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Structure
- Acid fast mycobacteria
- Obligate intracellular parasite, replicates in skin macrophages and shwann cells
- Slow grower: doubling time in 11-13 days
- Hgih mycolic acid content
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Epidemiology
- Spread unknown but likely from nasal secretions
- Traumatic innoculation also possible
- Humans are reservoir
- Incubation is years
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Pathogenesis
- Replicate in host cells
- Macrophages an schwann cells
- Few organisms in tuberloid lesions -> granulomatous
- lepramotous -> CMI inefficient
- Immunity: CMI mediated
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Manifestations
- Tuberculoid: development of macules/plaques on face, truck, and limbs with raised, erythematous edges; Invasion of nerves leads to anaesthesia; Indolent, slow progression; usually non-infectious
- Lepromatous: Anergy to lepromin, growth unimpeded; extensive, symmetric, and diffuse skin lesions, specifically on face; damage can be severe with loss of nasal bones and septum, and digits
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Diagnosis
- Acid fast stainings of scrapings of infected tissue
- Tuberculoid: clinical and histology
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Treatment
- Sulfones
- Rifampin and dapsone
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