In Bergen, Norway, an ancient disease stalked the city. For centuries, leprosy was seen as a divine curse or a hereditary stain. But on February 28, 1873, a young physician named Gerhard Armauer Hansen changed everything. At Lungegård Hospital, he peered through a basic microscope at a tissue sample from a patient's face. Using osmic acid as a stain, he saw what no one had before: tiny, rod-shaped bodies inside the cells. This was Mycobacterium leprae, the bacterium that caused the disease. For the first time, a specific microbe was linked to a chronic human illness. The discovery proved that leprosy was not a curse, but a bacterial infection. The path to a cure, however, would be a long one.
Why Leprosy Is Now Rare
How leprosy went from a feared curse to a curable disease after Gerhard Hansen identified its bacterium in 1873.
Chapter 1
The Doctor and the Microscope
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Frequently Asked Questions
What is Hansen's disease?
Hansen's disease is the modern medical name for leprosy. It is a chronic infectious disease caused by the slow-growing bacterium Mycobacterium leprae. The name honors Gerhard Armauer Hansen, who discovered the bacterium in 1873, and is used to distance patients from the historical stigma of the word 'leper'.
How is leprosy spread?
Leprosy is not very contagious. It is thought to be spread through droplets from the nose and mouth during close and frequent contact with untreated cases. About 95% of people have a natural immunity to the bacteria, and patients are no longer infectious after just a few days of starting multidrug therapy.
Is leprosy still a problem today?
Leprosy was declared 'eliminated' as a global public health problem in 2000, meaning its prevalence fell below 1 case per 10,000 people. However, it is not eradicated. Around 200,000 new cases are still diagnosed each year, primarily in countries like India, Brazil, and Indonesia.
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