Leprosy may be the oldest recorded disease — it is mentioned 68 times in the Bible (55 in the Old Testament and 13 in the New), where most likely it meant a variety of infectious skin diseases.

While the precise meaning of leprosy in the Old and New Testament might be in dispute, it no doubt included the actual illness, now commonly called Hansen’s disease.

The fact that leprosy has been with us so long is indicative of how persistent the causative agent is. And while leprosy is classified as rare, it still strikes some 200,000 people a year, most of them in Brazil, India, Mexico, the Pacific Islands and other Third World nations. Approximately 200 cases occur annually in the United States, almost all of which involve immigrants from developing countries who have settled in California, Hawaii and Texas.

Perhaps the presentation of the disease is what fascinates and frightens us most. An infected patient may have grotesque skin lesions and disfigurement, including clawed hands and feet, and a face that resembles a gargoyle. These bizarre symptoms led people to believe that leprosy was a curse, or a punishment from God. Lepers were considered dangerous and stigmatized: They had to wear special torn clothing, cover the lower part of their faces, cry out “Unclean! Unclean! and ring bells to warn others of their approach. They also had to live in isolation outside of town.

In modern times, treatment is confined to separate hospitals or live-in colonies called leprosariums. Despite its notoriety and antiquity, leprosy continues to surprise and confound researchers, and is still in the news.

Leprosy has terrified humanity from the beginning of recorded time — it was reported as early as 600 BC in India, China and Egypt, and genomic studies of certain strains of the disease suggest that leprosy’s parasitism in humans dates back more than 100,000 years.

It is most likely that the leprosy bacilli started parasitic evolution in early hominids millions of years ago. The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations. Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years.

Leprosy is a chronic infection of the skin and nerves caused by Mycobacterium leprae (lepra is the Greek word for scaly). It causes bodywide symptoms, deformities and disabilities, and some patients develop unusual blood clots. Armauer Hansen, a Norwegian scientist, identified the agent responsible for the disease in 1873 but had no success in transmitting it to himself or to others.

Leprosy is strictly a human disease, although rare infections have been seen in chimpanzees and monkeys, and naturally in armadillos, particularly in the southern United States. Armadillos are a large natural reservoir for M. leprae, and leprosy may be a zoonosis (infectious diseases in animals) in the region. The relationship with the disease and armadillos is bizarre and the precise route of transmission remains unclear. It may be that wild armadillos first contracted the infection from European settlers a couple of centuries ago.

The means of transmission is uncertain, but, like tuberculosis, the infection is thought to be spread by the respiratory route by sneezing or coughing because lepers harbor bacilli in their nasal passages. The bacteria accumulate principally in the extremities of the body, where they reside and infect certain cells of the peripheral nervous system.

Leprosy may occur at any age, although the peak age of onset is in the first, second and third decades. The most vulnerable persons are children who have prolonged contact with infected patients.

There are three clinical types: tuberculoid, lepromatous and borderline. Lepromatous leprosy is much more serious; patients develop symmetric skin nodules loaded with the bacteria. These patients may develop a serious reaction associated with ulcers (especially of the legs) that often become secondarily infected, resulting in bacteremia and death. Lepromatous leprosy wrecks the body in slow, debilitating ways: sores appear on the face, hands and feet, and fingers and toes mysteriously shorten in length. Lacking sensation of pain, patients have little regard for the dangers of infection, which results in raw, oozing sores and deformed hands and feet. Moreover, such patients appear to become a welcome mat for trillions of foreign bacteria.

Current Treatment

The drugs generally used and recommended by the World Health Organization are a combination of rifampicin, clofazimine and dapsone. Rifampicin is the most important antileprosy drug and therefore is included in the treatment of all types of leprosy. Treatment with only one antileprosy drug will always result in drug resistance. Treatment with dapsone or any other antileprosy drug used as monotherapy should be considered as unethical practice.

According to a recent letter from a leprosy researcher, the medical world still does not know exactly how leprosy is transmitted. Much remains to be learned about a disease that is not yet a thing of the past.

Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, will touch on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at maxsherman339@gmail.com.