Leprosy elimination---a virtual phenomenon or a reality?

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Abstract
Controlling and treating leprosy Leprosy is a complex mycobacterial disease whose manifestations and complications are determined by the immune response. Many patients experience immune mediated nerve damage, which may occur before, during, or after treatment. Recent field based cohort studies have shown that at diagnosis many patients already have established nerve damage; rates vary from 20% in Bangladesh to 56% in Ethiopia, 3 4 and these patients have a worse prognosis for disability. Up to 30% of multibacillary patients have acute inflammatory episodes (reactions) affecting skin and nerves. Prednisolone is used to suppress reactions and ameliorates acute nerve damage in about 60% of patients.5 Anaesthesis and paresis in the hands and feet put them at risk of secondary damage from trauma and infection, which cause the highly visible deformities of leprosy (fig 1). The purpose of controlling leprosy is to reduce the rate and severity of disability. The key to effective management of leprosy is early diagnosis and treatment and early recognition and management of nerve damage, combined with effective health education. WHO clinical classification for field programmes1 Paucibacillary single lesion leprosy (one skin lesion) Paucibacillary (two to five skin lesions) Multibacillary (more than five skin lesions) Neurological assessment and slit skin smears do not contribute to this classification. What has the elimination campaign achieved? People and governments were mobilised, leprosy programmes were revitalised, and drug treatment for leprosy was provided free of cost by the Sasakawa Foundation through the World Health Organization. Imaginative programmes were devised, such as monthly drug delivery circuits by paramedical workers to supervise taking the monthly components of multidrug therapy. Morale among patients and workers improved. Eleven million patients have been given multidrug therapy. The number of registered patients fell from 5 million in 1985 to 0.7 million in 2001. But this fall was almost entirely attributable to a change of case definition that includes patients only during the course of multidrug therapy—that is, those with active infection.6 Patients with ongoing complications or disabilities due to the disease are excluded. In 2001 WHO claimed that leprosy had been eliminated “at a global level,” even though 719 330 new patients were registered in 2000 (fig 2).7 In the 27 top countries where leprosy is endemic, the incidence did not fall between 1985 and 1999, and in the six countries that account for 88% of new cases the numbers and incidence of new cases are rising (figs 3 and 4).9 Children comprise 15% of cases, indicating that active transmission continues. WHO has now rescheduled elimination for 2005. Integration of previous leprosy-only programmes into primary health care is the preferred model. Leprosy is not an easy disease to diagnose, and patients seen at peripheral clinics will go undiagnosed, thus apparently reducing the incidence of the disease further. View larger version: In this window In a new window Fig 1. Nerve impairment with secondary damage. The boy has bilateral ulnar and median nerve involvement affecting the hands, with small muscle wasting and finger clawing; he has lost temperature sensation and burnt his hands when standing by a fire View larger version: In this window In a new window Fig 2. Global prevalence of leprosy