Multidrug therapy cut global leprosy cases below 200,000
Leprosy, or Hansen’s disease, is a chronic infection by Mycobacterium leprae or M. lepromatosis that can damage nerves, skin, eyes, and airways. Spread needs close contact; about ninety-five percent of exposed people never fall ill. Multidrug therapy cures it, and global cases fell from 5.2 million in the 1980s to under 200,000 by 2020.
Paucibacillary cases take six months of dapsone, rifampicin and clofazimine; multibacillary cases take the same three drugs for a year. Between 1994 and 2014 some 16 million people were cured. Most new cases now arise in 14 countries, and India alone reports more than half. Poverty raises the odds, and living near a patient makes illness five to eight times likelier than in the general public.
Incubation averages five years, and symptoms can appear within the first year or two decades later. The first sign is often a pale or pinkish skin patch that no longer feels heat or pain, sometimes after numbness or tenderness in hands and feet. Roughly thirty percent of patients suffer nerve injury, reversible if treated early but permanent after months of delay; secondary infections can then shorten and deform fingers and toes.
Both causative bacteria live only inside host cells and cannot be cultured in a dish, though mice and armadillos can grow them; M. lepromatosis was identified only in 2008, from a fatal case. Transmission is now thought to run mainly through airway secretions rather than skin, and it is neither sexual nor passed to an unborn child. Armadillos, several primates and red squirrels carry natural infections. A pre-Norman skull dug up at Hoxne in Suffolk in 2017 held a strain closely matching that of modern red squirrels on Brownsea Island, and the medieval fur trade has been suggested as a driver of Europe’s epidemic.
The name comes from the Greek word for scale, and Norwegian physician Gerhard Armauer Hansen gave the modern alternative. Stigma still deters people from coming forward, and leprosy colonies, unsupported by evidence, persisted in parts of Asia and Africa into the late 2000s. World Leprosy Day has run since 1954.
Source: Leprosy
