Who discovered the bacterium that causes leprosy?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

The bacterium that causes leprosy, Mycobacterium leprae, was discovered in 1873 by the Norwegian physician G.H. Armauer Hansen.12

Working in a leprosy hospital in Bergen, Norway, Hansen identified the bacillus in a tissue sample taken from one of his patients. By observing the organism under a microscope, he demonstrated that leprosy is an infectious disease caused by a specific microorganism, rather than a hereditary condition as was previously believed. This discovery was a pivotal moment in medical history, shifting the focus of leprosy management from mere containment to the modern era of treatment.21