Leprosy (Hepatic Disorders): Health Significance Of The Organism And Its Transmission

Funom Makama By Funom Makama, 20th Mar 2014 | Follow this author | RSS Feed | Short URL http://nut.bz/2lh0dq43/
Posted in Wikinut>Health>General Health>Diseases & Infections

Leprosy is a chronic communicable disease caused by Mycobacterium leprae. Mainly, the nerves and skin are affected but it may also involved mucous membranes and other internal organs. Hansen identified the organism in 1868.

Leprosy In General

Leprosy has been known to afflict mankind from biblical times. At present, it is very common in tropical regions of Asia, Africa and central and south America. Low standards of living, poverty and overcrowding favour its transmission and prevalence. But the disease is not confined to this group. Persons belonging to all socio-economic groups may be affected. At present, leprosy affects about 15 to 20 million people worldwide. In places like India alone, a whooping 4 million known cases are known with almost an equal number undetected. Though the prevalence of leprosy has remained static in the last 30 years in many endemic areas, the incidence has been brought down by effective methods of

The Organism

Mycobacterium leprae is a rod- shaped, Gram positive, acid fast bacillus varying in size from 1.8 to 2.5 um in length. It is less acid fast than M. tuberculosis. It is decolourised by 20% sulphuric acid and therefore 5% acid is used for staining by Ziehl Neelson’s method. The bacterial morphology helps in assessing the viability and the effects of drug therapy. Viable bacilli appear as regular rods. Bacillin appear as regular rods. Bacilli which appear irregular and granula are probably dead. Mycobacterium leprae is grown experimentally in the foot pads of mice and in the nine-branded armadillo.


Portal of entry is through abrasions in the skin or mucous membranes or the upper respiratory tract. Untreated subjects with lepromatous leprosy shed numerous bacilli in nasal discharges and minor abrasions in the skin even before they are clinically detectable. Other possible sources of spread such as insect vectors and fomites have also been incriminated.

The incubation period is ordinarily 2 to 7 years, but this may vary from a few months to 30 years. Since man has natural immunity against lepra bacilli, lesions do not develop in the majority of cases, or they remain subclinical. Adults are more resistant, but 30% of children living in intimate contact with infective cases develop early lesions. In most of them, the lesions heal spontaneously. Chronic progressive disease develops only in about 8% cases. Majority of the patients initially present with the disease within the first three decades of life. In lepromatous leprosy, males are twice more commonly affected than women, but in tuberculoid leprosy such a predeliction is not noted. Irrespective of the virulence of the infecting organism, the clinicsl outcome is so varied, depending on the immune status of the individual which is the deciding factor in pathogenesis. Both cellular and humoral immune mechanisms operate. The cellular immunity is protective, whereas the humoral antibodies are not. Cell-mediated immunity (CMI) which develops against the lipid components of M. leprae determines the progress of the disease.

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3. Diseases Of The Myocardium II: Cardiomyopathy
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author avatar Fern Mc Costigan
23rd Mar 2014 (#)

Interesting post!

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author avatar Funom Makama
24th Mar 2014 (#)

Thanks a lot Fern

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