(snip) European colonialism and the slave trade probably played a key
role in the spread of leprosy, research suggests. The disease appears
to have originated in East Africa, and spread to Asia and Europe
before reaching West Africa, and then the Caribbean and South America.
The findings are based on a genetic analysis of different strains of
the bacterium which causes leprosy.
http://news.bbc.co.uk/1/low/health/4540461.stm