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Title: Leprosy  
Author: World Heritage Encyclopedia
Language: English
Subject: Neglected tropical diseases, List of notifiable diseases, Pathogenic bacteria, Father Damien, Histoid leprosy
Collection: Leprosy, Rtt
Publisher: World Heritage Encyclopedia


Classification and external resources
A 24-year-old man from Norway, infected with leprosy, 1886.
ICD-10 A30
ICD-9 030
OMIM 246300
DiseasesDB 8478
MedlinePlus 001347
eMedicine med/1281 derm/223 neuro/187
Patient UK Leprosy
MeSH D007918

Leprosy, also known as Hansen's disease (HD), is a

  • Leprosy at DMOZ
  • Dr. George J. Hill Leprosy Collection, Marshall University Virtual exhibit of books on leprosy.

External links

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  29. ^ Kaur H, Van Brakel W; Van Brakel (2002). "Dehabilitation of leprosy-affected people—a study on leprosy-affected beggars". Leprosy review 73 (4): 346–55.  
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  32. ^ a b "What Is Leprosy?" THE MEDICAL NEWS | from News-Medical.Net - Latest Medical News and Research from Around the World. Web. 20 Nov. 2010. [1].
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  36. ^ Shepard CC (1960). "Acid-fast bacilli in nasal excretions in leprosy, and results of inoculation of mice". Am J Hyg 71: 147–57.  
  37. ^ Pedley JC (1973). "The nasal mucus in leprosy". Lepr Rev 44 (1): 33–5.  
  38. ^ Davey TF, Rees RJ; Rees (1974). "The nasal discharge in leprosy: clinical and bacteriological aspects". Lepr Rev 45 (2): 121–34.  
  39. ^ Rees RJ, McDougall AC; McDougall (1977). "Airborne infection with Mycobacterium leprae in mice". J Med Microbiol 10 (1): 63–8.  
  40. ^ Chehl S, Job CK, Hastings RC; Job; Hastings (1985). "Transmission of leprosy in nude mice". Am J Trop Med Hyg 34 (6): 1161–6.  
  41. ^ Montestruc E, Berdonneau R; Berdonneau (1954). "2 New cases of leprosy in infants in Martinique". Bull Soc Pathol Exot Filiales (in French) 47 (6): 781–3.  
  42. ^ "Diagnosis of Leprosy." WHO. from accessed on 14 July 2014.
  43. ^ U.S. Department of Health and Human Services, Health Resources and Services Administration. (n.d.). National Hansen's disease (leprosy) program Retrieved from
  44. ^ Smith DS (2008-08-19). "Leprosy: Overview". eMedicine Infectious Diseases. Retrieved 2010-02-01. 
  45. ^ Singh N, Manucha V, Bhattacharya SN, Arora VK, Bhatia A; Manucha; Bhattacharya; Arora; Bhatia (June 2004). "Pitfalls in the cytological classification of borderline leprosy in the Ridley-Jopling scale". Diagn. Cytopathol. 30 (6): 386–8.  
  46. ^ Ridley DS, Jopling WH; Jopling (1966). "Classification of leprosy according to immunity. A five-group system". Int. J. Lepr. Other Mycobact. Dis. 34 (3): 255–73.  
  47. ^ Modlin RL (June 1994). "Th1-Th2 paradigm: insights from leprosy". J. Invest. Dermatol. 102 (6): 828–32.  
  48. ^ James, William D.; Berger, Timothy G.; and others (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier.  
  49. ^ Jardim MR, Antunes SL, Santos AR, Nascimento OJ, Nery JA, Sales AM, Illarramendi X, Duppre N, Chimelli L, Sampaio EP, Sarno EP; Antunes; Santos et al. (July 2003). "Criteria for diagnosis of pure neural leprosy". J. Neurol. 250 (7): 806–9.  
  50. ^ Mendiratta V, Khan A, Jain A; Khan; Jain (2006). "Primary neuritic leprosy: a reappraisal at a tertiary care hospital". Indian J Lepr 78 (3): 261–7.  
  51. ^ Ishida Y, Pecorini L, Guglielmelli E; Pecorini l; Guglielmelli e (July 2000). "Three cases of pure neuritic (PN) leprosy at detection in which skin lesions became visible during their course". Nihon Hansenbyo Gakkai Zasshi 69 (2): 101–6.  
  52. ^ Mishra B, Mukherjee A, Girdhar A, Husain S, Malaviya GN, Girdhar BK; Mukherjee; Girdhar; Husain; Malaviya; Girdhar (1995). "Neuritic leprosy: further progression and significance". Acta Leprol 9 (4): 187–94.  
  53. ^ Talwar S, Jha PK, Tiwari VD; Jha; Tiwari (September 1992). "Neuritic leprosy: epidemiology and therapeutic responsiveness". Lepr Rev 63 (3): 263–8.  
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  55. ^ Duthie MS, Gillis TP, Reed SG; Gillis; Reed (November 2011). "Advances and hurdles on the way toward a leprosy vaccine". Hum Vaccin 7 (11): 1172–83.  
  56. ^ Setia MS, Steinmaus C, Ho CS, Rutherford GW; Steinmaus; Ho; Rutherford (March 2006). "The role of BCG in prevention of leprosy: a meta-analysis". Lancet Infect Dis 6 (3): 162–70.  
  57. ^ Merle CS, Cunha SS, Rodrigues LC; Cunha; Rodrigues (2010). "BCG vaccination and leprosy protection: Review of current evidence and status of BCG in leprosy control". Expert Review of Vaccines 9 (2): 209–222.  
  58. ^ "Mortality and Burden of Disease Estimates for WHO Member States in 2002" (xls). World Health Organization. 2002. 
  59. ^ WHO (1995). "Leprosy disabilities: magnitude of the problem". Weekly Epidemiological Record 70 (38): 269–75.  
  60. ^ Surgery grants for leprosy sufferers in India. Times of India. February 2, 2009.
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  64. ^ "DNA of Jesus-Era Shrouded Man in Jerusalem Reveals Earliest Case of Leprosy". ScienceDaily. 2009-12-16. Retrieved 2010-01-31. 
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Notable cases

People with leprosy in India, like many parts of the world, suffer under some of the worst conditions and stereotypes. Depending on the level of disfigurement, a leper could receive harsher stigma and ostracism. People with leprosy earn less: 16–44% of them report their pay dropped as a result of having leprosy. Women suffer greater restrictions and social stigma than men. Leprosy prevents mothers from getting too close to their children out of fear that they could infect them. In a report, 49% of women stopped breast-feeding their babies as a result of having leprosy. Doctors and other health care providers and NGOs are working hard to educate people about the disease. In one study when leprosy treatment and education were mixed in with the local healthcare program, the attitudes towards the disease were somewhat alleviated as people had a better understanding of it. Now the disease prevalence has been reduced to less than 1 per million population in most parts of the country.[73]

Stigma in India

Between 1995 and 1999, WHO, with the aid of the non-government organizations (NGOs) affiliated with the national programme will continue to be provided with an appropriate free supply of this WHO-supplied MDT by the government.

Treatment cost

Society and culture

Many English translations of the Bible translate tzaraath as "leprosy," a confusion that derives from the use of the koine cognate "Λέπρα" (which can mean any disease causing scaly skin) in the Septuagint. Ancient sources such as the Talmud (Sifra 63) make clear that tzaraath refers to various types of lesions or stains associated with ritual impurity and occurring on cloth, leather, or houses as well as skin. While it may sometimes be a symptom of the disease described in this article, but has many other causes as well.

The Bible

Japan still has sanatoriums (although Japan's sanatoriums no longer have active leprosy cases, nor are survivors held in them by law).[72]

Leprosy was once believed to be highly contagious and was treated with mercury—all of which applied to syphilis, which was first described in 1530. It is possible that many early cases thought to be leprosy could actually have been syphilis.[70] Effective treatment first appeared in the late 1940s. Resistance has developed to initial treatment. It was not until the introduction of MDT in the early 1980s that the disease could be diagnosed and treated successfully within the community.[71]

The causative agent of leprosy, Mycobacterium leprae, was discovered by G. H. Armauer Hansen in Norway in 1873, making it the first bacterium to be identified as causing disease in humans.[67] The first effective treatment (promin) became available in the 1940s.[63] In the 1950s dapsone was introduced. The search for further effective anti-leprosy drugs led to the use of clofazimine and rifampicin in the 1960s and 1970s.[68] Later, Indian scientist Shantaram Yawalkar and his colleagues formulated a combined therapy using rifampicin and dapsone, intended to mitigate bacterial resistance.[69] Multidrug therapy (MDT) combining all three drugs was first recommended by the WHO in 1981. These three anti-leprosy drugs are still used in the standard MDT regimens.

The term leprosy is derived from either the Indo-European term lap, which means the removal of scales, or the Greek word for "scales", lepia.[65] Historically, people infected were often confined against their will in leper colonies and in Medieval Europe were required to carry a bell to identify their presence.[66] Attempted treatments have included arsenic, elephants' teeth, creosote, and mercury.[66]

Evidence of leprosy dates back to ancient Egypt in 4000 BC and was discussed by Hippocrates in 460 BC.[63] It was recognized in the civilizations of ancient China, Egypt, Israel, and India.[23] The earliest proven human case was verified by DNA taken from the shrouded remains of a man discovered in a tomb next to the Old City of Jerusalem dated by radiocarbon methods to 1–50 AD.[64]

G. H. A. Hansen, discoverer of M. leprae


Endemic countries also report the number of new cases with established disabilities at the time of detection, as an indicator of the backlog prevalence. Determination of the time of onset of the disease is, in general, unreliable, is very labor-intensive, and is seldom done in recording these statistics.

New case detection is another indicator of the disease that is usually reported by countries on an annual basis. It includes cases diagnosed with onset of disease in the year in question (true incidence) and a large proportion of cases with onset in previous years (termed a backlog prevalence of undetected cases).

Although the number of new leprosy cases occurring each year is important as a measure of transmission, it is difficult to measure due to leprosy's long incubation period, delays in diagnosis after onset of the disease, and the lack of laboratory tools to detect it in the very early stages. Instead, the registered prevalence is used. Registered prevalence is a useful proxy indicator of the disease burden, as it reflects the number of active leprosy cases diagnosed with the disease and receiving treatment with MDT at a given point in time. The prevalence rate is defined as the number of cases registered for MDT treatment among the population in which the cases have occurred, again at a given point in time.[62]

Disease burden

While the number of cases of leprosy was in the tens of millions in the 1960s, a series of national (The International Federation of Anti-Leprosy Associations) and international (the WHO's "Global Strategy for Reducing Disease Burden Due to Leprosy") initiatives have reduced the total number and the number of new cases the disease.[61]

In 1995 two to three million people were estimated to be permanently disabled because of leprosy.[59] India has the greatest number of cases, with endemic. India, Burma, and Nepal contained 70% of cases. India reports over 50% of the world's leprosy cases.[60] In 2002, 763,917 new cases were detected worldwide, and in that year the WHO listed Brazil, Madagascar, Mozambique, Tanzania, and Nepal as having 90% of leprosy cases. Although the number of cases worldwide continues to fall, pockets of high prevalence continue in certain areas such as Brazil, South Asia (India, Nepal), some parts of Africa (Tanzania, Madagascar, Mozambique), and the western Pacific.

Globally in 2012 the number of cases of leprosy was 180,000.[4] In 2011 the approximate number of new cases diagnosed was 220,000.[4] The number of cases has decreased significantly from the 1960s to the 2010s.[5]

Disability-adjusted life year for leprosy per 100,000 inhabitants in 2004.[58]
  no data
World distribution of leprosy, 2003.


Multi-drug therapy (MDT) remains highly effective, and people are no longer infectious after the first monthly dose.[23] It is safe and easy to use under field conditions due to its presentation in calendar blister packs.[23] Relapse rates remain low, and there is no known resistance to the combined drugs.[23]

A number of leprostatic agents are available for treatment. For paucibacillary (PB or tuberculoid) cases treatment with daily dapsone and monthly rifampicin for six months is recommended.[3] While for multibacillary (MB or lepromatous) cases treatment with daily dapsone and clofazimine along with monthly rifampicin for twelve months is recommended.[3]

MDT anti-leprosy drugs: standard regimens


The Bacillus Calmette–Guérin (BCG) vaccine offers a variable amount of protection against leprosy in addition to tuberculosis.[55] It appears to be 26 to 41% effective (based on controlled trials) and about 60% effective based on observational studies with two doses possibly working better than one.[56][57] Development of a more effective vaccine is ongoing as of 2011.[54]

Medications can decrease the risk of those living with people with leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home.[54] There are however concerns of resistance, cost, and disclosure of a person's infection status when doing follow up of contacts, thus the WHO however recommends that people who live in the same household be examined for leprosy and only be treated if symptoms are present.[54]


This disease may also occur with only neural involvement, without skin lesions.[23][49][50][51][52][53]

Leprosy may also be divided into the following types:[48]:344–346

There is a difference in immune response to the tuberculoid and lepromatous forms.[47]

WHO Ridley-Jopling ICD-10 MeSH Description Lepromin test Immune target
Paucibacillary tuberculoid ("TT"),
borderline tuberculoid ("BT")
A30.1, A30.2 Tuberculoid It is characterized by one or more hypopigmented skin macules and anaesthetic patches, where skin sensations are lost because of damaged peripheral nerves that have been attacked by the human host's immune cells. Positive bacillus (Th1)
Multibacillary midborderline or borderline ("BB") A30.3 Borderline Borderline leprosy is of intermediate severity and is the most common form. Skin lesions resemble tuberculoid leprosy but are more numerous and irregular; large patches may affect a whole limb, and peripheral nerve involvement with weakness and loss of sensation is common. This type is unstable and may become more like lepromatous leprosy or may undergo a reversal reaction, becoming more like the tuberculoid form.
Multibacillary borderline lepromatous ("BL"),
and lepromatous ("LL")
A30.4, A30.5 Lepromatous It is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis (nose bleeds), but, typically, detectable nerve damage is late. Negative plasmid inside bacillus

  • The [44]("pauci-" refers to a low quantity.)
  • The SHAY scale provides five gradations.[45][46]
  • The ICD-10, though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry.[32]
  • In MeSH, three groupings are used.

There are several different approaches for classifying leprosy; however, parallels exist.


There are many kinds of leprosy but there are common symptoms, including: runny nose; dry scalp; eye problems; skin lesions; muscle weakness; reddish skin; smooth shiny diffuse thickening of facial skin, ear, and hand; loss of sensation in fingers and toes; thickening of peripheral nerves; and flat nose due to destruction of nasal cartilage. There is also phonation and resonation of sound during speech. Often there is atrophy of the testes and impotency.

Diagnosis in the U.S. is often delayed because healthcare providers are unaware of leprosy and its symptoms. Early diagnosis and treatment prevents nerve involvement, the hallmark of leprosy, and the disability it causes.[43]

United States

Positive skin smears: In some case, acid fast leprosy bacilli, are considered diagnostic; however, it should be emphasized that the diagnosis is clinical [42]

Thickened nerves are associated with leprosy and can be accompanied by loss of sensation, muscle weakness. However, without the characteristic skin lesion and without the sensory loss and/or muscle weakness is not considered a reliable sign of leprosy.

Skin lesions can be single or multiple, usually hypopigmented although occasionally reddish or copper colored. The lesions may be macules (flat), papules (raised), or nodular. Sensory loss at the skin lesion is important because this feature can help differentiate from other causes of skin lesions such as tinea versicolor.

  • Skin lesion consistent with leprosy and with definite sensory loss
  • Positive skin smears

Per the World Health Organization, diagnosis in an endemic area is based on one of the following cardinal signs:

Endemic areas


In leprosy, both the reference points for measuring the incubation period and the times of infection and onset of disease are difficult to define, the former because of the lack of adequate immunological tools and the latter because of the disease's slow onset. Even so, several investigators have attempted to measure the incubation period for leprosy. The minimum incubation period reported is as short as a few weeks and this is based on the very occasional occurrence of leprosy among young infants.[41] The maximum incubation period reported is as long as 30 years, or over, as observed among war veterans known to have been exposed for short periods in endemic areas but otherwise living in non-endemic areas. It is generally agreed that the average incubation period is between three and five years.

The entry route of M. leprae into the human body is also not definitively known: The skin and the upper respiratory tract are most likely. While older research dealt with the skin route, recent research has increasingly favored the respiratory route. Rees and McDougall succeeded in the experimental transmission of leprosy through aerosols containing M. leprae in immune-suppressed mice, suggesting a similar possibility in humans.[39] Successful results have also been reported on experiments with nude mice when M. leprae were introduced into the nasal cavity by topical application.[40] In summary, entry through the respiratory route appears the most probable route, although other routes, particularly broken skin, cannot be ruled out.

The importance of the nasal mucosa was recognized as early as 1898 by Schäffer, in particular that of the ulcerated mucosa.[35] The quantity of bacilli from nasal mucosal lesions in lepromatous leprosy was demonstrated by Shepard as large, with counts ranging from 10,000 to 10,000,000.[36] Pedley reported that the majority of lepromatous patients showed leprosy bacilli in their nasal secretions as collected through blowing the nose.[37] Davey and Rees indicated that nasal secretions from lepromatous patients could yield as much as 10 million viable organisms per day.[38]

Two exit routes of M. leprae from the human body often described are the skin and the nasal mucosa, although their relative importance is not clear. Lepromatous cases show large numbers of organisms deep in the sebaceous secretions.[34]

The most widely held belief is that the disease is transmitted by contact between infected persons and healthy persons.[29] 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, although the incidence among contacts and the relative risk for them appear to vary considerably in different studies. In incidence studies, infection rates for contacts of lepromatous leprosy have varied from 6.2 per 1000 per year in Cebu, Philippines[30] to 53 per 1000 per year in part of Western India to 55.8 per 1000 per year in a part of Southern India[31]

The precise mechanism of transmission of leprosy is unknown; however, both prolonged close contact and transmission by nasal droplet are thought to be implicated.[23] In addition to humans, leprosy has been observed in the nine-banded armadillo, (which, it has recently been confirmed, is among the primary sources of new cases of leprosy in the population of North America),[24] and three species of non-human primates.[25] The bacterium can also be grown in the laboratory by injection into the footpads of mice.[26] There is evidence that not all people who are infected with M. leprae develop leprosy, and genetic factors have long been thought to play a role, due to the observation of clustering of leprosy around certain families, and the failure to understand why certain individuals develop lepromatous leprosy while others develop other types of leprosy.[27] It is estimated that due to genetic factors, only 5% of the population is susceptible to leprosy.[28] This is mostly because the body is naturally immune to the bacteria, and those persons that do become infected experience severe allergic reactions to the disease. However, the role of genetic factors is not entirely clear in determining this clinical expression. In addition, malnutrition and prolonged exposure to infected persons may play a role in development of the overt disease.


Although the mode of transmission of leprosy remains uncertain, many think that M. leprae is usually spread from person to person in nasal droplets.[5] Studies have shown that leprosy can be transmitted to humans by armadillos.[20][21][22] Leprosy is not known to be either sexually transmitted or highly infectious after treatment. Approximately 95% of people are naturally immune and sufferers are no longer infectious after as little as two weeks of treatment.[17]


There appears to be little interaction between HIV and the risk of leprosy.[19]

At highest risk are those living in areas with polluted water and poor diet or people suffering from diseases that compromise immune function.

Risk factors

Several genes have been associated with a susceptibility to leprosy. It is believed that around 95% of people are naturally immune.[17] Recent research suggests that there is a defect in cell-mediated immunity that causes susceptibility to leprosy. The region of DNA responsible for this variability is also involved in Parkinson's disease, giving rise to current speculation that the two disorders may be linked in some way at the biochemical level.[18]

Name Locus OMIM Gene
LPRS1 10p13 609888
LPRS2 6q25 607572 PARK2, PACRG
LPRS3 4q32 246300 TLR2
LPRS4 6p21.3 610988 LTA
LPRS5 4p14 613223 TLR1
LPRS6 13q14.11 613407


Naturally occurring infection also has been reported in non-human primates including the African chimpanzee, sooty mangabey, and cynomolgus macaque, as well as in armadillos and red squirrels.[16]

While the causative organisms have to date been impossible to culture in vitro, it has been possible to grow them in animals.

Due to extensive loss of Koch's postulates.[2][15] The use of non-culture-based techniques such as molecular genetics has allowed for alternative establishment of causation.

An intracellular, aerobic and rod-shaped, and is surrounded by the waxy cell membrane coating characteristic of the Mycobacterium genus.[14]

Mycobacterium leprae and Mycobacterium lepromatosis are the causative agents of leprosy. M. lepromatosis is a relatively newly identified mycobacterium isolated from a fatal case of diffuse lepromatous leprosy in 2008.[2][10]

Mycobacterium leprae, one of the causative agents of leprosy. As acid-fast bacteria, M. leprae appear red when a Ziehl-Neelsen stain is used.

Mycobacterium leprae


Leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions are the primary external sign.[10] Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs and eyes. Contrary to folklore, leprosy does not cause body parts to fall off, although they can become numb or diseased as a result of secondary infections; these occur as a result of the body's defenses being compromised by the primary disease.[11][12] Secondary infections, in turn, can result in tissue loss causing fingers and toes to become shortened and deformed, as cartilage is absorbed into the body.[11][12][13]

Lepers in Tahiti, c. 1895
Hands deformed by leprosy, 1990, India

Signs and symptoms


  • Signs and symptoms 1
  • Cause 2
    • Mycobacterium leprae 2.1
    • Genetics 2.2
    • Risk factors 2.3
    • Transmission 2.4
  • Pathophysiology 3
  • Diagnosis 4
    • Endemic areas 4.1
    • United States 4.2
    • Classification 4.3
  • Prevention 5
  • Treatment 6
  • Epidemiology 7
    • Disease burden 7.1
  • History 8
    • The Bible 8.1
  • Society and culture 9
    • Treatment cost 9.1
    • Stigma in India 9.2
    • Notable cases 9.3
  • References 10
  • External links 11

[9] was started in 1954 to draw awareness to those affected by leprosy.World Leprosy Day which remains a barrier to self-reporting and early treatment. [1] for much of history,social stigma Leprosy has been associated with [8] However, most colonies have closed.[8] and in the continent of Africa.[7], where there are hundreds;China [6], where there are more than a thousand;India still occurs in countries like leper colonies Separating people in [3].Gerhard Armauer Hansen, which means "scaly", while the term "Hansen's disease" is named after the physician lepra word Latin The disease takes its name from the [3] Leprosy has affected humanity for thousands of years.[1] In the past 20 years, 16 million people worldwide have been cured of leprosy.[3][1] Most new cases occur in 16 countries, with India accounting for more than half.[5][4][1] The number of chronic cases has decreased from some 5.2 million in the 1980s.[1] Globally in 2012 the number of chronic cases of leprosy was 189,000 and the number of new cases was 230,000.[3] A number of other antibiotics may also be used.[1]

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