Tuberculosis: symptoms, transmission, what treatments?

Tuberculosis is a notifiable disease in France. Its incidence is 6.8 cases per 100,000 inhabitants. Its vaccine, BCG, has not been compulsory since 2007 for children. What are the symptoms of tuberculosis? What typical cough? Fever ? Is it contagious? How to treat it? Know everything.

Tuberculosis is a notifiable disease in France. His impact is of 6.8 cases per 100,000 population (2020). The disease has therefore not completely disappeared. Since 2004, Tuberculosis Centers (CLAT) are responsible, in each department, for carrying out investigations into cases of tuberculosis, detecting contact topics, and participate in the BCG vaccination children at risk. the BCG vaccine is no longer mandatory since 2007.

What is tuberculosis?

“Tuberculosis is a contagious infectious disease caused by a bacterium of the genus Mycobacterium, of which the germ most often involved is Mycobacterium tuberculosis or Koch’s bacillus” explains Dr. Jacques Amselem, general practitioner in Seine-et-Marne. After a first contact with the bacillus, which may go unnoticed or give a few minor signs, the disease may be localized in an organ and remain latent. We distinguish two main forms, the pulmonary tuberculosis and the extra-pulmonary tuberculosis (when it develops outside the lungs).

How common is tuberculosis in France?

Tuberculosis is a disease that must be declared in France since 1964. Tuberculosis has not disappeared from France but its incidence is low: 6.8 cases per 100,000 inhabitants in the 2020 figures published by Santé Publique France. “This incidence has been steadily declining for decades” comments the agency. According to his observations, the modification of the BCG vaccination policy (no longer mandatory since 2007) and the vaccine shortage of the last 6 years have not impacted the epidemiology of childhood tuberculosis. The TB reporting rates among children remain “very low”. The serious forms of the child (meningeal or miliary) are stable (9 cases in 2020 compared to 10 in 2019). At the regional level, Ile-de-France accounts for 38% of tuberculosis cases. The Seine-Saint Denis is the French department most affected by tuberculosis (23.8 cases per 100,000 inhabitants). The risk groups are essentially the immigrants from countries with high prevalence, people homelessthe the elderlythe people infected with HIV and inmates.

Evolution of tuberculosis in France. © Public Health France

What is Kock’s bacillus?

Kock’s bacillus is a bacteria that infects the lungs and causes tuberculosis. This bacillus was demonstrated by Robert Koch in 1882 who gave him his name. The bacteria enters the airways creating chest pain, fever and coughing up blood. In the lungs, the bacterium multiplies, invading the bronchi and lung tissue. Contamination is most often by air.

What is latent tuberculosis?

There are two stages in tuberculosis: the bacteria infection time and the time of declared illness and symptomatic. After an infectious contact, Koch’s bacillus most often remains silent without causing disease: we then speak of“latent” TB infection and the person is not sick or contagious. A minority of these people will develop tuberculosis disease. Thus, at the adultthe risk of passing from latent tuberculosis to tuberculosis is of the order of 10% during life. This risk is greater in young children, older adolescents and people with weakened immunity. The risk of developing the disease after being infected is higher in the 2 years following the infectious contact.

What is pulmonary tuberculosis?

The most common, it is manifested by coughing, sneezing and weight loss. It is a contagious disease that is transmitted through the air. Developing countries are the most affected because patients cannot always access treatment. Treatment is with medication (antibiotic therapy).

Tuberculosis can also affect other organs than the lungs. For example, ganglia and bones.

What is lymph node tuberculosis?

The organ most often affected is the lung, but the lymph nodes can also be the target of quiescent bacilli. Tuberculosis is then manifested by the appearance of adenopathies, an increase in the volume of the affected lymph nodes. The diagnosis can be made by biopsy of an affected lymph node, that is to say a sample which will make it possible to search for the presence of Koch’s bacilli.

What is bone tuberculosis?

Bone tuberculosis is one of the extra-pulmonary forms of the disease. It affects the spine in one out of two patients (Pott’s disease), the knee or the hip. People with a weak immune system (immunocompromised) are particularly at risk. Medical imaging (MRI, scanner) strongly suggests the diagnosis. Only the demonstration of Koch’s Bacillus confirms the diagnosis. Treatment is based on taking antibiotics.

What are the symptoms of tuberculosis?

The symptoms of tuberculosis are easily recognizable:

  • a cough that produces sputum, sometimes even with blood,
  • chest pain,
  • respiratory distress,
  • bouts of fever,
  • a lack of appetite,
  • weight loss
  • and night sweats.

As soon as the first symptoms appear, it is best to consult a doctor quickly in order to receive adequate treatment, especially if there has been contact with an infected patient.

Tuberculosis is a contagious disease that is transmitted through the air from man to man. From droplets contaminated are projected during the coughing, sneezing or spitting up. Whoever inhales these droplets therefore finds himself contaminated in turn. The risk of transmission of Koch’s bacillus is all the higher than the contacts were close, frequent and repeated. The transmission will be facilitated in a confined and poorly ventilated area. It is accepted thata patient is contagious within 3 months preceding the diagnosis.

What is the incubation time for tuberculosis?

Tuberculosis has 2 incubation times distinct:

► The first concerns the primary infection: this is the time (4 to 12 weeks) separating the contact with Koch’s bacillus, and the positive turn of the tests tuberculin. This time is asymptomatic.

► Once this primary infection has been carried out, a time before onset of tuberculosis “disease” and first symptoms. This second incubation period can be short (immediate) or long (up to several years). the risk to develop the disease after being infected is higher within 2 years that follow the infectious contact.

Screening is done around a person with contagious tuberculosis in order to detect any symptoms as early as possible and be able to offer care that avoids any complications. It includes a medical consultation, a blood or skin test and a chest X-ray Screening is free. the screening for latent tuberculosis (without symptoms) is classically based on the intra-dermo reaction (IDR) to tuberculin (Tubertest). This test requires a reading at 72 hours which means reviewing the people in consultation. In recent years, the IDR can be replaced by the blood assay of gamma interferon (Quantiferon) which requires only one consultation. Its use is only indicated for people over 15 years of age.

Who should get the BCG vaccine?

Vaccination against tuberculosis is called BCG from the name of its inventors (Bacille Calmette and Guérin). This vaccine mainly concerns infants in order to protect them from serious forms of tuberculosis. Its efficiency would vary from 75 to 85%. It has not been compulsory since 2007. vaccination is recommended from the age of 1 month for children who are at high risk of tuberculosis (from 3 months for others), and up to the age of 15. Risk factors: birth in a country where the risk is high, residence in Guyana, Mayotte and in some cases in Ile-de-France, a stay of at least one month in one of these countries, a case of tuberculosis in the family less than 5 years ago. Injection of the vaccine is contraindicated in the event of sensitivity to one of the components of the vaccine, treatment with corticosteroids or immunosuppressants (chemotherapy, antiTNF treatment), and immunosuppression or HIV seropositivity.

What are the treatments for tuberculosis?

Tuberculosis treatment usually lasts 6 months and involves taking several antibiotics simultaneously. However, with the development of resistance to antibiotics, some cases become more and more complicated to treat.

If you are going to a country where there are many cases of tuberculosis, remember to adopt reinforced hygiene, by washing your hands frequently. Take care of your immune system by eating and sleeping well, and limiting stressors. Primary prevention of tuberculosis, including childhood vaccination with BCG for children exposed to a high risk of tuberculosis in their surroundings or in their environment, protects against serious forms of this disease.


Tuberculosis in France: 2020 figures. Public Health France. December 6, 2021.

Questions and answers on tuberculosis. ARS New Aquitaine, 2015

Thanks to Dr Jacques Amselem, general practitioner. Comments collected in 2019.

Leave a Comment