G. Armauer (Gerhard Armauer) Hansen

Born in Bergen, Norway, in 1841, Gerhard Armauer Hansen trained as a physician and spent much of his career studying leprosy, which was a major public health problem in Norway during his lifetime. He is remembered for identifying the microorganism linked to the disease in 1873, a discovery that led to the bacterium Mycobacterium leprae and the illness itself being widely associated with his name.

Hansen's research helped support the growing idea that infectious diseases could be caused by specific germs rather than heredity or environment alone. That made his work important not only for leprosy research but also for the broader development of bacteriology in the 19th century.

He died in 1912, but his legacy has lasted. The term "Hansen's disease" is still used for leprosy today, reflecting the lasting impact of his scientific work and the role he played in changing how the disease was understood.