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| {{DiseaseDisorder infobox | | | {{DiseaseDisorder infobox | |
| Name = Leprosy | | | Name = Leprosy | |
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| MeshNumber = C01.252.410.040.552.386 | | | MeshNumber = C01.252.410.040.552.386 | |
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| {{SI}} | | {{Leprosy}} |
| {{CMG}} | | {{CMG}} |
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| ==Overview== | | ==[[Leprosy overview|Overview]]== |
| '''Leprosy''', or '''Hansen's disease''', is a [[chronic]] [[infectious disease]] caused by the [[Bacteria|bacterium]] ''[[Mycobacterium leprae]]''.<ref name=Sasaki_2001>{{cite journal |author=Sasaki S, Takeshita F, Okuda K, Ishii N |title=Mycobacterium leprae and leprosy: a compendium |journal=Microbiol Immunol |volume=45 |issue=11 |pages=729-36 |year=2001 |url = http://www.jstage.jst.go.jp/article/mandi/45/11/729/_pdf |pmid=11791665}}</ref> Leprosy is primarily a [[granuloma]]tous disease of the [[peripheral nerves]] and [[mucosa]] of the [[upper respiratory tract]]; skin lesions are the primary external symptom.<ref name=Sherris /> Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs, and eyes. Contrary to popular conception, leprosy does not cause body parts to simply fall off, and it differs from tzaraath, the malady described in the Hebrew scriptures and previously translated into English as ''leprosy''.<ref>Leviticus 13:59, Artscroll Tanakh and Metsudah Chumash translations, 1996 and 1994, respectively.</ref>
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| Historically, has affected humanity since at least 300 BC, and was well-recognized in the civilizations of ancient China, Egypt and India.<ref name=WHO_Factsheet>{{cite web | title = Leprosy | work = WHO | url = http://www.who.int/mediacentre/factsheets/fs101/en/ | accessdate = 2007-08-22}}</ref> In 1995, the [[World Health Organization]] (WHO) estimated that between two and three million individuals were permanently disabled because of leprosy.<ref name=WHO_1995>{{cite journal |author=WHO|title=Leprosy disabilities: magnitude of the problem |journal=Weekly Epidemiological Record |volume=70 |issue=38 |pages=269-75 |year=1995 |pmid=7577430}}</ref> Although the forced [[quarantine]] or segregation of patients is unnecessary—and can be considered unethical—a few [[leper colony|leper colonies]] still remain around the world, in countries such as India, and Vietnam.
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| The age-old [[social stigma]] associated with the advanced form of leprosy lingers in many areas, and remains a major obstacle to self-reporting and early treatment. Effective treatment for leprosy appeared in the late 1940s with the introduction of [[dapsone]] and its derivatives. However, leprosy bacilli resistant to dapsone gradually [[Antibiotic resistance|evolved]] and became widespread, and it was not until the introduction of multidrug therapy (MDT) in the early 1980s that the disease could be diagnosed and treated successfully within the community.
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| ==Characteristics==
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| [[Image:Leprosy_thigh_demarcated_cutaneous_lesions.jpg|left|thumb|Cutaneous leprosy lesions on a patient's thigh.]]
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| The clinical manifestations of leprosy vary but primarily affect the skin, nerves, and [[mucous membrane]]s.<ref name=Naafs_2001>{{cite journal |author=Naafs B, Silva E, Vilani-Moreno F, Marcos E, Nogueira M, Opromolla D |title=Factors influencing the development of leprosy: an overview |journal=Int J Lepr Other Mycobact Dis |volume=69 |issue=1 |pages=26-33 |year=2001 |pmid=11480313}}</ref> Patients with this chronic infectious disease are classified as having '''paucibacillary''' (tuberculoid leprosy), '''multibacillary Hansen's disease''' (lepromatous leprosy), or borderline leprosy.
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| Borderline leprosy (also termed multibacillary), of intermediate severity, 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.
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| Paucibacillary Hansen's disease is characterized by one or more [[Hypopigmentation|hypopigmented]] skin [[macule]]s and anaesthetic patches, i.e., damaged peripheral nerves that have been attacked by the human host's immune cells.
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| Multibacillary Hansen's disease is associated with symmetric skin [[lesion]]s, [[nodule]]s, 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.
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| Contrary to popular belief, Hansen's bacillus does not cause rotting of the flesh; rather, a long investigation by [[Paul Wilson Brand|Paul Brand]] yielded that insensitivity in the limbs extremities was the reason why unfelt wounds or lesions, however minute, lead to undetected deterioration of the tissues, the lack of pain not triggering an immediate response as in a fully functioning body. Recently, leprosy has also emerged as a problem in [[HIV]] patients on [[antiretroviral drugs]].<ref name=McNeil_2006>{{cite news | author = McNeil Jr DG|title = Worrisome New Link: AIDS Drugs and Leprosy |url = http://www.nytimes.com/2006/10/24/health/24lepr.html | work = New York Times |date = 2006-10-24 |accessdate=2007-05-07 }}</ref>
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| ==Cause==
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| {{main|Mycobacterium leprae}}
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| [[Image:M leprae ziehl nielsen2.jpg|thumb|left|''Mycobacterium leprae'', the causative agent of leprosy. As [[acid-fast]] bacteria, ''M. leprae'' appear red when a [[Ziehl-Neelsen stain]] is used.]]
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| ''Mycobacterium leprae'' is the causative agent of leprosy.<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | pages = 451-3 | publisher = McGraw Hill | year = 2004 | isbn = 0838585299}}</ref> An intracellular, [[acid-fast]] [[Bacteria|bacterium]], ''M. leprae'' is [[aerobic]], [[Gram-positive|gram-positive]], and rod-shaped, and is surrounded by the waxy [[cell membrane]] coating characteristic of ''[[Mycobacterium]]'' species.<ref name=Baron>{{cite book | author = McMurray DN | title = Mycobacteria and Nocardia. ''in:'' Baron's Medical Microbiology ''(Baron S ''et al'', eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1833 | isbn = 0-9631172-1-1 }}</ref>
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| Due to extensive loss of [[gene]]s necessary for independent growth, ''M. leprae'' is [[Microbiological culture|unculturable]] in the laboratory, a factor which leads to difficulty in definitively identifying the organism under a strict interpretation of [[Koch's postulates]].<ref name=Bhattacharya_2002>{{cite journal |author=Bhattacharya S, Vijayalakshmi N, Parija SC |title=Uncultivable bacteria: Implications and recent trends towards identification |journal=Indian journal of medical microbiology |volume=20 |issue=4 |pages=174-7 |year=2002 |pmid=17657065 |url=http://www.ijmm.org/article.asp?issn=0255-0857;year=2002;volume=20;issue=4;spage=174;epage=177;aulast=Bhattacharya}}</ref> The use of non-culture-based techniques such as [[molecular genetics]] has allowed for alternative establishment of causation.<ref name=Bhattacharya_2002 />
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| == Pathophysiology ==
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| The exact mechanism of transmission of leprosy is not known: prolonged close contact and transmission by nasal droplet have both been proposed, and, while the latter fits the pattern of disease, both remain unproved.<ref>{{cite journal |author=Reich CV |title=Leprosy: cause, transmission, and a new theory of pathogenesis |journal=Rev. Infect. Dis. |volume=9 |issue=3 |pages=590-4 |year=1987 |pmid=3299638 |doi=}}</ref> The only other animals besides humans to contract leprosy are the armadillo, chimpanzees, sooty mangabeys, and Crab-eating Macaque]].<ref>{{cite journal |author=Rojas-Espinosa O, Løvik M |title=Mycobacterium leprae and Mycobacterium lepraemurium infections in domestic and wild animals |journal=Rev. - Off. Int. Epizoot. |volume=20 |issue=1 |pages=219-51 |year=2001 |pmid=11288514 |doi=}}</ref> The bacterium can also be grown in the laboratory by injection into the footpads of mice.<ref>{{cite journal |author=Hastings RC, Gillis TP, Krahenbuhl JL, Franzblau SG |title=Leprosy |journal=Clin. Microbiol. Rev. |volume=1 |issue=3 |pages=330-48 |year=1988 |pmid=3058299 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=3058299}}</ref> 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.<ref>{{cite journal |author=Alcaïs A, Mira M, Casanova JL, Schurr E, Abel L |title=Genetic dissection of immunity in leprosy |journal=Curr. Opin. Immunol. |volume=17 |issue=1 |pages=44-8 |year=2005 |pmid=15653309 |doi=10.1016/j.coi.2004.11.006}}</ref> However, the role of genetic factors is not clear in determining this clinical expression. In addition, malnutrition and possible prior exposure to other environmental [[mycobacteria]] may play a role in development of the overt disease.
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| The most widely-held belief is that the disease is transmitted by contact between infected persons and healthy persons.<ref>{{cite journal |author=Kaur H, Van Brakel W |title=Dehabilitation of leprosy-affected people--a study on leprosy-affected beggars |journal=Leprosy review |volume=73 |issue=4 |pages=346-55 |year=2002 |pmid=12549842 |doi=}}</ref> 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 actual incidence among contacts and the relative risk for them appear to vary considerably in different studies. In [[Incidence (epidemiology)|incidence studies]], infection rates for contacts of lepromatous leprosy have varied from 6.2 per 1000 per year in Cebu, Philippines<ref name=Doull_1942>{{cite journal | author = Doull JA, Guinto RA, Rodriguez RS, et al. | title = The incidence of leprosy in Cordova and Talisay, Cebu, Philippines | journal = International Journal of Leprosy | year = 1942 | volume = 10 | pages = 107–131 | url= }}</ref> to 55.8 per 1000 per year in a part of Southern India.<ref name=Noordeen_1978>{{cite journal |author=Noordeen S, Neelan P |title=Extended studies on chemoprophylaxis against leprosy |journal=Indian J Med Res |volume=67 |issue= |pages=515-27 |year=1978 |pmid=355134}}</ref>
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| 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. It is true that lepromatous cases show large numbers of organisms deep down in the [[dermis]]. However, whether they reach the skin surface in sufficient numbers is doubtful. Although there are reports of [[Acid-fast|acid-fast bacilli]] being found in the desquamating [[epithelium]] of the skin, Weddell ''et al'' have reported that they could not find any acid-fast bacilli in the [[epidermis]], even after examining a very large number of specimens from patients and contacts.<ref name=Weddell_1963>{{cite journal |author=Weddell G, Palmer E |title=The pathogenesis of leprosy. An experimental approach |journal=Leprosy Review |volume=34 |issue= |pages=57-61 |year=1963 |pmid=13999438}}</ref> In a recent study, Job ''et al'' found fairly large numbers of ''M. leprae'' in the superficial [[keratin]] layer of the skin of lepromatous leprosy patients, suggesting that the organism could exit along with the [[Sebaceous gland|sebaceous]] secretions.<ref name=Job_1999>{{cite journal |author=Job C, Jayakumar J, Aschhoff M |title="Large numbers" of Mycobacterium leprae are discharged from the intact skin of lepromatous patients; a preliminary report |journal=Int J Lepr Other Mycobact Dis |volume=67 |issue=2 |pages=164-7 |year=1999 |pmid=10472371}}</ref>
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| The importance of the [[nasal mucosa]] was recognized as early as 1898 by Schäffer, particularly that of the ulcerated mucosa. <ref name=Schaffer_1898>''Arch Dermato Syphilis'' 1898; 44:159–174</ref> 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.<ref name=Shepard_1960>{{cite journal |author=Shepard C |title=Acid-fast bacilli in nasal excretions in leprosy, and results of inoculation of mice |journal=Am J Hyg |volume=71 |issue= |pages=147-57 |year=1960 |pmid=14445823}}</ref> Pedley reported that the majority of lepromatous patients showed leprosy bacilli in their nasal secretions as collected through blowing the nose.<ref name=Pedley_1973>{{cite journal |author=Pedley J |title=The nasal mucus in leprosy |journal=Lepr Rev |volume=44 |issue=1 |pages=33-5 |year=1973 |pmid=4584261}}</ref> Davey and Rees indicated that nasal secretions from lepromatous patients could yield as much as 10 million viable organisms per day.<ref name=Davey_1974>{{cite journal |author=Davey T, Rees R |title=The nasal dicharge in leprosy: clinical and bacteriological aspects |journal=Lepr Rev |volume=45 |issue=2 |pages=121-34 |year=1974 |pmid=4608620}}</ref>
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| The entry route of ''M. leprae'' into the human body is also not definitely known. The two seriously considered are the skin and the upper respiratory tract. 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.<ref name=Rees_1977>{{cite journal |author=Rees R, McDougall A |title=Airborne infection with Mycobacterium leprae in mice |journal=J Med Microbiol |volume=10 |issue=1 |pages=63-8 |year=1977 |pmid=320339}}</ref> Successful results have also been reported on experiments with [[nude mice]] when ''M. leprae'' were introduced into the nasal cavity by topical application. <ref name=Chehl_1985>{{cite journal |author=Chehl S, Job C, Hastings R |title=Transmission of leprosy in nude mice |journal=Am J Trop Med Hyg |volume=34 |issue=6 |pages=1161-6 |year=1985 |pmid=3914846}}</ref> In summary, entry through the respiratory route appears the most probable route, although other routes, particularly broken skin, cannot be ruled out. The CDC notes the following assertion about the transmission of the disease: "''Although the mode of transmission of Hansen's disease remains uncertain, most investigators think that ''M. leprae'' is usually spread from person to person in respiratory droplets''."<ref name=CDC_2005>{{cite web | title = Hansen's Disease (Leprosy) | work = Technical Information | publisher = Centers for Disease Control and Prevention | date = 2005-10-12 | url = http://www.cdc.gov/ncidod/dbmd/diseaseinfo/hansens_t.htm | accessdate = 2007-03-22}}</ref>
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| 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. <ref name=Montestruc_1954>{{cite journal |author=Montestruc E, Berdonneau R |title=2 New cases of leprosy in infants in Martinique. |journal=Bull Soc Pathol Exot Filiales |volume=47 |issue=6 | language = French | pages=781-3 |year=1954 |pmid=14378912}}</ref> 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 3 to 5 years.
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| == Diagnosis ==
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| === History and Symptoms ===
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| This chronic infectious disease usually affects the skin and peripheral nerves but has a wide range of possible clinical manifestations. Patients are classified as having paucibacillary or multibacillary Hansen's disease.
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| *'''Paucibacillary Hansen's disease''' is milder and characterized by one or more hypopigmented skin macules.
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| *'''Multibacillary Hansen's disease''' is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and [[epistaxis]].
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| == Treatment ==
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| [[Image:Blisters01.jpg|thumb|left|200px|MDT patient packs and blisters]]
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| Until the development of [[dapsone]], [[rifampin]], and [[clofazimine]] in the 1940s, there was no effective cure for leprosy. However, dapsone is only weakly bactericidal against ''[[M. leprae]]'' and it was considered necessary for patients to take the drug indefinitely. Moreover, when dapsone was used alone, the ''M. leprae'' population quickly [[evolution|evolved]] [[antibiotic resistance]]; by the 1960s, the world's only known anti-leprosy drug became virtually useless.
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| The search for more effective anti-leprosy drugs to dapsone led to the use of clofazimine and rifampicin in the 1960s and 1970s.<ref name=Rees_1970>{{cite journal | author= Rees RJ, Pearson JM, Waters MF | title=Experimental and clinical studies on rifampicin in treatment of leprosy | journal=Br Med J | year=1970 | pages=89-92 | volume= 688 | issue= 1 | pmid=4903972}}</ref> Later, Shantaram Yawalkar and colleagues formulated a combined therapy using rifampicin and dapsone, intended to mitigate bacterial resistance.<ref name=Yawalkar_1982>{{cite journal | author=Yawalkar SJ, McDougall AC, Languillon J, Ghosh S, Hajra SK, Opromolla DV, Tonello CJ | title=Once-monthly rifampicin plus daily dapsone in initial treatment of lepromatous leprosy | journal=Lancet | year=1982 | pages=1199-1202 | volume= 8283 | issue= 1 | pmid = 6122970}}</ref> Multidrug therapy (MDT) and combining all three drugs was first recommended by a WHO Expert Committee in 1981. These three anti-leprosy drugs are still used in the standard MDT regimens. None of them are used alone because of the risk of developing resistance.
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| Because this treatment is quite expensive, it was not quickly adopted in most endemic countries. In 1985 leprosy was still considered a public health problem in 122 countries. The 44th World Health Assembly (WHA), held in Geneva in 1991 passed a resolution to eliminate leprosy as a public health problem by the year 2000 — defined as reducing the global [[prevalence]] of the disease to less than 1 case per 100,000. At the Assembly, the World Health Organization (WHO) was given the mandate to develop an elimination strategy by its member states, based on increasing the geographical coverage of MDT and patients’ accessibility to the treatment.
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| The WHO Study Group's report on the ''Chemotherapy of Leprosy'' in 1993 recommended two types of standard MDT regimen be adapted.<ref name=WHO_1993>{{cite web | title = Chemotherapy of Leprosy | work = WHO Technical Report Series 847 | publisher = WHO | date = 1994 | url = http://www.who.int/lep/mdt/chemotherapy/en/index.html | accessdate = 2007-03-24}}</ref> The first was a 24-month treatment for multibacillary (MB or lepromatous) cases using rifampicin, clofazimine, and dapsone. The second was a six-month treatment for paucibacillary (PB or tuberculoid) cases, using rifampicin and dapsone. At the First International Conference on the Elimination of Leprosy as a Public Health Problem, held in Hanoi the next year, the global strategy was endorsed and funds provided to WHO for the procurement and supply of MDT to all endemic countries.
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| [[Image:MDTRegimens.jpg|thumb|left|200px|MDT anti-leprosy drugs: standard regimens]]
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| Since 1995, WHO has supplied all endemic countries with free MDT in blister packs, supplied through Ministries of Health. This free provision was extended in 2000, and again in 2005, and will run until at least the end of 2010. At the national level, non-government organisations (NGOs) affiliated to the national programme will continue to be provided with an appropriate free supply of this MDT by the government.
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| MDT remains highly effective and patients are no longer infectious after the first monthly dose.<ref name="WHO_Factsheet" /> It is safe and easy to use under field conditions due to its presentation in calendar blister packs.<ref name="WHO_Factsheet" /> [[Relapse]] rates remain low, and there is no known [[Antibiotic resistance|resistance]] to the combined drugs.<ref name="WHO_Factsheet" /> The Seventh WHO Expert Committee on Leprosy, <ref name=WHO_1998>{{cite web | title = Seventh WHO Expert Committee on Leprosy| work = WHO Technical Report Series 874 | publisher = WHO | date = 1998 | url = http://www.who.int/lep/resources/expert/en/index.html | accessdate = 2007-03-24}}</ref> reporting in 1997, concluded that the MB duration of treatment—then standing at 24 months—could safely be shortened to 12 months "without significantly compromising its efficacy."
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| Persistent obstacles to the elimination of the disease include improving detection, educating patients and the population about its cause, and fighting social taboos about a disease for which patients have historically been considered "unclean" or "cursed by God" as outcasts. Where taboos are strong, patients may be forced to hide their condition (and avoid seeking treatment) to avoid discrimination. The lack of awareness about Hansen's disease can lead people to falsely believe that the disease is highly contagious and incurable.
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| == Epidemiology ==
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| [[Image:Lepra 2003.png|left|250px|thumb|World distribution of leprosy, 2003.]]
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| Worldwide, two to three million people are estimated to be permanently disabled because of Hansen's disease.<ref name=WHO_1995 /> India has the greatest number of cases, with Brazil second and Myanmar third.
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| In 1999, the world [[Incidence (epidemiology)|incidence]] of Hansen's disease was estimated to be 640,000; in 2000, 738,284 cases were identified. In 1999, 108 cases occurred in the United States. In 2000, the [[World Health Organization]] (WHO) listed 91 countries in which Hansen's disease is [[endemic (epidemiology)|endemic]].
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| India, Myanmar and Nepal contained 70% of cases. 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 Hansen's disease cases.
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| According to recent figures from the WHO, new cases detected worldwide have decreased by approximately 107,000 cases (or 21%) from 2003 to 2004. This decreasing trend has been consistent for the past three years.
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| In addition, the global registered prevalence of HD was 286,063 cases; 407,791 new cases were detected during 2004.
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| Hansen's disease is tracked by the [[Centers for Disease Control and Prevention]] (CDC). Its [[prevalence]] in the United States is believed to be rising and underreported.<ref>{{cite news | author = Levis W | date = 2007-05-20 | url = http://transcripts.cnn.com/TRANSCRIPTS/0705/20/ldtw.01.html |title = Leprosy rising | work = CNN}}</ref> There are a rising number of cases worldwide, though 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.
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| Due to the rising numbers, several support groups exist, the headquarters of which is currently in Lynbrook, NY and headed by Brian Marasco, leprosy survivor.
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| === Risk groups ===
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| At highest risk are those living in endemic areas with poor conditions such as inadequate bedding, contaminated water and insufficient diet, or other diseases (such as [[HIV]]) that compromise immune function. Recent research suggests that there is a defect in cell-mediated immunity that causes susceptibility to the disease. Less than ten percent of the world's population are actually capable of acquiring the disease. 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 [[biochemistry|biochemical]] level. In addition, men are twice as likely to contract leprosy as women.
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| === Disease burden ===
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| Although annual [[Incidence (epidemiology)|incidence]]—the number of new leprosy cases occurring each year—is important as a measure of transmission, it is difficult to measure in leprosy due to its long incubation period, delays in diagnosis after onset of the disease and the lack of laboratory tools to detect leprosy in its very early stages.
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| 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 retrieving treatment with MDT at a given point in time.
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| 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.<ref name=WHO_1985>{{cite journal |author= |title=Epidemiology of leprosy in relation to control. Report of a WHO Study Group |journal=World Health Organ Tech Rep Ser |volume=716 |issue= |pages=1-60 |year=1985 |pmid=3925646}}</ref>
| | ==[[Leprosy characteristics|Characteristics]]== |
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| 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).
| | ==[[Leprosy historical perspective|Historical Perspective]]== |
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| The new case detection rate (NCDR) is defined by the number of newly detected cases, previously untreated, during a year divided by the population in which the cases have occurred.
| | ==[[Leprosy pathophysiology|Pathophysiology]]== |
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| Endemic countries also report the number of new cases with established disabilities at the time of detection, as an indicator of the backlog prevalence. However, determination of the time of onset of the disease is generally unreliable, is very labour-intensive and is seldom done in recording these statistics.
| | ==[[Leprosy epidemiology and demographics|Epidemiology & Demographics]]== |
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| === Global situation === | | ==[[Leprosy epidemiology and demographics|Risk Factors]]== |
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| As reported to [[WHO]] by 115 countries and territories in 2006, and published in the Weekly Epidemiological Record the global registered [[prevalence]] of leprosy at the beginning of the year was 219,826 cases. <ref name=WHO_2006>{{cite journal | author = | title = Global leprosy situation, 2006 | journal = Weekly Epidemiological Record | year = 2006 | volume = 81 | number = 32 | pages =309–16 | url= http://www.who.int/lep/resources/wer8132.pdf}}</ref> New case detection during the previous year (2005 - the last year for which full country information is available) was 296,499. The reason for the annual detection being higher than the prevalence at the end of the year can be explained by the fact that a proportion of new cases complete their treatment within the year and therefore no longer remain on the registers. The global detection of new cases continues to show a sharp decline, falling by 110,000 cases (27%) during 2005 compared with the previous year.
| | ==[[Leprosy screening|Screening]]== |
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| {| class = "prettytable" style = "float:center; font-size:85%; margin-left:15px"
| | ==[[Leprosy causes|Causes]]== |
| | + colspan="7" | '''Table 1:''' Prevalence at beginning of 2006, and trends in new case detection 2001-2005, excluding Europe
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| !rowspan=2|Region
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| !colspan=1 width=160|Registered Prevalence
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| (rate/10,000 pop.)
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| !colspan=5 width=400|New Case Detection during the year
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| ! Start of 2006 !! 2001 !! 2002 !! 2003 !! 2004 !! 2005
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| | align="left" | Africa
| | ==[[Leprosy differential diagnosis|Differentiating Leprosy from other Diseases]]== |
| | 40,830 (0.56) || 39,612 || 48,248 || 47,006 || 46,918 || 42,814
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| | align="left" | Americas
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| | 32,904 (0.39) || 42,830 || 39,939 || 52,435 || 52,662 || 41,780
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| | align="left" | South-East Asia
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| | 133,422 (0.81) || 668,658 || 520,632 || 405,147 || 298,603 || 201,635
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| |-
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| | align="left" | Eastern Mediterranean
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| | 4,024 (0.09) || 4,758 || 4,665 || 3,940 || 3,392 || 3,133
| |
| |-
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| | align="left" | Western Pacific
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| | 8,646 (0.05) || 7,404 || 7,154 || 6,190 || 6,216 || 7,137
| |
| |-
| |
| |- style="border: 1px solid #BFA3A3; margin: auto" bgcolor="#F5FFFC" | background:#F2CECE
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| | align="left" |Totals
| |
| | 219,826 || 763,262 || 620,638 || 514,718 || 407,791 || 296,499
| |
| |}
| |
| '''Table 1''' shows that global annual detection has been declining since 2001. The African region reported an 8.7% decline in the number of new cases compared with 2004. The comparable figure for the Americas was 20.1%, for South-East Asia 32% and for the Eastern Mediterranean it was 7.6%. The Western Pacific area, however, showed a 14.8% increase during the same period.
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| <br clear="left"/>
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| {| class = "prettytable" style = "float:center; font-size:85%; margin-left:15px"
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| | + colspan="7" | '''Table 2:''' Prevalence and Detection, countries still to reach elimination | |
| |-
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| !rowspan=2|Countries
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| !colspan=3 width=240|Registered Prevalence
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| (rate/10,000 pop.)
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| !colspan=3 width=240|New Case Detection
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| (rate/100,000 pop.)
| |
| |-
| |
| ! Start of 2004 !! Start of 2005 !! Start of 2006 !! During 2003 !! During 2004 !! During 2005
| |
| |-
| |
| | align="left" |Brazil
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| | 79,908 (4.6) || 30,693 (1.7) || 27,313 (1.5) || 49,206 (28.6) || 49,384 (26.9) || 38,410 (20.6)
| |
| |-
| |
| | align="left" |Democratic Republic of the Congo
| |
| | 6,891 (1.3) || 10,530 (1.9) || 9,785 (1.7) || 7,165 (13.5) || 11,781 (21,1) || 10,737 (18.7)
| |
| |-
| |
| | align="left" |Madagascar
| |
| | 5,514 (3.4) || 4,610 (2.5) || 2,094 (1.1) || 5,104 (31.1) || 3,710 (20.5) || 2,709 (14.6)
| |
| |-
| |
| | align="left" |Mozambique
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| | 6,810 (3.4) || 4,692 (2.4) || 4,889 (2.5) || 5,907 (29.4) || 4,266 (22.0) || 5,371 (27.1)
| |
| |-
| |
| | align="left" |Nepal
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| | 7,549 (3.1) || 4,699 (1.8) || 4,921 (1.8) || 8,046 (32.9) || 6,958 (26.2) || 6,150 (22.7)
| |
| |-
| |
| | align="left" |Tanzania
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| | 5,420 (1.6) || 4,777 (1.3) || 4,190 (1.1) || 5,279 (15.4) || 5,190 (13.8) || 4,237 (11.1)
| |
| |- style="border: 1px solid #BFA3A3; margin: auto" bgcolor="#F5FFFC" | background:<tt>#F2CECE
| |
| | align="left" |Totals
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| | 112,092 || 60,001 || 53,192 || 80,707 || 81,289 || 67,614
| |
| |}
| |
|
| |
|
| '''Table 2''' shows the leprosy situation in the six major countries which have yet to achieve the goal of elimination at the national level. It should be noted that: a) Elimination is defined as a prevalence of less than 1 case per 10,000 population; b) Madagascar reached elimination at the national level in September 2006; and c) Nepal detection reported from mid-November 2004 to mid-November 2005.
| | ==[[Leprosy natural history|Natural History, Complications & Prognosis]]== |
| <br clear="left"/>
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| == History == | | ==Diagnosis== |
| [[Image:Gerhard Hansen.jpg|thumb|left|[[Gerhard Armauer Hansen|G. H. A. Hansen]], discoverer of ''[[Mycobacterium leprae|M. leprae]]'']] | | [[Leprosy history and symptoms|History & Symptoms]] | [[Leprosy physical examination|Physical Examination]] | [[Leprosy staging|Staging]] | [[Leprosy laboratory tests|Lab Tests]] | [[Leprosy electrocardiogram|Electrocardiogram]] | [[Leprosy chest x ray|Chest X Ray]] | [[Leprosy CT|CT]] | [[Leprosy MRI|MRI]] | [[Leprosy echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Leprosy other imaging findings|Other Imaging Findings]] | [[Leprosy other diagnostic studies|Other Diagnostic Studies]] |
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| Numerous ''leprosaria'', or leper hospitals, sprang up in the Middle Ages, particularly in England, where there were 250 by A.D. 1230. The first recorded leprosarium was in Harbledown. (See [[Leper colony]].) These institutions were run along monastic lines and, while lepers were encouraged to live in these monastic-type establishments, this was for their own health as well as quarantine. Indeed, some medieval sources indicate belief that those suffering from leprosy were considered to be going through Purgatory on Earth, and for this reason their suffering was considered more holy than the ordinary person's. More frequently, lepers were seen to exist in a place between life and death: they were still alive, yet many chose or were forced to completely separate themselves from mundane existence.
| | ==Treatment== |
| | [[Leprosy medical therapy|Medical Therapy]] | [[Leprosy surgery|Surgery]] | [[Leprosy primary prevention|Primary Prevention]] | [[Leprosy secondary prevention|Secondary Prevention]] |
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| Radegund was noted for washing the feet of lepers. Orderic Vitalis writes of a monk, Ralf, who was so overcome by the plight of lepers that he prayed to catch leprosy himself (which he eventually did). The leper would carry a clapper and bell to warn of his approach, and this was as much to attract attention for charity as to warn people that a diseased person was near.
| | ==Related chapters== |
| | |
| ''[[Mycobacterium leprae]]'', the causative agent of leprosy, was discovered by [[Gerhard Armauer Hansen|G. H. Armauer Hansen]] in Norway in 1873, making it the first bacterium to be identified as causing disease in man.<ref name=Hansen_1874>{{cite journal | author = Hansen GHA | title = Undersøgelser Angående Spedalskhedens Årsager (Investigations concerning the etiology of leprosy) | journal = Norsk Mag. Laegervidenskaben | year = 1874 | volume = 4| pages = pp. 1–88 | language = Norwegian }}</ref><ref name=Irgens_2002>{{cite journal |author=Irgens L |title=The discovery of the leprosy bacillus |journal=Tidsskr Nor Laegeforen |volume=122 |issue=7 |pages=708-9 |year=2002 |pmid=11998735}}</ref> Historically, individuals with Hansen's disease have been known as ''lepers'', however, this term is falling into disuse as a result of the diminishing number of leprosy patients and the [[wikt:pejorative|pejorative]] connotations of the term. The term most widely accepted among people and agencies working in the field of Hansen's disease is "people affected by Hansen's disease."
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| Historically, the term ''Tzaraath'' from the Hebrew Bible was, erroneously, commonly translated as leprosy, although the symptoms of Tzaraath were not entirely consistent with leprosy and rather referred to a variety of disorders other than Hansen's disease.<ref>Artscroll Tanakh, Leviticus 13:59, 1996</ref>
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| In particular [[tinea capitis]] ([[fungal]] scalp infection) and related infections on other body parts caused by the [[dermatophyte]] fungus ''Trichophyton violaceum'' are abundant throughout the Middle East and North Africa today and might also have been common in biblical times. Similarly, the related agent of the disfiguring skin disease [[favus]], ''Trichophyton schoenleinii'', appears to have been common throughout Eurasia and Africa before the advent of modern medicine. Persons with severe favus and similar fungal diseases (and potentially also with severe [[psoriasis]] and other diseases not caused by microorganisms) tended to be classed as having leprosy as late as the 17th century in Europe.<ref name=Kane_1997>{{cite book | author = Kane J, Summerbell RC, Sigler L, Krajden S, Land G | title = Laboratory Handbook of Dermatophytes: A clinical guide and laboratory manual of dermatophytes and other filamentous fungi from skin, hair and nails | publisher = Star Publishers (Belmont, CA) | year = 1997 | isbn = 0898631572 }}</ref> This is clearly shown in the painting ''Governors of the Home for Lepers at Haarlem 1667'' by Jan de Bray (Frans Hals Museum, Haarlem, the Netherlands), where a young Dutch man with a vivid scalp infection, almost certainly caused by a fungus, is shown being cared for by three officials of a charitable home intended for leprosy sufferers. The use of the word "leprosy" before the mid-19th century, when microscopic examination of skin for medical diagnosis was first developed, can seldom be correlated reliably with Hansen's disease as we understand it today.
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| The word "leprosy" derives from the ancient Greek words ''lepros'', a scale, and ''lepein'', to peel.<ref name=Barnhart_1995>{{cite book | author = Barnhart RK | title = Barnhart Concise Dictionary of Etymology | publisher = Harper Collins | location = New York | year = 1995 | isbn = 0062700847}}</ref> The word came into the English language via Latin and Old French. The first attested English use is in the ''Ancrene Wisse,'' a 13th-century manual for nuns ("Moyseses hond..bisemde o þe spitel uuel & þuhte lepruse." ''The Middle English Dictionary,'' s.v., "leprous"). A roughly contemporaneous use is attested in the Anglo-Norman ''Dialogues of Saint Gregory,'' "Esmondez i sont li lieprous" (''Anglo-Norman Dictionary,'' s.v., "leprus").
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| ==See also==
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| * [[Tuberculosis]] | | * [[Tuberculosis]] |
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| == References ==
| | ==Further reading== |
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| == External links == | | ==Resources== |
| {{commons|Leprosy}} | | {{commons|Leprosy}} |
| * [http://www.hrsa.gov/hansens/ National Hansen's Disease Programs (NHDP), U.S. Health Resources and Services Administration] | | * [http://www.hrsa.gov/hansens/ National Hansen's Disease Programs (NHDP), U.S. Health Resources and Services Administration] |
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| * [http://dx.doi.org/10.1371/journal.pmed.0020341 The Global Campaign to Eliminate Leprosy] article from ''PLoS Medicine'' | | * [http://dx.doi.org/10.1371/journal.pmed.0020341 The Global Campaign to Eliminate Leprosy] article from ''PLoS Medicine'' |
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| ; '''History of leprosy'''
| | ====History of leprosy==== |
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| * [http://www.leprosyhistory.org/ ILA Global Project on the History of Leprosy] | | * [http://www.leprosyhistory.org/ ILA Global Project on the History of Leprosy] |
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| * {{cite web | title = Interview with author John Tayman (''The Colony'') | work = IT Conversations Tech Nation | url = http://www.itconversations.com/shows/detail975.html | format = MP3 audio: runtime = 00:23:20, 10.7 mb | date = 2006-02-07 | accessdate = 2007-03-22}} | | * {{cite web | title = Interview with author John Tayman (''The Colony'') | work = IT Conversations Tech Nation | url = http://www.itconversations.com/shows/detail975.html | format = MP3 audio: runtime = 00:23:20, 10.7 mb | date = 2006-02-07 | accessdate = 2007-03-22}} |
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| ; '''Research'''
| | ====Research==== |
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| * [http://www.granuloma.homestead.com/leprosy.html Pathology Images of Leprosy and Other Granulomatous diseases] Yale Rosen, M.D. | | * [http://www.granuloma.homestead.com/leprosy.html Pathology Images of Leprosy and Other Granulomatous diseases] Yale Rosen, M.D. |
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| | [[Category:Disease]] |
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| | [[Category:Infectious disease]] |
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| [[Category:Leprosy]] | | [[Category:Leprosy]] |
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| [[Category:Infectious skin diseases]] | | [[Category:Infectious skin diseases]] |
| [[Category:Bacterial diseases]] | | [[Category:Bacterial diseases]] |
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| [[Category:Neglected diseases]] | | [[Category:Neglected diseases]] |
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| [[Category:Overview complete]] | | [[Category:Overview complete]] |
