Leprosy incidence

Interest in the nontuberculous (atypical) mycobacteria, especially members of the Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium scro-fulaceum complex, has also been stimulated by AIDS. Infection with the M. avium complex is seen in up to 50% of patients with AIDS in some areas of the world.3 A review of U.S. cases found an overall 5.5% incidence of M. avium complex in AIDS patients.3 Leprosy, however, is clearly on the wane, although it remains a substantial problem.4 Its prevalence has been steadily diminished to a present-day worldwide figure of about 3 million registered cases and 5.5 million estimated cases, owing in part to a most effective multiple-drug regimen. The World Health Assembly has dedicated itself to the technical elimination of leprosy (that is, a prevalence of less than 1 per 10,000 population) by the turn of the century. 

Clearly, serology based on the PGL-I-related NGCs has a place in the control of leprosy, although it does not meet pressing needs in terms of measuring incidence and reservoirs of infection, chains of disease transmission, and early diagnosis. 

Richardus JH, Smith TC. Increased incidence in leprosy of hypersensitivity reactions to dapsone after introduction of multidrug therapy. Lepr Rev 1989 60(4) 267-73. 

When thionamides are used in combination with rifam-picin, hepatotoxicity is more common and severe (18,19). There was a 13% incidence of hepatotoxicity in patients with multibaciUary leprosy treated with dap-sone, rifampicin, and protionamide 10 mg/kg/day, and a 17% incidence in 110 patients treated with dapsone, rifampicin, and protionamide 5 mg/kg/day however, although the lower dose of protionamide did not reduce the incidence of hepatotoxicity, it did reduce its severity (20). Protionamide does not affect the pharmacokinetics of rifampicin (21). 

In patients with leprosy, HIV infection, and multiple myeloma, the incidences of somnolence, fatigue, and weakness were 36-43%, 48%, and 6-22% respectively (21). Administration of thalidomide at bedtime minimizes appreciation of the drowsiness that it produces, and daytime drowsiness usually abates over several weeks. 

The incidence of peripheral neuropathy, with sjmmetrical painful paresthesia of the hands and feet often accompanied by sensory loss in the legs, seems to vary with the condition that is being treated, and ranges from under 1% in patients with leprosy to over 70% in patients with prurigo nodularis (41,52). The symptoms do not correlate with either the duration of treatment or the dose. Women and elderly people seem to have an increased risk of neuropathy (53). 

Protection from mbercnlosis is characterized by effective Mycobacterium-specific Thl responses and it has been hypothesized that co-infections with helminths will prevent the necessary Thl response by either disturbing the Thl/Th2 balance, or by driving the immune response towards a more anti-inflammatory status. Early observations showed that the incidence of lepromatous leprosy was twice as high in areas where onchocerciasis was endemic (Prost et al. 1979). 

The worldwide incidence of leprosy (Hansen s disease) has plummeted by nearly 90% to -534,000. The cornerstone of this global elimination strategy is the provision of effective multidrug chemotherapy, namely dapsone, rifampin, and clofazimine (Table 47-1), to all leprosy patients in the world. The success of the strategy is evident by the end of 2003, over half of the countries considered endemic for leprosy in 1985 had achieved disease elimination (i.e., a prevalence rate of <1 case per 10,000 inhabitants). 

Sheen YS, Chu CY, Wang SH, Tsai TF. Dapsone hypersensitivity syndrome in non-leprosy patients a retrospective study of its incidence in a tertiary referral center in Taiwan. J Dermatolog Treat 2009 20 (6) 340-3. 

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