Today, March 24 is World Tuberculosis (TB) Day. On that very day, in fact, in 1882, the German physician, bacteriologist and microbiologist Robert Koch (1483-1910) announced to the scientific community the discovery of the etiological agent of this disease which today affects 10 million people worldwide, with still 1, 5 million deaths a year. In Italy the situation is clearly improving and from 2010 to today the cases have been steadily decreasing. In 2019 they were 3,346, in 2020 they were 2,287. In 2022, 27 cases of pulmonary tuberculosis were reported in the province of Modena. Tuberculosis is a disease with a strong social connotation and the progressive decrease in new cases is also linked to the improvement of living, housing and nutrition conditions.
It is operational in the province of Modena an Intercompany Group for the surveillance and control of tuberculosis – which involves Local Health Authority, University Hospital and Sassuolo Hospital – with dedicated courses for the care of patients with tuberculosis disease and latent tuberculosis infection.
At the Polyclinic of Modena, professionals belonging to the Unit of Respiratory Apparatus Diseases, directed by prof. Enrico Cliniand to the Infectious Diseases Unit, directed by prof Cristina Mussini. In particular, a dedicated pulmonary clinic it is inserted in the context of the provincial control and prevention activities.
“Tuberculosis (TB) – recalls Prof. Enrico CliniDirector of the Complex Structure of Diseases of the Respiratory System of the Polyclinic – is an infectious and contagious disease, caused by a bacterium, Mycobacterium tuberculosis, commonly called Koch’s bacillus, from the name of the German doctor who discovered it. It most often affects the lungs but other parts of the body may be involved. Italy is defined by the WHO as a “low endemic” country, as there are less than 10 cases of the disease per 100,000 inhabitants, with about 4,000 new cases per year. Most of the cases occur in subjects belonging to the weakest categories or who have more difficulty in accessing social and health services. The low incidence of tuberculosis in Italy is also linked to the improvement of diagnosis and therapy”.
Once the tuberculous disease has been ascertained, it is the Public Hygiene Service of the Modena Local Health Authority that deals with the management of contacts, screening them to exclude latent infection. The national and local health authorities indicate active contact tracing as one of the most important measures for the prevention of tuberculosis disease. Public Hygiene also deals with screening activities in subjects coming from highly endemic areas with the same purposes of surveillance and prevention to counter the spread of the disease.
“The test of choice that is performed following contact with a sick person is a skin test (called Mantoux) – explains the doctor Zaynalabedin Kahfiandoctor of Public Health Ausl, coordinator of the Intercompany Group for the surveillance and control of tuberculosis –. This test is repeated three months after the last contact with the patient. In case of positivity, further tests are performed to detect the possible diagnosis of latent tuberculosis infection. If this diagnosis is confirmed, the person concerned is referred to the specialist for taking charge and for the instrumental investigations of the case, and the administration of antimicrobial drugs can be advised to prevent the multiplication of pathogens in healthy individuals. Adherence to both this type of treatment and anti-tuberculosis therapy (respectively for contacts and patients) is essential to counteract the phenomenon of antibiotic resistance”.
TB is present in all parts of the world, but most cases occur in 30 high-incidence countries, mainly in Southeast Asia (particularly India and China) and the Western Pacific (62% of new cases) and in Africa (25% of new cases). In general, the incidence of TB is declining by about 2% per year.
“TB – adds the doctor Stephanie Cerripulmonologist at the Polyclinic and contact person for the tuberculosis clinic at the Department of Respiratory Apparatus Diseases – it is transmitted by air, through respiratory secretions released into the air by a contagious individual, for example by saliva, sneeze or cough. Fortunately, the transmission of the bacillus is not automatic but requires some conditions. In particular, the patient must be affected by active contagious pulmonary TB with a significant bacterial load. Furthermore, the risk of contagion is greater the closer and more prolonged the contact with a contagious subject. Not all people who become infected develop the disease; in fact, the immune system can cope with the infection and the bacterium can remain dormant for years. This condition is called latent tuberculosis infection and affects about a quarter of the world‘s population. People with latent tuberculosis infection have no symptoms and are not contagious. Many people will never develop the disease, while others may become ill years later. It is estimated that 5-15% of people with latent infection develop the disease in their lifetime.”.
“People at high risk of developing active TB disease – adds prof Cristina MussiniDirector of the Complex Structure of Infectious Diseases – they include HIV-positive people who have a 20-30 times greater risk of getting TB if infected. In general, patients most at risk are those with conditions that weaken the immune system (e.g. diabetes, malnutrition, oncohaematological diseases, immunosuppressive therapies), infants and children under the age of 5, people who use drugs, the elderly”.
“Pulmonary TB symptoms – adds the doctor Cerri – they are cough (lasting more than 3 weeks), chest pain, fever and night sweats. Over time, the cough may be accompanied by blood in the sputum. Other symptoms include tiredness and weakness, weight loss. Symptoms of pulmonary TB can be mild for months. This can lead to a delay in diagnosis and transmission of infection. If the TB is extrapulmonary, the symptoms depend on the site involved. Today we have molecular tests capable of identifying the presence of mycobacterium in sputum in a few hours of patients with pulmonary TB, rather than in 3-4 weeks as in the past. The rapidity of diagnosis is very important in order to be able to start antibiotic therapy as soon as possible and interrupt the chain of transmission of the infection from the sick to healthy people”.
Today, TB is a treatable disease. Drug treatment is based on the use of various antibiotics for quite a long time; therefore, checking that the drugs are taken regularly (adherence) is essential to avoid the onset of resistance and ineffective treatment. In the event of drug resistance, it is necessary to intervene with second-line drugs, which are more expensive and sometimes have more side effects.