View source for Leprosy

{{Short description|Chronic disease caused by infection of two mycobacterial species}}
{{Other uses}}
{{Use dmy dates|date=May 2024}}
{{cs1 config |name-list-style=vanc |display-authors=6}}
{{Infobox medical condition (new)
| name            = Leprosy
| synonyms        = Hansen's disease (HD)<ref>{{cite journal |author=Sophie M. Worobec |title=Treatment of leprosy/Hansen's disease in the early 21st century |journal=Dermatologic Therapy |volume=22 |issue=6 |pages=518–537 |date=2008 |pmid=19889136 |doi=10.1111/j.1529-8019.2009.01274.x |s2cid=42203681 |doi-access=free  | issn = 1396-0296 }}</ref>
| image           = Tropmed-91-216-g001.jpg
| caption         = Rash on the chest and abdomen caused by leprosy
| field           = [[Infectious diseases]]
| pronounce       = {{IPAc-en|ˈ|l|ɛ|p|r|ə|s|i}}<ref>{{Cite web |url=http://www.thefreedictionary.com/leprosy |title=Definition of leprosy |publisher=The Free Dictionary |access-date=25 January 2015 |archive-date=22 February 2015 |archive-url=https://web.archive.org/web/20150222163011/http://www.thefreedictionary.com/leprosy |url-status=live }}</ref>
| symptoms        = Decreased ability to feel pain<ref name=Aka2012 />
| complications   =
| onset           =
| duration        =
| causes          = ''[[Mycobacterium leprae]]'' or ''[[Mycobacterium lepromatosis]]''<ref name="WHO Fact Sheet" /><ref name=New2008/>
| risks           = Close contact with a case of leprosy, living in poverty<ref name=Aka2012 /><ref name=Schreuder2016/>
| diagnosis       =
| differential    =
| prevention      =
| treatment       = Multidrug therapy<ref name="WHO Fact Sheet" />
| medication      = [[Rifampicin]], [[dapsone]], [[clofazimine]]<ref name=Aka2012 />
| prognosis       =
| frequency       = 209,000 (2018)<ref name="WHO Fact Sheet">{{cite web |title=Leprosy |url=https://www.who.int/en/news-room/fact-sheets/detail/leprosy |publisher=[[World Health Organization]] (WHO) |access-date=10 February 2020 |archive-date=31 January 2021 |archive-url=https://web.archive.org/web/20210131111807/https://www.who.int/en/news-room/fact-sheets/detail/leprosy |url-status=live }}</ref>
| deaths          =
| named after     = [[Gerhard Armauer Hansen]]
}}
'''Leprosy''', also known as '''Hansen's disease''' ('''HD'''), is a [[Chronic condition|long-term]] infection by the bacteria ''[[Mycobacterium leprae]]'' or ''[[Mycobacterium lepromatosis]]''.<ref name="WHO Fact Sheet"/><ref>{{cite journal | vauthors = Sotiriou MC, Stryjewska BM, Hill C | title = Two Cases of Leprosy in Siblings Caused by Mycobacterium lepromatosis and Review of the Literature | journal = The American Journal of Tropical Medicine and Hygiene | volume = 95 | issue = 3 | pages = 522–527 | date = September 2016 | pmid = 27402522 | pmc = 5014252 | doi = 10.4269/ajtmh.16-0076 }}</ref> Infection can lead to damage of the [[Peripheral nervous system|nerves]], [[respiratory tract]], skin, and eyes.<ref name="WHO Fact Sheet" /> This nerve damage may result in a lack of ability to feel pain, which can lead to the loss of parts of a person's [[Extremities skeleton|extremities]] from repeated injuries or infection through unnoticed wounds.<ref name=Aka2012 /> An infected person may also experience muscle weakness and poor eyesight.<ref name=Aka2012 /> Leprosy symptoms may begin within one year, but, for some people, symptoms may take 20 years or more to occur.<ref name="WHO Fact Sheet" />
Leprosy is spread between people, although extensive contact is necessary.<ref name=Aka2012/><ref name=CDC2013T/> Leprosy has a low [[pathogenicity]] and 95% of people who contract or who are exposed to ''M. leprae'' do not develop the disease.<ref name=WHO2018Tx/> Spread is thought to occur through a cough or contact with fluid from the nose of a person infected by leprosy.<ref name="CDC2013T">{{cite web|title=Hansen's Disease (Leprosy) Transmission|url=https://www.cdc.gov/leprosy/transmission/|website=cdc.gov|access-date=28 February 2015|date=29 April 2013|url-status=live|archive-url=https://web.archive.org/web/20150313120028/http://www.cdc.gov/leprosy/transmission/|archive-date=13 March 2015}}</ref><ref name=WHO2018Tx/> Genetic factors and immune function play a role in how easily a person catches the disease.<ref name="WHO2018Tx" /><ref>{{cite book | vauthors = Montoya D, Modlin RL | title = Learning from leprosy: insight into the human innate immune response | series = Advances in Immunology | volume = 105 | pages = 1–24 | year = 2010 | pmid = 20510728 | doi = 10.1016/S0065-2776(10)05001-7 | isbn = 978-0-12-381302-2 }}</ref> Leprosy does not spread during pregnancy to the unborn child or through sexual contact.<ref name=CDC2013T/> Leprosy occurs more commonly among people living in poverty.<ref name=Aka2012 /> There are two main types of the disease – paucibacillary and multibacillary, which differ in the number of bacteria present.<ref name=Aka2012 /> A person with paucibacillary disease has five or fewer [[hypopigmentation|poorly pigmented]], numb skin patches, while a person with multibacillary disease has more than five skin patches.<ref name=Aka2012 /> The diagnosis is confirmed by finding [[Acid-fastness|acid-fast]] bacilli in a biopsy of the skin.<ref name=Aka2012 />
Leprosy is curable with multidrug therapy.<ref name="WHO Fact Sheet" /> Treatment of paucibacillary leprosy is with the medications [[dapsone]], [[rifampicin]], and [[clofazimine]] for six months.<ref name="WHO2018Tx">{{cite book |title=Guidelines for the diagnosis, treatment and prevention of leprosy |date=2018 |publisher=World Health Organization. Regional Office for South-East Asia |isbn=978-92-9022-638-3 |hdl=10665/274127 |hdl-access=free |page=xiii }}</ref> Treatment for multibacillary leprosy uses the same medications for 12 months.<ref name=WHO2018Tx/> A number of other antibiotics may also be used.<ref name=Aka2012 /> These treatments are provided free of charge by the [[World Health Organization]].<ref name="WHO Fact Sheet" />
Leprosy is not highly contagious.<ref name=Byr2008/> People with leprosy can live with their families and go to school and work.<ref>{{Cite web |url=https://www.cdc.gov/features/world-leprosy-day/index.html |title=World Leprosy Day |last=CDC |date=2018-01-26 |website=Centers for Disease Control and Prevention |access-date=2019-07-15 |archive-date=2019-06-15 |archive-url=https://web.archive.org/web/20190615103205/https://www.cdc.gov/features/world-leprosy-day/index.html |url-status=live}}</ref> In the 1980s, there were 5.2&nbsp;million cases globally, but by 2020 this decreased to fewer than 200,000.<ref name="WHO Fact Sheet" /><ref name="WHOEpi2012">{{cite journal |vauthors = |title = Global leprosy situation, 2012 |journal = Weekly Epidemiological Record |volume = 87 |issue = 34 |pages = 317–328 |date = August 2012 |pmid = 22919737 }}</ref><ref name="Rod2011">{{cite journal |vauthors = Rodrigues LC, Lockwood DN |title = Leprosy now: epidemiology, progress, challenges, and research gaps |journal = The Lancet. Infectious Diseases |volume = 11 |issue = 6 |pages = 464–470 |date = June 2011 |pmid = 21616456 |doi = 10.1016/S1473-3099(11)70006-8 }}</ref> Most new cases occur in 14 countries, with India accounting for more than half.<ref name="Aka2012" /><ref name="WHO Fact Sheet" /> In the 20 years from 1994 to 2014, 16&nbsp;million people worldwide were cured of leprosy.<ref name="WHO Fact Sheet" /> About 200 cases per year are reported in the United States.<ref>{{cite web |title=Hansen's Disease Data & Statistics |url=http://www.hrsa.gov/hansensdisease/dataandstatistics.html |website=Health Resources and Services Administration |access-date=12 January 2015 |url-status=live |archive-url=https://web.archive.org/web/20150104183206/http://www.hrsa.gov/hansensdisease/dataandstatistics.html |archive-date=4 January 2015}}</ref> Central Florida accounted for 81% of cases in Florida and nearly 1 out of 5 leprosy cases nationwide.<ref>{{Cite web |title=Central Florida is a hot spot for leprosy, report says |website=[[CNN]] |date=August 2023 |url=https://www.cnn.com/2023/08/01/health/leprosy-central-florida/index.html |access-date=6 August 2023 |archive-date=6 August 2023 |archive-url=https://web.archive.org/web/20230806212546/https://www.cnn.com/2023/08/01/health/leprosy-central-florida/index.html |url-status=live }}</ref> Separating people affected by leprosy by placing them in [[leper colonies]] still occurs in some areas of India,<ref name="Leprosy">{{cite news |url=http://news.bbc.co.uk/2/hi/programmes/from_our_own_correspondent/6510503.stm |author=Walsh F |title=The hidden suffering of India's lepers |work=BBC News |date=31 March 2007 |url-status=live |archive-url=https://web.archive.org/web/20070529003040/http://news.bbc.co.uk/2/hi/programmes/from_our_own_correspondent/6510503.stm |archive-date=29 May 2007 }}</ref> China,<ref>{{cite news |url=http://www.iol.co.za/index.php?set_id=1&click_id=117&art_id=qw1158139440409B243 |title=Ignorance breeds leper colonies in China |author=Lyn TE |publisher=Independat News & Media |date=13 September 2006 |access-date=31 January 2010|url-status=dead|archive-url=https://web.archive.org/web/20100408075048/http://www.iol.co.za/index.php?set_id=1&click_id=117&art_id=qw1158139440409B243 |archive-date=8 April 2010}}</ref> Africa,<ref name="Byr2008">{{cite book |vauthors = Byrne JP |title=Encyclopedia of pestilence, pandemics, and plagues |year=2008 |publisher= Greenwood Press |location=Westport, Conn.[u.a.]|isbn=978-0-313-34102-1 |page=[https://archive.org/details/encyclopediaofpe00jose_0/page/351 351] |url=https://archive.org/details/encyclopediaofpe00jose_0 |url-access=registration}}</ref> and Thailand.<ref>{{cite news |vauthors=Pisuthipan A |title=Forgotten victims of the virus |url=https://www.bangkokpost.com/life/social-and-lifestyle/1946504/forgotten-victims-of-the-virus |access-date=6 July 2020 |work=Bangkok Post |date=6 July 2020 |archive-date=28 August 2021 |archive-url=https://web.archive.org/web/20210828142052/https://www.bangkokpost.com/life/social-and-lifestyle/1946504/forgotten-victims-of-the-virus |url-status=live }}</ref>
Leprosy has affected humanity for thousands of years.<ref name="Aka2012" /> The disease takes its name from the [[Greek language|Greek]] word {{langx|grc|λέπρα|label=none}} ({{Lang|grc-latn|lépra}}), from {{langx|grc|λεπίς|label=none}} ({{Lang|grc-latn|lepís}}; 'scale'), while the term "Hansen's disease" is named after the Norwegian physician [[Gerhard Armauer Hansen]].<ref name="Aka2012">{{cite journal |vauthors = Suzuki K, Akama T, Kawashima A, Yoshihara A, Yotsu RR, Ishii N |title = Current status of leprosy: epidemiology, basic science and clinical perspectives |journal = The Journal of Dermatology |volume = 39 |issue = 2 |pages = 121–129 |date = February 2012 |pmid = 21973237 |doi = 10.1111/j.1346-8138.2011.01370.x |s2cid = 40027505 }}</ref> Leprosy has historically been associated with [[Leprosy stigma|social stigma]], which continues to be a barrier to self-reporting and early treatment.<ref name="WHO Fact Sheet" /> Leprosy is classified as a [[Neglected tropical diseases|neglected tropical disease]].<ref name="NTD2017">{{cite web |url=https://www.cdc.gov/globalhealth/ntd/diseases/index.html |title=Neglected Tropical Diseases |date=6 June 2011 |website=cdc.gov |url-status=live |archive-url=https://web.archive.org/web/20141204084219/http://www.cdc.gov/globalhealth/ntd/diseases/index.html |archive-date=4 December 2014 |access-date=28 November 2014}}</ref> [[World Leprosy Day]] was started in 1954 to draw awareness to those affected by leprosy.<ref>{{cite book |vauthors = McMenamin D |title=Leprosy and stigma in the South Pacific: a region-by-region history with first person accounts |year=2011 |publisher=McFarland |location=Jefferson, N.C. |isbn=978-0-7864-6323-7 |page=17 |url=https://books.google.com/books?id=lZPvQTJ8SE0C&pg=PA17 |url-status=live |archive-url=https://web.archive.org/web/20160519061228/https://books.google.com/books?id=lZPvQTJ8SE0C&pg=PA17 |archive-date=19 May 2016}}</ref><ref name="WHO Fact Sheet" />
The study of leprosy and its treatment is known as leprology.<ref>{{cite web|url=https://www.merriam-webster.com/medical/leprology |title=Leprology |website=Merriam-Webster.com Medical Dictionary |publisher=Merriam-Webster|access-date=18 November 2024 }}</ref>
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== Signs and symptoms ==
Common symptoms present in the different types of leprosy include a runny nose; dry [[scalp]]; eye problems; skin [[lesion]]s; muscle weakness; reddish skin; smooth, shiny, diffuse thickening of facial skin, ear, and hand; loss of sensation in fingers and toes; thickening of [[Peripheral nervous system|peripheral nerves]]; a flat nose from destruction of [[nasal cartilage]]s; and changes in [[phonation]] and other aspects of speech production.<ref>{{Cite web|url=https://www.cdc.gov/leprosy/symptoms/index.html|title=Signs and Symptoms {{!}} Hansen's Disease (Leprosy) {{!}} CDC|date=22 October 2018|website=www.cdc.gov|access-date=22 July 2019|archive-date=22 July 2019|archive-url=https://web.archive.org/web/20190722225129/https://www.cdc.gov/leprosy/symptoms/index.html|url-status=live}}</ref> In addition, [[atrophy]] of the testes and [[Erectile dysfunction|impotence]] may occur.<ref>{{Cite web|url=https://internationaltextbookofleprosy.org/chapter/pathology|title=Pathogenesis and Pathology of Leprosy|date=11 February 2016|website=International Textbook of Leprosy|access-date=22 July 2019|archive-date=22 July 2019|archive-url=https://web.archive.org/web/20190722225142/https://internationaltextbookofleprosy.org/chapter/pathology|url-status=live}}</ref>
Leprosy can affect people in different ways.<ref name="WHO2018Tx" /> The average [[incubation period]] is five years.<ref name="WHO Fact Sheet" /> People may begin to notice symptoms within the first year or up to 20 years after infection.<ref name="WHO Fact Sheet" /> The first noticeable sign of leprosy is often the development of pale or pink coloured patches of skin that may be insensitive to temperature or pain.<ref name="WHO">{{cite book|url=http://www.searo.who.int/entity/global_leprosy_programme/publications/8th_expert_comm_2012.pdf |archive-url=https://web.archive.org/web/20130805125140/http://www.searo.who.int/entity/global_leprosy_programme/publications/8th_expert_comm_2012.pdf |url-status=dead |archive-date=5 August 2013 |access-date=9 May 2018 |date=2012 |title=WHO Expert Committee on Leprosy – Eight report |publisher=[[World Health Organization]] (WHO) |isbn=978-9241209687 |pages=11–12}}</ref> Patches of discolored skin are sometimes accompanied or preceded by nerve problems including numbness or tenderness in the hands or feet.<ref name="WHO" /><ref>{{cite journal | vauthors = Talhari C, Talhari S, Penna GO | title = Clinical aspects of leprosy | journal = Clinics in Dermatology | volume = 33 | issue = 1 | pages = 26–37 | date = 2015 | pmid = 25432808 | doi = 10.1016/j.clindermatol.2014.07.002 }}</ref> [[Secondary infection]]s (additional bacterial or viral infections) can result in tissue loss, causing fingers and toes to become shortened and deformed, as cartilage is absorbed into the body.<ref name="Kulkarni2008">{{cite book |title=Textbook of Orthopedics and Trauma |edition= 2nd |page=779 |publisher=Jaypee Brothers Publishers |year=2008 |isbn=978-81-8448-242-3 |author=Kulkarni GS}}</ref><ref name="Q and A about leprosy">{{cite web |url=http://www.leprosy.org/leprosy-faqs |title=Q and A about leprosy |quote=Do fingers and toes fall off when someone gets leprosy? No. The bacillus attacks nerve endings and destroys the body's ability to feel pain and injury. Without feeling pain, people injure themselves on fire, thorns, rocks, even hot coffee cups. Injuries become infected and result in tissue loss. Fingers and toes become shortened and deformed as the cartilage is absorbed into the body. |access-date=22 January 2011 |publisher=American Leprosy Missions |url-status=live |archive-url=https://web.archive.org/web/20121004072853/http://www.leprosy.org/leprosy-faqs |archive-date=4 October 2012 }}</ref> A person's immune response differs depending on the form of leprosy.<ref name="de SousaSotto2017">{{cite journal | vauthors = de Sousa JR, Sotto MN, Simões Quaresma JA | title = Leprosy As a Complex Infection: Breakdown of the Th1 and Th2 Immune Paradigm in the Immunopathogenesis of the Disease | journal = Frontiers in Immunology | volume = 8 | pages = 1635 | date = 28 November 2017 | pmid = 29234318 | pmc = 5712391 | doi = 10.3389/fimmu.2017.01635 | doi-access = free }}</ref>
Approximately 30% of people affected with leprosy experience nerve damage.<ref name="Rei2019" /> The nerve damage sustained is reversible when treated early, but becomes permanent when appropriate treatment is delayed by several months. Damage to nerves may cause loss of muscle function, leading to paralysis. It may also lead to sensation abnormalities or [[numbness]], which may lead to additional infections, ulcerations, and joint deformities.<ref name="Rei2019">{{cite journal | vauthors = Reinar LM, Forsetlund L, Lehman LF, Brurberg KG | title = Interventions for ulceration and other skin changes caused by nerve damage in leprosy | journal = The Cochrane Database of Systematic Reviews | volume = 2019 | pages = CD012235 | date = July 2019 | issue = 7 | pmid = 31425632 | pmc = 6699662 | doi = 10.1002/14651858.CD012235.pub2 }}</ref>
<gallery mode="packed" heights="200">
File:Paucibacillary leprosy (PB).jpg|Paucibacillary leprosy (PB): Pale skin patch with loss of sensation
File:Leprosy thigh demarcated cutaneous lesions.jpg|Skin lesions on the thigh of a person with leprosy
File:Leprosy deformities hands.jpg|Hands deformed by leprosy
File:Fox Plate XL.jpg|Face mildly deformed by leprosy
File:Tuberous Leprosy Wellcome L0032810.jpg|Face severely deformed by leprosy
</gallery>
== Cause ==
=== ''M. leprae'' and ''M. lepromatosis'' ===
{{Main|Mycobacterium leprae|Mycobacterium lepromatosis}}
[[File:Mycobacterium leprae in Magnification of 2000X.jpg|thumb|upright=1.3|''M. leprae'', one of the causative agents of leprosy: As an [[acid-fast]] bacterium, ''M. leprae'' appears red when a [[Ziehl–Neelsen stain]] is used.]]
''M. leprae'' and ''M. lepromatosis'' are the mycobacteria that cause leprosy.<ref name=Rei2019 /> ''M. lepromatosis'' is a relatively newly identified mycobacterium isolated from a fatal case of [[diffuse lepromatous leprosy]] in 2008.<ref name="New2008">{{cite web|url=https://www.sciencedaily.com/releases/2008/11/081124141047.htm|title=New Leprosy Bacterium: Scientists Use Genetic Fingerprint To Nail 'Killing Organism'|date=28 November 2008|work=ScienceDaily|archive-url=https://web.archive.org/web/20100313064458/https://www.sciencedaily.com/releases/2008/11/081124141047.htm|archive-date=13 March 2010|url-status=live|access-date=31 January 2010}}</ref><ref name="Sherris">{{cite book | veditors = Ryan KU, Ray CJ |title=Sherris Medical Microbiology |url=https://archive.org/details/sherrismedicalmi00ryan |url-access=limited |edition= 4th |pages=[https://archive.org/details/sherrismedicalmi00ryan/page/n468 451]–53 |publisher=McGraw Hill |year=2004 |isbn=978-0-8385-8529-0 |oclc=61405904}}</ref> ''M. lepromatosis'' is indistinguishable clinically from ''M. leprae''.<ref>{{Cite web|url=https://internationaltextbookofleprosy.org/chapter/genomic-insights-biology-and-evolution-leprosy-bacilli|title=Genomics Insights into the Biology and Evolution of Leprosy Bacilli|date=11 February 2016|website=International Textbook of Leprosy|access-date=11 February 2019|archive-date=12 February 2019|archive-url=https://web.archive.org/web/20190212070703/https://internationaltextbookofleprosy.org/chapter/genomic-insights-biology-and-evolution-leprosy-bacilli|url-status=live}}</ref>
''M. leprae'' is an [[Aerobic organism|aerobic]], rod-shaped, acid-fast [[Bacteria|bacterium]] with a waxy [[cell envelope]] characteristic of the genus ''[[Mycobacterium]]''.<ref name="Baron">{{cite book |author=McMurray DN |chapter=Mycobacteria and Nocardia |title=Baron's Medical Microbiology |editor1=Baron S |display-editors=etal |edition= 4th |publisher=Univ of Texas Medical Branch |year=1996 |chapter-url=https://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1833 |isbn=978-0-9631172-1-2 |oclc=33838234 |url-status=live |archive-url=https://web.archive.org/web/20090212202626/http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1833 |archive-date=12 February 2009 }}</ref>
''M. leprae'' and ''M. lepromatosis'' are [[Intracellular parasite#Obligate|obligate intracellular pathogens]], and cannot grow or be [[Cell culture|cultured]] outside of host tissues.<ref name=New2008 /><ref name="Bhattacharya-2002">{{cite journal | vauthors = 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 = 174–177 | date = October 2002 | pmid = 17657065 | doi = 10.1016/S0255-0857(21)03184-4 | doi-access = free }}</ref>
However, they can be grown using research animals such as mice and [[armadillo]]s.<ref>{{Cite web|url=https://www.who.int/lep/in_vitro/en/|archive-url=https://web.archive.org/web/20200809141738/https://www.who.int/lep/in_vitro/en/|url-status=dead|archive-date=9 August 2020|title=WHO {{!}} Microbiology: culture in vitro|publisher=[[World Health Organization]] (WHO)|access-date=22 July 2019}}</ref><ref>{{Cite web|url=https://internationaltextbookofleprosy.org/chapter/armadillos|title=The Armadillo Model for Leprosy|date=11 February 2016|website=International Textbook of Leprosy|access-date=22 July 2019|archive-date=22 July 2019|archive-url=https://web.archive.org/web/20190722225203/https://internationaltextbookofleprosy.org/chapter/armadillos|url-status=live}}</ref>
Naturally occurring infection has been reported in nonhuman primates (including the African [[Common chimpanzee|chimpanzee]], the [[sooty mangabey]], and the [[cynomolgus]] macaque), armadillos,<ref>Loughry WJ, Truman RW, McDonough CM, Tilak MK, Garnier S, et al. (2009) "Is leprosy spreading among nine-banded armadillos in the southeastern United States?" ''J Wildl Dis'' 45: 144–52.</ref> and [[red squirrel]]s.<ref name="Meredith2004">{{cite journal | vauthors = Meredith A, Del Pozo J, Smith S, Milne E, Stevenson K, McLuckie J | title = Leprosy in red squirrels in Scotland | journal = The Veterinary Record | volume = 175 | issue = 11 | pages = 285–286 | date = September 2014 | pmid = 25234460 | doi = 10.1136/vr.g5680 | s2cid = 207046489 }}</ref> [[Multilocus sequence typing]] of the armadillo ''M. leprae'' strains suggests that they were of human origin for at most a few hundred years.<ref>Monot M, Honoré N, Garnier T, Araoz R, Coppee JY, et al. (2005). "On the origin of leprosy". ''Science'' 308: 1040–42.</ref> Thus, it is suspected that armadillos first acquired the organism incidentally from early European explorers of the Americas.<ref name="Han-2014" /> This incidental transmission was sustained in the armadillo population, and it may be transmitted back to humans, making leprosy a [[zoonotic disease]] (spread between humans and animals).<ref name="Han-2014">{{cite journal | vauthors = Han XY, Silva FJ | title = On the age of leprosy | journal = PLOS Neglected Tropical Diseases | volume = 8 | issue = 2 | pages = e2544 | date = February 2014 | pmid = 24551248 | pmc = 3923669 | doi = 10.1371/journal.pntd.0002544 | doi-access = free }}</ref>
[[Red squirrel|Red squirrels (''Sciurus vulgaris'')]], a threatened species in Great Britain, were found to carry leprosy in November 2016.<ref>[https://www.science.org/doi/10.1126/science.aah3783 "Red squirrels in the British Isles are infected with leprosy bacilli"] {{Webarchive|url=https://web.archive.org/web/20220612182108/https://www.science.org/doi/10.1126/science.aah3783|date=12 June 2022}}, Dr. Andrej Benjak, Prof Anna Meredith and others. ''Science'', 11 November 2016. [https://www.science.org/doi/10.1126/science.aah3783] {{Webarchive|url=https://web.archive.org/web/20220612182108/https://www.science.org/doi/10.1126/science.aah3783|date=12 June 2022}}. Retrieved 11 November 2016.</ref> It has been suggested that the trade in red squirrel fur, highly prized in the medieval period and intensively traded, may have been responsible for the leprosy epidemic in medieval Europe.<ref name="ScienceDaily" /> A pre-[[Norman era]] skull excavated in [[Hoxne|Hoxne, Suffolk]], in 2017 was found to carry DNA from a strain of ''Mycobacterium leprae,'' which closely matched the strain carried by modern red squirrels on [[Brownsea Island]], UK.<ref name="ScienceDaily">{{cite web|url=https://www.sciencedaily.com/releases/2017/10/171025103109.htm|title=Could squirrel fur trade have contributed to England's medieval leprosy outbreak?|website=ScienceDaily|access-date=21 November 2018|archive-date=22 November 2018|archive-url=https://web.archive.org/web/20181122005829/https://www.sciencedaily.com/releases/2017/10/171025103109.htm|url-status=live}}</ref><ref>{{cite journal | vauthors = Inskip S, Taylor GM, Anderson S, Stewart G | title = Leprosy in pre-Norman Suffolk, UK: biomolecular and geochemical analysis of the woman from Hoxne | journal = Journal of Medical Microbiology | volume = 66 | issue = 11 | pages = 1640–1649 | date = November 2017 | pmid = 28984227 | doi = 10.1099/jmm.0.000606 | s2cid = 33997231 | doi-access = free }}</ref>
=== Risk factors ===
The greatest risk factor for developing leprosy is contact with another person infected by leprosy.<ref name="WHO Fact Sheet" /> People who are exposed to a person who has leprosy are 5–8 times more likely to develop leprosy than members of the general population.<ref name="Schreuder2016">{{cite journal | vauthors = Schreuder PA, Noto S, Richardus JH | title = Epidemiologic trends of leprosy for the 21st century | journal = Clinics in Dermatology | volume = 34 | issue = 1 | pages = 24–31 | date = January 2016 | pmid = 26773620 | doi = 10.1016/j.clindermatol.2015.11.001 }}</ref> Leprosy also occurs more commonly among those living in poverty.<ref name=Aka2012 /> Not all people who are infected with ''M. leprae'' develop symptoms.<ref name="Penna-2016">{{cite journal | vauthors = Penna ML, Penna GO, Iglesias PC, Natal S, Rodrigues LC | title = Anti-PGL-1 Positivity as a Risk Marker for the Development of Leprosy among Contacts of Leprosy Cases: Systematic Review and Meta-analysis | journal = PLOS Neglected Tropical Diseases | volume = 10 | issue = 5 | pages = e0004703 | date = May 2016 | pmid = 27192199 | pmc = 4871561 | doi = 10.1371/journal.pntd.0004703 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Alcaïs A, Mira M, Casanova JL, Schurr E, Abel L | title = Genetic dissection of immunity in leprosy | journal = Current Opinion in Immunology | volume = 17 | issue = 1 | pages = 44–48 | date = February 2005 | pmid = 15653309 | doi = 10.1016/j.coi.2004.11.006 }}</ref>
Conditions that reduce immune function, such as malnutrition, other illnesses, or genetic mutations, may increase the risk of developing leprosy.<ref name=Schreuder2016 /> Infection with HIV does not appear to increase the risk of developing leprosy.<ref>{{cite journal | vauthors = Lockwood DN, Lambert SM | title = Human immunodeficiency virus and leprosy: an update | journal = Dermatologic Clinics | volume = 29 | issue = 1 | pages = 125–128 | date = January 2011 | pmid = 21095536 | doi = 10.1016/j.det.2010.08.016 }}</ref> Certain genetic factors in the person exposed have been associated with developing lepromatous or tuberculoid leprosy.<ref>{{Cite web|url=https://www.internationaltextbookofleprosy.org/chapter/epidemiology-leprosy|title=Epidemiology of Leprosy|date=11 February 2016|website=International Textbook of Leprosy|access-date=30 July 2019|archive-date=23 July 2019|archive-url=https://web.archive.org/web/20190723224457/https://www.internationaltextbookofleprosy.org/chapter/epidemiology-leprosy|url-status=live}}</ref>
=== Transmission ===
Transmission of leprosy occurs during close contact with those who are infected.<ref name="WHO Fact Sheet" /> Transmission of leprosy is through the upper [[respiratory tract]].<ref name="WHO2018Tx" /><ref>{{cite journal | vauthors = Chavarro-Portillo B, Soto CY, Guerrero MI | title = Mycobacterium leprae's evolution and environmental adaptation | journal = Acta Tropica | volume = 197 | pages = 105041 | date = September 2019 | pmid = 31152726 | doi = 10.1016/j.actatropica.2019.105041 | s2cid = 173188912 }}</ref> Older research suggested the skin as the main route of transmission, but research has increasingly favored the respiratory route.<ref>{{cite journal | vauthors = Eichelmann K, González González SE, Salas-Alanis JC, Ocampo-Candiani J | title = Leprosy. An update: definition, pathogenesis, classification, diagnosis, and treatment | journal = Actas Dermo-Sifiliograficas | volume = 104 | issue = 7 | pages = 554–563 | date = September 2013 | pmid = 23870850 | doi = 10.1016/j.adengl.2012.03.028 | s2cid = 3442319 | doi-access = free }}</ref> Transmission occurs through inhalation of bacilli present in upper airway secretion.<ref>{{cite journal | vauthors = Joel Carlos Lastória JC, Milanez Morgado de Abreu MA | title = Leprosy: review of the epidemiological, clinical, and etiopathogenic aspects - Part 1 | journal = An Bras Dermatol | volume = 89 | issue = 2 | pages = 205–218 | date = Mar–Apr 2014 | pmid = 24770495| doi = 10.1590/abd1806-4841.20142450 | pmc = 4008049 | s2cid = | doi-access = free }}</ref>
Leprosy is not sexually transmitted and is not spread through pregnancy to the unborn child.<ref name="WHO Fact Sheet" /><ref name="CDC2013T" /> The majority (95%) of people who are exposed to ''M. leprae'' do not develop leprosy; casual contact such as shaking hands and sitting next to someone with leprosy does not lead to transmission.<ref name="WHO Fact Sheet" /><ref name="CDC2013T3">{{cite web|url=https://www.cdc.gov/leprosy/transmission/|title=Hansen's Disease (Leprosy) Transmission|date=29 April 2013|website=cdc.gov|archive-url=https://web.archive.org/web/20150313120028/http://www.cdc.gov/leprosy/transmission/|archive-date=13 March 2015|access-date=28 February 2015|url-status=live}}</ref> People are considered non-infectious 72 hours after starting appropriate multi-drug therapy.<ref>{{cite journal | vauthors = Lockwood DN, Kumar B | title = Treatment of leprosy | journal = BMJ | volume = 328 | issue = 7454 | pages = 1447–1448 | date = June 2004 | pmid = 15205269 | pmc = 428501 | doi = 10.1136/bmj.328.7454.1447 }}</ref>
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 [[dermis]], but whether they reach the skin surface in sufficient numbers is doubtful.<ref name="news-medical" />
Leprosy may also be transmitted to humans by [[armadillo]]s, although the mechanism is not fully understood.<ref name="CDC2013T" /><ref name="Truman 2011">{{cite journal | vauthors = Truman RW, Singh P, Sharma R, Busso P, Rougemont J, Paniz-Mondolfi A, Kapopoulou A, Brisse S, Scollard DM, Gillis TP, Cole ST | title = Probable zoonotic leprosy in the southern United States | journal = The New England Journal of Medicine | volume = 364 | issue = 17 | pages = 1626–1633 | date = April 2011 | pmid = 21524213 | pmc = 3138484 | doi = 10.1056/NEJMoa1010536 }}</ref><ref name="CDC2013T2">{{cite web|url=https://www.cdc.gov/leprosy/transmission/|title=Hansen's Disease (Leprosy) Transmission|date=29 April 2013|website=cdc.gov|archive-url=https://web.archive.org/web/20150313120028/http://www.cdc.gov/leprosy/transmission/|archive-date=13 March 2015|url-status=live|access-date=28 February 2015}}</ref>
=== Genetics ===
{| class="wikitable" style="float: right; margin-left:15px; text-align:center"
|-
! Name
! [[Locus (genetics)|Locus]]
! [[OMIM]]
! Gene
|-
| LPRS1
| 10p13
| {{OMIM|609888||none}}
|
|-
| LPRS2
| 6q25
| {{OMIM|607572||none}}
| ''[[PARK2]], [[PACRG]]
|-'
<!--\
] -->
| LPRS3
| 4q32
| {{OMIM|246300||none}}
| ''[[TLR2]]''
|-
| LPRS4
| 6p21.3
| {{OMIM|610988||none}}
| ''[[Lymphotoxin alpha|LTA]]''
|-
| LPRS5
| 4p14
| {{OMIM|613223||none}}
| ''[[TLR1]]''
|-
| LPRS6
| 13q14.11
| {{OMIM|613407||none}}
|
|}
Not all people who are infected or exposed to ''M. leprae'' develop leprosy, and genetic factors are suspected to play a role in susceptibility to an infection.<ref name="Cambri-2018">{{cite journal | vauthors = Cambri G, Mira MT | title = Genetic Susceptibility to Leprosy-From Classic Immune-Related Candidate Genes to Hypothesis-Free, Whole Genome Approaches | journal = Frontiers in Immunology | volume = 9 | pages = 1674 | date = 20 July 2018 | pmid = 30079069 | pmc = 6062607 | doi = 10.3389/fimmu.2018.01674 | doi-access = free }}</ref> Cases of leprosy often cluster in families and several genetic variants have been identified.<ref name="Cambri-2018" /> In many people who are exposed, the immune system is able to eliminate the leprosy bacteria during the early infection stage before severe symptoms develop.<ref>{{cite book| vauthors = Cook GC |title=Manson's tropical diseases|date=2009|publisher=Saunders|location=[Edinburgh]|isbn=978-1-4160-4470-3|page=1056|edition= 22nd|url=https://books.google.com/books?id=CF2INI0O6l0C&pg=PA1056|url-status=live|archive-url=https://web.archive.org/web/20170904030040/https://books.google.com/books?id=CF2INI0O6l0C&pg=PA1056|archive-date=4 September 2017}}</ref> A genetic defect in [[cell-mediated immunity]] may cause a person to be susceptible to develop leprosy symptoms after exposure to the bacteria.<ref name="Buschman-2004" /> 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 at the [[biochemistry|biochemical]] level.<ref name="Buschman-2004">{{cite journal |last1=Buschman |first1=Ellen |last2=Skamene |first2=Emil |title=Linkage of leprosy susceptibility to Parkinson's disease genes |journal=International Journal of Leprosy and Other Mycobacterial Diseases |volume=72 |issue=2 |pages=169–170 |date=June 2004 |doi=10.1489/1544-581X(2004)072<0169:LOLSTP>2.0.CO;2 |doi-broken-date=1 November 2024 |url=http://ijl.ilsl.br/detalhe_artigo.php?id=OTg%3D |pmid=15301585 |s2cid=43103579 }}</ref>
== Mechanism ==
Most leprosy complications are the result of nerve damage. The nerve damage occurs from direct invasion by the ''M. leprae'' bacteria and a person's immune response resulting in inflammation.<ref name="Rei2019"/> The molecular mechanism underlying how ''M. leprae'' produces the symptoms of leprosy is not clear,<ref name=Rod2011/> but ''M. leprae'' has been shown to bind to [[Schwann cell]]s, which may lead to nerve injury including [[demyelination]] and a loss of nerve function (specifically a loss of [[axon]]al conductance).<ref name="pmid22988457">{{cite journal | vauthors = Bhat RM, Prakash C | title = Leprosy: an overview of pathophysiology | journal = Interdisciplinary Perspectives on Infectious Diseases | volume = 2012 | pages = 181089 | date = 2012 | pmid = 22988457 | pmc = 3440852 | doi = 10.1155/2012/181089 | doi-access = free }}</ref> Numerous molecular mechanisms have been associated with this nerve damage including the presence of a [[laminin]]-binding [[protein]] and the glycoconjugate (PGL-1) on the surface of ''M. leprae'' that can bind to laminin on [[peripheral nerves]].<ref name="pmid22988457"/>
As part of the human immune response, [[white blood cell]]-derived [[macrophage]]s may engulf ''M. leprae'' by [[phagocytosis]].<ref name="pmid22988457"/>
In the initial stages, small sensory and [[autonomic nerve]] fibers in the skin of a person with leprosy are damaged.<ref name="Rei2019"/> This damage usually results in hair loss to the area, a loss of the ability to sweat, and numbness (decreased ability to detect sensations such as temperature and touch). Further peripheral nerve damage may result in skin dryness, more numbness, and muscle weaknesses or paralysis in the area affected.<ref name="Rei2019"/> The skin can crack and if the skin injuries are not carefully cared for, there is a risk for a secondary infection that can lead to more severe damage.<ref name="Rei2019"/>
== Diagnosis ==
[[File:Monofilament testing.jpg|alt=|thumb|right|Testing for loss of sensation with monofilament]]
In countries where people are frequently infected, a person is considered to have leprosy if they have one of the following two signs:
* Skin lesion consistent with leprosy and with definite sensory loss.<ref name="WHO Fact Sheet" />
* Positive skin smears.<ref name="WHO Fact Sheet" />
Skin lesions can be single or many, and usually [[Hypopigmentation|hypopigmented]], although occasionally reddish or copper-colored.<ref name="WHO Fact Sheet" /> The lesions may be flat ([[macule]]s), raised ([[papule]]s), or solid elevated areas ([[nodule (medicine)|nodular]]).<ref name="WHO Fact Sheet" /> Experiencing sensory loss at the skin lesion is a feature that can help determine if the lesion is caused by leprosy or by another disorder such as [[tinea versicolor]].<ref name="WHO Fact Sheet" /><ref>{{Cite web |url=https://www.internationaltextbookofleprosy.org/sites/default/files/ITL_2_3%20FINAL.pdf |title=International Textbook of Leprosy |vauthors=Moschella SL, Garcia-Albea V |date=September 2016 |website=Differential Diagnosis of Leprosy |page=3, Section 2.3 |access-date=4 July 2019 |archive-date=16 July 2020 |archive-url=https://web.archive.org/web/20200716191216/https://www.internationaltextbookofleprosy.org/sites/default/files/ITL_2_3%20FINAL.pdf |url-status=live }}</ref> Thickened nerves are associated with leprosy and can be accompanied by loss of sensation or muscle weakness, but muscle weakness without the characteristic skin lesion and sensory loss is not considered a reliable sign of leprosy.<ref name="WHO Fact Sheet" />
In some cases, [[Acid-fastness|acid-fast]] leprosy [[bacilli]] in skin smears are considered diagnostic; however, the diagnosis is typically made without laboratory tests, based on symptoms.<ref name="WHO Fact Sheet" /> If a person has a new leprosy diagnosis and already has a visible disability caused by leprosy, the diagnosis is considered late.<ref name="Rei2019" />
In countries or areas where leprosy is uncommon, such as the United States, diagnosis of leprosy is often delayed because healthcare providers are unaware of leprosy and its symptoms.<ref name="hrsa.gov" /> Early diagnosis and treatment prevent nerve involvement, the hallmark of leprosy, and the disability it causes.<ref name="WHO Fact Sheet" /><ref name="hrsa.gov">U.S. Department of Health and Human Services, Health Resources and Services Administration. (n.d.). National Hansen's disease (leprosy) program Retrieved from {{cite web |url=http://www.hrsa.gov/hansens/ |title=National Hansen's Disease (Leprosy) Program |access-date=12 May 2013 |url-status=dead |archive-url=https://web.archive.org/web/20110210202131/http://www.hrsa.gov/hansens/ |archive-date=10 February 2011 }}</ref>
There is no recommended test to diagnose latent leprosy in people without symptoms.<ref name="WHO2018Tx" /> Few people with latent leprosy test positive for anti PGL-1.<ref name="Penna-2016" /> The presence of ''M. leprae'' bacterial [[DNA]] can be identified using a [[polymerase chain reaction]] (PCR)-based technique.<ref name="Martinez-2014">{{cite journal | vauthors = Martinez AN, Talhari C, Moraes MO, Talhari S | title = PCR-based techniques for leprosy diagnosis: from the laboratory to the clinic | journal = PLOS Neglected Tropical Diseases | volume = 8 | issue = 4 | pages = e2655 | date = April 2014 | pmid = 24722358 | pmc = 3983108 | doi = 10.1371/journal.pntd.0002655 | doi-access = free }}</ref> This molecular test alone is not sufficient to diagnose a person, but this approach may be used to identify someone who is at high risk of developing or transmitting leprosy such as those with few lesions or an atypical clinical presentation.<ref name="Martinez-2014" /><ref>{{cite journal | vauthors = Tatipally S, Srikantam A, Kasetty S | title = Polymerase Chain Reaction (PCR) as a Potential Point of Care Laboratory Test for Leprosy Diagnosis-A Systematic Review | journal = Tropical Medicine and Infectious Disease | volume = 3 | issue = 4 | pages = 107 | date = October 2018 | pmid = 30275432 | pmc = 6306935 | doi = 10.3390/tropicalmed3040107 | doi-access = free }}</ref>
New approaches propose tools to diagnose leprosy through artificial intelligence.<ref>{{Cite journal |last1=Quilter |first1=Emily E. V. |last2=Butlin |first2=Cynthia Ruth |last3=Carrion |first3=Carme |last4=Ruiz-Postigo |first4=Jose-Antonio |date=1 June 2024 |title=The WHO Skin NTD mobile application – a paradigm shift in leprosy diagnosis through Artificial Intelligence? |url=https://leprosyreview.org/article/95/2/20-24030 |journal=Leprosy Review |volume=95 |issue=2 |pages=1–3 |doi=10.47276/lr.95.2.2024030 |issn=2162-8807 |access-date=27 May 2024 |archive-date=28 May 2024 |archive-url=https://web.archive.org/web/20240528055811/https://leprosyreview.org/article/95/2/20-24030 |url-status=live |doi-access=free }}</ref>
=== Classification ===
Several different approaches for classifying leprosy exist. There are similarities between the classification approaches.
* The World Health Organization system distinguishes "paucibacillary" and "multibacillary" based upon the proliferation of bacteria.<ref>{{cite web |author=Smith DS |url=http://emedicine.medscape.com/article/220455-overview |title=Leprosy: Overview |work=eMedicine Infectious Diseases |date=19 August 2008 |access-date=1 February 2010 |url-status=live |archive-url=https://web.archive.org/web/20100218142511/http://emedicine.medscape.com/article/220455-overview |archive-date=18 February 2010 }}</ref> ("[[wikt:paucus#Latin|pauci]]-" refers to a small quantity.)
* The Ridley-Jopling scale provides five gradations.<ref name="pm hippopotamus id15176024">{{cite journal | vauthors = Singh N, Manucha V, Bhattacharya SN, Arora VK, Bhatia A | title = Pitfalls in the cytological classification of borderline leprosy in the Ridley-Jopling scale | journal = Diagnostic Cytopathology | volume = 30 | issue = 6 | pages = 386–388 | date = June 2004 | pmid = 15176024 | doi = 10.1002/dc.20012 | s2cid = 29757876 }}</ref><ref name="pmid5950347">{{cite journal | vauthors = Ridley DS, Jopling WH | title = Classification of leprosy according to immunity. A five-group system | journal = International Journal of Leprosy and Other Mycobacterial Diseases | volume = 34 | issue = 3 | pages = 255–273 | year = 1966 | pmid = 5950347 }}</ref><ref name="Andrews">{{cite book|title=Andrews' Diseases of the Skin: clinical Dermatology|url=https://archive.org/details/andrewsdiseasess00mdwi_659|url-access=limited| vauthors = James WD, Berger TG, Elston DM, Odom RB |publisher=Saunders Elsevier|year=2006|isbn=978-0-7216-2921-6|pages=[https://archive.org/details/andrewsdiseasess00mdwi_659/page/n354 344]–46}}</ref>
* The [[ICD-10]], though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry.<ref name="news-medical">"What Is Leprosy?"| from News-Medical.Net – Latest Medical News and Research from Around the World. Web. 20 November 2010. {{cite news |url=http://www.news-medical.net/health/What-is-Leprosy.aspx |title=What is Leprosy? |newspaper=News-Medical.net |access-date=14 May 2013 |url-status=live |archive-url=https://web.archive.org/web/20130606033328/http://www.news-medical.net/health/What-is-Leprosy.aspx |archive-date=6 June 2013 |date=18 November 2009 }}.</ref>
* In [[Medical Subject Headings|MeSH]], three groupings are used.
{{Clear}}
{| class="wikitable"
|-
! WHO
! Ridley-Jopling
! [[ICD-10]]
! [[Medical Subject Headings|MeSH]]
! Description
! [[Lepromin]] test
|-
| Paucibacillary
| tuberculoid ("TT"),<br />borderline<br />tuberculoid ("BT")
| style="white-space:nowrap;"| A30.1, A30.2
| Tuberculoid
| It is characterized by one or more [[Hypopigmentation|hypopigmented]] skin macules and patches where skin sensations are lost because of damaged peripheral nerves that have been attacked by the human host's immune cells. TT is characterized by the formation of [[epithelioid cell]] granulomas with a large number of [[epithelioid cell]]s. In this form of leprosy Mycobacterium leprae are either absent from the lesion or occur in very small numbers. This type of leprosy is most benign.<ref name="pmid22988457"/><ref name="pmid24937811">{{cite journal | vauthors = Lastória JC, Abreu MA | title = Leprosy: a review of laboratory and therapeutic aspects--part 2 | journal = Anais Brasileiros de Dermatologia | volume = 89 | issue = 3 | pages = 389–401 | date = 2014 | pmid = 24937811 | pmc = 4056695 | doi = 10.1590/abd1806-4841.20142460 | doi-access = free }}</ref>
| Positive
|-
| Multibacillary
| style="white-space:nowrap;"|midborderline<br />or<br />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.{{citation needed|date=May 2021}}
|Negative
|-
| Multibacillary
| borderline lepromatous ("BL"),<br />and lepromatous ("LL")
| A30.4, A30.5
| Lepromatous
| It is associated with symmetric skin [[lesion]]s, [[Nodule (medicine)|nodules]], [[Plaque (dermatology)|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. Loss of eyebrows and lashes can be seen in advanced disease.<ref>{{Cite web|url=https://internationaltextbookofleprosy.org/chapter/diagnosis-leprosy|title=Clinical Diagnosis of Leprosy|author1=Kumar, Bhushan|author2=Uprety, Shraddha|author3=Dogra, Sunil|date=11 February 2016|website=International Textbook of Leprosy|access-date=12 February 2019|archive-date=13 February 2019|archive-url=https://web.archive.org/web/20190213064205/https://internationaltextbookofleprosy.org/chapter/diagnosis-leprosy|url-status=live}}</ref> LL is characterized by the absence of [[epithelioid cell]]s in the lesions. In this form of leprosy, Mycobacteria leprae are found in lesions in large numbers. This is the most unfavorable clinical variant of leprosy, which occurs with a generalized lesion of the skin, mucous membranes, eyes, peripheral nerves, lymph nodes, and internal organs.<ref name="pmid22988457" /><ref name="pmid24937811" /> [[Histoid leprosy]] is a rare variation of multibacillary, lepromatous leprosy.
| Negative
|}
Leprosy may also occur with only neural involvement, without skin lesions.<ref name="WHO Fact Sheet" /><ref name="pmid12883921">{{cite journal | vauthors = Jardim MR, Antunes SL, Santos AR, Nascimento OJ, Nery JA, Sales AM, Illarramendi X, Duppre N, Chimelli L, Sampaio EP, Sarno EP | title = Criteria for diagnosis of pure neural leprosy | journal = Journal of Neurology | volume = 250 | issue = 7 | pages = 806–809 | date = July 2003 | pmid = 12883921 | doi = 10.1007/s00415-003-1081-5 | s2cid = 20070335 }}</ref><ref name="pmid17120509">{{cite journal | vauthors = Mendiratta V, Khan A, Jain A | title = Primary neuritic leprosy: a reappraisal at a tertiary care hospital | journal = Indian Journal of Leprosy | volume = 78 | issue = 3 | pages = 261–267 | year = 2006 | pmid = 17120509 }}</ref><ref name="pmid10979277">{{cite journal | vauthors = Ishida Y, Pecorini L, Guglielmelli E | title = Three cases of pure neuritic (PN) leprosy at detection in which skin lesions became visible during their course | journal = Nihon Hansenbyo Gakkai Zasshi = Japanese Journal of Leprosy | volume = 69 | issue = 2 | pages = 101–106 | date = July 2000 | pmid = 10979277 | doi = 10.5025/hansen.69.101 | doi-access = free }}</ref><ref name="pmid8711979">{{cite journal | vauthors = Mishra B, Mukherjee A, Girdhar A, Husain S, Malaviya GN, Girdhar BK | title = Neuritic leprosy: further progression and significance | journal = Acta Leprologica | volume = 9 | issue = 4 | pages = 187–194 | year = 1995 | pmid = 8711979 }}</ref><ref name="pmid1406021">{{cite journal | vauthors = Talwar S, Jha PK, Tiwari VD | title = Neuritic leprosy: epidemiology and therapeutic responsiveness | journal = Leprosy Review | volume = 63 | issue = 3 | pages = 263–268 | date = September 1992 | pmid = 1406021 | doi = 10.5935/0305-7518.19920031 | doi-access = free }}</ref>
== Complications ==
Leprosy may cause the victim to lose limbs and digits but not directly. ''M. leprae'' attacks nerve endings and destroys the body's ability to feel pain and injury. Without feeling pain, people with leprosy have an increased risk of injuring themselves. Injuries become infected and result in tissue loss. Fingers, toes, and limbs become shortened and deformed as the tissue is absorbed into the body.<ref>{{Cite web |url=https://www.embraceavillage.org/what-is-leprosy/ |title=Embrace a village - FAQ |date=3 June 2021 |access-date=2 February 2023 |archive-date=2 February 2023 |archive-url=https://web.archive.org/web/20230202235306/https://www.embraceavillage.org/what-is-leprosy/?utm_id=Awareness-MXC&utm_medium=Leads&utm_source=CPC |url-status=live }}</ref>
== Prevention ==
Early detection of the disease is important, since physical and neurological damage may be irreversible even if cured.<ref name="WHO Fact Sheet" /> Medications can decrease the risk of those living with people who have leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home.<ref name="Rod2011" /> The WHO recommends that preventive medicine be given to people who are in close contact with someone who has leprosy.<ref name="WHO2018Tx" /> The suggested preventive treatment is a single dose of rifampicin (SDR) in adults and children over 2 years old who do not already have leprosy or tuberculosis.<ref name="WHO2018Tx" /> Preventive treatment is associated with a 57% reduction in infections within 2 years and a 30% reduction in infections within 6 years.<ref name="WHO2018Tx" />
The [[Bacillus Calmette-Guérin|Bacillus Calmette–Guérin (BCG)]] vaccine offers a variable amount of protection against leprosy in addition to its closely related target of [[tuberculosis]].<ref>{{cite journal | vauthors = Duthie MS, Gillis TP, Reed SG | title = Advances and hurdles on the way toward a leprosy vaccine | journal = Human Vaccines | volume = 7 | issue = 11 | pages = 1172–1183 | date = November 2011 | pmid = 22048122 | pmc = 3323495 | doi = 10.4161/hv.7.11.16848 }}</ref> 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.<ref>{{cite journal | vauthors = Setia MS, Steinmaus C, Ho CS, Rutherford GW | title = The role of BCG in prevention of leprosy: a meta-analysis | journal = The Lancet. Infectious Diseases | volume = 6 | issue = 3 | pages = 162–170 | date = March 2006 | pmid = 16500597 | doi = 10.1016/S1473-3099(06)70412-1 }}</ref><ref name="Merle2010">{{cite journal | vauthors = Merle CS, Cunha SS, Rodrigues LC | title = BCG vaccination and leprosy protection: review of current evidence and status of BCG in leprosy control | journal = Expert Review of Vaccines | volume = 9 | issue = 2 | pages = 209–222 | date = February 2010 | pmid = 20109030 | doi = 10.1586/ERV.09.161 | s2cid = 34309843 }}</ref> The WHO concluded in 2018 that the BCG vaccine at birth reduces leprosy risk and is recommended in countries with high incidence of TB and people who have leprosy.<ref>{{cite journal | title = BCG vaccine: WHO position paper, February 2018 - Recommendations | journal = Vaccine | volume = 36 | issue = 24 | pages = 3408–3410 | date = June 2018 | pmid = 29609965 | doi = 10.1016/j.vaccine.2018.03.009 | s2cid = 4570754 | last1 = World Health Organization }}</ref> People living in the same home as a person with leprosy are suggested to take a BCG booster which may improve their immunity by 56%.<ref>{{cite journal | vauthors = Moraes MO, Düppre NC | title = Leprosy post-exposure prophylaxis: innovation and precision public health | journal = The Lancet. Global Health | volume = 9 | issue = 1 | pages = e8–e9 | date = January 2021 | pmid = 33338461 | doi = 10.1016/S2214-109X(20)30512-X | doi-access = free }}</ref><ref>{{cite journal | vauthors = Yamazaki-Nakashimada MA, Unzueta A, Berenise Gámez-González L, González-Saldaña N, Sorensen RU | title = BCG: a vaccine with multiple faces | journal = Human Vaccines & Immunotherapeutics | volume = 16 | issue = 8 | pages = 1841–1850 | date = August 2020 | pmid = 31995448 | pmc = 7482865 | doi = 10.1080/21645515.2019.1706930 }}</ref> Development of a more effective vaccine is ongoing.<ref name="Rod2011" /><ref>{{cite web| url=http://www.leprosy.org/leprosy-vaccine/| title=Leprosy Vaccine| publisher=American Leprosy Missions| access-date=20 October 2015| url-status=dead| archive-url=https://web.archive.org/web/20151115010651/http://www.leprosy.org/leprosy-vaccine/| archive-date=15 November 2015}}</ref><ref>{{cite news| url=https://www.theguardian.com/global-development/2014/jun/06/trial-world-first-leprosy-vaccine| title=Trial set for world's first leprosy vaccine| newspaper=[[The Guardian]]| date=6 June 2014| access-date=20 October 2015| url-status=live| archive-url=https://web.archive.org/web/20151011092728/http://www.theguardian.com/global-development/2014/jun/06/trial-world-first-leprosy-vaccine| archive-date=11 October 2015}}</ref><ref>{{cite journal | vauthors = | title = China's Mars plans, leprosy vaccine and self-driving taxis | journal = Nature | volume = 537 | issue = 7618 | pages = 12–13 | date = September 2016 | pmid = 27582199 | doi = 10.1038/537012a | doi-access = free | bibcode = 2016Natur.537...12. }}</ref>
A novel vaccine called LepVax entered clinical trials in 2017 with the first encouraging results reported on 24 participants published in 2020.<ref>{{ClinicalTrialsGov|NCT03302897|Phase 1 LEP-F1 + GLA-SE Vaccine Trial in Healthy Adult Volunteers}}</ref><ref>{{cite journal | vauthors = Duthie MS, Frevol A, Day T, Coler RN, Vergara J, Rolf T, Sagawa ZK, Marie Beckmann A, Casper C, Reed SG | title = A phase 1 antigen dose escalation trial to evaluate safety, tolerability and immunogenicity of the leprosy vaccine candidate LepVax (LEP-F1 + GLA-SE) in healthy adults | journal = Vaccine | volume = 38 | issue = 7 | pages = 1700–1707 | date = February 2020 | pmid = 31899025 | doi = 10.1016/j.vaccine.2019.12.050 | s2cid = 209677501 }}</ref> If successful, this would be the first leprosy-specific vaccine available.
== Treatment ==
[[File:MDTRegimens.jpg|thumb|upright=1.4|MDT antileprosy drugs: standard regimens from 2010]]
A number of [[leprostatic agent]]s are available for treatment. A three-drug regimen of [[rifampicin]], [[dapsone]] and [[clofazimine]] is recommended for all people with leprosy, for six months for paucibacillary leprosy and 12 months for multibacillary leprosy.<ref name="WHO2018Tx" />
Multidrug therapy (MDT) remains highly effective, and people are no longer infectious after the first monthly dose.<ref name="WHO Fact Sheet" /> MDT is safe and easy to use under field conditions because of it is available in calendar labelled blister packs.<ref name="WHO Fact Sheet" /> Post-treatment relapse rates remain low.<ref name="WHO Fact Sheet" /> Resistance has been reported in several countries, although the number of cases is small.<ref>{{Cite web|url=https://www.who.int/lep/mdt/resistance/en/|archive-url=https://web.archive.org/web/20141004050047/http://www.who.int/lep/mdt/resistance/en/|url-status=dead|archive-date=4 October 2014|title=WHO {{!}} MDT and drug resistance|publisher=[[World Health Organization]] (WHO)|access-date=22 July 2019}}</ref> People with rifampicin-resistant leprosy may be treated with second line drugs such as [[fluoroquinolones]], [[minocycline]], or [[clarithromycin]], but the treatment duration is 24 months because of their lower [[Bactericide|bactericidal]] activity.<ref>{{cite journal | vauthors = Reibel F, Cambau E, Aubry A | title = Update on the epidemiology, diagnosis, and treatment of leprosy | journal = Médecine et Maladies Infectieuses | volume = 45 | issue = 9 | pages = 383–393 | date = September 2015 | pmid = 26428602 | doi = 10.1016/j.medmal.2015.09.002 | doi-access = free }}</ref> Evidence on the potential benefits and harms of alternative regimens for drug-resistant leprosy is not available.<ref name="WHO2018Tx" />
For people with nerve damage, protective footwear may help prevent ulcers and secondary infection.<ref name=Rei2019 /> Canvas shoes may be better than PVC boots.<ref name=Rei2019 /> There may be no difference between double rocker shoes and below-knee plaster.<ref name=Rei2019 /> Topical [[ketanserin]] seems to have a better effect on ulcer healing than [[clioquinol]] cream or zinc paste, but the evidence for this is weak.<ref name=Rei2019 /> [[Phenytoin]] applied to the skin improves skin changes to a greater degree when compared to saline dressings.<ref name=Rei2019 />
== Outcomes ==
Although leprosy has been curable since the mid-20th century, left untreated it can cause permanent physical impairments and damage to a person's nerves, skin, eyes, and limbs.<ref name="WHO Fact Sheet" /> Despite leprosy not being very infectious and having a low pathogenicity, there is still significant stigma and prejudice associated with the disease.<ref name="Somar et al 2020">{{cite journal | vauthors = Somar P, Waltz MM, van Brakel WH | title = The impact of leprosy on the mental wellbeing of leprosy-affected persons and their family members - a systematic review | journal = Global Mental Health | volume = 7 | pages = e15 | date = 2020 | pmid = 32742673 | pmc = 7379324 | doi = 10.1017/gmh.2020.3 }}</ref> Because of this stigma, leprosy can affect a person's participation in social activities and may also affect the lives of their family and friends.<ref name="Somar et al 2020"/> People with leprosy are also at a higher risk for problems with their mental well-being.<ref name="Somar et al 2020"/> The social stigma may contribute to problems obtaining employment, financial difficulties, and social isolation.<ref name="Somar et al 2020"/> Efforts to reduce discrimination and reduce the stigma surrounding leprosy may help improve outcomes for people with leprosy.<ref>{{cite journal | vauthors = Rao D, Elshafei A, Nguyen M, Hatzenbuehler ML, Frey S, Go VF | title = A systematic review of multi-level stigma interventions: state of the science and future directions | journal = BMC Medicine | volume = 17 | issue = 1 | pages = 41 | date = February 2019 | pmid = 30770756 | pmc = 6377735 | doi = 10.1186/s12916-018-1244-y | doi-access = free }}</ref>
== Epidemiology ==
{{Main|Epidemiology of leprosy}}
[[File:Leprosy new case detection 2016 rates, 2016 (cropped).png|alt=|upright=1.8|thumb|New cases of leprosy in 2016.<ref>{{cite journal | vauthors = | title = Global leprosy update, 2016: accelerating reduction of disease burden | journal = Weekly Epidemiological Record | volume = 92 | issue = 35 | pages = 501–519 | date = September 2017 | pmid = 28861986 | hdl-access = free | hdl = 10665/258841 }}</ref><ref>{{cite web |title=Leprosy new case detection rates, 2016 |url=http://gamapserver.who.int/mapLibrary/Files/Maps/Leprosy_DR_2016.png |publisher=[[World Health Organization]] (WHO) |access-date=19 December 2019 |archive-date=19 December 2019 |archive-url=https://web.archive.org/web/20191219151719/http://gamapserver.who.int/mapLibrary/Files/Maps/Leprosy_DR_2016.png |url-status=live }}</ref>]]
[[File:Leprosy world map - DALY - WHO2004.svg|thumb|upright=1.4|[[Disability-adjusted life year]] for leprosy per 100,000&nbsp;inhabitants in 2004<ref>{{cite web |url=https://www.who.int/entity/healthinfo/statistics/bodgbddeathdalyestimates.xls |title=Mortality and Burden of Disease Estimates for WHO Member States in 2002 |format=xls |publisher=[[World Health Organization]] (WHO) |year=2002 |url-status=live |archive-url=https://web.archive.org/web/20130116174540/http://www.who.int/healthinfo/statistics/bodgbddeathdalyestimates.xls |archive-date=16 January 2013 }}</ref>
{{Colbegin}}
{{Div col|small=yes|colwidth=10em}}
{{legend|#b3b3b3|No data}}
{{legend|#ffff65|<&nbsp;1.5}}
{{legend|#fff200|1.5–3}}
{{legend|#ffdc00|3–4.5}}
{{legend|#ffc600|4.5–6}}
{{legend|#ffb000|6–7.5}}
{{legend|#ff9a00|7.5–9}}
{{legend|#ff8400|9–10.5}}
{{legend|#ff6e00|10.5–12}}
{{legend|#ff5800|12–13.5}}
{{legend|#ff4200|13.5–15}}
{{legend|#ff2c00|15–20}}
{{legend|#cb0000|>&nbsp;20}}
{{div col end}}
{{colend}}
]]
In 2018, there were 208,619 new cases of leprosy recorded, a slight decrease from 2017.<ref>{{cite web |title=WHO {{!}} Leprosy: new data show steady decline in new cases |url=https://www.who.int/neglected_diseases/news/Leprosy-new-data-show-steady-decline-in-new-cases/en/ |archive-url=https://web.archive.org/web/20191022195923/https://www.who.int/neglected_diseases/news/Leprosy-new-data-show-steady-decline-in-new-cases/en/ |url-status=dead |archive-date=22 October 2019 |website=WHO |access-date=26 February 2020}}</ref> In 2015, 94% of the new leprosy cases were confined to 14 countries.<ref name="World Health Organization (WHO)">{{Cite web|url=https://www.who.int/lep/resources/who_wer9135/en/|archive-url=https://web.archive.org/web/20161018145241/http://www.who.int/lep/resources/who_wer9135/en/|url-status=dead|archive-date=18 October 2016|title=WHO {{!}} Global leprosy update, 2015: time for action, accountability and inclusion|publisher=[[World Health Organization]] (WHO)|access-date=14 January 2019}}</ref> India reported the greatest number of new cases (60% of reported cases), followed by Brazil (13%) and [[Indonesia]] (8%).<ref name="World Health Organization (WHO)" /> Although the number of cases worldwide continues to fall, there are parts of the world where leprosy is more common, including Brazil, South Asia (India, Nepal, Bhutan), some parts of Africa (Tanzania, Madagascar, Mozambique), and the western Pacific.<ref name="World Health Organization (WHO)" /> About 150 to 250 cases are diagnosed in the United States each year.<ref>{{cite web|title=Leprosy still lurks in United States, study says|author=Maggie Veatch|website=CNN|date=21 February 2019|url=https://www.cnn.com/2019/02/21/health/leprosy-cases-study/index.html|access-date=24 February 2019|archive-date=20 August 2020|archive-url=https://web.archive.org/web/20200820134443/https://www.cnn.com/2019/02/21/health/leprosy-cases-study/index.html|url-status=live}}</ref>
In the 1960s, there were tens of millions of leprosy cases recorded when the bacteria started to develop resistance to [[dapsone]], the most common treatment option at the time.<ref name="WHO Fact Sheet" /><ref name="Rod2011" /> International (e.g., the [[World Health Organization|WHO]]'s "Global Strategy for Reducing Disease Burden Due to Leprosy") and national (e.g., the International Federation of Anti-Leprosy Associations) initiatives have reduced the total number and the number of new cases of the disease.<ref name="Rod2011" /><ref>{{cite web |url=http://www.ilep.org.uk/about-ilep/ |title=About ILEP |publisher=ILEP |access-date=25 August 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140812170909/http://www.ilep.org.uk/about-ilep/ |archive-date=12 August 2014 }}</ref>
The number of new leprosy cases is difficult to measure and monitor because of leprosy's long incubation period, delays in diagnosis after onset of the disease, and lack of medical care in affected areas.<ref>{{Cite web|url=https://www.internationaltextbookofleprosy.org/chapter/epidemiology-leprosy|title=Epidemiology of Leprosy|date=11 February 2016|website=International Textbook of Leprosy|access-date=23 July 2019|archive-date=23 July 2019|archive-url=https://web.archive.org/web/20190723224457/https://www.internationaltextbookofleprosy.org/chapter/epidemiology-leprosy|url-status=live}}</ref> The registered [[prevalence]] of the disease is used to determine [[disease burden]].<ref name="WHO_1985" /> 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.<ref name="WHO_1985" /> 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 book |title=Epidemiology of leprosy in relation to control. Report of a WHO Study Group |series=World Health Organization technical report series |date=1985 |volume=716 |pages=1–60 |pmid=3925646 |isbn=978-92-4-120716-4 |oclc=12095109 |hdl=10665/40171 |hdl-access=free | publisher = World Health Organization |last1=Organization |first1=World Health }}</ref>
{| class="wikitable" style="text-align:center"
|-
! Year
! 2005
! 2006
! 2007
! 2008
! 2009
! 2010
! 2011
! 2012
! 2013
! 2014
! 2015
! 2016
! 2017
! 2018
! 2019
! 2020
! 2021
! 2022
! 2023
|-
| No. of new cases<ref>{{cite web |title=Number of new leprosy cases |url=https://apps.who.int/gho/data/node.main.A1639?lang=en |publisher=[[World Health Organization]] (WHO) |date=13 September 2021 |access-date=3 June 2022 |archive-date=26 September 2021 |archive-url=https://web.archive.org/web/20210926232241/https://apps.who.int/gho/data/node.main.A1639?lang=en |url-status=live }}</ref>
| 296,479
| 258,980
| 252,541
| 249,018
| 244,797
| 228,488
| 224,344
| 232,847
| 215,636
| 213,861
| 211,945
| 217,927
| 210,973
| 208,613
| 202,166
| 127,506
| 140,546
| 174,059
| 182,792
|}
== History ==
{{Main|History of leprosy}}
[[File:Gerhard Armauer Hansen.jpg|thumb|[[Gerhard Armauer Hansen|G. H. A. Hansen]], discoverer of ''[[Mycobacterium leprae|M. leprae]]'']]
=== Historical distribution ===
Using [[comparative genomics]], in 2005, geneticists traced the origins and worldwide distribution of leprosy from East Africa or the Near East along human migration routes. They found four strains of ''M. leprae'' with specific regional locations:<ref name=Monot-et-al-2005>{{cite journal |last1=Monot |first1=Marc |last2=Honoré |first2=Nadine |last3=Garnier |first3=Thierry |last4=Araoz |first4=Romul |last5=Coppée |first5=Jean-Yves |last6=Lacroix |first6=Céline |last7=Sow |first7=Samba |last8=Spencer |first8=John S. |last9=Truman |first9=Richard W. |last10=Williams |first10=Diana L. |last11=Gelber |first11=Robert |last12=Virmond |first12=Marcos |last13=Flageul |first13=Béatrice |last14=Cho |first14=Sang-Nae |last15=Ji |first15=Baohong |last16=Paniz-Mondolfi |first16=Alberto |last17=Convit |first17=Jacinto |last18=Young |first18=Saroj |last19=Fine |first19=Paul E. |last20=Rasolofo |first20=Voahangy |last21=Brennan |first21=Patrick J. |last22=Cole |first22=Stewart T. |year=2005 |title=On the origin of leprosy |journal=Science |volume=308 |issue=5724 |pages=1040–1042 |doi=10.1126/science/1109759 |pmid=15894530 |s2cid=86109194 |url=https://hal-pasteur.archives-ouvertes.fr/pasteur-00204117/file/Monot_science.pdf |access-date=22 November 2022 |archive-date=25 January 2023 |archive-url=https://web.archive.org/web/20230125030851/https://hal-pasteur.archives-ouvertes.fr/pasteur-00204117/file/Monot_science.pdf |url-status=live }}</ref> Monot ''et al.'' (2005) determined that leprosy originated in East Africa or the Near East and traveled with humans along their migration routes, including those of trade in goods and slaves. The four strains of ''M.&nbsp;leprae'' are based in specific geographic regions where each predominantly occurs:<ref name=Monot-et-al-2005/>
* strain 1 in Asia, the Pacific region, and East Africa;
* strain 2 in Ethiopia, [[Malawi]], Nepal, north India, and [[New Caledonia]];
* strain 3 in Europe, North Africa, and the Americas;
* strain 4 in West Africa and the Caribbean.
This confirms the spread of the disease along the migration, colonisation, and slave trade routes taken from East Africa to India, West Africa to the New World, and from Africa into Europe and vice versa.<ref>{{cite journal | vauthors = Monot M, Honoré N, Garnier T, Araoz R, Coppée JY, Lacroix C, Sow S, Spencer JS, Truman RW, Williams DL, Gelber R, Virmond M, Flageul B, Cho SN, Ji B, Paniz-Mondolfi A, Convit J, Young S, Fine PE, Rasolofo V, Brennan PJ, Cole ST | title = On the origin of leprosy | journal = Science | volume = 308 | issue = 5724 | pages = 1040–1042 | date = May 2005 | pmid = 15894530 | doi = 10.1126/science/1109759 | author-link17 = Jacinto Convit | s2cid = 86109194 | url = https://hal-pasteur.archives-ouvertes.fr/pasteur-00204117/file/Monot_science.pdf | access-date = 22 November 2022 | archive-date = 25 January 2023 | archive-url = https://web.archive.org/web/20230125030851/https://hal-pasteur.archives-ouvertes.fr/pasteur-00204117/file/Monot_science.pdf | url-status = live }}</ref>
Skeletal remains discovered in 2009 represent the oldest documented evidence for leprosy, dating to the [[2nd millennium BC]].<ref name="Schug2009">{{cite journal | vauthors = Robbins G, Tripathy VM, Misra VN, Mohanty RK, Shinde VS, Gray KM, Schug MD | title = Ancient skeletal evidence for leprosy in India (2000 B.C.) | journal = PLOS ONE | volume = 4 | issue = 5 | pages = e5669 | date = May 2009 | pmid = 19479078 | pmc = 2682583 | doi = 10.1371/journal.pone.0005669 | doi-access = free | bibcode = 2009PLoSO...4.5669R }}</ref><ref name="Schug2013">{{cite journal | vauthors = Robbins Schug G, Blevins KE, Cox B, Gray K, Mushrif-Tripathy V | title = Infection, disease, and biosocial processes at the end of the Indus Civilization | journal = PLOS ONE | volume = 8 | issue = 12 | pages = e84814 | date = December 2013 | pmid = 24358372 | pmc = 3866234 | doi = 10.1371/journal.pone.0084814 | doi-access = free | bibcode = 2013PLoSO...884814R }}</ref> Located at [[Balathal]], Rajasthan, in northwest India, the discoverers suggest that, if the disease did migrate from Africa to India during the [[3rd millennium BC]] "at a time when there was substantial interaction among the Indus Civilization, Mesopotamia, and Egypt, there needs to be additional skeletal and molecular evidence of leprosy in India and Africa to confirm the African origin of the disease".<ref>{{cite journal | vauthors = Robbins G, Tripathy VM, Misra VN, Mohanty RK, Shinde VS, Gray KM, Schug MD | title = Ancient skeletal evidence for leprosy in India (2000 B.C.) | journal = PLOS ONE | volume = 4 | issue = 5 | pages = e5669 | date = May 2009 | pmid = 19479078 | pmc = 2682583 | doi = 10.1371/journal.pone.0005669 | bibcode = 2009PLoSO...4.5669R | doi-access = free }}</ref> A proven human case was verified by DNA taken from the shrouded remains of a man discovered by researchers from the [[Hebrew University of Jerusalem]] in a tomb in [[Akeldama]], next to the [[Old City (Jerusalem)|Old City]] of [[Jerusalem]], [[State of Israel|Israel]], dated by radiocarbon methods to the first half of the 1st century.<ref>{{cite web |title=DNA of Jesus-Era Shrouded Man in Jerusalem Reveals Earliest Case of Leprosy |website=ScienceDaily |date=16 December 2009 |url=https://www.sciencedaily.com/releases/2009/12/091216103558.htm |access-date=31 January 2010 |url-status=live |archive-url=https://web.archive.org/web/20091220033542/https://www.sciencedaily.com/releases/2009/12/091216103558.htm |archive-date=20 December 2009 }}</ref>
The oldest strains of leprosy known from Europe are from [[Great Chesterford]] in southeast England and dating back to AD 415&ndash;545. These findings suggest a different path for the spread of leprosy, meaning it may have originated in Western Eurasia. This study also indicates that there were more strains in Europe at the time than previously determined.<ref>{{cite journal | vauthors = Schuenemann VJ, Avanzi C, Krause-Kyora B, Seitz A, Herbig A, Inskip S, Bonazzi M, Reiter E, Urban C, Dangvard Pedersen D, Taylor GM, Singh P, Stewart GR, Velemínský P, Likovsky J, Marcsik A, Molnár E, Pálfi G, Mariotti V, Riga A, Belcastro MG, Boldsen JL, Nebel A, Mays S, Donoghue HD, Zakrzewski S, Benjak A, Nieselt K, Cole ST, Krause J | title = Ancient genomes reveal a high diversity of Mycobacterium leprae in medieval Europe | journal = PLOS Pathogens | volume = 14 | issue = 5 | pages = e1006997 | date = May 2018 | pmid = 29746563 | pmc = 5944922 | doi = 10.1371/journal.ppat.1006997 | doi-access = free }}</ref>
=== Discovery and scientific progress ===
Literary attestation of leprosy is unclear because of the ambiguity of many early sources, including the [[Ancient India|India]]n [[Atharvaveda]] and Kausika Sutra, the [[ancient Egypt|Egyptian]] [[Ebers Papyrus]], and the Hebrew [[Hebrew Bible|Bible]]'s various sections regarding signs of impurity ({{lang|he-Latn|[[tzaraath]]}}).<ref>{{cite book |vauthors=Lendrum FC |date=1954 |contribution=The Name 'Leprosy' |title=Etc: A Review of General Semantics |volume=12 |issue=1 |jstor=24234298 |pages=37–47 |publisher=Institute of General Semantics |contribution-url=http://www.jstor.org/stable/24234298 |access-date=13 April 2022 |archive-date=13 April 2022 |archive-url=https://web.archive.org/web/20220413192502/https://www.jstor.org/stable/24234298 |url-status=live }}</ref> Clearly leprotic symptoms are attested in the Indian doctor [[Sushruta]]'s [[Sushruta Samhita|''Compendium'']], originally dating to c.&nbsp;600&nbsp;BC but only surviving in emended texts no earlier than the 5th century. Symptoms consistent with leprosy were possibly described by [[Hippocrates]] in 460&nbsp;BC.<ref>{{Cite journal |date=2021-12-10 |title=Mycobacterium leprae: A historical study on the origins of leprosy and its social stigma |url=https://www.infezmed.it/media/journal/Vol_29_4_2021_18.pdf |journal=Infezioni in Medicina |volume=29 |issue=4 |doi=10.53854/liim-2904-18 |pmc=8805473 |pmid=35146374 |pages=623–632 | vauthors = Santacroce L, Del Prete R, Charitos IA, Bottalico L }}</ref> However, Hansen's disease probably did not exist in Greece or the Middle East before the [[Common Era]].<ref name="Haubrich2003">{{cite book|first=William S. |last=Haubrich|title=Medical Meanings: A Glossary of Word Origins|url=https://books.google.com/books?id=NXmlIwkQBLAC&pg=PA133 |year=2003 |publisher=ACP Press|isbn=978-1-930513-49-5|page=133}}</ref><ref name="WilkinsEvans2013">{{cite book|first1=Michael |last1=Wilkins|first2=Craig A. |last2=Evans|first3=Darrell |last3=Bock|first4=Andreas J. |last4=Köstenberger|title=The Gospels and Acts|url=https://books.google.com/books?id=QPKsBAAAQBAJ&pg=PT194|date=1 October 2013|publisher=B&H |isbn=978-1-4336-8101-1|page=194|access-date=15 July 2018|archive-date=12 January 2023|archive-url=https://web.archive.org/web/20230112232559/https://books.google.com/books?id=QPKsBAAAQBAJ&pg=PT194|url-status=live}}</ref><ref>{{cite book |title=Encyclopedia of Jewish Medical Ethics |url=https://books.google.com/books?id=aaklGZAID08C&pg=PA951|year=2003|publisher=Feldheim Publishers|isbn=978-1-58330-592-8|page=951}}</ref> In 1846, [[Francis Adams (translator)|Francis Adams]] produced ''The Seven Books of Paulus Aegineta'' which included a commentary on all medical and surgical knowledge and descriptions and remedies to do with leprosy from the Romans, Greeks, and Arabs.<ref>{{cite book |first=Francis |last=Adams |title=The Seven Books of Paulus Aegineta: Translated from the Greek with Commentary Embracing a Complete View of the Knowledge Possessed by the Greeks, Romans and Arabians on all Subjects Connected with Medicine and Surgery |location=London |publisher=Sydenham Society |year=1678}}</ref><ref>Roman: [[Celsus]], [[Pliny the Elder|Pliny]]<!--presumably as the Younger was not a scientist-->, [[Serenus Samonicus]], [[Scribonius Largus]], [[Caelius Aurelianus]], [[Themison of Laodicea|Themison]], [[Octavius Horatianus]], [[Marcellus the Emperic]]; Greek: [[Aretaeus]], [[Plutarch]], [[Galen]], [[Oribasius]], Aetius ([[Aëtius of Amida]] or [[Sicamus Aëtius]])<!--assuming they were not distinguished, but perhaps one of the other was meant-->, [[Joannes Actuarius|Actuarius]], Nonnus,<!--unclear who this refers to – none of the people of this name with articles were physicians--> [[Psellus]], Leo,<!--can this be disambiguated?--> [[Myrepsus]]; Arabic: [[Scrapion]], [[Ibn Zuhr|Avenzoar]], [[Al-Zahrawi|Albucasis]], [['Ali ibn al-'Abbas al-Majusi|Haly Abbas]] translated by [[Stephanus Antiochensis]], [[Alsharavius]], Rhases ([[Abū Bakr al-Rāzī]]), and [[Guido de Cauliaco]].</ref>
Leprosy did not exist in the Americas before [[European colonization of the Americas|colonization]] by modern Europeans<ref name="Rotberg2001">{{cite book|first=Robert I. |last=Rotberg|title=Population History and the Family: A Journal of Interdisciplinary History Reader|url=https://books.google.com/books?id=OiQM-GIe69kC&pg=PA132|year=2001|publisher=MIT Press|isbn=978-0-262-68130-8|page=132}}</ref> nor did it exist in [[Polynesia]] until the middle of the 19th century.<ref>{{cite journal | vauthors = Montgomerie JZ | title = Leprosy in New Zealand | journal = The Journal of the Polynesian Society | volume = 97 | issue = 2 | pages = 115–152 | date = 1988 | pmid = 11617451 | url = http://www.jps.auckland.ac.nz/document/Volume_97_1988/Volume_97%2C_No._2/Leprosy_in_New_Zealand%2C_by_J._Z._Montgomerie%2C_p_115-152?action=null | access-date = 3 September 2019 | archive-date = 11 February 2018 | archive-url = https://web.archive.org/web/20180211031412/http://www.jps.auckland.ac.nz/document/Volume_97_1988/Volume_97%2C_No._2/Leprosy_in_New_Zealand%2C_by_J._Z._Montgomerie%2C_p_115-152?action=null | url-status = live }}</ref>
[[File:Distribution of leprosy around the world Wellcome L0032805.jpg|thumb|upright=1.4|Distribution of leprosy around the world in 1891]]
The causative agent of leprosy, ''M. leprae'', was discovered by [[Gerhard Armauer Hansen]] in [[Union between Sweden and Norway|Norway]] in 1873, making it one of the first species of pathogenic bacteria identified.<ref name="Irgens_2002">{{cite journal | vauthors = Irgens LM | title = Oppdagelsen av leprabasillen |trans-title = The discovery of the leprosy bacillus |language=no | journal = Tidsskrift for den Norske Laegeforening | volume = 122 | issue = 7 | pages = 708–709 | date = March 2002 | pmid = 11998735 }}</ref>
=== Treatment ===
[[Chaulmoogra]] tree oil was used topically to manage Hansen's disease for centuries. Chaulmoogra oil could not be taken orally without causing nausea or injected without forming an abscess.<ref name="SmithMag">{{cite web |last1=Magazine |first1=Smithsonian |last2=Wong |first2=Kathleen M. |title=The Trailblazing Black Woman Chemist Who Discovered a Treatment for Leprosy |url=https://www.smithsonianmag.com/history/the-trailblazing-black-woman-chemist-who-discovered-a-treatment-for-leprosy-180979772/ |website=Smithsonian Magazine |access-date=27 December 2023 |archive-date=11 December 2023 |archive-url=https://web.archive.org/web/20231211200621/https://www.smithsonianmag.com/history/the-trailblazing-black-woman-chemist-who-discovered-a-treatment-for-leprosy-180979772/ |url-status=live }}</ref> In 1915, [[Alice Ball]], the first Black woman to graduate from the University of Hawai'i with a masters in chemistry, discovered how to make the oil water-soluble.<ref name="SmithMag" /> This technique led to marked improvements in patients with Hansen's disease who were treated in Hawai'i.<ref name="SmithMag" />
The first effective drug ([[promin]]) became available in the 1940s.<ref name="Cam1997">{{cite book|author1=Andrew Baum|display-authors=etal|title=Cambridge handbook of psychology, health and medicine|year=1997|publisher=Cambridge University Press|location=Cambridge, UK|isbn=978-0-521-43686-1|page=521|url=https://books.google.com/books?id=zVh30FrAuDsC&pg=PA521|url-status=live|archive-url=https://web.archive.org/web/20160611001757/https://books.google.com/books?id=zVh30FrAuDsC&pg=PA521|archive-date=11 June 2016}}</ref> In the 1950s, [[dapsone]] was introduced. The search for further effective antileprosy drugs led to the use of [[clofazimine]] and [[rifampicin]] in the 1960s and 1970s.<ref name="Rees_1970">{{cite journal | vauthors = Rees RJ, Pearson JM, Waters MF | title = Experimental and clinical studies on rifampicin in treatment of leprosy | journal = British Medical Journal | volume = 1 | issue = 5688 | pages = 89–92 | date = January 1970 | pmid = 4903972 | pmc = 1699176 | doi = 10.1136/bmj.1.5688.89 }}</ref> Later, Indian scientist Shantaram Yawalkar and his colleagues formulated a combined therapy using rifampicin and dapsone, intended to mitigate bacterial resistance.<ref name="Yawalkar_1982">{{cite journal | vauthors = 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 | volume = 1 | issue = 8283 | pages = 1199–1202 | date = May 1982 | pmid = 6122970 | doi = 10.1016/S0140-6736(82)92334-0 | s2cid = 38629414 }}</ref> Multi-drug therapy (MDT) combining all three drugs was first recommended by the [[World Health Organization|WHO]] in 1981. These three antileprosy drugs are still used in the standard MDT regimens.<ref>{{Cite web |date=22 October 2018 |title=Treatment {{!}} Hansen's Disease (Leprosy) |publisher=Centers for Disease Control and Prevention |url=https://www.cdc.gov/leprosy/health-care-workers/treatment.html |access-date=7 October 2022 |archive-date=7 October 2022 |archive-url=https://web.archive.org/web/20221007055454/https://www.cdc.gov/leprosy/health-care-workers/treatment.html |url-status=live }}</ref>
Leprosy was once believed to be highly contagious and was treated with [[Mercury (element)|mercury]], as was [[syphilis]], which was first described in 1530. Many early cases thought to be leprosy could actually have been syphilis.<ref>[https://www.britannica.com/EBchecked/topic/578770/syphilis/253277/Syphilis-through-history#ref252973 "Syphilis through history"]. {{webarchive|url=https://web.archive.org/web/20130513015053/https://www.britannica.com/EBchecked/topic/578770/syphilis/253277/Syphilis-through-history |date=13 May 2013 }} ''[[Encyclopædia Britannica]]''.</ref>
Resistance has developed to initial treatment. Until the introduction of MDT in the early 1980s, leprosy could not be diagnosed and treated successfully within the community.<ref name="WHOleprosyFAQ">{{cite web | url=http://www.searo.who.int/en/section10/section373_11716.htm | title=Communicable Diseases Department, Leprosy FAQ | publisher=[[World Health Organization]] (WHO) | date=25 May 2006 | access-date=31 January 2010 | url-status=dead | archive-url=https://web.archive.org/web/20100201182128/http://www.searo.who.int/EN/Section10/Section373_11716.htm | archive-date=1 February 2010 }}</ref>
[[National Hansen's Disease Museum (Japan)|Japan]] still has sanatoriums (although Japan's sanatoriums no longer have active leprosy cases, nor are survivors held in them by law).<ref>Japan repealed its "Leprosy Prevention Laws" in 1996, but former patients still reside in sanatoriums.
*{{cite news |url=http://news.bbc.co.uk/2/hi/asia-pacific/1350630.stm |title=Koizumi apologises for leper colonies |date=25 May 2001 |work=BBC News |url-status=live |archive-url=https://web.archive.org/web/20090417085921/http://news.bbc.co.uk/2/hi/asia-pacific/1350630.stm |archive-date=17 April 2009 }}
* {{cite news|url=http://search.japantimes.co.jp/cgi-bin/nn20070607f2.html |title=Former Hansen's disease patients still struggling with prejudice |work=Japan Times |date=7 June 2007 |archive-url=https://web.archive.org/web/20090826074049/http://search.japantimes.co.jp/cgi-bin/nn20070607f2.html |archive-date=26 August 2009 }}</ref>
The importance of the nasal mucosa in the transmission of ''[[Mycobacterium leprae|M. leprae]]'' was recognized as early as 1898 by Schäffer, in particular, that of the ulcerated mucosa.<ref name=Schaffer_1898>''Arch Dermato Syphilis'' 1898; 44:159–174</ref>{{verify source|reason=Unable to find this abbreviated title anywhere online relating to an 1898 journal. Please expand the full name. Possibly "Archives of Dermatology and Syphilis" or "Archives of Dermatology and Syphilology". Latter vol. 1 is 1920, but according to Internet Archive also called vol. 38|date=October 2023}} The mechanism of plantar ulceration in leprosy and its treatment was first described by [[Ernest W. Price]].<ref>{{cite journal | vauthors = Vernon G | title = Dr E W Price, the discoverer of podoconiosis | journal = Journal of Medical Biography | volume = 30 | issue = 1 | pages = 2–5 | date = February 2022 | pmid = 31735101 | doi = 10.1177/0967772019888406 | s2cid = 208142196 }}</ref>
== Etymology ==
The word "leprosy" comes from the Greek word "λέπος (lépos) – skin" and "λεπερός (leperós) – scaly man".{{citation needed|date=October 2022}}
== Society and culture ==
[[File:Leprosorium.jpg|thumb|upright=1.3|Two lepers denied entrance to town, 14th century]]
=== Treatment cost ===
Between 1995 and 1999, the WHO, with the aid of the [[Nippon Foundation]], supplied all endemic countries with free multidrug therapy in blister packs, channeled through ministries of health.<ref name="WHO Fact Sheet" /> This free provision was extended in 2000 and again in 2005, 2010 and 2015 with donations by the multidrug therapy manufacturer [[Novartis]] through the WHO. In the latest agreement signed between the company and the WHO in October 2015, the provision of free multidrug therapy by the WHO to all endemic countries will run until the end of 2025.<ref>[https://www.novartis.com/our-impact/global-health/leprosy leprosy] {{Webarchive|url=https://web.archive.org/web/20210414095950/https://www.novartis.com/our-impact/global-health/leprosy |date=14 April 2021 }} Novartis (accessed on 14 April 2021)</ref><ref name="WHO Fact Sheet" /> At the national level, [[Non-governmental organization|nongovernment organizations]] affiliated with the national program will continue to be provided with an appropriate free supply of multidrug therapy by the WHO.<ref>{{Cite web|url=https://www.who.int/lep/mdt/donation/en/|archive-url=https://web.archive.org/web/20141011061223/http://www.who.int/lep/mdt/donation/en/|url-status=dead|archive-date=11 October 2014|title=WHO donated MDT|publisher=[[World Health Organization]] (WHO)|access-date=23 July 2019}}</ref>
=== Historical texts ===
Written accounts of leprosy date back thousands of years. Various skin diseases translated as leprosy appear in the ancient Indian text, the ''[[Atharava Veda]]'', by 600 BC.<ref>{{Cite journal|vauthors=Singh KS, Pandey BD|date=March 2012|title=Leprosy – Hidden Disease?|url=http://nopr.niscair.res.in/handle/123456789/13672|journal=Science Reporter|volume=49|issue=3|access-date=4 August 2019|archive-date=3 August 2020|archive-url=https://web.archive.org/web/20200803022616/http://nopr.niscair.res.in/handle/123456789/13672|url-status=live}}</ref> Another Indian text, the ''[[Manusmriti]]'' (200 BC), &nbsp;prohibited contact with those infected with the disease and made marriage to a person infected with leprosy punishable.<ref>{{cite journal | vauthors = Jacob JT, Franco-Paredes C | title = The stigmatization of leprosy in India and its impact on future approaches to elimination and control | journal = PLOS Neglected Tropical Diseases | volume = 2 | issue = 1 | pages = e113 | date = January 2008 | pmid = 18235845 | pmc = 2217676 | doi = 10.1371/journal.pntd.0000113 | doi-access = free }}</ref>
The Hebraic root tsara or [[tsaraath]] (צָרַע, – tsaw-rah' – to be struck with leprosy, to be leprous) and the Greek (λεπρός–lepros), are of broader classification than the more narrow use of the term related to Hansen's Disease.<ref>{{cite journal | vauthors = Grzybowski A, Nita M | title = Leprosy in the Bible | journal = Clinics in Dermatology | volume = 34 | issue = 1 | pages = 3–7 | date = January 2016 | pmid = 26773616 | doi = 10.1016/j.clindermatol.2015.10.003 }}</ref> Any progressive skin disease (a whitening or splotchy bleaching of the skin, raised manifestations of scales, scabs, infections, rashes, etc....), as well as generalized molds and surface discoloration of any clothing, leather, or discoloration on walls or surfaces throughout homes all, came under the "law of leprosy" (Leviticus 14:54–57).<ref>[See: Orr, James, M.A., D.D. General Editor. "Entry for 'Leper; Leprosy'". "International Standard Bible Encyclopedia". 1915. Access-date=6 January 2017</ref> 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. Traditional Judaism and Jewish rabbinical authorities, both historical and modern, emphasize that the ''tsaraath'' of Leviticus is a spiritual ailment with no direct relationship to Hansen's disease or physical contagions. The relation of ''tsaraath'' to "leprosy" comes from translations of Hebrew Biblical texts into Greek and ensuing misconceptions.<ref>{{Cite web |vauthors=Shurpin Y |date=6 April 2022 |title=Is Tzaraat Leprosy? |url=https://www.chabad.org/library/article_cdo/aid/4714280/jewish/Is-Tzaraat-Leprosy.htm |website=Chabad.org |access-date=6 April 2022 |archive-date=6 April 2022 |archive-url=https://web.archive.org/web/20220406180106/https://www.chabad.org/library/article_cdo/aid/4714280/jewish/Is-Tzaraat-Leprosy.htm |url-status=live }}</ref>
All three Synoptic Gospels of the [[New Testament]] describe instances of Jesus healing people with leprosy ([https://www.biblegateway.com/passage/?search=Matthew+8%3A1-4&version=ESV Matthew 8:1–4], [https://www.biblegateway.com/passage/?search=Mark%201%3A40-45&version=ESV Mark 1:40–45], and [https://www.biblegateway.com/passage/?search=Luke+5%3A12-16&version=ESV Luke 5:12–16]). The Bible's description of leprosy is congruous (if lacking detail) with the symptoms of modern leprosy, but the relationship between this disease, ''tzaraath'', and Hansen's disease has been disputed.<ref>{{cite book|vauthors=van der Loos H|url=https://books.google.com/books?id=n4geAAAAIAAJ&pg=PA464|title=The Miracles of Jesus|date=1968|publisher=Brill Archive|page=464|access-date=21 May 2022|archive-date=1 May 2023|archive-url=https://web.archive.org/web/20230501050107/https://books.google.com/books?id=n4geAAAAIAAJ&pg=PA464|url-status=live}}</ref> The biblical perception that people with leprosy were unclean can be found in a passage from [[Leviticus]] 13: 44–46. While this text defines the leper as [[Tumah and taharah|impure]], it did not explicitly make a moral judgement on those with leprosy.<ref>{{cite journal | vauthors = Lewis G |title=A Lesson from Leviticus: Leprosy |journal=Man |date=December 1987 |volume=22 |issue=4 |page=598 |doi=10.2307/2803354|jstor=2803354 }}</ref> Some [[Early Christianity|Early Christians]] believed that those affected by leprosy were being punished by God for sinful behavior. Moral associations have persisted throughout history. Pope [[Gregory the Great]] (540–604) and [[Isidore of Seville]] (560–636) considered people with the disease to be heretics.<ref name="Covey-2001">{{cite journal | url=http://his.library.nenu.edu.cn/upload/soft/haoli/114/372.pdf | title=People with leprosy (Hansen's disease) during the Middle Ages | vauthors = Covey HC | journal=[[Social Science Journal]] | year=2001 | volume=38 | issue=2 | pages=315–21 | doi=10.1016/S0362-3319(01)00116-1 | s2cid=145166840 | access-date=25 June 2016 | url-status=dead | archive-url=https://web.archive.org/web/20160815003614/http://his.library.nenu.edu.cn/upload/soft/haoli/114/372.pdf | archive-date=15 August 2016 }}</ref>
=== Middle Ages ===
[[File:Leprosy bell.JPG|thumb|Medieval leper bell]]
The social perception of leprosy in the general population was in general mixed. On one hand, people feared getting infected with the disease and thought of people suspected of leprosy to be unclean, untrustworthy, and occasionally morally corrupt.<ref name="Covey-2001" /> On the other hand, Jesus' interaction with lepers, the writing of church leaders and the Christian focus on charitable works led to viewing the lepers as "chosen by God"<ref>{{cite journal |vauthors=Brenner E |title=Recent Perspectives on Leprosy in Medieval Western Europe |journal=History Compass |date=2010 |volume=8 |issue=5 |pages=388–406 |doi=10.1111/j.1478-0542.2009.00674.x |url=https://doi.org/10.1111/j.1478-0542.2009.00674.x |access-date=10 November 2022 |archive-date=1 May 2023 |archive-url=https://web.archive.org/web/20230501050024/https://compass.onlinelibrary.wiley.com/doi/10.1111/j.1478-0542.2009.00674.x |url-status=live }}</ref> or seeing the disease as a means of obtaining access to heaven.<ref name="Barber_1994">{{cite journal | vauthors = Barber M |title=The Order of Saint Lazarus and the Crusades |journal=The Catholic Historical Review |date=July 1994 |volume=80 |issue=3 |pages=439–456}}</ref>
Early medieval understanding of leprosy was influenced by early Christian writers such as [[Gregory of Nazianzus]] and [[John Chrysostom]], whose writings were later embraced
by Byzantine and Latin writers.<ref name="MillerSmithSavage">{{cite journal |vauthors=Miller TS, Smith-Savage R |title=Medieval Leprosy Reconsidered |journal=International Social Science Review |date=2006 |volume=81 |issue=1/2 |pages=16–28 |jstor=41887256 |url=https://www.jstor.org/stable/41887256 |access-date=10 November 2022 |archive-date=10 November 2022 |archive-url=https://web.archive.org/web/20221110153048/https://www.jstor.org/stable/41887256 |url-status=live }}</ref> Gregory, for example, did not only compose sermons urging Christians to assist victims of the disease, but also condemned pagans or Christians who justified rejecting lepers on the allegation that God had sent them the disease to punish them. As cases of leprosy increased during these years in the [[Eastern Roman Empire]], becoming a major health issue, the ecclesiastic leaders of the time discussed how to assist those affected as well as change the attitude of society towards them. They also tried this by using the name "Holy disease" instead of the commonly used "Elephant's disease" (elephantiasis), implying that God did not create this disease to punish people but to purify them for heaven.<ref name="MillerNesbit">{{cite book | vauthors = Miller TS, Nesbitt JW |title=Walking Corpses: Leprosy in Byzantium and the Medieval West |date=19 April 2014 |publisher=Cornell University Press |isbn=978-0801470769}}</ref> Although not always successful in persuading the public and a cure was never found by Greek medicians, they created an environment where victims could get [[palliative care]] and were never expressly banned from society, as sometimes happened in Western Europe. Theodore Balsamon, a 12th-century jurist in [[Constantinople]], noted that lepers were allowed to enter the same churches, cities and assemblies that healthy people attended.<ref name="MillerSmithSavage" />
As the disease became more prevalent in Western Europe in the fifth century, efforts began to set up permanent institutions to house and feed lepers. These efforts were, inclusively, the work of bishops in France at the end of the sixth century, such as in [[Chalon-sur-Saône]].<ref name="MillerSmithSavage" /> The increase in hospitals or [[leprosaria]] (sing. leprosarium) that treated people with leprosy in the 12th and 13th century seems to indicate a rise in cases,<ref>{{Cite book|title=The Medieval world| vauthors = Le Goff J |author-link=Jacques Le Goff|publisher=Collins & Brown|year=1990|isbn=978-1-85585-081-1|location=London|url-access=registration|url=https://archive.org/details/medievalworld0000unse}}</ref><ref>{{Cite book|title=The Medieval Hospitals of EnglishLand| vauthors = Clay R |publisher=Cornell University Library|year=1909|isbn=978-1-112-20443-2}}</ref><ref>{{Cite book|title=Medieval English medicine| vauthors = Rubin S |publisher=Newton Abbot: [[David & Charles]] |year=1974 |isbn=978-0-06-496016-8 |location=New York: Barnes & Noble Books |url= https://archive.org/details/medievalenglishm0000rubi }}</ref> possibly in connection with the increase in urbanisation <ref name="IntHistory">{{cite web |title=Medieval Leprosy |url=https://intriguing-history.com/medieval-leprosy/ |website=Intriguing history |date=24 April 2017 |access-date=10 November 2022 |archive-date=6 December 2022 |archive-url=https://web.archive.org/web/20221206050123/https://intriguing-history.com/medieval-leprosy/ |url-status=live }}</ref> as well as returning crusaders from the Middle East.<ref name="MillerSmithSavage" /> France alone had nearly 2,000 leprosaria during this period.<ref name="Covey-2011">{{cite journal | vauthors = Covey HC |title=People with leprosy (Hansen's disease) during the Middle Ages |journal=The Social Science Journal |date=1 June 2001 |volume=38 |issue=2 |pages=315–21 |doi=10.1016/S0362-3319(01)00116-1 |s2cid=145166840 }}</ref> Additionally to the new leprosia, further steps were taken by secular and religious leaders to prevent further spread of the disease. The [[third Lateran Council]] of 1179 required lepers to have their own priests and churches<ref name="IntHistory" />{{failed verification|date=February 2024}} and a 1346 edict by [[Edward III of England|King Edward]] expelled lepers from city limits. Segregation from mainstream society became common, and people with leprosy were often required to wear clothing that identified them as such or carry a bell announcing their presence.<ref name="Covey-2011" /> As in the East, it was the [[Catholic Church|Church]] who took care of the lepers due to the still persisting moral stigma and who ran the leprosaria.<ref name="Covey-2001" /><ref>{{Cite book|title=The Formation of a Persecuting Society| vauthors = Moore RI |publisher=Blackwell|year=2007|isbn=978-1-4051-2964-0|location=Oxford}}</ref> Although the leprosaria in Western Europe removed the sick from society, they were never a place to quarantine them or from which they could not leave: lepers would go beg for alms for the upkeep of the leprosaria or meet with their families.<ref name="IntHistory" /><ref name="MillerSmithSavage" />
Multiple groups in western Europe from the middle ages faced social ostracization and discrimination that was justified, in part, due to claims that they were the descendants of lepers. These groups included the [[Cagot]]s and the [[Caquins of Brittany|Caquins]].<ref>{{cite journal |last=von Zach |first=Franz Xaver |author-link=Franz Xaver von Zach |title=Einige Nachrichten von den Cagots in Frankreich |language=de |trans-title=Some news of the Cagots in France |journal=Allgemeine geographische Ephemeriden |volume=1 |number=5 |pages=509–524 |date=March 1798 |url=https://zs.thulb.uni-jena.de/rsc/viewer/jportal_derivate_00200951/AGE_1798_Bd01_0509.tif |archive-url=https://web.archive.org/web/20211008082132/https://zs.thulb.uni-jena.de/rsc/viewer/jportal_derivate_00200951/AGE_1798_Bd01_0509.tif |archive-date=8 October 2021}}</ref><ref>{{cite journal |last=Tuke |first=D. Hack |author-link=Daniel Hack Tuke |title=The Cagots |journal=The Journal of the Anthropological Institute of Great Britain and Ireland |volume=9 |date=1880 |pages=376–385 |jstor=2841703 |doi=10.2307/2841703 |publisher=[[Wiley (publisher)|Wiley]] |url=https://zenodo.org/record/2119746 |archive-url=https://web.archive.org/web/20220627154521/https://zenodo.org/record/2119746#.YrnQlnPP1qY |archive-date=27 June 2022}}</ref><ref>{{cite journal |author=[[British Medical Journal]] |title=Cagots |journal=[[British Medical Journal]] |volume=1 |number=2680 |date=11 May 1912 |pages=1091–1092 |jstor=25297157}}</ref>
=== 19th century ===
[[File:Leprosy.jpg|thumb|upright| A 24-year-old man with leprosy (1886)]]
==== Norway ====
Norway was the location of a progressive stance on leprosy tracking and treatment and played an influential role in European understanding of the disease. In 1832, Dr. JJ Hjort conducted the first leprosy survey, thus establishing a basis for epidemiological surveys. Subsequent surveys resulted in the establishment of a national leprosy registry to study the causes of leprosy and for tracking the rate of infection.{{citation needed|date=October 2022}}
Early leprosy research throughout Europe was conducted by Norwegian scientists [[Daniel Cornelius Danielssen]] and [[Carl Wilhelm Boeck]]. Their work resulted in the establishment of the National Leprosy Research and Treatment Center. Danielssen and Boeck believed the cause of leprosy transmission was hereditary. This stance was influential in advocating for the isolation of those infected by sex to prevent reproduction.<ref>{{Cite book |author=Alter A. |display-authors=etal |year=2010 |title=Genetic susceptibility to leprosy |isbn=978-0-494-72613-6 |publisher=McGill University }}</ref><ref>{{cite web|url= https://snl.no/Daniel_Cornelius_Danielssen|title= Daniel Cornelius Danielssen|publisher= Store norske leksikon|author= Svein Atle Skålevåg|access-date= 1 January 2017|url-status= live|archive-url= https://web.archive.org/web/20170113154202/https://snl.no/Daniel_Cornelius_Danielssen|archive-date= 13 January 2017}}</ref><ref>{{cite web|url= https://snl.no/Carl_Wilhelm_Boeck|title= Carl Wilhelm Boeck|publisher= Store norske leksikon|author= Svein Atle Skålevåg|access-date= 1 January 2017|url-status=live|archive-url= https://web.archive.org/web/20170113170144/https://snl.no/Carl_Wilhelm_Boeck|archive-date= 13 January 2017|date= 28 September 2014}}</ref>
==== Leprosy and imperialism ====
[[File:Father Damien on his deathbed.jpg|thumb|[[Father Damien]] on his deathbed in 1889]]
Though leprosy rates were again on the decline in the [[Western world]] by the 1860s, authorities in the West frequently embraced isolation treatment due to a combination of reasons, including fears of the disease spreading from the [[Global North and Global South|Global South]], efforts by Christian missionaries and a lack of understanding concerning [[bacteriology]], [[medical diagnosis]] and how contagious the disease was.<ref name="Gussow-2021">{{Cite book|first=Zachary|last=Gussow|title=Leprosy, Racism, And Public Health: Social Policy In Chronic Disease Control|year=2021|orig-year=1989|publisher=[[Routledge]]|isbn=978-0-3670-0292-3}}</ref> The rapid expansion of Western [[imperialism]] during the [[Victorian era]] resulted in Westerners coming into increasing contact with regions where the disease was endemic, including British India. English surgeon [[Henry Vandyke Carter]] observed isolation treatment for leprosy patients first-hand while visiting Norway, applying these methods in British India with the financial and logistical assistance of Protestant missionaries. Colonialist and religious viewpoints of the disease continued to be a major factor in the treatment and public perception of the disease in the Global South until [[decolonization]] in the mid-twentieth century.<ref name="Gussow-2021" />
=== 20th century ===
=== India ===
{{see also|Leprosy in India}}
In 1898, the [[British Empire|colonial government]] in [[British Raj|British India]] enacted the Leprosy Act of 1898, which mandated the compulsory segregation of people with leprosy by authorities in newly established leper asylums, where they were segregated by sex to prevent sexual activity. The act, which proved difficult to enforce, was repealed in 1983 by the [[Government of India|Indian government]] after multidrug therapy had become widely available in India. In 1983, the National Leprosy Elimination Programme, previously the National Leprosy Control Programme, changed its methods from surveillance to the treatment of people with leprosy. India still accounts for over half of the global disease burden. According to WHO, new cases in India during 2019 diminished to 114,451 patients (57% of the world's total new cases).<ref>{{cite journal |title=Global leprosy (Hansen disease) update, 2019: time to step-up prevention initiatives |journal=Weekly Epidemiological Record |date=4 September 2020 |volume=95 |issue=36 |pages=417–40 |hdl=10665/334140 |hdl-access=free }}</ref><ref name="Gussow-2021"/> Until 2019, Indians could justify a petition for divorce with their spouse's diagnosis of leprosy.<ref>{{Cite news|date=13 February 2019|title=Hindu Marriage Act: Parliament passes law removing leprosy as ground for divorce|work=The Economic Times|url=https://economictimes.indiatimes.com/news/politics-and-nation/parliament-passes-law-removing-leprosy-as-ground-for-divorce/articleshow/67974143.cms?from=mdr|access-date=14 July 2020|archive-date=15 July 2020|archive-url=https://web.archive.org/web/20200715020656/https://economictimes.indiatimes.com/news/politics-and-nation/parliament-passes-law-removing-leprosy-as-ground-for-divorce/articleshow/67974143.cms?from=mdr|url-status=live}}</ref>
==== United States ====
The National Leprosarium at [[Carville, Louisiana]], known in 1955 as the Louisiana Leper Home, was the only leprosy hospital on the mainland United States. Leprosy patients from all over the United States were sent to Carville in order to be kept in isolation away from the public, as not much about leprosy transmission was known at the time and stigma against those with leprosy was high (see [[Leprosy stigma]]). The Carville leprosarium was known for its innovations in reconstructive surgery for those with leprosy. In 1941, 22 patients at Carville underwent trials for a new drug called [[promin]]. The results were described as miraculous, and soon after the success of promin came [[dapsone]], a medicine even more effective in the fight against leprosy.<ref>{{cite book| vauthors = Dobson M |title=Disease: The extraordinary stories behind history's deadliest killers|publisher=Quercus Editions Ltd|orig-date=2007|year= 2013|isbn=978-1-4351-5166-6|location=UK|pages=26–27}}</ref>
=== 21st century ===
==== United States ====
Leprosy incidence peaked in the United States in 1983, followed by a steep decline.<ref name="Bhukhan" /> However, case numbers have been slowly rising again since 2000. In 2020, 159 cases of leprosy were reported in the country.<ref name="Bhukhan">{{Cite journal |last1=Bhukhan |first1=Aashni |last2=Dunn |first2=Charles |last3=Nathoo |first3=Rajiv |title=Case Report of Leprosy in Central Florida, USA, 2022 |journal= Emerging Infectious Diseases|date=2023 |volume=29 |issue=8 |pages=1698–1700 |doi=10.3201/eid2908.220367 |pmid=37486691 |pmc=10370849 }}</ref>
=== Stigma ===
{{See also|Leprosy stigma|Leper colony stigma}}
Despite now effective treatment and education efforts, leprosy stigma continues to be problematic in developing countries where the disease is common. Leprosy is most common amongst impoverished populations where social stigma is likely to be compounded by poverty. Fears of ostracism, loss of employment, or expulsion from family and society may contribute to a delayed diagnosis and treatment.<ref>{{Cite web |last=admin |date=11 February 2016 |title=Stigma Related to Leprosy – A Scientific View |url=https://internationaltextbookofleprosy.org/chapter/stigma-quantitative |access-date=7 October 2022 |website=International Textbook of Leprosy |archive-date=7 October 2022 |archive-url=https://web.archive.org/web/20221007055504/https://internationaltextbookofleprosy.org/chapter/stigma-quantitative |url-status=live }}</ref>
Folk beliefs, lack of education, and religious connotations of the disease continue to influence social perceptions of those affected in many parts of the world. In Brazil, for example, folklore holds that leprosy is a disease transmitted by dogs, or that it is associated with sexual promiscuity, or that it is a punishment for sins or moral transgressions (distinct from other diseases and misfortunes, which are in general thought of as being according to the will of God).<ref>{{cite journal | vauthors = White C | title = Explaining a complex disease process: talking to patients about Hansen's disease (leprosy) in Brazil | journal = Medical Anthropology Quarterly | volume = 19 | issue = 3 | pages = 310–330 | date = September 2005 | pmid = 16222964 | doi = 10.1525/maq.2005.19.3.310 | doi-access = free }}</ref> Socioeconomic factors also have a direct impact. Lower-class domestic workers who are often employed by those in a higher socioeconomic class may find their employment in jeopardy as physical manifestations of the disease become apparent. Skin discoloration and darker pigmentation resulting from the disease also have social repercussions.<ref>{{Cite web |title=Leprosy and Its Stigma Are Both Curable |url=https://www.mcgill.ca/oss/article/health-and-nutrition-history/leprosy-and-its-stigma-are-both-curable |access-date=7 October 2022 |website=Office for Science and Society |archive-date=7 October 2022 |archive-url=https://web.archive.org/web/20221007055454/https://www.mcgill.ca/oss/article/health-and-nutrition-history/leprosy-and-its-stigma-are-both-curable |url-status=live }}</ref>
In extreme cases in northern India, leprosy is equated with an "untouchable" status that "often persists long after individuals with leprosy have been cured of the disease, creating lifelong prospects of divorce, eviction, loss of employment, and ostracism from family and social networks."<ref>{{cite journal | vauthors = Barrett R | title = Self-mortification and the stigma of leprosy in northern India | journal = Medical Anthropology Quarterly | volume = 19 | issue = 2 | pages = 216–230 | date = June 2005 | pmid = 15974328 | doi = 10.1525/maq.2005.19.2.216 | jstor = 3655487 }}</ref>
<gallery widths="300px" heights="200px">
File:Three Tahitians suffering from leprosy, Tahiti, approximately 1895.jpg|Leprosy in Tahiti, {{circa|1895}}
File:A 26 year old woman with leprous lesions Wellcome L0074857.jpg|A 26-year-old woman with leprous lesions
File:13 year old boy with severe leprosy Wellcome L0074842.jpg|A 13-year-old boy with severe leprosy
</gallery>
== Public policy ==
A goal of the World Health Organization is to "eliminate leprosy" and in 2016 the organization launched "Global Leprosy Strategy 2016–2020: Accelerating towards a leprosy-free world".<ref name="WHOstrategy">{{Cite web|title=WHO {{!}} The Global Leprosy Strategy|url=http://www.who.int/lep/strategy/en/|archive-url=https://web.archive.org/web/20060917130403/http://www.who.int/lep/strategy/en/|url-status=dead|archive-date=17 September 2006|access-date=9 February 2021|website=WHO}}</ref><ref>{{cite web | title=The final push strategy to eliminate leprosy as a public health problem: questions and answers | website=[[World Health Organization]] (WHO) | date=18 September 2003 | url=https://www.who.int/publications/i/item/WHO-CDS-CPE-CEE-2003.37 | access-date=28 May 2024 | archive-date=28 May 2024 | archive-url=https://web.archive.org/web/20240528055808/https://www.who.int/publications/i/item/WHO-CDS-CPE-CEE-2003.37 | url-status=live }}</ref> Elimination of leprosy is defined as "reducing the proportion of leprosy patients in the community to very low levels, specifically to below one case per 10,000 population".<ref>{{Cite web|title=WHO {{!}} Elimination of leprosy FAQ|url=http://www.who.int/lep/strategy/faqs/en/|archive-url=https://web.archive.org/web/20141018141200/http://www.who.int/lep/strategy/faqs/en/|url-status=dead|archive-date=18 October 2014|access-date=9 February 2021|website=WHO}}</ref> Diagnosis and treatment with multidrug therapy are effective, and a 45% decline in disease burden has occurred since multidrug therapy has become more widely available.<ref name="WHOeliminate">{{Cite web|title=Leprosy elimination |publisher=[[World Health Organization]] (WHO) |url=https://www.who.int/lep/en/|url-status=live|archive-url=https://web.archive.org/web/20140314203445/http://www.who.int/lep/en/|archive-date=14 March 2014|access-date=3 July 2019}}</ref> The organization emphasizes the importance of fully integrating leprosy treatment into public health services, effective diagnosis and treatment, and access to information.<ref name="WHOeliminate" /> The approach includes supporting an increase in health care professionals who understand the disease, and a coordinated and renewed political commitment that includes coordination between countries and improvements in the methodology for collecting and analysing data.<ref name="WHOstrategy" />
Interventions in the "Global Leprosy Strategy 2016–2020: Accelerating towards a leprosy-free world":<ref name="WHOstrategy" />
* Early detection of cases focusing on children to reduce transmission and disabilities.
* Enhanced healthcare services and improved access for people who may be marginalized.
* For countries where leprosy is endemic, further interventions include an improved screening of close contacts, improved treatment regimens, and interventions to reduce stigma and discrimination against people who have leprosy.
In some instances in India, community-based rehabilitation is embraced by local governments and [[NGO]]s alike. Often, the identity cultivated by a community environment is preferable to reintegration, and models of self-management and collective agency independent of NGOs and government support have been desirable and successful.<ref>{{cite journal | vauthors = Staples J | title = Communities of the afflicted: constituting leprosy through place in South India | journal = Medical Anthropology | volume = 33 | issue = 1 | pages = 6–20 | date = 2014 | pmid = 24383749 | doi = 10.1080/01459740.2012.714021 | s2cid = 24595253 | url = https://bura.brunel.ac.uk/handle/2438/10276 | access-date = 22 November 2022 | archive-date = 13 February 2023 | archive-url = https://web.archive.org/web/20230213111214/https://bura.brunel.ac.uk/handle/2438/10276 | url-status = live }}</ref>
==Notable cases==
* [[Josephine Cafrine]] of [[Seychelles]] had leprosy from the age of 12 and kept a personal journal that documented her struggles and suffering.<ref name=sna1>{{cite news|title=A look at 6 contested historical events of Seychelles|url=http://www.seychellesnewsagency.com/articles/7354/A+look+at++contested+historical+events+of+Seychelles|access-date=15 November 2017|work=Seychelles News Agency|archive-date=17 November 2017|archive-url=https://web.archive.org/web/20171117070106/http://www.seychellesnewsagency.com/articles/7354/A+look+at++contested+historical+events+of+Seychelles|url-status=live}}</ref><ref name=alla>{{cite news|title=Seychelles: 14 Inspiring Women of Seychelles|url=http://allafrica.com/stories/201703090796.html|access-date=15 November 2017|work=Seychelles News Agency (Victoria)|date=9 March 2017|archive-date=17 November 2017|archive-url=https://web.archive.org/web/20171117065414/http://allafrica.com/stories/201703090796.html|url-status=live}}</ref><ref name=nation>{{cite news|title=Nation Home|url=http://www.nation.sc/article.html?id=248100|access-date=16 November 2017|work=Seychelles Nation|date=14 January 2016|archive-date=17 November 2017|archive-url=https://web.archive.org/web/20171117070239/http://www.nation.sc/article.html?id=248100|url-status=live}}</ref> It was published as an autobiography in 1923.<ref name=sna1/><ref name=alla/><ref name=nation/><ref name=weekly>{{cite news|title=Diocesan committee prepares to commemorate Josephine Cafrine's 109th death anniversary|url=http://www.seychellesweekly.com/2016/January%204,%202016/soc1aa_commemorate_josephine_cafrine.html|access-date=15 November 2017|work=Seychelles Weekly|date=8 January 2016|archive-date=4 April 2016|archive-url=https://web.archive.org/web/20160404025046/http://www.seychellesweekly.com/2016/January%204,%202016/soc1aa_commemorate_josephine_cafrine.html|url-status=live}}</ref>
* [[Father Damien|Saint Damien De Veuster]], a Catholic priest from Belgium, himself eventually contracting leprosy, ministered to lepers who had been placed under a government-sanctioned medical quarantine on the island of [[Moloka{{okina}}i]] in the [[Kingdom of Hawai{{okina}}i]].<ref name="Tayman">{{Cite book| vauthors = Tayman J | title = The Colony: The Harrowing True Story of the Exiles of Molokai| publisher = Simon and Schuster| year = 2007| location = New York| url = https://books.google.com/books?id=rKUaLE6s1lgC| isbn = 978-0-7432-3301-9| url-status=live| archive-url = https://web.archive.org/web/20160102160605/https://books.google.com/books?id=rKUaLE6s1lgC| archive-date = 2 January 2016}}</ref>
* [[Baldwin IV of Jerusalem]] was a Catholic Christian king of Latin Jerusalem who had leprosy.<ref>{{cite book |author=Hamilton, Bernard |title=The leper king and his Heirs: Baldwin IV and the Crusader Kingdom of Jerusalem |publisher=Cambridge University Press |location=Cambridge |year=2000 |isbn=978-0-521-64187-6 }}</ref>
*[[Ingeborg Grytten]], Norwegian writer whose leprosy is thought to have influenced her poetry, which is characterized by a strong religious faith in God's salvation.<ref>{{cite book|last1=Ring|first1=Barbra|last2=Aubert|first2=Elise|last3=Winsnes|first3=Hanna|last4=Vogt|first4=Johanne|editor1-last=Aasen|editor1-first=Elisabeth|title=Fra gamle dage: memoarer, dagbøker, salmer og dikt av kvinner ca. 1660-1880|date=1983|publisher=Universitetsforlaget|isbn=8200062503|pages=69–75|url=https://www.nb.no/items/URN:NBN:no-nb_digibok_2007062801008?page=69|language=no}}</ref>
*[[Josefina Guerrero]] was a Filipina spy during [[World War II]], who used the Japanese fear of her leprosy to listen to their battle plans and deliver the information to the American forces under [[Douglas MacArthur]].<ref>{{cite news |vauthors=Lazatin H |title=5 Famous Spies Who Made Philippine History |url=https://www.esquiremag.ph/the-good-life/pursuits/5-famous-spies-that-made-philippine-history-a00184-20180108-lfrm |newspaper=Esquiremag.ph |date=8 January 2018 |access-date=23 March 2022 |archive-date=22 September 2021 |archive-url=https://web.archive.org/web/20210922165217/https://www.esquiremag.ph/the-good-life/pursuits/5-famous-spies-that-made-philippine-history-a00184-20180108-lfrm |url-status=live }}</ref>
* King [[Henry IV of England]] (reigned 1399 to 1413) possibly had leprosy.<ref>{{cite book| vauthors = Webber R |title = Disease Selection: The Way Disease Changed the World|date=2015|publisher=CABI|isbn=978-1-78064-682-4|page=8|url=https://books.google.com/books?id=jC8ZCwAAQBAJ&pg=PA8|url-status=live|archive-url=https://web.archive.org/web/20170908221750/https://books.google.com/books?id=jC8ZCwAAQBAJ&pg=PA8|archive-date=8 September 2017}}</ref>
* Vietnamese poet [[Hàn Mặc Tử]]<ref name="Nguyên">{{cite journal| doi=10.2307/40093803| title=Contemporary Vietnamese Writing | author=Cung giu Nguyên | journal = Books Abroad | volume = 29 | issue = 1 | year = 1955 | pages=19–25 | publisher = University of Oklahoma | jstor =40093803}}</ref>
* [[Ōtani Yoshitsugu]], a Japanese ''[[daimyō]]''<ref name="Bryant">{{cite book |author=Bryant A |title=Sekigahara 1600: The Final Struggle for Power (Campaign Series, 40) |publisher=Osprey Publishing (UK) |year=1995 |isbn=978-1-85532-395-7 |access-date=28 February 2010 |url=https://books.google.com/books?id=UzhzhxfmncsC&q=Otani%20Yoshitsugu%20leprosy&pg=PA24 }}{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> (feudal lord).
* British writer [[Peter Greave]] (1910–1977).
== Leprosy in media ==
* {{date table sorting|1891|08|  }} — the short story collection ''Life's Handicap'' [[Rudyard Kipling bibliography|by]] [[Rudyard Kipling]] has a story "The Mark of the Beast" in which a traveller on horseback literally stumbles into a leper colony in India.<ref>{{cite journal |doi=10.1353/vcr.2016.0011 |url=https://muse.jhu.edu/article/635693 |title=Recognizing the Leper: Hindu Myth, British Medicine, and the Crisis of Realism in Rudyard Kipling's "The Mark of the Beast" |journal=[[Victorian Review]] |date=2016 |last1=Fernandez |first1=Jean |volume=41 |pages=89–105 |s2cid=164335632 |access-date=21 February 2024 |archive-date=2 June 2018 |archive-url=https://web.archive.org/web/20180602092307/https://muse.jhu.edu/article/635693 |url-status=live }}</ref>
* {{date table sorting|1909|  |  }} —  Jack London published [[Jack London#Race|"Koolau the Leper"]] in his ''Tales of Hawai'i'' about Molokai and people consigned to it circa 1893.
* {{date table sorting|1959|  |  }} — [[James Michener]]'s novel ''[[Hawaii (novel)|Hawaii]]'' dramatizes the island of [[Molokai]]'s leper settlement, including Father Damien.
* {{date table sorting|1959|  |  }} — [[Ben-Hur (1959 film)|''Ben-Hur'']] depicts the title character's mother, Miriam, and younger sister, Tirzah, are imprisoned by the Roman empire. When they are freed years later, they have leprosy and leave town for the Valley of the Lepers, rather than stay and reunite with Ben-Hur. They leave the colony, and when Jesus dies on the cross, they are miraculously cured.
* {{date table sorting|1960|  |  }} — English author Graham Greene's novel ''[[A Burnt-Out Case]]'' is set in a leper colony in Belgian Congo. The story is also predominantly about a disillusioned architect working with a doctor on devising new cure and amenities for mutilated victims of lepers; the title, too, refers to the condition of mutilation and disfigurement in the disease.<ref>{{Cite web|title=A Burnt-Out Case {{!}} novel by Greene|url=https://britannica.com/topic/A-Burnt-Out-Case|access-date=16 August 2021|website=Encyclopedia Britannica|archive-date=16 August 2021|archive-url=https://web.archive.org/web/20210816060511/britannica.com/topic/A-Burnt-Out-Case|url-status=live}}</ref>
* {{date table sorting|1962|  |  }} —  [[Forugh Farrokhzad]] made a 22-minute documentary about a leprosy colony in [[Iran]] titled ''[[The House Is Black]]''. The film humanizes the people affected and opens by saying that "there is no shortage of ugliness in the world, but by closing our eyes on ugliness, we will intensify it."
* {{date table sorting|1965|05|  }} — The [[Roald Dahl]] short story ''[[The Visitor (short story)#Publication history|The Visitor]]'' in the ''[[My Uncle Oswald]]'' series has a character with leprosy.
* {{date table sorting|1977|  |  }} —  The lead character in ''[[The Chronicles of Thomas Covenant]]'' by [[Stephen R. Donaldson]] suffers from leprosy. His condition seems to be cured by the magic of the fantasy land he finds himself in, but he resists believing in its reality, for example, by continuing to perform a regular [[visual surveillance of extremities]] as a safety check. Donaldson gained experience with the disease as a young man in India, where his father worked in a missionary for people with leprosy.
* {{date table sorting|1988|08|  }} —  Death metal band [[Death (metal band)|Death]] has an album titled ''[[Leprosy (album)|Leprosy]]''.
* {{date table sorting|2003|05|  }} —  [["Weird Al" Yankovic]] has a song titled "Party at the Leper Colony" on his album ''[[Poodle Hat]]''.
* {{date table sorting| 2005|05|  }} — In [[Kingdom of Heaven (film)]] directed by [[Ridley Scott]] and written by [[William Monahan]], [[Baldwin IV of Jerusalem]], played by [[Edward Norton]], is portrayed by wearing a mask to conceal his leprosy. There is no historical account that Baldwin wore a mask to hide his leprosy.
* {{date table sorting| 2005|12|  }} — In [[Monk (TV Series)]] Season 5, Episode 10,  "Mr. Monk and the Leper" directed by [[Randy Zisk]], a person with leprosy asks private investigator Adrian Monk (played by [[Tony Shalhoub]]) to act on his behalf at a probate hearing, but proves to be using the outward trappings of chronic illness to conceal a deadly secret agenda.
* {{date table sorting|2006|  |  }} —  ''Moloka'i'' is a novel by [[Alan Brennert]] about a leper colony in Hawaii. This novel follows the story of a seven-year-old girl taken from her family and put on [[Molokai]]'s leper settlement.
* {{date table sorting|2009|  |  }} —  ''Squint: My Journey with Leprosy'' is a memoir by Jose P. Ramirez.<ref>{{Cite book |url=https://www.upress.state.ms.us/Books/S/Squint |title=Squint |access-date=20 January 2024 |archive-date=6 July 2022 |archive-url=https://web.archive.org/web/20220706184627/https://www.upress.state.ms.us/Books/S/Squint |url-status=live }}</ref>
* {{date table sorting|2010|  |  }} — In the novel ''[[Gone (novel series)#Lies|Lies]]'' by Michael Grant, Sanjit and Virtue claim that ''San Francisco de Sales Island'' is a leper colony and that they themselves are lepers in an attempt to deter Caine and Diana after they land there.<ref>{{Cite book |last=Grant |first=Michael |title=Lies |date=2024-05-04 |publisher=[[HarperCollins]] |isbn=978-0-0614-4911-6 |pages=77 |language=en}}</ref>
* {{date table sorting|2016|01|  }} —  In the video game ''[[Darkest Dungeon]]'' by Red Hook Studios, a hero character known as the Leper suffers from this disease. He was once a benevolent king who embraced the sick and downtrodden, but abdicated his throne following an assassination attempt after he was infected to wander the world and marvel at its beauty.
* {{date table sorting|2021|  |  }} —  ''[[The Second Life of Mirielle West]]'' , a novel by Amanda Skenandore, is set in Carville.
* {{date table sorting|2022|  |  }} —  ''[[The Wind & the Reckoning]]'' is a movie about Pi'ilani, whose husband, Ko'olau, and son, Kalei, contracted Hansen's disease. The family fought those who sought to capture and kill Hawaiians afflicted with Hansen's disease.
* {{date table sorting|2022|08|  }} —  In ''[[House of the Dragon]]'', the TV adaptation of [[George R. R. Martin]]'s ''[[Fire & Blood (novel)|Fire and Blood]]'', King [[Viserys I Targaryen]] suffers from a debilitating disease where parts of his body develop lesions and slowly rot away over time. [[Paddy Considine]], the actor playing the role, explained on a [[podcast]] with ''[[Entertainment Weekly]]'' that Viserys suffers from "a form of leprosy".<ref>{{Cite web |title=EW's West of Westeros: EW goes to the set of House of the Dragon episode 8 on Apple Podcasts |url=https://podcasts.apple.com/us/podcast/ew-goes-to-the-set-of-house-of-the-dragon-episode-8/id1099326209?i=1000582095526 |access-date=20 October 2022 |website=Apple Podcasts |archive-date=20 October 2022 |archive-url=https://web.archive.org/web/20221020230621/https://podcasts.apple.com/us/podcast/ew-goes-to-the-set-of-house-of-the-dragon-episode-8/id1099326209?i=1000582095526 |url-status=live }}</ref> Leprosy is not mentioned in the novel, where Viserys instead suffers from various health issues relating to his obesity, including infections and [[gout]].<ref>{{Cite web|title=House of the Dragon: All the Fire and Blood Easter Eggs From Episode 8|url=https://www.vanityfair.com/hollywood/2022/10/house-of-the-dragon-all-the-fire-and-blood-easter-eggs-from-episode-8|access-date=28 December 2022|website=[[Vanity Fair (magazine)|Vanity Fair]]|date=10 October 2022|archive-date=26 November 2022|archive-url=https://web.archive.org/web/20221126085719/https://www.vanityfair.com/hollywood/2022/10/house-of-the-dragon-all-the-fire-and-blood-easter-eggs-from-episode-8|url-status=live}}</ref>
* {{date table sorting|2023|  |  }} —  ''[[The Covenant of Water]],'' a family saga novel by Abraham Verghese.
== Infection of animals ==
Wild [[nine-banded armadillos]] (''Dasypus novemcinctus'') in south central United States often carry ''Mycobacterium leprae''.<ref>{{cite journal | vauthors = Truman R | title = Leprosy in wild armadillos | journal = Leprosy Review | volume = 76 | issue = 3 | pages = 198–208 | date = September 2005 | pmid = 16248207 | doi = 10.47276/lr.76.3.198 | doi-access = free }}</ref> This is believed to be because armadillos have a low body temperature. Leprosy lesions appear mainly in cooler body regions such as the skin and mucous membranes of the [[upper respiratory tract]]. Because of armadillos' armor, skin lesions are hard to see.<ref>{{cite journal | vauthors = Sharma R, Lahiri R, Scollard DM, Pena M, Williams DL, Adams LB, Figarola J, Truman RW | title = The armadillo: a model for the neuropathy of leprosy and potentially other neurodegenerative diseases | journal = Disease Models & Mechanisms | volume = 6 | issue = 1 | pages = 19–24 | date = January 2013 | pmid = 23223615 | pmc = 3529335 | doi = 10.1242/dmm.010215 }}</ref> Abrasions around the eyes, nose and feet are the most common signs. Infected armadillos make up a large reservoir of ''M. leprae'' and may be a source of infection for some humans in the United States or other locations in the armadillos' home range. In armadillo leprosy, lesions do not persist at the site of entry in animals, ''M. leprae'' multiply in [[macrophage]]s at the site of [[inoculation]] and lymph nodes.<ref>{{cite journal | vauthors = Job CK, Drain V, Truman R, Deming AT, Sanchez RM, Hastings RC | title = The pathogenesis of leprosy in the nine-banded armadillo and the significance of IgM antibodies to PGL-1 | journal = Indian Journal of Leprosy | volume = 64 | issue = 2 | pages = 137–151 | date = April 1992 | pmid = 1607712 | id = {{INIST|4390813}} }}</ref>
Across America, there has been a pattern of nine-banded armadillos (Dasypus novemcinctus) carrying [[Mycobacterium leprae]]. It was first demonstrated in 1971 to develop leprosy after inoculation with M. leprae.<ref name=":0">Adams L. B. (2021). Susceptibility and resistance in leprosy: Studies in the mouse model. ''Immunological reviews'', ''301''(1), 157–174. <nowiki>https://doi.org/10.1111/imr.12960</nowiki></ref> As a result of their low body temperature their tissues commonly contain massive numbers of organisms which helps in the dissemination of the infection. Between 15-20% of Armadillos carry the M. leprae bacteria causing the risk of human infection when in contact with Armadillos quite high.<ref name=":1">Liang, Jiayu (10/16/2023). "Leprosy in Florida: medical experts monitoring unusual, new cases of Hansen's disease". ''University of Florida Emerging Pathogens Institute''. [https://epi.ufl.edu/2023/10/16/leprosy-in-florida-medical-experts-monitoring-unusual-new-cases-of-hansens-disease/#:~:text=A%20major%20hint%20that%20someone,leprae%20bacteria. https://epi.ufl.edu/2023/10/16/leprosy-in-florida-medical-experts-monitoring-unusual-new-cases-of-hansens-disease/#:~:text=A%20major%20hint%20that%20someone,leprae%20bacteria.]</ref>
[[Armadillo|Armadillos]] have been used in immunological research to fight leprosy. Some notable reagents include recombinant interleukin-2 and recombinant interferon-gamma reagents.<ref name=":0" /> Additionally, they have been key and have been useful models of leprosy for studies regarding neuropathy.<ref name=":2">Truman, R. W., Ebenezer, G. J., Pena, M. T., Sharma, R., Balamayooran, G., Gillingwater, T. H., Scollard, D. M., McArthur, J. C., & Rambukkana, A. (2014). The armadillo as a model for peripheral neuropathy in leprosy. ''ILAR journal'', ''54''(3), 304–314. <nowiki>https://doi.org/10.1093/ilar/ilt050</nowiki></ref> In clinical procedures such as electrophysiological nerve conduction tests Armadillo's nerve function has been properly assessed.<ref name=":2" /> Despite the studies mentioned regarding Armadillo's relationship to neuropathy and other effects of leprosy, there is still a lack of proper study on Armadillos, and in conducting more armadillo-specific regents our understanding of Leprosy’s effects on armadillos and possible humans can be found. Armadillos are a key component of modern-day research on leprosy.
There is a stigma surrounding armadillos and the carrying of leprosy. Because many people do not understand Armadillos very well it is common for people to think of them as being dangerous to society and, as a result valuing their lives less than other animals. But Armadillos are an essential part of our ecosystem, especially in areas where they are native. There is an issue on the other end of the spectrum as well. It has become more common in parts of America for people to eat raw or undercooked Armadillo meat as around 15-20% of American Armadillos carry leprosy<ref name=":1" />, making the chances high that if not properly handled with care, one will become infected.<ref>Bittel, Jason (06/28/2016). [https://www.nationalgeographic.com/animals/article/Armadillos-leprosy-bacteria-amazon-brazil-nine-banded-animals# "Humans Gave Leprosy to Armadillos. Now, They're Giving It Back"]. ''National Geographic''.</ref> We must find a happy medium to not put ourselves at risk of getting sick as a result of the Armadillos carrier status, but also not to harm Armadillos out of fear.
An outbreak in chimpanzees in West Africa is showing that the bacteria can infect another species and also possibly have additional rodent hosts.<ref>{{cite web |url=https://www.science.org/content/article/leprosy-ancient-scourge-humans-found-assail-wild-chimpanzees |title=Leprosy, ancient scourge of humans, found to assail wild chimpanzees |work=Science |vauthors=Kupferschmidt K |date=11 November 2020 |access-date=1 July 2021 |archive-date=13 October 2021 |archive-url=https://web.archive.org/web/20211013190915/https://www.science.org/content/article/leprosy-ancient-scourge-humans-found-assail-wild-chimpanzees |url-status=live }}</ref>
Studies have demonstrated that the disease is endemic in the UK red Eurasian squirrel population, with ''Mycobacterium leprae'' and ''Mycobacterium lepromatosis'' appearing in different populations. The ''Mycobacteria leprae'' strain discovered on [[Brownsea Island]] is equated to one thought to have died out in the human population in mediaeval times.<ref>{{cite web |url=https://www.researchgate.net/publication/332568227 |title=Leprosy in Red Squirrels in the UK |work=Vet Record |date=30 March 2019 |access-date=25 May 2022}}</ref> Despite this, and speculation regarding past transmission through trade in squirrel furs, there does not seem to be a high risk of squirrel to human transmission from the wild population. Although Leprosy continues to be diagnosed in immigrants to the UK, the last known human case of leprosy arising in the UK was recorded over 200 years ago.<ref>{{cite web |url=https://www.theguardian.com/science/2017/oct/25/medieval-love-of-squirrel-fur-may-have-helped-spread-leprosy-study-reveals |title=Medieval love of squirrel fur may have helped spread leprosy, study reveals |work=Guardian |date=25 October 2017 |access-date=25 May 2022 |archive-date=25 May 2022 |archive-url=https://web.archive.org/web/20220525101307/https://www.theguardian.com/science/2017/oct/25/medieval-love-of-squirrel-fur-may-have-helped-spread-leprosy-study-reveals |url-status=live }}</ref>
It has been shown that leprosy can reprogram cells in mouse<ref>{{cite journal | vauthors = Masaki T, Qu J, Cholewa-Waclaw J, Burr K, Raaum R, Rambukkana A | title = Reprogramming adult Schwann cells to stem cell-like cells by leprosy bacilli promotes dissemination of infection | journal = Cell | volume = 152 | issue = 1–2 | pages = 51–67 | date = January 2013 | pmid = 23332746 | pmc = 4314110 | doi = 10.1016/j.cell.2012.12.014 }}</ref><ref>{{Cite news |date=17 January 2013 |title=Leprosy bacteria use 'biological alchemy' |work=BBC News |url=https://www.bbc.com/news/health-21056644 |access-date=18 November 2022 |archive-date=18 November 2022 |archive-url=https://web.archive.org/web/20221118021715/https://www.bbc.com/news/health-21056644 |url-status=live }}</ref> and armadillo<ref>{{cite journal | vauthors = Hess S, Kendall TJ, Pena M, Yamane K, Soong D, Adams L, Truman R, Rambukkana A | title = In vivo partial reprogramming by bacteria promotes adult liver organ growth without fibrosis and tumorigenesis | journal = Cell Reports. Medicine | volume = 3 | issue = 11 | pages = 100820 | date = November 2022 | pmid = 36384103 | doi = 10.1016/j.xcrm.2022.100820 | pmc = 9729881 | s2cid = 253577148 | doi-access = free }}</ref><ref>{{Cite news |date=16 November 2022 |title=Leprosy: Ancient disease able to regenerate organs |work=BBC News |url=https://www.bbc.com/news/health-63626239 |access-date=18 November 2022 |archive-date=18 November 2022 |archive-url=https://web.archive.org/web/20221118020211/https://www.bbc.com/news/health-63626239 |url-status=live }}</ref> models, similar to how [[induced pluripotent stem cell]]s are generated by the [[transcription factors]] [[Myc]], [[Oct-4|Oct3/4]], [[Sox2]], and [[Klf4]].
An animal that is a large component of study on Leprosy is the mouse ([[House mouse|Mus musculus]]) A notable study, conducted by [[Charles C. Shepard|Charles Shepard]] used mice to find how Leprosy, which is an infection that has a preference for cooler areas of the body, would work in a warm-blooded animal. This mice study helped further the understanding of how leprosy works in humans. This was called “The Mouse Model.”<ref name=":0" /> The main findings were that even in mice whose immune systems were severely impaired and at a perceived high risk of developing leprosy, the body was still in most cases able to fight off leprosy. The findings suggest that in mice, the body will use their body's energy to fight leprosy.<ref name=":0" />
Using The Mouse Model Shepard was able to conduct new research regarding Leprosy. This model can now be used as a tool to further studies of M. leprae.<ref name=":0" /> The Mouse Model takes a more easily accessible animal model to better understand this complex disease. Although Armadillos are one of the best animals to use to better understand M. leprae, they are not the only ones that can provide potential insights into this disease.
There are a few other up-and-coming models for M. leprae including the use of other animals including but not limited to mammals, birds, and cold-blooded animals.<ref name=":0" /> These animals do not tend to give as great results as the Armadillos and the mice as different animals have different levels of disease resistance.
== References ==
{{Reflist}}
== Further reading ==
* {{cite book |title=Carville's Cure: Leprosy, Stigma, and the Fight for Justice |year=2020 |author=Pam Fessler |isbn=978-1631495038 |publisher=Liveright}}
* {{cite report | title=Guidelines for the diagnosis, treatment and prevention of leprosy | website=[[World Health Organization]] (WHO) | date=October 2018 | url=https://www.who.int/publications/i/item/9789290226383 | isbn=978-92-9022-638-3 | hdl=10665/274127 | hdl-access=free }}
== External links ==
{{Commons}}
{{Medical condition classification and resources
| DiseasesDB      = 8478
| ICD11           = {{ICD11|1B20}}
| ICD10           = {{ICD10|A|30||a|30}}
| ICD9            = {{ICD9|030}}
| ICDO            =
| OMIM            = 246300
| MedlinePlus     = 001347
| eMedicineSubj   = med
| eMedicineTopic  = 1281
| eMedicine_mult  = {{eMedicine2|derm|223}} {{eMedicine2|neuro|187}}
| MeshID          = D007918
| Scholia         = Q36956
}}
{{Diseases of the skin and appendages by morphology}}
{{Gram-positive actinobacteria diseases}}
{{Portal bar | Medicine}}
{{Authority control}}
[[Category:Leprosy| ]]
[[Category:Bacterial diseases]]
[[Category:Tropical diseases]]
[[Category:Wikipedia infectious disease articles ready to translate]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Diseases named after discoverers|Hansens's disease]]