95% of people are naturally immune to leprosy!

Leprosy is also known as Hansen’s Disease or HD. It is a chronic disease caused by the bacteria Mycobacterium leprae. The external signs of leprosy are skin lesions. Internally, it attacks the respiratory tract and the peripheral nerves. 

Untreated, leprosy is severely damaging to the skin, nerves, limbs, and eyes. Body parts do not fall off from leprosy, but they may feel numb and be diseased. Fingers and toes can be deformed and shortened due to the disease. It is still unclear how leprosy is transferred from person to person, but it is believed that it probably is transferred in respiratory droplets. 

Today we know that leprosy can be transmitted from armadillos to humans and that it cannot be transmitted through sexual interaction. Neither is it highly infectious after treatment. Actually 95% of people are naturally immune and those who suffer from the disease are no longer infectious after 2 weeks of treatment. 

(Source)