Leprosy originated in Africa or Near East - study

Leprosy, a disease widely believed to have been spread out of India, in fact appears to have originated in Africa or the Near East, scientists said on Thursday.

"The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations," researchers reported in Friday's issue of the journal Science.

This is not what historians had believed.

"Leprosy is believed to have originated in the Indian subcontinent and to have been introduced into Europe by Greek soldiers returning from the Indian campaign of Alexander the Great. From Greece, the disease is thought to have spread around the Mediterranean basin, with the Romans introducing leprosy into the Western part of Europe," the researchers wrote.

Leprosy is an infectious disease that has been known since biblical times. It is characterized by disfiguring skin lesions, peripheral nerve damage, and progressive debilitation.
Causes, incidence, and risk factors
Leprosy is caused by the organism Mycobacteriumleprae. It is a difficult disease to transmit and has a long incubation period, which makes it difficult to determine where or when the disease was contracted. Children are more susceptible than adults to contracting the disease.
Leprosy has two common forms, tuberculoid and lepromatous, and these have been further subdivided. Both forms produce lesions on the skin, but the lepromatous form is most severe, producing large disfiguring nodules.
All forms of the disease eventually cause peripheral neurological damage (nerve damage in the extremities) manifested by sensory loss in the skin and muscle weakness. People with long-term leprosy may lose the use of their hands or feet due to repeated injury resulting from lack of sensation.

In fact, the new study suggests that until Europeans explored and conquered much of the world, the disease that carries perhaps more stigma than any other was fairly contained, they said.

A careful genetic analysis of the bacteria that causes the disease, which attacks the nerves and skin, suggests that colonial-era explorers and slave traders spread leprosy across the rest of Africa and into the Americas in relatively recent times.

"Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years," the researchers wrote.

ARMADILLOS HELP STUDY

It has been difficult to study Mycobacterium leprae because the bacillus does not grow well in lab dishes. It grows and spreads slowly in humans, too, and significant studies were only possible after it was found that armadillos are easily infected and can be used to grow large amounts of the bacteria.