Outline of Leprosy

I. Name of Disease

Leprosy; different forms being Lepromatus, Tuberculoid, Multibacilliary, and Paucibacilliary

II. Name of Bacteria

Mycobacterium leprae

III. Description of the Bacteria

Mycobacterium leprae, the bacteria which causes leprosy, is a rod-like bacillus with parallel sides and rounded ends measuring 2-7 micro-millimeters in length and 0.3-0.4 micro-millimeters in width. It can only be seen under the electron microscope when stained. It is acid-fast and alcohol-fast, meaning not decolorized by acid or alcohol after staining, as most bacteria retain dye after an acid or alcohol rinse. It occurs in large numbers in the lesions of Lepromatous leprosy, chiefly in masses within the Lepra cells, often arranged like bundles of cigars. Chains are never seen. Intracellular and extra-cellular masses, known as globi, consist of clumps of bacilli in capsular material. Under the electron microscope, the bacillus appears to have a great mixture of forms. The most common is a slightly curved filament containing irregular arrangements of dense material in the shape of rods. Short rod-shaped structures can also be seen and also dense spherical forms.

The leprosy causing bacteria are probably spread through skin breaks, such as a contaminated needle, and sneezing and coughing. The leprosy bacilli travel through the air in droplets released when people cough or sneeze. The bacteria can survive three weeks or longer even outside the human body, such as in dust or on clothing.

IV. Description of the Disease

When Mycobacterium leprae was discovered by G. Armauer Hansen in 1873, it was the first bacterium to be identified as causing disease in man. Leprosy, also called Hansen’s disease, is an infectious disease that affects skin, peripheral nerves, mucous membranes, such as eyes and respiratory tract. Though slow growing, it is one of the world’s most crippling diseases. The effects of leprosy are discolored patches on the skin, which are followed by numbness in the patches, leading to gradual but total loss of feeling. The skin lesion can be single or multiple, usually less pigmented than the surrounding normal skin. Sometimes the lesion is reddish or copper-colored. A variety of skin lesions may be seen but flat, raised, or nodule-like are common. Sometimes, people will have sharp pains of “pins and needles”. Leprosy is also one of the leading causes of blindness.

Although infectious, leprosy is one of the least contagious of all diseases. Only a small number of people with this disease are actually contagious, and with regular medication, they soon become non-contagious. Most people acquire natural immunity and have mild symptoms, sometimes called tuberculoid leprosy, but an estimated five percent cannot develop this immunity and contract the severe form of the disease, known as lepromatous leprosy. As many as one quarter of untreated patients become disabled.

V. Prognosis

When leprosy attacks the skin, it destroys nerve endings, sweat glands, hair follicles, and pigment-producing cells. It also attacks peripheral nerves, so the ability to feel light touches and hot or cold goes first. After a time the affected part may lose the ability to feel anything. Injuries, cuts, and burns that patients do not feel become a constant danger. For people who develop some immunity to leprosy, this is about as far as the disease progresses.

In those with lepromatous leprosy, the disease can inflict great devastation. If left untreated, bacilli entering the mucus lining of the nose can lead to internal damage, which in time causes the nose to collapse. If the facial nerve is affected, one loses the blinking reflex of the eye, which can lead to blindness. if the nerve about the elbow is affected, part of the hand becomes numb and the small muscles become paralyzed. Over time people with advanced leprosy may need artificial feet or legs, or wheelchairs.

Death from leprosy itself is rare, although the body is weakened and more susceptible to other diseases.

VI. Methods of Defense

Researchers in the past had been unable to create a vaccine against leprosy because they were unable to grow a culture in a test tube. More recently, it was learned that armadillos can develop leprosy. This provided an experimental animal for the first time, and a vaccine is now available. Several antibiotics are also available. A three-drug combination as standard treatment, known as MDT, is commonly recommended. Many cases can be cured between six months to three years. MDT usually makes a patient non-contagious within only a few days. Recently, the Food and Drug Administration, or FDA, approved thalidomide for the treatment of certain forms of leprosy. Since this medication can cause birth defects, there are strict guidelines for its use in women of childbearing age. Surgery, amputation, transplants, or cosmetic surgery may be needed to help patients regain self-esteem. Deformities such as wrist-drop, foot-drop, or claw-hand may require surgery for correction.

VII. Methods of Immunization

The best way to prevent the spread of leprosy is the early diagnosis and treatment of people who are infected. Immediate and annual examination for at least five years after last contact with a person who is infectious is recommended.

VIII. Conclusion

Attitudes and traditions about leprosy in the ancient world continue to influence the way we think about the disease today. For thousands of years, people with leprosy were taken to a priest for exorcism instead of to a doctor for treatment. In the Middle Ages, people with leprosy were required to wear clappers or bells to cry out “unclean” when approaching others. People with leprosy and there uninfected children were banished from their communities and confined in leper colonies.

Leprosy in all ages has been considered one of the more despicable diseases, and victims have been despised throughout history and kept in separate places like leper colonies and sanitariums. Even today, most people with leprosy are shunned by their neighbors and are held at arms length. In the medieval period, leper colonies sprung up where victims of this then-untreatable disease would go to slowly die from the illness.

The disease still occurs in tropical and subtropical countries of Asia, Africa, and Latin America, especially where crowded and unsanitary conditions contribute to its spread, and even in the more developed countries it crops up from time to time. In the United States, the disease is found mostly in Louisiana, Texas, Florida, Hawaii, and occasionally in California, New York City, and other areas where immigrants from endemic areas have settled. Modern treatment has significantly reduced the number of cases, however, and the World Health Organization, or WHO, is working to eradicate the disease worldwide.