Progress towards the elimination of leprosy in Nigeria: a review of the role of policy implementation and operational factors

The annual reports of the national leprosy control programme in Nigeria were reviewed to study the trends of the indices of leprosy control from 1992 to 2003 and determine the influence of operational and policy factors. By 2003, both national prevalence and case detection rates had reached below 0.5 per 10,000. Sub-nationally, all except three contiguous States in the Southeast, had prevalence rates below one case per 10,000. Over the 12 years, the prevalence rate decreased by 94.1%, from 7.14 to 0.42 per 10,000, with two periods of rapid decline: 1992-1994 and 1998. Remarkable surges of discharges from multi-drug therapy (MDT) occurred in these same periods. The period 1992-1994 corresponds to the years of introduction of MDT, case reviews, and clean-up of leprosy registers nationwide, while 1998 corresponds to the year the programme adopted the shortened 12-month MDT regime for multibacillary (MB) leprosy. The overall trend of case detection since 1992 was relatively stable, but had three significant periods of initial increase (1992-1994), stability (1994-1999) and recent decline (1999-2003), apparently related to the changing levels of activeness of the national programme. The pattern of new cases detected revealed increasing MB classification and lower disability, but a relatively stable child rate since 1992. The trend of MB proportion was also related to the years of MDT introduction and the adoption of a new leprosy case definition and classification policies. Thus, Nigeria has attained a low leprosy endemic status mainly through operational and policy influences. The challenges that remain include reducing the relatively high leprosy burden in the Southeastern States and evolving effective case detection interventions that will make an observable impact on the incidence of leprosy.