Is leprosy a fatal disease?

Sort of. Leprosy is a chronic slowly progressive illness and it is treatable. Left untreated, it can cause death after a number of years of being ill with the disease.
Leprosy. Or Hansen's Disease is an infection caused by Mycobacterium lepromatosis & Mycobacterium Leprae. One may carry these bacteria for five to 20 years before becoming symptomatic. 95% of us have natural immunity to the bacteria that causes Leprosy. According to the World Health Organization – the major ^ in mortality is related to indirect effects of Leprosy rather than the disease itself.