Evidence of leprosy (Hansen's disease) has been detected in prehistoric human remains, and the disease has been described in Biblical and other historical records dating as far back as the 2nd millennium B.C.E. It was a feared disease, and its victims were shunned because of their disfiguring stigmata—collapsed facial bones, fingers, and toes, with the hands and feet ultimately rotted away. Leprosy was among the first diseases identified as contagious. Early societies took measures to shield their healthy members from contagion: lepers were obliged to wear distinctive clothing and carry a bell to warn others of their presence, or they were segregated in lazarettos, precursors of quarantine stations and isolation hospitals. Segregation remained part of the control measures for leprosy in modern industrial nations until late in the twentieth century, and it still persists in some countries. This is a questionable practice, because the causative acid-fast bacillus that causes leprosy is only sluggishly infective. Transmission usually requires prolonged close personal contact, and children are most vulnerable. Transmission is mainly by nasal secretions, though bedbugs have been suspected as vectors.

The lepra bacillus, Mycobacterium leprae, belongs to the same family as tuberculosis. It attacks the skin and peripheral nerves, slowly destroying tissue, deforming the extremities, and disfiguring the face; it runs a natural course over many years, and death is as often due to other infections as to leprosy itself. Worldwide, ten to twelve million people suffer from leprosy, mainly in the Indian subcontinent, parts of the Middle East, and Latin America. Approximately 500,000 new cases are reported annually with about 300 cases per year in the United States, mainly among immigrants who harbored the infection on arrival. Control requires early detection and active treatment with one or more of several effective antibiotics, such as Rifampin. Once treatment is initiated, the risk of transmission is minimized. BCG vaccine confers some resistance to infection, while HIV (human immunodeficiency virus) infection increases the risk of infection with leprosy.

Leprosy is now known as Hanson's disease, named after Armauer Hanson, the Norwegian physician who discovered the cause of the disease in 1873.

JOHN M. LAST

(SEE ALSO: Contagion; Isolation; Quarantine)