leprosy

Chronic, progressive disease caused by the bacterium Mycobacterium leprae, closely related to that of tuberculosis. The infection attacks the skin and nerves. Leprosy is endemic in 28 countries, and confined almost entirely to the tropics. It is controlled with drugs. Worldwide, there were 400,000 new cases of leprosy in 2004, a 21% decrease from the previous year.

There are two principal manifestations. Lepromatous leprosy is a contagious, progressive form distinguished by the appearance of raised blotches and lumps on the skin and thickening of the skin and nerves, with numbness, weakness, paralysis, and ultimately deformity of the affected parts. In tuberculoid leprosy, sensation is lost in some areas of the skin; sometimes there is loss of pigmentation and hair. The visible effects of long-standing leprosy (joint damage, paralysis, loss of fingers or toes) are due to nerve damage and injuries of which the sufferer may be unaware. A technique that uses the patient's muscle material to encourage nerve regrowth is being explored.

In 2005 the World Health Organization (WHO) presented a global strategy for reducing and controlling leprosy for the years 2006–10. Countries where leprosy control remains a challenge include: Angola, Brazil, Central African Republic, Democratic Republic of Congo, India, Madagascar, Mozambique, Nepal, and Tanzania.

Researchers at the Pasteur Institute in Paris, France, completed sequencing the genome of Mycobacterium leprae in February 2001.