— What is leprosy, what pathogen causes this disease, and how long has it been known?
— Leprosy is caused by Mycobacterium leprae and Mycobacterium lepromatosis, with a long incubation period, various clinical manifestations of granulomatous lesions of the skin, mucosa of the upper respiratory tract, peripheral nervous system, musculoskeletal system and internal organs, sometimes the anterior chamber eyes.
This disease has been known since biblical times. The first reported cases of leprosy are more than 3000 years old. It is believed that the first cases of leprosy appeared in Asia or Africa and that leprosy was diagnosed in B.C. It is thought to have been brought to Europe from India by the troops of Alexander the Great around 300 BC. As in the Middle East, the incidence of leprosy in Europe was particularly high during the Middle Ages.
— In which year was the causative agent of leprosy discovered and what is it? What organisms can live and reproduce?
— In 1873, Norwegian doctor Gerhard Armauer Hansen discovered the causative agent of leprosy for the first time and showed that the cause of the disease was Mycobacterium leprae bacillus. Until 2008, leprosy was thought to be caused solely by M. leprae. However, a study on leprosy patients in Mexico showed that the disease could also be caused by M. lepromatosis. The main reservoir and source of pathogens are humans. Among animals, the only proven natural host and reservoir of M. leprae is the nine-banded armadillo (Dasypus novemcinctus) found in South America.
— How is leprosy transmitted? Do you get sick from swimming in the pool or contact with animals?
— Transmission of leprosy pathogens occurs through close and prolonged contact between an infected person and a healthy person, who release bacteria in small droplets from the nasal cavity when sneezing and coughing. Less commonly, person-to-person transmission may occur through damaged skin surfaces. It is thought that the pathogen can be transmitted from mother to fetus through breast milk, blood and insect bites.
Animals through which the pathogen can be transmitted to humans are nine-banded armadillos. M. leprae has been found to be transmitted from armadillos to humans when they handle or consume these animals. But for most people who encounter armadillos, the risk of illness is minimal.
— How long is the incubation period? Are there people who live with sick people and do not get sick? What is the reason for their resistance to leprosy?
— Leprosy has a long incubation period. From the moment of infection, the pathogen can persist in the body for years or even decades without causing any symptoms.
The long incubation period is one factor that contributes to the fact that many people living with patients do not develop leprosy during their lifetime. Research has shown that people’s resistance to leprosy stems from their immune system.
— What are the symptoms of leprosy, how can you suspect you have this disease, and what tests do you need to have to find out for sure?
—The first symptoms of leprosy are nonspecific and can vary. They appear as reddish or hypopigmented spots. Such spots can be seen in various skin diseases. Sometimes patients complain of weakness, nosebleeds, crawling sensations or numbness in the limbs. Darkening and thickening of the skin and tenderness or thickening of the nerves may be observed on the face and extremities. One sign that a patient has leprosy is loss of sensation (pain, temperature, and touch) within the lesions and beyond. Therefore, it is important to determine the sensitivity of the lesions for the diagnosis of leprosy. The diagnosis of leprosy is confirmed by detection of the pathogen by microscopic examination of scars (damages) on the skin and scrapings on the nasal mucosa or by histological examination of skin biopsies taken from the lesions.
— Why do spots on the skin become insensitive to pain and touch?
— Loss of sensation in lesions is due to M. leprae affecting the sensory nerves responsible for sensing and transmitting signals regarding the appropriate effect on the skin.
— Does leprosy really cause impotence? Does this happen to every sick man?
— According to available data, 60% of patients with leprosy have decreased libido and erectile dysfunction. Their development is associated with hormonal imbalance and inflammation of the testicles in patients with leprosy. Testicular inflammation can be severe. According to various sources, 51-76% of patients experience a decrease in testicular size. Patients with leprosy also show increased levels of follicle-stimulating hormone and luteinizing hormone in blood serum and decreased levels of testosterone. At the same time, patients’ sexual behavior may also be affected by the emergence of this disease.
— How exactly does bone and cartilage melting occur in leprosy?
— In fact, in leprosy, changes occur in the bone tissue in the distal parts of the lower and upper extremities over time. Specific changes are characterized by foci of inflammatory destruction in the substance of the phalanges of the fingers, metacarpal and metatarsal bones. Neurotrophic changes in bones are characterized by osteoporosis, atrophy and resorption (resorption) of bone tissue.
Leprosy is characterized by concentric atrophy of the phalanges and a peculiar deformation of the bones, taking on a “chess pawn” appearance. Periostitis, hyperostitis of the metatarsals, metacarpals and, less commonly, the long tubular bones of the forearm and tibia may also develop. Marked changes lead to the development of neurotrophic disabling complications.
— How many patients are currently being treated in Russia? Were they placed in a leper colony? How many of these organizations are there in Russia?
— Cases of leprosy have long been sporadic in Russia. Thanks to the success of home health care, the total number of registered leprosy patients in the Russian Federation has decreased over the last 20 years, from 711 in 2000 to 143 in 2020.
However, there has been an increase in the number of new cases in recent years. In the last decade (2010-2020), 15 new cases of leprosy were detected in the Russian Federation, and 13 (86.6%) of the total number of newly detected cases were residents of the Lower Volga region (mostly Astrakhan region). ). Among the newly identified patients, the majority are elderly people with multibacterial leprosy, which is the most epidemiologically unfavorable disease.
Patients are treated in leprosy colonies. Currently, there are three leprosy colonies in Russia: Sergiev Posad branch of the Federal State Budgetary Institution “State Scientific Center of Dermatovenereology and Cosmetology” of the Ministry of Health of Russia, Abinsk leprosy colony (Krasnodar Territory) and Tersky (Stavropol Territory).
— How are these patients treated now?
—The main strategy used in the past to prevent the spread of leprosy was the forced isolation of patients in leper colonies. With the advent of sulfones (organic compounds derived from sulfuric acid) in the 1940s and their effectiveness in treating leprosy, isolation of patients was no longer necessary.
In 1970, the World Health Organization (WHO) recommended the use of multidrug regimens due to cases of resistance to sulfone monotherapy. After completing such a comprehensive course, patients are considered cured.
Now, in accordance with WHO recommendations, sulfone drugs (dapsone), rifampicin and clofazimine (the latter is not registered in Russia) are used to treat patients with leprosy. In the Russian Federation, active leprosy treatment is carried out with drugs such as dapsone and rifampicin.
— Is there drug resistance to these drugs?
– It’s coming out. In this case, they are treated with fluoroquinolones and minocycline. Physiotherapeutic procedures are also prescribed to patients with leprosy.
Doctors pay attention to deformities in the musculoskeletal system and treat them through physical therapy, occupational therapy, prosthetics and, in severe cases, surgical correction of the deformities.
— Are scientific studies being conducted in Russia regarding the search for new treatments for leprosy?
— Currently, scientific studies are being carried out in the Russian Federation, the purpose of which is to evaluate the effectiveness of domestic medicines in the treatment of patients with leprosy. Additionally, to diagnose leprosy, experts at our center (State Scientific Center for Dermatovenereology and Cosmetology of the Russian Ministry of Health) have developed a diagnostic testing system that allows the detection of M. leprae DNA in humans. State registration is currently underway.