LEPROSY

Leprosy is a chronic infection caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis.Initially, infections are without symptoms and typically remain this way for 5 to as long as 20 years

SIGNS AND SYMPTOMS

Skin lesions light or dark patches are the primary external sign.If untreated, leprosy can progress and cause permanent damage to the skin, nerves, limbs, and eyes. Contrary to folklore, leprosy does not cause body parts to fall off, although they can become numb or diseased as a result of secondary infections; these occur as a result of the body's defenses being compromised by the primary disease.Secondary infections, in turn, can result in tissue loss causing fingers and toes to become shortened and deformed, as cartilage is absorbed into the body.

CAUSE

An intracellular, acid-fast bacterium, M. leprae is aerobic and rod-shaped, and is surrounded by the waxy cell membrane coating characteristic of the Mycobacterium genus.

Due to extensive loss of genes necessary for independent growth, M. leprae and M. lepromatosis are obligate intracellular pathogens, and unculturable in the laboratory, a factor that leads to difficulty in definitively identifying the organism under a strict interpretation of Koch's postulates.The use of nonculture-based techniques such as molecular genetics has allowed for alternative establishment of causation.

Leprosy be transmitted to humans by armadillos and may be present in three species of non-human primates.

Two exit routes of M. leprae from the human body often described are the skin and the nasal mucosa, although their relative importance is not clear. Lepromatous cases show large numbers of organisms deep in the dermis, but whether they reach the skin surface in sufficient numbers is doubtful.

PREVENTION/ TREATMENT

Medications can decrease the risk of those living with people with leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home.However, concerns are known of resistance, cost, and disclosure of a person's infection status when doing follow-up of contacts. Therefore, the WHO recommends that people who live in the same household be examined for leprosy and only be treated if symptoms are present.

Multidrug therapy remains highly effective, and people are no longer infectious after the first monthly dose.It is safe and easy to use under field conditions due to its presentation in calendar blister packs.Relapse rates remain low, and no resistance to the combined drugs is seen.