A: Armauer Hansen
described his first
observation of
Mycobacterium
leprae on 28
February 1873.
Harboe M. [Gerhard Henrik Armauer
Hansen--still of current interest]
[Article in Norwegian]. Tidsskr Nor
Laegeforen. 1992 Dec
10;112(30):3795-8.
described his first
observation of
Mycobacterium
leprae on 28
February 1873.
Harboe M. [Gerhard Henrik Armauer
Hansen--still of current interest]
[Article in Norwegian]. Tidsskr Nor
Laegeforen. 1992 Dec
10;112(30):3795-8.
What is Hansen's disease?
Leprosy (Hansen's disease) is a chronic infection caused by the bacterium
Mycobacterium leprae that results in damage primarily to the peripheral nerves (the
nerves outside the brain and spinal cord), skin, testes, eyes, and mucous membrane of
the nose.
Because of the visible disfigurement in untreated people, people with leprosy have long
been feared and shunned by others. Although leprosy is not highly contagious, does not
cause death, and can be effectively treated with antibiotics, the disease still causes
widespread anxiety. As a result, people with leprosy often suffer psychologic and social
problems.
http://www.merck.com/mmhe/sec17/ch194/ch194a.html
History of Leprosy
The earliest description of leprosy comes from India around 600 BCE. It was then
described in the Far East around 400 BCE. In the fourth century, the disease was
imported into Europe, where its incidence peaked in the 13th century. The disease has
now nearly disappeared from Europe. Affected immigrants spread leprosy to North
America.
Armauer Hansen discovered M leprae in Norway in 1873. It was the first bacillus to be
associated with human disease. Despite this discovery, leprosy was not initially thought to
be an infectious disease.
Humans are the primary reservoir of M leprae. Animal reservoirs of leprosy have been
found in 3 species: 9-banded armadillos, chimpanzees, and mangabey monkeys.
http://www.emedicine.com/derm/topic223.htm
Natural disease course
Leprosy is not a highly infectious disease. The principal means of transmission is by
aerosol spread from infected nasal secretions to exposed nasal and oral mucosa.
Leprosy is not generally spread by means of direct contact through intact skin, though
close contacts are most vulnerable. The incubation period is 6 months to 40 years or
longer. The mean incubation period is 4 years for tuberculoid leprosy (TT) and 10 years
for lepromatous leprosy (LL).
http://www.emedicine.com/derm/topic223.htm
Leprosy facts
http://www.emedicine.com/derm/topic223.ht
Leprosy (Hansen's disease) is a chronic infection caused by the bacterium
Mycobacterium leprae that results in damage primarily to the peripheral nerves (the
nerves outside the brain and spinal cord), skin, testes, eyes, and mucous membrane of
the nose.
Because of the visible disfigurement in untreated people, people with leprosy have long
been feared and shunned by others. Although leprosy is not highly contagious, does not
cause death, and can be effectively treated with antibiotics, the disease still causes
widespread anxiety. As a result, people with leprosy often suffer psychologic and social
problems.
http://www.merck.com/mmhe/sec17/ch194/ch194a.html
History of Leprosy
The earliest description of leprosy comes from India around 600 BCE. It was then
described in the Far East around 400 BCE. In the fourth century, the disease was
imported into Europe, where its incidence peaked in the 13th century. The disease has
now nearly disappeared from Europe. Affected immigrants spread leprosy to North
America.
Armauer Hansen discovered M leprae in Norway in 1873. It was the first bacillus to be
associated with human disease. Despite this discovery, leprosy was not initially thought to
be an infectious disease.
Humans are the primary reservoir of M leprae. Animal reservoirs of leprosy have been
found in 3 species: 9-banded armadillos, chimpanzees, and mangabey monkeys.
http://www.emedicine.com/derm/topic223.htm
Natural disease course
Leprosy is not a highly infectious disease. The principal means of transmission is by
aerosol spread from infected nasal secretions to exposed nasal and oral mucosa.
Leprosy is not generally spread by means of direct contact through intact skin, though
close contacts are most vulnerable. The incubation period is 6 months to 40 years or
longer. The mean incubation period is 4 years for tuberculoid leprosy (TT) and 10 years
for lepromatous leprosy (LL).
http://www.emedicine.com/derm/topic223.htm
Leprosy facts
- Leprosy is caused by M leprae, an obligate intracellular, acid-fast, gram-positive
bacillus.
- Most persons are immune to leprosy. Subclinical disease is common in endemic
areas, and the infection progresses to clinical disease in only a select few.
- Exposure to the nasal discharge of those that remain untreated for years is thought
to be the main cause of infection. Transmission is not completely understood.
- In addition to exposure respiratory secretions, exposure to insect vectors and
infected soil has been suspected as a possible mode of transmission.
- In endemic countries, household contacts of patients are at increased risk for
leprosy. The relative risk is 8-10 for LL and 2-4 for TT. In nonendemic countries,
household contacts rarely acquire the disease.
- HIV infection is not a risk factor for acquiring leprosy, nor does it increase the
clinical symptoms or virulence of leprosy.
- The following genes have been associated with leprosy. Hence, susceptibility to
leprosy may be at least partially inheritable.
- Susceptible loci on chromosome band 10p13 and chromosome 6
- Polymorphisms in the gene promoter regions of TNF (multibacillary leprosy) and
interleukin 10 (IL–10)
- Human leukocyte antigen (HLA)-DR2 and HLA-DR3 (tuberculoid disease), as well
as HLA-DQ1 (LL)
- TLR2 mutations in LL
- Polymorphisms in the NRAMP1 gene in multibacillary disease in African patients
http://www.emedicine.com/derm/topic223.ht
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