Generality
Leprosy is a chronic infectious disease caused by the Mycobacterium leprae, which mainly affects the skin, peripheral nerves, mucous membranes of the upper respiratory tract and eyes.
Leprosy is also known as Hansen's disease and it is one of the oldest diseases known to mankind. The ancient civilizations of China, Egypt and India feared leprosy, as it represented an incurable, mutilating, contagious disease often surrounded by negative stigmas. In reality, leprosy is an easily diagnosed and treatable disease with antibiotic therapy, and only if neglected can it progressively cause serious and permanent damage to the skin, nerves, limbs and eyes.
Infection
The M. leprae it multiplies very slowly (twelve or more days) and symptoms can take several years to appear. Leprosy has a rather modest contagion capacity.
Transmission occurs through close and prolonged contact with infected individuals, although the mechanism is not yet fully understood. It is believed that the contagion can be favored by exposure to body fluids emitted by the sick person by air diffusion, such as nasal secretions or through the droplets of saliva expelled from the mouth with coughs or sneezing (droplet transmission). These particles would go to constitute an aerosol, which can come into contact with the eyes or mucous membranes of the upper airways and be inhaled up to the lungs.
The Mycobacterium leprae it can also be released into the environment from the skin lesions of infected patients. In ideal conditions, the infectious agent can survive even weeks outside the human organism.
Most people exposed to and infected with M. leprae does not develop the disease, because their immune response is adequate to fight the infectious agent. People whose immune systems are weakened by concomitant chronic diseases (diabetes, HIV / AIDS or heart disease) are at greater risk of contracting leprosy , as their defenses are not strong enough to effectively attack and kill mycobacteria.
