Tuberculosis in history and culture
In the 18th and 19th centuries, tuberculosis (consumption) was extremely widespread and paradoxically romanticized: pale, delicate skin, a feverish flush, sparkling eyes, and thinness were considered signs of refined beauty. The disease affected models and heroines of famous portraits—K. Somov's "Lady in Blue" and Borovikovsky's portrait of Maria Lopukhina. The prototype of Alexandre Dumas's "The Lady of the Camellias," the courtesan Marie Duplessis, died of tuberculosis at the age of 23.
In the 19th century, methods of early diagnosis did not exist, and the diagnosis was made only at late stages. Treatment included expectorants and drops based on lead, mercury, and arsenic, which often accelerated the patient's death. Fresh air walks and rest were also recommended. It was only at the end of the 19th century, after the contagious nature of the disease was established, that patients began to be isolated.
The causative agent and Robert Koch's discovery
In 1882, Robert Koch announced the discovery of the bacterium that causes tuberculosis. Examining the lung tissue of a 36-year-old worker who died of acute consumption, he prepared a smear on a glass slide, dried it, and stained it with a special dye. Microscopy revealed slender rods, which were named Koch's bacilli.
The causative agents are grouped into the Mycobacterium tuberculosis complex. Of particular importance are:
- M. tuberculosis (humanis) — the primary causative agent of human tuberculosis;
- M. bovis — affects cattle, can cross the species barrier, and infect humans through contaminated milk.
Today, the proportion of M. bovis in the disease structure is small thanks to veterinary control and milk pasteurization.
BCG vaccine
BCG is a transliteration of the French abbreviation BCG (Bacillus Calmette–Guérin). French scientists Albert Calmette and Camille Guérin cultivated an attenuated strain of live bovine tuberculosis bacillus that had lost its virulence while retaining the ability to stimulate immunity.
- 1921 — creation of the first tuberculosis vaccine;
- 1925 — the vaccine was delivered to Moscow;
- 1928 — start of active vaccination of newborns;
- since 1950, BCG vaccination became mandatory.
The vaccine is given to newborns for the prevention of severe forms of the disease, primarily tuberculous meningitis. The vaccine does not completely prevent infection, but significantly reduces the risk of fatal complications. The characteristic scar on the left shoulder is a trace of the BCG vaccination.
Clinical presentation and diagnostics
Main symptoms of tuberculosis:
- prolonged, distressing cough, sometimes with hemoptysis;
- fever;
- chest pain and shortness of breath;
- weight loss, weakness, fatigue;
- night sweats without apparent exertion.
The leading method of immunodiagnosis is the Mantoux test, proposed in 1908 by the French physician Charles Mantoux. Tuberculin, an extract of mycobacterial proteins, is injected intradermally into the forearm; the result is evaluated after 72 hours by the size of the papule. Common restrictions (ban on citrus fruits, chocolate, contact with water) are largely mythologized. Citrus fruits are excluded only if there is an allergy that could distort the result. Water does not affect intact skin, but the skin must not be rubbed, scratched, or steamed—this causes a false-positive reaction or the risk of infection.
Myths about tuberculosis
- "Tuberculosis only affects the lungs." There are extrapulmonary forms: tuberculosis of the genitourinary system, gastrointestinal tract, bones and joints, nervous system, eyes, and skin.
- "Koch's bacillus inevitably causes disease." According to WHO data, about 25% of the Earth's population is infected with the mycobacterium, but is in a state of latent infection and is not contagious. Activation occurs when immunity is weakened.
- "All patients are contagious." Only patients with the active form and bacterial excretion are dangerous; such patients must be isolated. Transmission occurs via airborne droplets during prolonged close contact.
- "This is a disease of the poor only." Anyone can become infected. Risk factors include irregular and unbalanced nutrition, lack of sleep, bad habits, chronic stress, and concomitant chronic diseases.
- "Tuberculosis is incurable." Modern therapy is effective, but requires continuous intake of drugs for at least 6 months, sometimes several years, due to the slow reproduction of mycobacteria. With early diagnosis, the cure rate approaches 100%.
Key points
- The causative agent of tuberculosis is Mycobacterium tuberculosis, discovered by R. Koch in 1882.
- M. bovis is transmitted through contaminated milk and is used to prepare the BCG vaccine.
- The BCG vaccine was created by Calmette and Guérin; in Russia, it has been mandatory since 1950.
- Typical symptoms: prolonged cough, low-grade fever, weight loss, night sweats.
- Mantoux test — intradermal administration of tuberculin with evaluation after 72 hours.
- About a quarter of the world's population are latent carriers of the mycobacterium.
- Only patients with active form and bacterial excretion are contagious.
- Treatment lasts at least 6 months; early diagnosis ensures maximum efficacy.