koch’s bacillus infection and active tuberculosis. Latent” or “dormant” infections are very common. It is estimated that almost 1/3 of the world’s population is infected with the bacillus, most of them without knowing it. This is an infection for life. In the vast majority of cases, the bacteria do not cause the disease because the immune system acts on the infection. Sometimes bacteria are completely eliminated from the body, but this is quite rare.
People with a latent infection have no symptoms and are therefore not contagious. If for some reason (e.g. illness) your immune system is weakened, bacteria can multiply. If they multiply sufficiently, this leads to the typical symptoms of tuberculosis. According to WHO statistics, 5-10% of infected people worldwide can become ill. The infection then enters its active phase. The risk of tuberculosis is higher in the first two years after infection.
Tuberculosis in the world
Tuberculosis is classified as a “disease of poverty ” because it occurs most often in environments where the following conditions prevail:
- Poor sanitary conditions
- Lack of medical care
It is therefore persistent in economically disadvantaged countries. According to WHO, one-third of tuberculosis cases are concentrated in the South East Asian region (which includes Indonesia, Cambodia, Thailand, and Vietnam). Africa (especially in the sub-Saharan region) and the Middle East follow closely. These three regions account for 85% of all TB cases. In these countries, the incidence of tuberculosis in prisons is often 100 times higher than in the general population. Refugee camps are also a major problem. Tuberculosis endemic areas are also found in India, China, and Mexico.
In the US, the emergence of antibiotic-resistant strains of bacteria and an increase in international travel led to the reappearance of the disease in the 1990s.
From sanatoriums to antibiotics
Even before their contagious nature, people with tuberculosis were isolated – sometimes by force – to prevent the population from being infected.
The German botanist, Hermann Brehmer, was considered the “inventor” of the sanatorium. When he fell ill, it is said that he went to the Himalayas to wait for death and, to his great surprise, recovered there. He returned to Germany and opened the sanatorium according to the recipe “clean air, fresh weather, sunshine, full rest, lots of food”. Soon these facilities were established in other places in Europe and later in North America.
The development of streptomycin and other antibiotics in the 1940s almost immediately put the sanatorium model for TB out of business. At that time, it was a common belief that in one day tuberculosis would be completely eradicated. This had not yet happened, unfortunately.
Symptoms, people at risk and risk factors for tuberculosis
The symptoms of TB are as follow:
- Moderate fever
- Persistent cough
- Abnormally colored or bloody sputum (sputum)
- Loss of appetite and weight
- Night sweats
- Chest pain while breathing or coughing
- Pain in the spine or joints
Even if the disease occurs without a clear cause, its appearance or activation of a ‘latent’ infection is more likely in people with a weakened immune system for one of the following reasons:
- Diseases of the immune system, such as HIV infection (this infection also significantly increases the risk of developing active TB)
- Childhood (under 5 years old) or old age
- Chronic diseases such as diabetes, cancer, kidney disease, etc.
- Severe medical conditions that require chemotherapy, oral corticosteroids, strong anti-inflammatory drugs, sometimes used to treat rheumatoid arthritis and anti-rejection drugs for organ transplants
- Abuse use of alcohol or drugs
- Working or living in an environment where active TB patients live or gather (hospitals, prisons, homes), or manipulating bacteria in a laboratory. In this case, regular skin tests are recommended to determine whether or not the patient has been infected.
- Being in a country where tuberculosis is common
- Being underweight
- Prevention of tuberculosis
Basic preventive measures
Hygiene measures must be observed. For people who have frequent contact with tuberculosis patients: wash hands frequently, wear a mask if necessary.
Take care of your health. Eat a healthy and balanced diet, have enough sleep, exercise regularly, avoid chronic stress, etc. This gives you the best chance to have a strong immune system.
Detecting and treating a latent infection. People working in high-risk environments or having long-term contact with an active patient should be tested for the presence of bacteria in the body. If the result is positive, preventive antibiotic treatment usually prevents the disease from developing. This preventive treatment is simpler and requires fewer drugs than the treatment of active TB. For more information, contact your doctor or the competent authorities in your workplace.
Precautions that infected people must take to prevent infecting others. The following must be observed during the 2 to 3 weeks of treatment:
- Stay home as much as possible;
- Get adequate ventilation;
- Wear a mask in public places.
Treatment of tuberculosis
In the active phase of the disease, symptoms (fever, night sweating, persistent cough, etc.) usually occur. The doctor relies on these symptoms, but also on the results of the following tests and examinations.
Skin test. A skin test can detect the presence of Koch’s bacillus in the body. In a newly infected person, this test will be positive 4 to 10 weeks after infection. A small amount of tuberculin (purified Mycobacterium tuberculosis protein) is injected under the skin. If a skin reaction (reddening or swelling) occurs at the injection site within 48 to 72 hours, this indicates an infection. If the result is negative, your doctor may suggest a second test a few weeks later.
Chest X-ray. If you have symptoms of persistent cough, for example, a chest x-ray will be requested to evaluate your lungs. During observation, the chest x-ray also allows the doctor to check the progress of the disease.
Biological analyses on samples of lung secretions. The secretions are first observed under the microscope to check whether the bacteria present belong to the mycobacteria family. The result of this test is obtained on the same day. The secretions are also cultivated to identify the bacteria and determine whether or not they are resistant to antibiotics. However, it takes two months to obtain results.
If the microscopic examination reveals the presence of mycobacteria and the medical evaluation suggests that it is tuberculosis, treatment with antibiotics begins without waiting for the result of the microbiological examination. This is done to relieve and control the patient’s symptoms and to make them less likely to pass the infection to others. If necessary, treatment can be adjusted.
First-line antibiotics can beat tuberculosis in almost all cases. People with TB are asked to stay at home or wear a mask in public places until their doctor determines that they are no longer contagious (usually after two to three weeks of treatment).
First-line treatment. Usually, four antibiotics are prescribed: isoniazid, rifampicin, ethambutol, and pyrazinamide, which are administered orally. To be effective and kill the bacteria completely, the treatment requires medication to be taken daily for a minimum of 6 months, sometimes up to 12 months. All these antibiotics can cause different degrees of liver damage. Tell your doctor if you feel symptoms such as nausea and vomiting, loss of appetite, jaundice, dark urine, or fever without a clear cause.
Second-line treatments. If these bacteria are resistant to the two main antibiotics (isoniazid and rifampicin), it is called multi-drug resistance (MDR-TB) and second-line treatment should be used. Sometimes 4 to 6 antibiotics are combined. They often have to be taken for a longer period of time, sometimes up to 2 years. They can also cause side effects such as numbness in the hands or feet and liver toxicity. Some of them are given intravenously.
Treatments for multidrug-resistance TB. If an infectious strain is resistant to several treatments normally offered in the first and second line, heavier and more toxic treatments, often given intravenously, are used to control this Extensively drug-resistant TB or XDR-TB.
Contraindications. Alcohol and acetaminophen (Tylenol®) are contraindicated throughout the treatment process. These substances increase the load on the liver and can cause severe hepatic injury.
If your diet is poor, taking multivitamins and mineral supplements can help prevent the recurrence of infections. More balanced eating habits should be encouraged to speed up treatment as much as possible.
Important. Even if the disease ceases to be contagious after 2 or 3 weeks the treatment should be maintained for the prescribed time. Incomplete or inadequate treatment is worse than no treatment at all.
If treatment is discontinued early, antibiotic-resistant bacteria can emerge. The disease is then much more difficult and time-consuming to treat and the treatments are more toxic to the body. It is also one of the main causes of death, especially in people infected with HIV.
Finally, if the bacteria that have become resistant are transmitted to other people, preventive treatments become no longer effective.