Leprosy, also known as Hansen's disease,[1] is an infectious disease caused by Hansen's bacillus (the Mycobacterium leprae bacterium). Leprosy can eventually cause a variety of skin problems, loss of feeling, and paralysis of the hands and feet.[2]
Gerhard Henrick Armauer Hansen (July 29, 1841 - February 12, 1912)
Although leprosy had been known to affect people for centuries, Gerhard Hansen, a Norwegian physician is widely recognized as the person who first identified the bacterium Mycobacterium leprae as the cause of the disease.[3] Hansen concluded on the basis of epidemiological studies that leprosy had a single specific cause.[3] Between 1870 and 1871, Hansen travelled to Bonn and Vienna to gain the training necessary for him to prove his hypothesis.[3] In 1873, he published the discovery of rod-shaped bodies (Mycobacterium leprae) in tissue samples from patients with leprosy and asserted that they were the disease agents. At the time, the disease was thought to be inherited and his result did not quickly gain acceptance.[3]
In 1879, Hansen gave tissue samples to Albert Neisser who successfully stained the bacteria and announced his findings in 1880, claiming to have discovered the disease-causing organism.[3] There was some conflict between Neisser and Hansen, Hansen as discoverer of the bacillus and Neisser as identifier of it as the etiological agent.[3]
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.[4] 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.”[5] 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.
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 term Tzaraath from the Hebrew Bible is commonly translated as leprosy, although the symptoms of Tzaraath are not entirely consistent with leprosy and might refer to a variety of skin disorders other than Hansen's disease.[6]
In particular tinea capitis (fungal scalp infection) and related infections on other body parts caused by the dermatophyte fungus Trichophyton violaceum, are abundant throughout the Middle East and North Africa today, and might also have been common in biblical times. Similarly, the related agent of the disfiguring skin disease favus, Trichophyton schoenleinii, appears to have been common throughout Eurasia and Africa prior to the advent of modern medicine. Persons with severe favus and similar fungal diseases (and potentially also with severe psoriasis and other diseases not caused by microorganisms) tended to be classed as having leprosy as late as the 17th century in Europe [7]: this is vividly as shown in the painting Governors of the Home for Lepers at Haarlem 1667 by Jan de Bray (Frans Hals Museum, Haarlem, the Netherlands), where a young Dutch man with a vivid scalp infection, almost certainly caused by a fungus, is shown being cared for by three officials of a charitable home intended for leprosy sufferers (painting reproduced in reference just cited). The use of the word ‘leprosy’ prior to the mid-19th century, when microscopic examination of skin for medical diagnosis was first developed, can seldom be correlated reliably with Hansen's disease as we understand it today.
The word “leprosy” derives from the ancient Greek words lepros, a scale, and lepein, to peel.[8] The word came into the English language via Latin and Old French. The first attested English use is in the Ancrene Wisse, a 13th-century manual for nuns (“Moyseses hond..bisemde o þe spitel uuel & þuhte lepruse.” The Middle English Dictionary, s.v., “leprous”). A roughly contemporaneous use is attested in the Anglo-Norman Dialogues of Saint Gregory, “Esmondez i sont li lieprous” (Anglo-Norman Dictionary, s.v., “leprus”).
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.
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.
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.
Hansen's disease is 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 include the armadillo, mangabey monkeys, rabbits, and mice (on their footpads).
Hansen's Disease (HD) is transmitted by Mycobacterium leprae. The bacillus M. leprae has never been grown in the laboratory. As a result it has been difficult to study the exact mechanisms of pathogenesis. However, the United States Centers for Disease Control's disease information statement about Hansen's [1] makes the following assertion about the transmission of the disease: “Although the mode of transmission of Hansen's disease remains uncertain, most investigators think that M. leprae is usually spread from person to person in respiratory droplets.”
At highest risk are those living in endemic areas with poor conditions such as inadequate bedding, contaminated water and insufficient diet, or other diseases (such as HIV) that compromise immune function. Recent research suggests that there is a defect in cell-mediated immunity that causes susceptibility to the disease. Less than ten percent of the world's population are actually capable of acquiring the disease. The region of DNA responsible for this variability is also involved in Parkinson's disease, giving rise to current speculation that the two disorders may be linked in some way at the biochemical level. In addition, men are two times more likely to contract leprosy than women.
The disease affects the skin, nerves and mucous membranes. This chronic infectious disease usually affects the skin and peripheral nerves but has a wide range of possible clinical manifestations. Patients are classified as having paucibacillary (tuberculoid leprosy), multibacillary Hansen's disease (lepromatous leprosy) or borderline leprosy. Borderline leprosy (also termed multibacillary), of intermediate severity, is the most common form. Skin lesions resemble tuberculoid leprosy but are more numerous and irregular; large patches may affect a whole limb, and peripheral nerve involvement with weakness and loss of sensation is common. This type is unstable and may become more like lepromatous leprosy or may undergo a reversal reaction, becoming more like the tuberculoid form. 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; rather, a long investigation by Dr. Paul Brand yielded that insensitivity in the limbs extremities was the reason why unfelt wounds or lesions, however minute, lead to undetected deterioration of the tissues, the lack of pain not triggering an immediate response as in a fully functioning body. Recently, leprosy has also emerged as a problem in HIV patients on antiretroviral drugs(NY Times).
A very great number of leprosaria, or leper hospitals, sprang up in the middle ages, particularly in England, where there were 250 by A.D. 1230 The first recorded leprosarium was in Harbledown. These institutions were run along monastic lines, and while lepers were encouraged to live in these monastic-type establishments, this was for their own health as well as quarantine. Indeed, 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.
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. According to the Bible[9], Jesus had not only walked with lepers, but touched and conversed with them, as have many workers since Jesus' time, without acquiring the disease 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 efficiency it was believed necessary to take dapsone for months if not years. Search for more effective medicines led to the discovery of clofazimine and rifampicin in the sixties. Of the two, rifampin was the most widely adopted. The first study using rifampicin to treat leprosy was published in 1970.[10] In 1982 Multi-Drug-Therapy (MDT) was introduced, based on studies published by Shantaram Yawalkar and colleagues.[11] The treatment Yawalkar formulated was a combination of rifampicin and dapsone.
Although treatment with antimicrobial drugs is effective, optimal multiple drug regimens remain uncertain. Drug sensitivity testing in mice is often recommended for lepromatous and borderline patients, particularly in the United States.
The WHO recommends multidrug regimens for all forms of leprosy. Treatment for lepromatous leprosy requires more intensive regimens and a greater duration than that for tuberculoid leprosy. For affected adults, the WHO advocates dapsone 100 mg once a day, clofazimine 50 mg once a day plus 300 mg once a month, and Rifampin 600 mg once a month for at least 2 years or until results of skin biopsies are negative (usually in about 5 years). For tuberculoid leprosy patients the WHO recommends dapsone 100 mg once a day and Rifampin 600 mg once a month for 6 months. Many authorities in India recommend that the duration be extended to 1 year.
In the US, lepromatous leprosy is usually treated with Rifampin 600 mg once a day for 2 to 3 years, plus dapsone 100 mg once a day for life. Tuberculoid leprosy is treated with dapsone 100 mg once a day for 5 years.
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. There is no known resistance to MDT drugs.
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