Mycobacterium leprae can cause leprosy, which is a chronic infectious disease with main lesions in the skin and peripheral nerves. The clinical manifestation is mainly numbness skin damage, nerve coarseness, and severe patients can also lead to limb disability. At present, it is mainly prevalent in Guangdong, Guangxi, Sichuan and Yunnan in China. Leprosy can also manifest different clinical symptoms through different types. After Mycobacterium leprae invades the organism, the general incubation period is 2-5 years, ranging from a few months in short cases to decades in long cases. Before the typical symptoms begin, some will have generalized prodromal symptoms such as general malaise, muscle and joint aches and pains, and abnormal sensation in the limbs. Those with strong immunity move towards the tuberculoid leprosy end of the spectrum, and those with low or defective immunity move towards the neoplastic end. Currently, there are five types of leprosy according to different conditions: the first is tuberculous leprosy; the second is borderline partial tuberculoid leprosy; the third is intermediate borderline leprosy; the fourth is borderline partial tuberculoid leprosy; the fifth is neoplastic leprosy; and there are also other relatively rare undetermined types of leprosy. Clinical manifestations vary, with most patients presenting with conjunctivitis, keratitis, iridocyclitis and nerve trunk involvement.