Leprosy

Kristopher Brevard1

What is leprosy?

• Ancient disease

• Causes skin sores, nerve damage and muscle weakness

• Worsens with time

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What causes leprosy?

• Mycobacterium leprae

• Not very contagious

• Spread through prolonged close contact.

• Long incubation period

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Prevalence of leprosy• About 41,780 new cases

in The United States in 2005

• Typically in the south, California, Hawaii, and U.S islands

• About 201,635 New Cases in Southeast Asia in 2005

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Mycobacterium leprae

• Causes leprosy

• Found in warm tropical countries

• Pleomorphic

• Acid-fast

• Can take up to 13 days for one replication cycle

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How does it get in?

• Binds to macrophages, and Schwann cells

• Phagocytosis

• Creates electron transparent zone

• Protects against phagolysosome

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Evasion !

• Replicates exclusively inside macrophages and Schwann cells

• Most phagocytes and APCs don't encounter pathogen

• Up regulated Mcl-1

• Down regulates Bak and Bad

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Evasion part 2

• NK cells and neutrophils are important in activating more immune response

• TH2 response not effective

• Bacteria is allowed to continue to replicate

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What are the symptoms?

• Skin lesions (lighter than normal skin)

• Decreased sensation to touch, heat or pain

• Muscle weakness

• Numbness

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Forms of leprosy

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•Tuberculoid• Less severe• Skin lesions• Asymmetrically

distributed

•Lepromatous • Pale macules • Failure of Th1 cell

activation.• More severe• Large lumps and

nodules

Diagnosis

• Lepromin skin test

• Skin lesion biopsy

• Skin scraping examination

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Treatments and Prevention

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• Multi drug therapy

• Rifampicin, Dapasone, Clofazimine

• Prevention is achieved by avoiding physical contact with untreated people

References

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• Sehgal, Virendra N., Kabir Sardana, and Sunil Dogra. "The Imperatives Of Leprosy

Treatment In The Pre- And Post-Global Leprosy Elimination Era: Appraisal Of

Changing The Scenario To Current Status." Journal Of Dermatological Treatment

19.2 (2008): 82-91. Academic Search Complete. Web. 28 Mar. 2012.Barker, L.

2006. Mycobacterium leprae interactions with the host cell: recent advances

(Review article). Indian J Med Res, 123: 748-59.

• “Leprosy Fact Sheet”. World Health Organization. October 2005. link

• “Hansen’s Disease: Leprosy”. Centers for Disease Control and Prevention: Division

of Bacterial and Mycotic Diseases. Dept. of Human Health and Services. October

2005. link

• Lavanya, M., Deena, V., Sujai, S., Balasubramanian, A., et al. 2001. Biochemical

aspects of mycobacterium leprae binding proteins: A review of their role in

pathogenesis. Int. J Leprosy and Other Mycobacterial Dis. Link

• Greer, Alex Mycobacterium Leprae. Davidson College, 2007. Web. 10 Mar. 2012

<http://www.bio.davidson.edu/people/sosarafova/Assets/Bio307/algreer/

evasion.html>.