Mycobacterium leprae
From IDWiki
Background
Microbiology
Epidemiology
- About 1 million cases worldwide each year, but is rare in North America
- Number may be underestimated due to difficulties with reliable diagnosis
- Most commonly occurs in Southeast Asia (especially India) and Brazil
- Decreasing incidence over the past several decades, likely due to short-course multidrug therapy starting in 1982
- Humans are thought to be the main reservoir, but it has been found in animals as well (particularly armadillos)
- Transmitted most likely by respiratory droplets, though can also be transmitted by direct contact, transplacentally, through breast milk, and after animal exposure
Risk Factors
- Age, with peaks in adolescence and ≥30 years
- Adult men (compared to adult women)
- Duration of contact with an infected patient, and the burden of bacilli in the patient
Pathophysiology
Clinical Presentation
- Incubation period of 3-5 years (with wide range)
- Classic presentation is anaesthetic hypopigmented skin lesion with thickened nerves
- Clinical spectrum from tuberculoid, paucibacillary disease to lepromatous, multibacillary disease
- Paucibacillary (PB) disease has 1 to 5 skin lesions, without bacilli on skin slit smear
- Multibacillary (MB) disease has more than 5 skin lesions, with or without nerve involvement or bacilli on slit-skin smear (regardless of number of lesions)
Management
| Disease | Treatment |
|---|---|
| Paucibacillary | 6 months of rifampin, dapsone, and clofazimine |
| Multibacillary | 12 months of rifampin, dapsone, and clofazimine |
| Rifampin resistance | 6 months of at least two second-line drugs with clofazimine, followed by 18 months of one second-line drug with clofazimine |
| Quinolone resistance | As for rifampin resistance, but without a fluoroquinolone |
