Leprosy is a chronic infectious disease that is caused by the bacterium Mycobacterium leprae. It affects the skin, mucosa of the upper respiratory system and eyes, peripheral nerves, and some other structures. The incubation period varies from three months to 40 years.

Transmission is thought to occur through inhalation of bacteria-laden dust particles. Environmental factors such as unhygienic and crowded living conditions contribute to the spread of the disease. Malnutrition and a weak immune system also favor infection.

Leprosy takes on two forms. Multibacillary leprosy occurs in patients with immune deficiencies. In this form, patients have numerous shiny, non-itching reddish nodules, tumours and raised patches with sloping edges. There is no sensory loss in the affected parts of the body, but skin smears are always positive for bacilli. Unless treated with multiple drug therapy, persons suffering from multibacillary leprosy constitute the principal source of infection. In such persons the bacilli multiply almost unchecked.

The damage that the bacilli cause to the peripheral nerves leads to numbness, muscle weakness or even paralysis (with consequent claw hand or foot drop), and dry skin. Because of the loss of sensation the patient fails to notice an injury. Injuries easily result in infections which lead in turn to ulcers that damage the dermal tissues, joints and bones with the consequent loss of extremities (toes and fingers) or secondary deformities. This happens in an estimated 25% of cases that are not treated at an early stage of the disease.

The second form of the disease is paucibacillary leprosy, which occurs in those with a stronger immune system. This latter form is relatively harmless and as a rule non-infectious. The most frequent form of leprosy, it accounts for between 70 and 80 percent of all cases. The typical signs are flat or slightly raised patches on the skin - usually single but at most three, well demarcated, non-itching, and hypopigmented or reddish. Patients feel nothing in the affected area. This sensory loss is very important for diagnosis because bacilli are often undetectable in skin smears.

Leprosy has afflicted humanity for millennia. It once affected every continent and it has left behind a terrifying image in history and human memory - of mutilation, rejection and exclusion from society (and for the anti-socialites, yes, that last one is supposed to be a bad thing). Leprosy has struck fear into human beings for thousands of years, and was well recognized in the oldest civilizations of China, Egypt and India. A cumulative total of the number of individuals who, over the millennia, have suffered its chronic course of incurable disfigurement and physical disabilities can never be calculated.

The ancient Greeks and Romans learned painful lessons about leprosy after their armies returned victorious from Asia—unwittingly bringing back the previously unknown affliction with their plunder. In the Middle Ages, sufferers had to wear special clothing, ring bells to warn others that they were close, and walk on a particular side of the road, depending on the direction of the wind.

Dr. Armauer Hansen first discovered the leprosy bacillus in Norway in 1873. He is credited with identifying one of the first bacteria known to be a human pathogen. Today, leprosy is often called Hansen's disease.

Leprosy Today
Leprosy is still extant today. Most cases are located in Asia. There are 700,000 new cases every year worldwide, with 200 of those cases in the United States. Rate of occurrence has declined steadily over the past few decades. Leprosy is rarely the cause of death in a patient, but many patients die from complications. The rate of mortality for people suffering from leprosy is estimated to be about four times that of the normal population.

The current recommended course of treatment is rifampicin, clofazimine and dapsone for multibacillary leprosy (MB) leprosy patients and rifampicin and dapsone for paucibacillary leprosy (PB) patients. This is known as multi-drug treatment. MB patients are cured in 12 months, PB in six. Cases resistant to treatment are extremely rare.

Do you ever wonder, "Do I have leprosy?" Now you can take this simple self-assessment test to determine whether you do!

1. Do you have red, raised patches on your skin?
2. Have you ever chewed through your cheek at breakfast because you couldn't feel anything? Is this a recurring problem?
3. Has your doctor performed a skin smear and come up with nothing? Did this self-same doctor rule out leprosy becuase of this? If so, you have an idiot for a doctor. Be particularly worried if you're in an HMO.

If you answer "yes" to the above three questions, you may have PB leprosy. Go see a non-HMO doctor immediately.

1. Are you covered with tumors?
2. Stick a finger or toe with the tumors into a food processor. Did you feel anything? If so, you are in the early stages of the disease. If not, start fretting and check to see if you still have all of your limbs.
3. Did you catch your dog burying one of your body parts in the backyard last night?
4. Have you suddenly developed claw foot?

If you answered "yes" to one or more of the above questions, you may have MB leprosy. Go see your doctor immediately for a skin smear, which will detect the bacteria. Or, if you feel qualified, grab your high-powered microscope, dab a swab from your skin beneath the lens, and look for the rod-shaped, red-stained leprosy bacilli.

This has been another public health service provided free as in beer by SueZVudu!

Also known as Hansen's disease, leprosy has been known to humankind for millenia.

The causative organism was not found until 1873, when a Dr. Gerhard A. Hansen (1841-1912) discovered that leprosy was caused by Mycobacterium leprae. Since then, leprosy has also been known as Hansen's disease (personally, I'm pretty sure I wouldn't like to be remembered as the guy whose name is associated with leprosy ...).

Mycobacterium leprae is an obligate intracellular parasite that is from the same family of acid-fast bacili that causes tuberculosis. This particular bug has never been grown on any sort of artificial medium. Humans were the only known natural reservoir for Mycobacterium leprae until recently when some armadillos in Louisiana and Texas were found to be infected. Armadillos also seem to be a good culture animal for leprosy for some reason, as Mycobacterium leprae creates an even bigger infection in armadillos than in humans.

Most cases of leprosy occur in Africa and Asia. Other endemic foci exist in Central and South America. In the U.S. and Europe, leprosy is almost unknown outside of immigrants from these areas.

Transmission of leprosy is uncertain. Leprosy was even thought to be a hereditary disease (a long time ago), as there did not seem to be any pattern for the transmission of this disease. Close contact is certainly necessary for transmission of leprosy and it is thought that Mycobacterium leprae is spread via the respiratory tract. Few who actually come into close contact with a leper end up getting leprosy but many will end up developing antibodies to Mycobacterium leprae.

The incubation period for leprosy can range from one year to 40 years, with an average of 5 to 7 years. Mycobacterium leprae grows very slowly, with a doubling time of about two weeks.

hmm... more later.

One thing that piqued my interest in an article on leprosy in the November 2000 edition of Discover magazine was that leprosy was brought back to Europe in large numbers by warriors returning from the Crusades. The church had trouble answering why these fighters were coming back diseased when they had gone on a holy war (as in "whose side was God on?") - leper colonies only became prominent after the Crusades. Leprosy in Europe died out when the Black Death a.k.a. the Plague came along and wiped out most of the lepers (along with a quarter of Europe's population).

Lep"ro*sy (?), n. [See Leprous.] Med.

A cutaneous disease which first appears as blebs or as reddish, shining, slightly prominent spots, with spreading edges. These are often followed by an eruption of dark or yellowish prominent nodules, frequently producing great deformity. In one variety of the disease, anaesthesia of the skin is a prominent symptom. In addition there may be wasting of the muscles, falling out of the hair and nails, and distortion of the hands and feet with destruction of the bones and joints. It is incurable, and is probably contagious.

<-- caused by the bacterium Mycobacterium leprae, curable in most cases by therapy with a combination of antibiotics, but cases resistant to therapy are increasing. -->

The disease now called leprosy, also designated as Lepra or Lepra Arabum, and Elephantiasis Graecorum, is not the same as the leprosy of the ancients. The latter was, indeed, a generic name for many varieties of skin disease (including our modern leprosy, psoriasis, etc.), some of which, among the Hebrews, rendered a person ceremonially unclean. A variety of leprosy of the Hebrews (probably identical with modern leprosy) was characterized by the presence of smooth, shining, depressed white patches or scales, the hair on which participated in the whiteness while the skin and adjacent flesh became insensible. It was incurable disease.


© Webster 1913.

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