Leprosy#Classification

Common symptoms present in the different types of leprosy include a runny nose; dry scalp; eye problems; skin lesions; muscle weakness; reddish skin; smooth, shiny, diffuse thickening of facial skin, ear, and hand; loss of sensation in fingers and toes; thickening of peripheral nerves; a flat nose from the destruction of nasal cartilages; and changes in phonation and other aspects of speech production.{{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}} In addition, atrophy of the testes and impotence may occur.{{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}}

Leprosy can affect people in different ways. The average incubation period is five years. People may begin to notice symptoms within the first year or up to 20 years after infection. 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.{{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}} Patches of discolored skin are sometimes accompanied or preceded by nerve problems including numbness or tenderness in the hands or feet.{{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 }} Secondary infections (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.{{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}}{{cite web |url=http://www.leprosy.org/leprosy-faqs |title=Q and A about leprosy |work=American Leprosy Missions |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, and 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 |url-status=live |archive-url=https://web.archive.org/web/20121004072853/http://www.leprosy.org/leprosy-faqs |archive-date=4 October 2012 }} A person's immune response differs depending on the form of leprosy.{{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 }}

Approximately 30% of people affected with leprosy experience nerve damage. 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.{{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 }}

File:Tuberous Leprosy Wellcome L0032810.jpg|Face severely deformed by leprosy, 1895

File:Leprosy deformities hands.jpg|Hands deformed by leprosy, 2022

File:Fox Plate XL.jpg|Face mildly deformed by leprosy, 1905

File:Mycobacterium leprae in Magnification of 2000X.jpg bacterium, M. leprae appears red when a Ziehl–Neelsen stain is used]]

Mycobacterioum leprae and Mycobacterium lepromatosis are the mycobacteria that cause leprosy. M. lepromatosis is a relatively newly identified mycobacterium isolated from a fatal case of diffuse lepromatous leprosy in 2008.{{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}}{{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}} M. lepromatosis is indistinguishable clinically from M. leprae.{{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}} M. leprae is an aerobic, rod-shaped, acid-fast bacterium with a waxy cell envelope characteristic of the genus Mycobacterium.{{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 }} M. leprae and M. lepromatosis are obligate intracellular pathogens and cannot grow or be cultured outside of host tissues.{{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 }} However, they can be grown using research animals such as mice and armadillos.{{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}}{{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}}

Naturally occurring infections have been reported in nonhuman primates (including the African chimpanzee, the sooty mangabey, and the cynomolgus macaque), armadillos,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. and red squirrels.{{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 }} Multilocus sequence typing of the armadillo M. leprae strains suggests that they were of human origin for at most a few hundred years.Monot M, Honoré N, Garnier T, Araoz R, Coppee JY, et al. (2005). "On the origin of leprosy". Science 308: 1040–42. Thus, it is suspected that armadillos first acquired the organism incidentally from early European explorers of the Americas. 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).{{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 }}

Red squirrels (Sciurus vulgaris), a threatened species in Great Britain, were found to carry leprosy in November 2016.[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] . Retrieved 11 November 2016. 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. A pre-Norman era skull excavated in Hoxne, Suffolk, in 2017 was found to carry DNA from a strain of M. leprae which closely matched the strain carried by modern red squirrels on Brownsea Island.{{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}}{{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 }}

The greatest risk factor for developing leprosy is contact with another person infected by leprosy. 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.{{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 }} Leprosy occurs more commonly among those living in poverty. Not all people who are infected with M. leprae develop symptoms.{{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 }}{{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 }}

Conditions that reduce immune function, such as malnutrition, other illnesses, or genetic mutations, may increase the risk of developing leprosy. Infection with HIV does not appear to increase the risk of developing leprosy.{{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 }} Certain genetic factors in the person exposed have been associated with developing lepromatous or tuberculoid leprosy.{{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}}

Transmission of leprosy occurs during close contact with those who are infected. Transmission of leprosy is through the upper respiratory tract.{{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 }} Older research suggested the skin as the main route of transmission, but research has increasingly favored the respiratory route.{{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 }} Transmission occurs through inhalation of bacilli present in upper airway secretion.{{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 }}

Leprosy is not sexually transmitted and is not spread through pregnancy to the unborn child. 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.{{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}} People are considered non-infectious 72 hours after starting appropriate multi-drug therapy.{{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 }} Two exit routes of M. leprae from the human body that are 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. Humans can acquire a leprosy infection from armadillos by handling them or consuming armadillo meat.{{Cite news |last=Harris |first=Gardiner |date=2011-04-27 |title=Armadillos Can Transmit Leprosy to Humans, Federal Researchers Confirm |url=https://www.nytimes.com/2011/04/28/health/28leprosy.html |access-date=2025-03-15 |work=The New York Times |language=en-US |issn=0362-4331}}{{Cite news |last=Guiden |first=Mary |date=2018-06-29 |title=New evidence that wild armadillos spread leprosy to humans |url=https://cvmbs.source.colostate.edu/new-evidence-that-wild-armadillos-spread-leprosy-to-humans/ |archive-url=https://web.archive.org/web/20241128000723/https://cvmbs.source.colostate.edu/new-evidence-that-wild-armadillos-spread-leprosy-to-humans/ |archive-date=28 November 2024 |access-date=2025-03-15 |work=News from the College of Veterinary Medicine and Biomedical Sciences |language=en-US |url-status=live }} The mechanism is not fully understood.{{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 }}{{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}}

Not all people infected or exposed to M. leprae develop leprosy, and genetic factors are suspected to play a role in susceptibility to an infection.{{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 }} Cases of leprosy often cluster in families, and several genetic variants have been identified. In many who are exposed, the immune system can eliminate the leprosy bacteria during the early infection stage before severe symptoms develop.{{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}} A genetic defect in cell-mediated immunity may cause a person to be susceptible to develop leprosy symptoms after exposure to the bacteria. 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 biochemical level.{{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 }}

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. The molecular mechanism underlying how M. leprae produces the symptoms of leprosy is not clear, but M. leprae has been shown to bind to Schwann cells, which may lead to nerve injury including demyelination and a loss of nerve function (specifically a loss of axonal conductance).{{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 }} 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.

As part of the human immune response, white blood cell-derived macrophages may engulf M. leprae by phagocytosis. In the initial stages, small sensory and autonomic nerve fibers in the skin of a person with leprosy are damaged. 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. 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.

File:Monofilament testing.jpg

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.
• Positive skin smears.

Skin lesions can be single or many, and usually hypopigmented, although occasionally reddish or copper-colored. The lesions may be flat (macules), raised (papules), or solid elevated areas (nodular). 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.{{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 }} 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. In some cases, the presence of acid-fast leprosy bacilli in skin smears is considered diagnostic; however, the diagnosis is typically made without laboratory tests, based on symptoms. If a person has a new leprosy diagnosis and already has a visible disability caused by leprosy, the diagnosis is considered late.

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. Early diagnosis and treatment prevent nerve involvement, the hallmark of leprosy, and the disability it causes.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 }} There is no recommended test to diagnose latent leprosy in people without symptoms. Few people with latent leprosy test positive for anti PGL-1. The presence of M. leprae bacterial DNA can be identified using a polymerase chain reaction (PCR)-based technique.{{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 }} 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.{{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 }} New approaches propose tools to diagnose leprosy through artificial intelligence.{{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 }}

Several different approaches for classifying leprosy exist. There are similarities between the classification approaches.

• The World Health Organization (WHO) system distinguishes patients with 5 or fewer skin lesions and no bacilli in a skin smear as "paucibacillary" ("pauci-" refers to a small quantity) from patients with more lesions or detected bacilli as "multibacillary".{{Cite web |title=Leprosy |url=https://www.who.int/news-room/fact-sheets/detail/leprosy |access-date=2025-02-13 |website=www.who.int |language=en}}
• The Ridley-Jopling scale provides five gradations.{{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 }}{{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 }}{{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}}
• The ICD-10, though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry."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 }}.
• In MeSH, three groupings are used.

{{Clear}}

Leprosy may also occur with only neural involvement, without skin lesions.{{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 }}{{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 }}{{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 }}{{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 }}{{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 }}

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.{{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 }}

File:Leprosy; patients showing symptoms. Wellcome L0077162.jpg

Early disease detection is important, since physical and neurological damage may be irreversible even if cured. 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. The WHO recommends that preventive medicine be given to people who are in close contact with someone who has leprosy. The suggested preventive treatment is a single dose of rifampicin in adults and children over 2 years old who do not already have leprosy or tuberculosis. Preventive treatment is associated with a 57% reduction in infections within 2 years and a 30% reduction in infections within 6 years.

The Bacillus Calmette–Guérin (BCG) vaccine offers a variable amount of protection against leprosy in addition to its closely related target of tuberculosis.{{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 }} 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.{{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 }}{{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 }} 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.{{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 }} 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%.{{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 }}{{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 }} Development of a more effective vaccine is ongoing.{{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}}{{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}}{{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. }}

A novel vaccine called LepVax entered clinical trials in 2017 with the first encouraging results reported on 24 participants published in 2020.{{ClinicalTrialsGov|NCT03302897|Phase 1 LEP-F1 + GLA-SE Vaccine Trial in Healthy Adult Volunteers}}{{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 }} If successful, this would be the first leprosy-specific vaccine available.

Image:Municipality_of_Culion_outlook_from_local_hillside.jpg in Culion old town in Palawan, Philippines used to shelter one of the largest population of lepers in Asia, numbering between 3,500-4,000 in the early 1900s.Dr. Heiser, V., An American Doctor's Odyssey. W. W. Norton & Company, 1936Victor G. Heiser, "Leprosy in the Philippine Islands," Public Health Report, 24 (Aug. 13, 1909)]]

File:MDTRegimens.jpg

Several leprostatic agents 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. Multidrug therapy (MDT) remains highly effective, and people are no longer infectious after the first monthly dose. MDT is safe and easy to use under field conditions because it is available in calendar-labelled blister packs. The treatment does pose compliance challenges for young children who find swallowing multiple solid pills difficult.{{Cite journal |last=da Silva Santos |first=Jocimar |last2=da Costa Alves |first2=Franciely |last3=José Dos Santos Júnior |first3=Efraim |last4=Soares Sobrinho |first4=José Lamartine |last5=de La Roca Soares |first5=Mônica Felts |date=2023-01-02 |title=Evolution of pediatric pharmaceutical forms for treatment of Hansen’s disease (leprosy) |url=https://www.tandfonline.com/doi/full/10.1080/13543776.2023.2178301 |journal=Expert Opinion on Therapeutic Patents |language=en |volume=33 |issue=1 |pages=1–15 |doi=10.1080/13543776.2023.2178301 |issn=1354-3776}} Post-treatment relapse rates remain low.

The combination treatment accelerates treatment and increases the chance creating a drug resistant bacteria. All three drugs in the three-drug regimen are antibacterial, with rifampicin being the most potent. Rifampicin is scheduled monthly since it interferes with dapsone by inducing its increased metabolism.{{cite journal |author=George J |title=Metabolism and interactions of antileprosy drugs |journal=Biochemical Pharmacology |year=2020 |volume=177 |issue=July |page=113993 |pmid=32339493 |doi=10.1016/j.bcp.2020.113993 |url=}}

Resistance to the three-drug regimen has been reported in several countries, although the number of cases is small.{{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}} People with rifampicin-resistant leprosy may be treated with second-line medications such as fluoroquinolones, minocycline, or clarithromycin, but the treatment duration is 24 months because of their lower bactericidal activity.{{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 }} Evidence on the potential benefits and harms of alternative regimens for drug-resistant leprosy is not available.

For people with nerve damage, protective footwear may help prevent ulcers and secondary infection. Canvas shoes may be better than PVC boots. There may be no difference between double rocker shoes and below-knee plaster. Topical ketanserin seems to have a better effect on ulcer healing than clioquinol cream or zinc paste, but the evidence for this is weak. Phenytoin applied to the skin improves skin changes to a greater degree when compared to saline dressings.

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. Despite leprosy not being very infectious and having a low pathogenicity, there is still significant stigma and prejudice associated with the disease.{{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 }} 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. People with leprosy are also at a higher risk for problems with their mental well-being. The social stigma may contribute to problems obtaining employment, financial difficulties, and social isolation. Efforts to reduce discrimination and reduce the stigma surrounding leprosy may help improve outcomes for people with leprosy.{{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 }}

{{Main|Epidemiology of leprosy}}

File:Leprosy new case detection 2016 rates, 2016 (cropped).png (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 }}]]

File:Leprosy world map - DALY - WHO2004.svg for leprosy per 100,000 inhabitants in 2004{{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 }}

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In 2018, there were 208,619 new cases of leprosy recorded, a slight decrease from 2017.{{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}} In 2015, 94% of the new leprosy cases were confined to 14 countries.{{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}} India reported the greatest number of new cases (60% of reported cases), followed by Brazil (13%) and Indonesia (8%). 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. About 150 to 250 cases are diagnosed in the United States each year.{{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}}

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. International (e.g., the WHO's "Global Strategy for Reducing Disease Burden Due to Leprosy" and the International Federation of Anti-Leprosy Associations) and national initiatives have reduced the total number and the number of new cases of the disease.{{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 }}

The number of new leprosy cases is difficult to measure and monitor because of leprosy's long incubation period, delays in diagnosis after the onset of the disease, and lack of medical care in affected areas.{{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}} The registered prevalence of the disease is used to determine disease burden. Registered prevalence is a useful proxy indicator of the disease burden, as it reflects the number of active leprosy cases diagnosed with the disease and receiving treatment with MDT at a given point in time. The prevalence rate is defined as the number of cases registered for MDT treatment among the population in which the cases have occurred, again at a given point in time.{{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 }}

{{Main|History of leprosy}}

File:Gerhard Armauer Hansen.jpg in 1873]]

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:{{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 }} 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. leprae are based in specific geographic regions where each predominantly occurs:

• 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 to Europe and vice versa.{{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 }}

Skeletal remains discovered in 2009 represent the oldest documented evidence for leprosy, dating to the 2nd millennium BC.{{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 }}{{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 }} 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".{{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 }} 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 of Jerusalem dated by radiocarbon methods to the first half of the 1st century.{{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 }}

The oldest strains of leprosy known from Europe are from Great Chesterford in southeast England and date back to AD 415–545. 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.{{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 }}

File:Distribution of leprosy around the world Wellcome L0032805.jpgLiterary attestation of leprosy is unclear because of the ambiguity of many early sources, including the Indian Atharvaveda and Kausika Sutra, the Egyptian Ebers Papyrus, and the Hebrew Bible's various sections regarding signs of impurity (tzaraath).{{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 }} Leprotic symptoms are attested in the Indian doctor Sushruta's Compendium, originally dating to c. 600 BC but only surviving in emended texts no earlier than the 5th century BC. Symptoms consistent with leprosy were possibly described by Hippocrates in 460 BC.{{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 }} However, Hansen's disease probably did not exist in Greece or the Middle East before the Common Era.{{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}}{{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}}{{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}} In 1846, 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.{{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}}Roman: Celsus, Pliny, Serenus Samonicus, Scribonius Largus, Caelius Aurelianus, Themison, Octavius Horatianus, Marcellus the Emperic; Greek: Aretaeus, Plutarch, Galen, Oribasius, Aetius (Aëtius of Amida or Sicamus Aëtius), Actuarius, Nonnus, Psellus, Leo, Myrepsus; Arabic: Scrapion, Avenzoar, Albucasis, Haly Abbas translated by Stephanus Antiochensis, Alsharavius, Rhases (Abū Bakr al-Rāzī), and Guido de Cauliaco.

Leprosy did not exist in the Americas before colonization by modern Europeans{{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}} nor did it exist in Polynesia until the middle of the 19th century.{{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 }} The causative agent of leprosy, M. leprae, was discovered by Gerhard Armauer Hansen in Norway in 1873, making it one of the first species of pathogenic bacteria identified.{{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 }}

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.{{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 }} Leprosy was once believed to be highly contagious and was treated with mercury, as was syphilis, which was first described in 1530. Many early cases thought to be leprosy could actually have been syphilis.[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. 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. This technique led to marked improvements in patients with Hansen's disease who were treated in Hawai'i.

The first effective drug (promin) became available in the 1940s.{{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}} 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.{{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 }} Later, Indian scientist Shantaram Yawalkar and his colleagues formulated a combined therapy using rifampicin and dapsone, intended to mitigate bacterial resistance.{{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 }} Combining all three drugs was first recommended by the WHO in 1981. These three drugs are still used in the standard MDT regimens.{{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 }} 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.{{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 }}

The importance of the nasal mucosa in the transmission of M. leprae was recognized as early as 1898 by Schäffer, in particular, that of the ulcerated mucosa.Arch Dermato Syphilis 1898; 44:159–174{{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.{{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 }}

The word "leprosy" comes from the Greek word "λέπος (lépos) – skin" and "λεπερός (leperós) – scaly man".{{citation needed|date=October 2022}}

File:Leprosorium.jpg

Between 1995 and 1999 the WHO, with the aid of the Nippon Foundation, supplied all endemic countries with free MDT in blister packs, channeled through ministries of health. This free provision was extended in 2000 and again in 2005, 2010, and 2015 with donations by the MDT manufacturer Novartis through the WHO.[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) At the national level, non-governmental organizations (NGOs) affiliated with the national program will continue to be provided with an appropriate free supply.{{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}}

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.{{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}} Another Indian text, the Manusmriti (200 BC),  prohibit contact with those infected with the disease and make marriage to a person infected with leprosy punishable.{{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 }}

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.{{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 }} 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).[See: Orr, James, M.A., D.D. General Editor. "Entry for 'Leper; Leprosy'". "International Standard Bible Encyclopedia". 1915. Access-date=6 January 2017 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.{{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 }}

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.{{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}} The biblical perception that people with leprosy were unclean can be found in a passage from [https://www.biblegateway.com/passage/?search=Leviticus%2013%3A44-46&version=NIV Leviticus 13:44–46]. While this text defines the leper as impure, it does not explicitly make a moral judgement on those with leprosy.{{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 }} Some early Christians believed that those affected by leprosy were being punished by God for sinful behavior. Moral associations have persisted throughout history. In the 6th century Pope Gregory the Great and Isidore of Seville considered people with the disease to be heretics.{{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 }}

File:Leprosy bell.JPG

The social perception of leprosy in the general population was 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. 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"{{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 }} or seeing the disease as a means of obtaining access to heaven.{{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}}

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.{{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 }} Gregory, for example, composed sermons urging Christians to assist victims of the disease, and he 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 in the Eastern Roman Empire, becoming a major health issue, the ecclesiastic leaders discussed how to assist those affected as well as how to 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.{{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}} 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.

As the disease became more prevalent in western Europe in the 5th 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. 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,{{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}}{{Cite book|title=The Medieval Hospitals of EnglishLand| vauthors = Clay R |publisher=Cornell University Library|year=1909|isbn=978-1-112-20443-2}}{{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 }} possibly in connection with the increase in urbanisation{{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 }} as well as returning crusaders from the Middle East. France alone had nearly 2,000 leprosaria during this period.{{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 }} 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{{failed verification|date=February 2024}} and a 1346 edict by 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. As in the East, it was the Church who took care of the lepers due to the persisting moral stigma and who ran the leprosaria.{{Cite book|title=The Formation of a Persecuting Society| vauthors = Moore RI |publisher=Blackwell|year=2007|isbn=978-1-4051-2964-0|location=Oxford}} 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.

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 Cagots and the Caquins.{{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}}{{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 |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}}{{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}}

File:Leprosy.jpg

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 to track 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.{{Cite book |author=Alter A. |display-authors=etal |year=2010 |title=Genetic susceptibility to leprosy |isbn=978-0-494-72613-6 |publisher=McGill University }}{{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}}{{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}}

Though leprosy rates were on the decline in the Western world by the 1860s, authorities frequently embraced isolation treatment due to a combination of reasons, including fears of the disease spreading from the Global South, efforts by Christian missionaries and a lack of understanding concerning bacteriology, medical diagnosis and how contagious the disease was.{{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}} 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-20th century.

{{see also|Leprosy in India}}

In 1898, the colonial government in 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 Indian government after MDT 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).{{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 }} Until 2019, Indians could justify a petition for divorce with their spouse's diagnosis of leprosy.{{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}}

The National Leprosarium at Carville, Louisiana, known in 1955 as the Louisiana Leper Home, was the only leprosy hospital in the mainland United States. Leprosy patients from all over the United States were sent to Carville 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. 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.{{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}} Leprosy incidence peaked in the United States in 1983, followed by a steep decline. However, case numbers have been slowly rising again since 2000. In 2020, 159 cases were reported in the country.{{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 }}

{{See also|Leprosy stigma|Leper colony stigma}}{{Multiple image

| image1 = A 26 year old woman with leprous lesions Wellcome L0074857.jpg

| image2 = 13 year old boy with severe leprosy Wellcome L0074842.jpg

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| footer = Depictions of a 26-year-old woman with leprous lesions and a 13-year-old boy with severe leprosy in Daniel Cornelius' 1847 Om Spedalskhed

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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.{{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 }}

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).{{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 }} 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.{{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 }}

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."{{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 }}

The World Health Organization maintains an Expert Committee on Leprosy since 1954, and a goal of the WHO is to "eliminate leprosy." In 2016 the organization launched "Global Leprosy Strategy 2016–2020: Accelerating towards a leprosy-free world".{{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}}{{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 }} Elimination of leprosy is defined as "reducing the proportion of (people with) leprosy in the community to very low levels, specifically to below one case per 10,000 population".{{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}} Diagnosis and treatment with multidrug therapy are effective, and a 45% decline in disease burden has occurred since MDT has become more widely available.{{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}} The organization emphasizes the importance of fully integrating leprosy treatment into public health services, effective diagnosis and treatment, and access to information. 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.

Interventions include:

• 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 NGOs 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.{{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 }}

File:Father Damien on his deathbed.jpg on his deathbed on 14 April 1889]]

• Josephine Cafrine of Seychelles (1877–1907) had leprosy from age 12 and kept a journal that documented her struggles and suffering.{{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}}{{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}}{{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}} It was published as an autobiography in 1923.{{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}}
• Saint Damien De Veuster (1840–1889), a Catholic priest from Belgium, contracted leprosy and ministered to lepers who had been placed under a government-sanctioned medical quarantine on Moloka{{okina}}i in the Kingdom of Hawai{{okina}}i.{{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}}
• Baldwin IV of Jerusalem (1161–1185), Catholic king of Latin Jerusalem, had leprosy.{{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 }}
• Ingeborg Grytten ({{circa|1668}} – after 1705), Norwegian writer whose leprosy is thought to have influenced her poetry, which is characterized by a strong religious faith in God's salvation.{{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}}
• Josefina Guerrero (1917–1996), Filipino World War II spy 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.{{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 }}
• King Henry IV of England ({{reign|1399|1413}}) possibly had leprosy.{{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}}
• Vietnamese poet Hàn Mặc Tử (1912–1940){{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}}
• Ōtani Yoshitsugu (1558 or 1565–1600), a Japanese daimyō (feudal lord).{{cite book |author=Bryant A |url=https://books.google.com/books?id=UzhzhxfmncsC&q=Otani%20Yoshitsugu%20leprosy&pg=PA24 |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}}{{Dead link|date=September 2023|bot=InternetArchiveBot|fix-attempted=yes}}
• British writer Peter Greave (1910–1977).
• Popular Indian actress Dimple Kapadia (1957–present) was diagnosed with leprosy a few months before the shoot of the 1973 musical romance film, Bobby (1973 film). She later recovered completely and went on to have a successful acting career. {{cite web |title=Dimple Kapadia: The Bollywood actress who has overcome leprosy |url=https://www.leprosymission.in/dimple-kapadia-the-bollywood-actress-who-has-overcome-leprosy/ |website=The Leprosy Mission Trust India |access-date=2025-04-08}}

• {{date table sorting|1891|08| }} — the short story collection Life's Handicap 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.{{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 }}
• {{date table sorting|1909| | }} — Jack London published "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 dramatizes Molokai's leper settlement, including Father Damien.
• {{date table sorting|1959| | }} — 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 cures and amenities for mutilated victims of lepers; the title, too, refers to the condition of mutilation and disfigurement in the disease.{{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/http://britannica.com/topic/A-Burnt-Out-Case|url-status=live}}
• {{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|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|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.{{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 }}

Between 15 and 20% of nine-banded armadillos (Dasypus novemcinctus) in the south-central United States carry M. leprae.{{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 }}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.] As a result of their low body temperature their tissues commonly contain massive numbers of organisms which help in the dissemination of the infection. Armadillos were first demonstrated in 1971 to develop leprosy after inoculation with M. leprae.Adams L. B. (2021). Susceptibility and resistance in leprosy: Studies in the mouse model. Immunological reviews, 301(1), 157–174. https://doi.org/10.1111/imr.12960 Because of armadillos' armor, skin lesions are difficult to ascertain.{{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 }} 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 macrophages at the site of inoculation and lymph nodes.{{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}} }}

Armadillos have been used in immunological research to fight leprosy. Some notable reagents include recombinant interleukin-2 and recombinant interferon-gamma reagents. Additionally, they have been key and have been useful models of leprosy for studies regarding neuropathy.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. https://doi.org/10.1093/ilar/ilt050 In clinical procedures such as electrophysiological nerve conduction tests Armadillo's nerve function has been properly assessed. 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. It has become more common in parts of America for people to eat raw or undercooked armadillo, making the chances high that if not properly handled with care, one may become infected.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.

An outbreak in chimpanzees in West Africa is showing that the bacteria can infect another species and also possibly have additional rodent hosts.{{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 }} Studies have demonstrated that the disease is endemic in the UK red Eurasian squirrel population, with M. leprae and M. lepromatosis appearing in different populations. The M. leprae strain discovered on Brownsea Island is equated to one thought to have died out in the human population in mediaeval times.{{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}} 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.{{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 }}

It has been shown that leprosy can reprogram cells in mouse{{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}}{{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 }} and armadillo{{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 }}{{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 }} models, similar to how induced pluripotent stem cells are generated by the transcription factors Myc, Oct3/4, Sox2, and Klf4. A notable study conducted by Charles Shepard used mice to find how leprosy, 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." 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. Using The Mouse Model Shepard was able to conduct new research regarding leprosy. This model can now be used as a tool to further study M. leprae. The Mouse Model takes a more easily accessible animal model to better understand this complex 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. These animals do not tend to give as great results as armadillos and mice as different animals have different levels of disease resistance.

{{Reflist}}

• {{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 }}

{{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}}

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Category:Bacterial diseases

Category:Tropical diseases

Category:Animal diseases

Category:Zoonoses

Category:Wikipedia infectious disease articles ready to translate

Category:Wikipedia medicine articles ready to translate

Hansens's disease