How did King Baldwin IV (1161-1185), got leprosy? I thought leprosy just happen in places of high insalubrity, right?.?

Long (several months) close contact with a sufferer (who might not be displaying symptoms) or an armadillo (true).

EDITED

Yes armadillos were transported from the Middle East to Texas by the Spanish.

Courtesans were not prostitutes – more like entertainment with benefits.

In 12th century Europe and nearby Mediterranean areas, everwhere was a place of high insalubrity.

And it's "how DID he GET," not "DID...GOT."

He must have had contact with an infected person. Baldwin had a sheltered childhood, so perhaps he contacted the disease from a court visitor.

Insalubrity? It's possible that the king had some other disease that doctors in his time misdiagnosed as leprosy.