-HDP- Leprosy

2. What is leprosy? Leprosy is a chronic infectious disease caused by mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes, apart from some other structures. Leprosy has afflicted humanity since time immemorial. 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

3. What causes Leprosy? The bacterium that causes Leprosy is rod-shaped and called Mycobacterium leprae. When Mycobacterium leprae enters the body, one of these things can happen: 1)Tuberculoid leprosy (TT) : the body's immune cells attempt to seal off the infection from the rest of the body by surrounding the offending pathogen. Because this response by the immune system occurs in the deeper layers of the skin, the hair follicles, sweat glands, and nerves can be destroyed. As a result, the skin becomes dry and discolored and loses its sensitivity. 2)Lepromatous leprosy (LL) : this is the more dangerous type, in which the body's immune system is unable to mount a strong response to the invading organism. Hence, the organism multiplies freely in the skin. This type of leprosy is also called the multibacillary (MB) leprosy, because of the presence of large numbers of bacteria. Occasionally, the mucous membranes of the eyes, nose, and throat may be involved. Facial involvement can produce a lion-like appearance (leonine facies). This type of leprosy can lead to blindness, drastic change in voice, or mutilation of the nose

4. 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.Since ancient times, leprosy has been regarded by the community as a contagious, mutilating and incurable disease. There are many countries in Asia, Africa and Latin America with a significant number of leprosy cases. It is estimated that there are between one and two million people visibly and irreversibly disabled due to past and present leprosy who require to be cared for by the community in which they live.When M.leprae was discovered by G.A. Hansen in 1873, it was the first bacterium to be identified as causing disease in man. However, treatment for leprosy only appeared in the late 1940s with the introduction of dapsone, and its derivatives. Leprosy bacilli resistant to dapsone gradually appeared and became widespread.

5. Leprosy is known to occur at all ages ranging from early infancy to very old age. The youngest age reported for occurrence of leprosy is three weeks in Martinique (Montestruc & Berdonneau, 1954). The youngest case seen by the author was in an infant of two-and-a-half months, where the diagnosis of leprosy was confirmed by histopathology. Occurrence of leprosy, presumably for the first time, is not uncommon even after the age of seventy. Method of transmission of leprosy The exact mechanism of transmission of leprosy is not known. At least until recently, the most widely held belief was that the disease was transmitted by contact between cases of leprosy and healthy persons. More recently the possibility of transmission by the respiratory route is gaining ground. There are also other possibilities such as transmission through insects which cannot be completely ruled out.

6. Transmission by contact The term 'contact' in leprosy is generally not clearly defined. All that we know at present is that individuals who are in close association or proximity with leprosy patients have a greater chance of acquiring the disease. It is with reference to this observation that the early workers appear to have used the term 'contact' as method of transmission. However, it is the definition of contact by later workers with qualifications such as 'skin to skin', 'intimate', 'repeated', etc. that has made it appear as if the disease could be acquired only under such conditions, and that the transmission involved some kind of 'inunction' or rubbing in of the organisms from the skin of affected persons into the skin of healthy subjects. Certainly, there is no proof that transmission takes place only through such inunction. In general, closeness of contact is related to the dose of infection which in turn is related to the occurrence of disease. Of the various situations that promote close contact, contact within the household is the only one that is easily identified. In that area the relative risk for contacts was about four times that of non-contacts. The actual incidence among contacts and the relative risk for them appear to vary considerably in different studies. Attack rates for contacts of lepromatous leprosy have varied from 6.2 per 1000 per year in Cebu (Doull et al, 1942) to 55.8 per 1000 per year in a part of South India (Noordeen & Neelan, 1978). The possibility of transmission of leprosy through the respiratory route is gaining increasing attention in recent years. It is interesting to note that as early as 1898 this possibility has also been discussed at some length by Sch ffer (Sch ffer, 1898). The possibility of transmission through the respiratory route is based on (a) the inability of the organisms to be found on the surface of the skin, (b) the demonstration of a large number of organisms in the nasal discharge, (c) the high proportion of morphologically intact bacilli in the nasal secretions, and (d) the evidence that M.leprae could survive outside the human host for several hours or days. Transmission through insects With the available evidence on intracutaneous inoculation as a successful method of transmission of M.leprae in the mouse footpad model and a similar situation possibly existing in human beings, the question arises whether insects could play any role in natural infection. Although a large number of experiments had been conducted in the past demonstrating AFB in biting insects, the question whether insects actually transmitted infection had remained unanswered.

7. Graphs

8. Human Body Diagram

9. Bibliography (Unknown Title)- http://www.tesarta.com/www/resources/library/leprosy.html Bayanihan- http://www.bayanihan.org/html/public_html/article.php?story=20030831193559038 The Dark Light- Mette Newth Ffd- http://www.thalidomide.org/English/Thalidomide/Against_Leprosy.html Genesis- http://www.genesishealth.com/micromedex/detaileddisease/00054640.aspx Invisible Enemies: Stories of Infectious Diseases- Jeanette Farell Yahoo (Health Page)- http://www.yahoo.com

10. This Slideshow was created by Johan Mickos