Notes on Leprosy

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What is Leprosy?

Leprosy, also known as Hansen's Disease, is a rare disease in the Western world today, however, it was a major disease in Europe and America. Just like tuberculosis, leprosy faded away for unknown reasons before a cure could be found. Nevertheless, leprosy still exists in certain tropical regions, economically backward and underdeveloped countries. There are estimated to be about 600,000 worldwide cases today.

Symptoms

Leprosy begins with increased or decreased sensation and pigmentation on skin. The skin swells and thickens, accompanied by hair-loss, overactive sweat glands and uneven sensations. Limbic nerves painfully swell and become visible through the skin. There is muscle loss, numbness, ulceration and loss of digits. Facial features also change dramatically - the ears and nose thicken, and wrinkles appear. The nose bridge collapses accompanied by bleeding.

Causative Agent

Leprosy is caused by Mycobacterium leprae, which looks identical to M. Tuberculosis. Some of its qualities are: it is fast, rod-shaped, acid-fast, aerobic, and stains in a beaded manner. M. leprae cannot be grown in the absence of living cells - although further research is being done in that area. Nevertheless, the organism can be grown in armadillos, and has a typical generation time of about 12 hours - which is considered to be slow. E. coli is being grown with part of M. leprae genome so that large quantities of the organism's antigens are available.

Pathogenesis

M. leprae first attacks small nerves of the skin - peripheral nerves to be specific. It is the only bacterium which attackes these nerves. M. leprae may also thrive within Macrophages . Some macrophages, however, become immune to attack and prevent the bacterium from growing within them. These immune macrophages in turn attack nerves, rendering them damaged, leading to deformity, skin ulceration and resorption of bone. The disease immediately stops progressing these symptoms, and irreversible nerve damage is done. This type of Hansen's disease which is suppressed by macrophages is called tuberoid leprosy. This type of leprosy is non-transmittable from person to person. On the other hand, if the macrophages fail to suppress M. leprae, a more deadly form of leprosy develops: lepromatous leprosy. The M. leprae bacteria thrives within the mucus of the throat and nose, making this type of leprosy easily transmitted from person to person.

Prevention and Treatment

There is a vaccine yet to be discovered. Leprosy is mainly caused by nasal secretions. M. leprae enters the body through skin abrasions. The only treatments are certain drugs like dapsone and rifapin - administered for months or years; clofazimine may be added for lepromatous disease.

Additional Readings:

Basic Bacteriology

1. Bacterial Locations and Toxins
2. Growth Medias and Oxygen Requirements
3. Staphylococus
4. Streptococcus
5. Enterococcus
6. Bacillus
7. Listeria
8. Corynebacterium
9. Actinomyces
10. Nocadria
11. Mycobacterium
12. Clostridium
13. Neisseria
14. Pseudomonas
15. Legionella
16. Bordetella
17. Francisella
18. Brucella
19. Campylobacter
20. Escherichia
21. Shigella
22. Klebsiella
23. Salmonella
24. Yersinia
25. Proteus
26. Vibrio
27. Pasteurella
28. Haemophilus
29. Bacteriodes and Prevotella
30. Treponema
31. Borrelia
32. Rickettsia
33. Coxiella
34. Ehrlichia
35. Chlamydia
36. Mycoplasma
37. What is an ELEK's Test?
38. Causes of Orchitis
39. What is Leprosy?
40. What is Folliculitis?
41. What is Botulism?
42. How to interpret PPD (Purified Protein Derivative) results?
43. Prenatal Infections

Related Topics

1. Bacterial vs viral infections

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