Gerhard Armauer Hansen that the leprosy acts of 1877 and 1885 were passed, leading to a steady decline of the disease in Norway from 1,800 known cases in 1875 to just 575 cases in 1901. His distinguished work was recognized at the International Leprosy Congress held at Bergen in 1909. Hansen had suffered from syphilis since the 1860s but died of heart disease. He was an atheist. Gerhard Armauer Hansen Gerhard Henrik Armauer Hansen (29 July 1841 – 12 February 1912) was a Norwegian physician, remembered for his identification of the bacterium "Mycobacterium leprae" in 1873 as the causative agent of leprosy. Hansen
Disease pathogenesis (mechanism by which the disease is caused), or by symptom(s). Alternatively, diseases may be classified according to the organ system involved, though this is often complicated since many diseases affect more than one organ. A chief difficulty in nosology is that diseases often cannot be defined and classified clearly, especially when cause or pathogenesis are unknown. Thus diagnostic terms often only reflect a symptom or set of symptoms (syndrome). Classical classification of human disease derives from observational correlation between pathological analysis and clinical syndromes. Today it is preferred to classify them by their cause if it is known. The