What is the link between Leprosy and a Stradivarius violin?

What is the link between Leprosy and a Stradivarius violin ?
-The answer is a once in a lifetime concert co-organized at the United Nations in Geneva by the Nippon Foundation (with 7 violins !)
-One of its key priorities is to support the Global Leprosy Program of the World Health Organization (WHO).
-The event was organized to commemorate the 70th anniversary of the Declaration of Human Rights (1948).