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Leprosy

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For the malady found in the Hebrew Bible, see the article Tzaraath. For the album by the band Death, see Leprosy (album).
Leprosy
SpecialtyInfectious diseases Edit this on Wikidata
Frequency0.002413966% (world)

Leprosy, also known as Hansen's disease, is a non-infectious disease caused by a DNA plasmid (transposon, or "ultravirus", a small circle of DNA) carried in Hansen's bacillus (the Mycobacterium leprae bacterium) which is thus the vector. The plasmid can exist separately from the bacterial chromosome, and from the bacterium, when it invades human nerves; Hansen's Disease may disfigure the body or skin. The modern, non-stigmatising term for the disease is named after Gerhard Armauer Hansen, the discoverer of the bacterium.

Term "Leprosy"

Sufferers of Hansen's disease have historically been known as lepers; however, this term is falling into disuse as a result of the diminishing number of Leprosy patients and the pejorative connotations of the term. In fact, the term that is now most widely accepted among people and agencies working in the field of Hansen's Disease is "people affected by Hansen's Disease". The terms "Leprosy" and "lepers" can also lead to public misunderstanding because the Bible uses these terms in reference to a wide range of skin conditions other than Hansen's disease. The term itself first appeared in the English language in the 1300s coming from Greek and Hebrew. [1]

Incidence

Worldwide, one to two million people are permanently disabled because of Hansen's disease. However, new understandings of the cause of the two forms of the disease may allow prevention, for example, by attention to minimising skin pressure points in endemic areas, avoiding sleeping on hard surfaces, general health measures to optimise immune function etc. India has the greatest number of HD cases, with Brazil second and Myanmar third.

According to recent figures from the World Health Organization (WHO), new cases detected worldwide have decreased by approximately 107,000 cases (or 21%) from 2003 to 2004. This decreasing trend has been consistent for the past three years. In addition, the global registered prevalence of HD was 286,063 cases; 407,791 new cases were detected during 2004.

In 1999, the world incidence of Hansen's disease was estimated to be 640,000; in 2000, 738,284 cases were identified. In 1999, 108 cases occurred in the United States. In 2000, the World Health Organization (WHO) listed 91 countries in which Hansen's disease is endemic. India, Myanmar and Nepal contained 70% of cases. In 2002, 763,917 new cases were detected worldwide, and in that year the WHO listed Brazil, Madagascar, Mozambique, Tanzania and Nepal as having 90% of Hansen's disease cases.

Hansen's disease is one of the diseases hitherto believed "infectious", tracked passively by the Centers for Disease Control and Prevention. Its prevalence in the United States has remained low and relatively stable. There are decreasing numbers of cases worldwide, though pockets of high prevalence continue in certain areas such as Brazil, South Asia (India, Nepal), some parts of Africa (Tanzania, Madagascar, Mozambique) and the western Pacific.

Aside from humans, other creatures that are known to be susceptible to leprosy are the armadillo, mangabey monkeys, rabbits, chimpanzees and mice (on their footpads).

Transmission

The mode of transmission of Hansen's Disease (HD) remained unknown until the understanding that the bacterium is not the cause of nerve damage (in the tuberculoid form of HD), but the wingless vector for a plasmid (transposon, or "ultravirus") that, carrying a neuron invasion gene and the replicator gene shared with the bacterium, may in some humans transfer from the bacterium into peripheral nerves (this seems to occur where pressure, for example through sleeping on hard surfaces, forces proximity). Once in the human nerve the replicating plasmid alters that tissue, inducing a non-specific immune response which causes the nerve damage with loss of sensation, and depigmentation, seen in tuberculoid lesions. The host bacterium is left unable to divide and is largely absent from these (tuberculoid) lesions. In Hansen's bacillus' resting state in the environment, the plasmid is attached to the inside wall so that the bacillus cannot reproduce itself. It is a very important fact that Hansen's bacillus has never been grown in the laboratory ("in vitro"), despite decades of sustained effort. Division (replication) of Hansen's bacillus only occurs inside a certain kind of macrophage (known as a Virchow cell) in certain people whose immune system recognises the specific threat posed by the neuron invasion gene in the plasid, which is lodged at the surface of the bacterium. The Virchow cell in these people effects detachment of the plasmid from the bacterial cell wall, eliminating the threat of nerve invasion, but at the cost of allowing the plasmid - with the replicator gene -to reintegrate into the bacterial chromosome and the bacterium to rapidly reproduce. These patients develop the skin nodules characteristic of Virchowian ("lepromatous") HD, in which nerve damage is absent. The bacterium is ubiquitous in HD endemic areas and approximately 95% of people who are exposed to it do not develop Leprosy due to natural immunity.

refs: Barksdale L "Concerning the NI (neuron Invasion) gene of Mycobacterium leprae". Int. J. Lepr. 47, (1979) Corcos MG "Tuberculoid contamination in Histoid hensniasis". Int. J. Lepr 62, No 2, 1992

Risk groups

At highest risk are those living in endemic areas with poor conditions such as adequate bedding, clean water and diet, or other diseases (HIV) that compromise immune function. Recent research suggests that there is genetic variation in susceptibility. The region of DNA responsible for this variability is also involved in Parkinson's disease, giving rise to current speculation that the two disorders may be linked in some way at the biochemical level. In addition, men are two times more likely to contract leprosy than women.

Clinical features

The disease affects the skin, nerves and mucous membranes. This chronic non-infectious disease usually affects the skin and peripheral nerves but has a wide range of possible clinical manifestations. Patients are classified as having paucibacillary (tuberculoid leprosy) or multibacillary Hansen's disease (lepromatous leprosy). Paucibacillary Hansen's disease is characterized by one or more hypopigmented skin macules and anaesthetic patches, i.e. damaged peripheral nerves which have been attacked by the human host's immune cells. Multibacillary Hansen's disease is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis (nose bleeds), but typically no nerve damage. Contrary to popular belief, Hansen's bacillus does not cause rotting of the flesh; however, due to the body's extensive attempts to rid itself of the plasmid in tuberculoid HD, and the masses of bacteria in the Virchowian ("lepromatous") form, defenses such as inflammation, cytokines, activated macrophages and other mechanisms cause tissue destruction and regeneration leading to excessive growth and eventually mutilation.

Treatment

Historically, the cause of Hansens Disease was not understood, and as a result "leposy" was an incurable and disfiguring disease, with sufferers feared and forcibly isolated.

A very great number of leprosaria, or leper hospitals, sprang up in the middle ages, particularly in England, and there were 250 in England around 1230 A.D. The first recorded leprosarium was in Harbledown. These institutions were run along monastic lines, and while lepers were encouraged to live in these monastic-type establishments, this was for the health of their own souls as well as quarantine. Indeed, in Catholic tradition, those suffering from leprosy were considered to be going through Purgatory on Earth, and for this reason their suffering was considered more holy than the ordinary person's. Saint Radegund was noted for washing the feet of lepers, and Orderic Vitalis writes of a monk, Ralf, who was so overcome by the plight of the leper that he prayed to catch leprosy himself (which he eventually did). The leper would carry a clapper and bell to warn of his approach, and this was as much to attract attention for charity as to warn people that a diseased person was near. Most importantly, Jesus had not only walked with lepers, but touched and conversed with them, as have many workers since Jesus' time, without acquiring the disease (we now understand that it is not infectious in the ordinary sense) and so in medieval religious society, it was a noble thing to be able to converse and build relationships with the leper.

Dapsone was used to treat leprosy from 1946, but because of low efficacy it was believed necessary to take dapsone for months if not years. Search for more effective medicines led to the discovery of clofazimine and rifampin in the sixties at Novartis. Of the two, rifampin was the most widely adopted. The first study using rifampin to treat leprosy was published in 1970.[2] In 1982 Multi-Drug-Therapy (MDT) was introduced, based on studies published by Shantaram Yawalkar and colleagues.[3] The treatment Yawalkar formulated consisted of dapsone and rifampin combination. Antibacterial treatments were based on the old, false assumption that "leprosy is caused by the leprosy bacillus", rather than on a contemporary understanding of the microbes involved, or the relationship of the pathogens with each other, or with their human hosts. The incidence and prevalence of the disease has been falling largely because of improvements in the living standards of popualtions in HD endemic areas. It's unlikely that pharmaceuticals reduce the bacillary load in those populations, especially when those bacteria - except in the specific case of Virchowian ("lepromatous") patients - exist in a vegetative, non-replicating state.

For most people, a six month course of tablets for the milder form of leprosy and two years for the more severe form is still given while they cure themselves of the disease. However, for those who suffer a disabling reaction caused by the build-up of dead bacilli in the body, additional steroid treatment is usually required.

The main challenge in the eradication of Hansen's disease are in the international medical community letting go of old dogma. Medical specialists need to work with virologists, microbiologists, molecular geneticists, molecular parasitologists and computer modellers to fully characterise the molecular ecology, and the dynamics of host-parasite relationships between Hansens bacillus, its plasmid and human beings.

Improving detection of the disease is important, as is education about its cause, providing patients with high-quality services, moving people in at-risk areas toward healthier living and fighting social taboos about a disease where, in the past, patients were considered to be "unclean" or "cursed by God" as outcasts. The last issue is important to address, because in such societies, patients may be forced to hide their condition (and thus avoid seeking treatment) in order to avoid discrimination, since the lack of awareness about Hansen's disease leads people to falsely believe that the disease is highly contagious and incurable. Since 1995, the World Health Organization (WHO) has provided all endemic countries with free MDT, supplied through Ministries of Health. In December 2005, an agreement was signed between the WHO and the pharmaceutical company Novartis to extend this free provision until at least the end of 2010.

Asylums

There are still a few leper colonies around the world, in countries such as India and the Philippines.

Western humanitarian and church organizations regularly send relief supplies, including handmade "leper bandages"; bandages knitted or crocheted out of cotton, for greater breathability and durability than traditional gauze. The bandages can also be washed, sterilized and reused, making them more cost-effective as well.

In 2001, government-run leper colonies in Japan came under judicial scrutiny, leading to the determination that the Japanese government had mistreated the patients, and the District Court ordered Japan to pay compensation to former patients [1]. In 2002, a formal inquiry into these colonies was set up, and in March of 2005 the policy was strongly denounced. "Japan's policy of absolute quarantine... did not have any scientific grounds." [2] The inquiry denounced not only the government and the doctors which are involved with the policy but also the court which repeatedly ruled in the favour of the government when the policy was challenged, as well as the media, which failed to report the plight of the victims. There are about 7000 records of forced abortion and sterilisation. In some instances, it was reported that babies were suffocated after birth. [3]

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Famous people with leprosy

  • Aleijadinho, a Brazilian sculptor in the 1700s, had been disfigured by the disease for more than twenty years.
  • Baldwin IV, Latin King of Jerusalem (1161-1185, reigned 1174-1185), who was depicted in the 2005 film Kingdom of Heaven
  • Joseph (Jozef) de Veuster (Father Damien), a Roman Catholic missionary who helped lepers on the Hawaiian island of Molokai, died of the disease
  • Henry (VII) of Germany, King of Sicily and Germany and Duke of Swabia
  • Hallgrímur Pétursson, one of Iceland's most famous poets and a priest, died from leprosy
  • Robert the Bruce of Scotland was said to have leprosy, and when his skull was unearthed it was missing the canine teeth—a likely skeletal sign of leprosy.

In literature and film

  • William Wyler's 1959 Academy Award winning Best Picture Ben-Hur, graphically depicted leprosy during the time of Christ. Judah Ben Hur's mother, Miriam, and his sister, Tirzah, were imprisoned and found four years later with advanced cases of leprosy. They were released and sent to a leper colony, which was a deserted rock quarry with many caves. The residents of the colony were fed by lowering food from the rim of the quarry.
  • Jack Whyte's historical fiction series "Camulod chronicles" has a main character who contracts leprosy in one of the later books. The books also cover the stigmatization that lepers suffered in the past
  • Walter Salles's film "Diarios de Motocicleta" portrayed Ernesto "Che" Guevara's time as a medical student volunteering at the San Pablo leprosy colony in the Amazon.
  • Episope 13 of Season 1 of the American television drama, House, shows a twelve year old boy who is stricken with Leprosy.
  • Mr. Burns claims to have leprosy in The Simpsons 7th season episode Team Homer. His nail falls off in a beverage, and he nonchalantly comments on the cause being this disease.
  • Victoria Hislop's novel, "The Island" (2005), depicts a leper colony on Spinalonga, a small island off the northeastern coast of Crete. A humanizing portrayal of lepers and their families as well as a highly readable story spanning four generations.

See also

References

  1. ^ "Leprosy". Oxford English Dictionary: Second Edition. 1989
  2. ^ Rees RJ, Pearson JM, Waters MF (1970). "Experimental and clinical studies on rifampicin in treatment of leprosy". Br Med J. 688 (1): 89–92. PMID 4903972.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ^ Yawalkar SJ, McDougall AC, Languillon J, Ghosh S, Hajra SK, Opromolla DV, Tonello CJ (1982). "Once-monthly rifampicin plus daily dapsone in initial treatment of lepromatous leprosy". Lancet. 8283 (1): 1199–1202. PMID 6122970.{{cite journal}}: CS1 maint: multiple names: authors list (link)

1. Barksdale L "Concerning the NI (neuron invasion) gene of mycobacterium leprae" 

  International Journal of Leprosy, 47, (1979)

2. Cantacuzine J, Longhin S. "De l'Existence d'un Ultra-Virus chez le Bacille de la Lepre 

  Humaine" CR Soc Biol, 1932, Vol 109, No 11

3. Novick RP. "Plasmids" Scientific American, vol 243, No 6, 1980 4. Corcos MG "A Transposon in Hansen's bacillus?" Transactions of the Royal Society of 

  Tropical Medicine and Hygiene, 87 (1993)

5. Corcos, MG "Tuberculoid Contamination in Histoid Hanseniasis", International Journal of 

  Leprosy, Vol 62, no 2 (1994)

Further reading

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