Leprosy – an old infectious disease with unsolved matters

Leprosy is a chronic disease with many clinical manifestations, which affect mainly the skin, the peripheral nerves, mucosa of the upper respiratory tract and the eyes. Although global elimination of leprosy was achieved globally in the year 2000 and the disease is actually rare in most parts of the world, a low but constant number of more than 200,000 new cases are still registered each year. Leprosy is caused by two acid-resistant, slow multiplying Gram-positive bacteria, i. e., Mycobacterium leprae and the recently discovered M. lepromatosis. The transmission routes of these pathogens are not completely understood. All forms of leprosy can be treated with long-lasting antibacterial combination therapy using dapsone and rifampicin and – in cases of multibacillar leprosy – clofazimin. Using this multi-drug approach, leprosy has been shown to be curable in most cases. However, immunological sequelae (leprosy reactions), which may appear during therapy or even several years later, are frequently difficult to treat. Although leprosy has been eliminated in most countries, its complete eradication is extremely unlikely.