The tuberculosis is a contagious disease that usually attacks the lungs, but sometimes to other parts of the body such as the kidneys, lymph nodes and bones. In the past, TB was often fatal and was called “consumption.” Nowadays, antibiotic treatment can cure it.
For most healthy people, the risk of getting TB is low. In Canada, it is reported about 1,600 new cases of TB each year, which is significantly less than at the beginning of the XX the century, when it was one of the main causes of death in the country. Although the disease is less common than it was, it remains an important public health problem in many parts of the world and killed 1.4 million people in 2010.
On March 24, 1882, the German physician Robert Koch isolated the bacillus Koch (or Mycobacterium tuberculosis), the bacterium responsible for tuberculosis, which has coexisted with humans for millions of years. This discovery earned him the Nobel Prize in Medicine or Physiology in 1905. The day of March 24 has also been declared World TB Day by the World Health Organization (WHO).
Types of Tuberculosis
There are 3 types of tuberculosis.
- The pulmonary tuberculosis or tuberculosis. This is the most common form of tuberculosis (about 70% of cases). Bacteria destroy lung tissue, creating cavities. The disease remains localized in the lungs;
- The 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 is associated with pulmonary tuberculosis or not;
- The disseminated tuberculosis or miliary (like millet seeds scattered throughout the lung, giving it a characteristic appearance). The bacteria spread through the bloodstream and attack the entire body. It is therefore pulmonary and extrapulmonary tuberculosis.
Some facts relating to the transmission of tuberculosis:
- The bacillus of Koch is transmitted by saliva droplets that are suspended in the air when a person coughs, sneezes, sings or plays a wind instrument, and not by touching a contagious person;
- It usually takes repeated or prolonged contact with an infectious person to get the infection;
- Only people who have symptoms are contagious;
- A contagious person following a treatment drug is no longer contagious after two or three weeks.
Latent infection and disease
A distinction must be made between infection with Koch bacillus and tuberculosis. “Latent” or “dormant” infection is widespread. It is estimated that around 1/3 of the world’s population is infected with the bacillus, most of the time without knowing it. It is an infection that persists throughout life. Thus, in the vast majority of cases, the bacterium does not cause disease, because the immune system acts on the infection. It also happens that the bacteria are completely eliminated from the body, but it is rather rare.
People with latent infection have no symptoms and therefore are not contagious. If, for some reason (such as a disease), their immune system weakens, bacteria can proliferate. If they multiply enough, it will cause the typical symptoms of tuberculosis. According to WHOM statistics, 5 to 10% of infected people worldwide can become ill. The infection then enters its active phase. The risk of tuberculosis is higher in the two years following the moment of infection.
Tuberculosis in the world
The tuberculosis is part of the so-called “diseases of poverty” because they spread especially in environments where rampant the following conditions:
- malnutrition ;
- poor sanitary conditions;
- a lack of medical follow-up
It is therefore persistent in economically disadvantaged countries. According to WHO, one-third of TB cases are concentrated in the South-East Asia region (which includes Indonesia, Cambodia, Thailand and Vietnam)? The Africa (especially in sub-Saharan Africa) and the Middle East are closely. These three regions of the world account for 85% of all TB cases 2. In these countries, the frequency of tuberculosis in prisons is often 100 times higher than in the general population. Refugee camps also present a major problem. There are also endemic areas of tuberculosis in India, China and Mexico.
In the West, the disease is more prevalent in underprivileged areas, among Aboriginal people, homeless people, intravenous drug users, people with AIDS, and those born in a country where TB is common.
In Canada, the emergence of strains of antibiotic-resistant bacteria and increased international travel led to a resurgence of the disease in the 1990s. However, the number of cases has stabilized since the following decade.
From sanatorium to antibiotics
Even before its infectious nature was established, people with TB were isolated – sometimes forcibly – to prevent them from contaminating the population.
German botanist Hermann Brehmer owes the “invention” of the sanatorium. Affected by the disease, it is said that he went to stay in the Himalayas waiting for death and that, to his great surprise, he recovered his health. He returned to Germany and opened an establishment according to the recipe “clean air, cool weather, sun, complete rest, abundant food”. Such establishments were quickly created elsewhere in Europe and, later, in North America. The first Quebec sanatorium opened in 1911 in Sainte-Agathe-des-Monts, a village in the Laurentians. At that time, tuberculosis was cutting back 12,000 lives a year in Quebec.
The development of streptomycin and other antibiotics in the 1940s almost immediately sidelined the sanatorium. The general belief at the time was that TB would one day be completely eradicated. What has not happened yet?
Symptoms of Tuberculosis
- Mild fever;
- Persistent cough;
- Sputum (sputum) of unusual color or bloody;
- Loss of appetite and weight;
- Night sweats ;
- Pain in the chest when breathing or while coughing;
- Pain in the spine or joints.
People at risk for Tuberculosis
Even if the disease occurs for no obvious reason, its onset or activation of a “dormant” infection is more likely to occur in people with compromised immune systems for any of the following reasons:
- Immune system disease, such as HIV infection (in addition, this infection greatly increases the risk of developing the active stage of tuberculosis);
- childhood (under five) or old age;
- Chronic disease (diabetes, cancer, kidney disease, etc.);
- heavy medical treatments, such as chemotherapy, oral corticosteroids , powerful anti-inflammatory drugs sometimes used to fight rheumatoid arthritis (“biological response modifiers” such as infliximab and etanercept) and medications antirejection (in case of organ transplant);
- Heavy use of alcohol or drugs.
Note. According to a study conducted in a hospital center in Montreal, 3 about 8% of children admitted through intercountry adoption are infected with the tuberculosis bacterium. Depending on the country of origin, a bacilli test may be recommended.
- Work or reside in an environment where active TB patients live or move (hospitals, prisons, reception centers), or manipulate bacteria in the laboratory. In this case, it is recommended to have a regular skin test to check whether or not one is infected. ;
- Stay in a country where TB is prevalent
- Have insufficient body weight (usually below normal as measured by body mass index or BMI).
Prevention of tuberculosis
|Basic preventive measures|
|Respect the hygiene measures. For people who are often in contact with tuberculosis: frequent hand washing, wearing a mask if necessary.
Take care of your health. Have a healthy and balanced diet, gets enough sleep, exercise regularly, avoid chronic stress, etc. This offers the best chance of having a strong immune system. For more information, visit our Strengthening Your Immune System and Healthy Living section.
Detect and treat a latent infection. People who work in high-risk environments or who have been in prolonged contact with an active patient may be screened for the presence of the bacteria in the body (see the description of the test in the Medical Treatments section). . If the result is positive, preventive treatment with antibiotics usually prevents the disease from being triggered. This preventive treatment is simpler and requires the use of fewer drugs than to treat active TB. Check with your doctor or the appropriate authorities at your place of work.
Tips for people infected to prevent contagion
To be respected during the 2 or 3 weeks of the treatment:
Medical treatment of tuberculosis
During the active phase of the disease, symptoms are usually present (fever, night sweats, persistent cough, etc.). The doctor relies on these symptoms, but also on the results of subsequent tests and examinations.
Skin test. The 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 tiny amount of tuberculin (a purified protein of Mycobacterium tuberculosis) is injected under the skin. If a skin reaction occurs at the site of the injection (redness or swelling) within 48 to 72 hours, this reveals the infection. If the result is negative, the doctor may suggest a second test a few weeks later.
Pulmonary radiography. If the patient has symptoms of persistent cough, for example, a chest x-ray will be prescribed to assess the condition of the lungs. During the follow-up, the X-ray also makes it possible to check the evolution of the disease.
Biological tests on samples of pulmonary secretions. The secretions are first observed under a microscope to check whether the bacteria present in the secretions are part of the family of mycobacteria (Koch’s bacillus is a mycobacterium). The result on this test is obtained the same day. Secretions are also cultured to identify bacteria and whether or not they are resistant to antibiotics. However, it takes 2 months to get the results.
If the microscopic test reveals the presence of mycobacteria and the medical evaluation suggests that it is tuberculosis, antibiotic treatment is undertaken without waiting for the result of the microbial culture test. Thus, the symptoms are relieved, the disease is curbed, and the person is less likely to spread the infection to those around him. The treatment can then be rectified, if necessary.
The first-line antibiotics can defeat tuberculosis in nearly all cases. Affected individuals are asked to stay at home or wear a mask in public until the doctor determines that they are no longer infectious (usually after two to three weeks of treatment).
First line treatment. The following four antibiotics are generally prescribed: isoniazid, rifampin, ethambutol and pyrazinamide, which are administered orally. To be effective and completely kill bacteria, medical treatment requires daily medication for a minimum of 6 months, sometimes up to 12 months. All these antibiotics can cause liver damage to varying degrees. Tell your doctor if you have symptoms such as nausea and vomiting, loss of appetite, jaundice (a yellowish complexion), dark urine, or fever with no apparent cause.
Second line treatments. If the bacteria are resistant to the two main antibiotics (isoniazid and rifampin), it is called multidrug resistance (MDR-TB) and must use the 2 drugs line. Sometimes 4 to 6 antibiotics are combined. They must often be taken over a longer period, sometimes up to 2 years. They can also cause side effects, for example, numbness in the hands or feet, and liver toxicity. Some of them are administered intravenously.
Treatments in case of ultra-resistant bacteria. If the strain of infection is resistant to several treatments normally offered in the first or second line, more severe and more toxic treatment, often administered intravenously, is used to control this so-called XDR-TB or XDR-TB.
Contraindications. The alcohol and acetaminophen (Tylenol) are cons-indicated during the entire duration of treatment. These substances impose an increased effort on the liver and may pose problems.
In case of power deficient, taking a multivitamin and minerals can help prevent a recurrence of the infection. Adopting more balanced eating habits should be favored to accelerate healing where possible. For more details on the basics of healthy eating, visit our Better Eating section.
|Important. Even if the disease is no longer contagious after 2 or 3 weeks of treatment, it must be continued for the entire prescribed period. Incomplete or inappropriate treatment is worse than no treatment.
Indeed, a treatment interrupted before term can lead to the spread of bacteria resistant to antibiotics. The disease is then much harder and longer to treat, and the treatments are more toxic to the body. In addition, it is an important cause of death, especially in people infected with HIV.
Finally, if the resistant bacterium is transmitted to other people, the preventive treatment is ineffective.