Dr S.K. Noordeen, the architect of WHO's elimination strategy, looks at what has been achieved and the work that remains to be done.

　

In the history of public health there are not many achievements as gratifying as the elimination of leprosy. But while leprosy is a relatively small problem today in public health terms, it continues to pose important challenges in terms of physical and social rehabilitation.
　The idea that leprosy could be addressed from the public health perspective developed in the wake of the introduction of the first effective anti-leprosy drug, Dapsone, back in the 1950s. As leprosy patients were the only source of infection, it was quite conceivable that by treating all patients in the community, leprosy transmission in time could be arrested and thus leprosy controlled. However, the results with Dapsone were generally disappointing due to the slow cure effected by the drug and the development of drug resistance over a period of time.
　The 1970s saw renewed interest in leprosy control largely due to the identification of newer drugs such as Rifampicin and Clofazimine as highly effective in the treatment of leprosy. However, the way the drugs were administered to patients by different health workers varied widely. Therefore, it was only natural for WHO to embark on an initiative to develop a consensus on treatment of leprosy for control programs through the establishment of a study group on the subject.

　

　The WHO Study Group which met in 1981 had a judicious combination of microbiologists, chemotherapy experts, leprologists and leprosy control program managers. The recommendation on multidrug therapy (MDT) made by the group was the result of intense analysis of all available scientific evidence, on-the-ground realities of implementing public health programs and a strong desire to bring about a major impact on the leprosy situation in endemic countries ― even if this meant compromising on some less critical scientific requirements.
　The report of the WHO Study Group on Chemotherapy of Leprosy for Control Programs, which was published in 1982, is considered today as a historic document that enabled patients to receive standard, highly effective and acceptable treatment for their disease through MDT.
　The initial reaction of leprosy workers to the WHO-recommended MDT varied widely as it had introduced some revolutionary changes such as treating patients for finite periods of time and simplifying classification of the disease. However, the early results of MDT as observed in the field were so highly encouraging that the initial reservations and criticisms died out over a period time. MDT was accepted in all countries and programs, and leprosy workers everywhere received it with great enthusiasm, leading to renewed motivation to control the disease.

　

　

The phenomenal reduction in the prevalence of leprosy seen even within five years of the introduction of MDT resulted in further intensification of leprosy control activities everywhere. This led WHO to recognize there was a historic opportunity to aim at the elimination of leprosy as a public health problem with a deadline of the year 2000.
　WHO defined elimination as reducing prevalence of the disease to less than one case per 10,000 population. This is not to be confused with eradication of the disease ― aiming at reaching zero prevalence and zero transmission, which is not possible. The idea was that when leprosy prevalence reached a level below one case per 10,000 population, the disease would die out over a period of time, provided anti-leprosy measures, including MDT, continued to be available.
　It may be argued that the definition of leprosy elimination, the target figure of one in 10,000 and the deadline of the year 2000 were arbitrary, and not open to strict scientific “proof.” Nonetheless, the goal set by WHO enabled development of strong political commitment everywhere and effective and widespread leprosy control programs in all endemic countries.
　With regard to the deadline itself, the year 2000 was essentially an aspirational goal. When progress proved insufficient, the goal was moved to the year 2005. It may be necessary to push the goal back further in a very small number of countries.
　The progress so far indicates that leprosy prevalence globally has been reduced by over 94%. At the country level it is expected that all but five or six countries will have reached leprosy elimination by the end of 2005.
　However, while prevalence measures the current disease burden, it does not fully reflect the rate of occurrence of new cases. Globally, the reduction in new case detection is only 32%. This is mainly due to the nature of the disease: a good proportion of currently occurring new cases are probably due to infections acquired several years earlier, and even prior to the introduction of MDT. Therefore, reductions in new case detection will be relatively slower, but the declining trend is clearly visible in most parts of the world.

　

　

Leprosy programs in most countries today are facing the problems associated with their success. With steep reductions in the disease burden, the question that governments, the NGO community, leprosy workers and donor agencies must now address is how to formulate a suitable and viable strategy to deal with residual leprosy, which will be a relatively small health problem.
　For any disease, fulfilling the needs of a very small number of patients will always be a challenge unless health care systems are very well developed and have a good referral network. Where leprosy is concerned, the enormous amount of capacity-building undertaken in the past to deal with the disease is not going to disappear overnight, so in one form or the other this is likely to benefit patients at least for the next five to ten years. At the same time, the strongly committed constituency of leprosy interest groups that exists has an important role to play in ensuring that the essential needs of leprosy patients are not ignored.
　On the question of sustainability of leprosy services, there is a general consensus that only through integrated services will sustainability be possible. That said, it is important to define what services will be provided and at which level.
　Sustainability will to a large extent depend upon two factors: first, capacity-building at the peripheral level, and establishment of referral services at the appropriate level (which in turn requires networking); and second, appropriate infrastructure.
　Depending upon the country and the development of its health infrastructure, as well as the size of the remaining leprosy problem it faces, these services will have to be adjusted so that they not only meet the needs of the leprosy patients but also remain cost effective.

　

Another oft-mentioned issue is the importance of maintaining quality services in the post-elimination period. Here we face a dilemma in terms of accommodating quality services within integrated health services, where it would be unrealistic to expect leprosy patients to receive a superior quality of service to patients suffering from other health problems.
　If the leprosy interest groups want to maintain their strong support to leprosy sufferers, the only alternative is to build up a good referral network where, at least at that level, leprosy patients would receive quality services. However, accessibility to such referral services will remain problematic.
　Even as the number of patients needing medical attention diminishes steeply, the issue of disabled leprosy patients needing rehabilitation ― whether physical, social or economic ― will persist for several years. Currently, rehabilitation programs for persons suffering from other disabilities in most developing countries, whether institution-based or community-based, are quite limited and even rudimentary. It is difficult for such programs to accommodate the requirements of leprosy-affected persons in the near future. As such, special initiatives for them will remain important for now.
　To sum up, elimination of leprosy as a public health problem has been quite a success story, notwithstanding the need to deal with the small number of new cases that will continue to occur. In addition, rehabilitation issues will be in the forefront of leprosy activities in the future.
　Let us not hesitate to celebrate our success so far; at the same time, we must not ignore the remaining challenges.

　

AUTHOR:
Dr. S.K. Noordeen

From 1979 to 1984, Dr. Noordeen coordinated WHO's leprosy research program, which eventually led to the development of multidrug therapy. From 1984 to 1988, he led the WHO global program on leprosy, and spearheaded the drive to eliminate leprosy as a public health problem. He is currently chair of the WHO South- East Asia Region's Regional Technical Advisory Group for the Elimination of Leprosy.