Causative organism and host response. International Leprosy Congress, Beijing, 7-12 September 1998. Workshop report.

Whether or not the leprosy elimination target is met in all endemic countries by the year 2000, the MDT programme will have greatly reduced worldwide prevalence. However, our workshop chairmen were asked to ignore the prevalence-based leprosy 'elimination' programme and focus on recommendations for a long term, incidence-based eradication target where transmission is blocked. They were asked to be concerned with basic leprosy research goals in the post 2000 era. The members of our workshops are actively productive workers, committed to their special interests. They are fully cognizant of the obstacles faced daily in working with leprosy and M. leprae, the requirement for clever experimental design even with the availability of the powerful tools of molecular biology which can now be brought to bear on some of the research obstacles. They are also aware of our lack of understanding about leprosy and M. leprae. How do you block transmission if you don't know how infection is transmitted? Can infection be detected, diagnosis made earlier? Is there a non-human reservoir host, a carrier state, an environmental source? What is the basis of M. leprae's predilection for nerves, the mechanisms underlying reactions? What needs to be targeted to treat reactions? Can a vaccine play a role? There is nothing startling in the workshops' recommendations. Other individuals and groups of experts have made the same suggestions, with slightly varying priorities. What one can read between the lines of these reports, is a sense of urgency to get as much done as soon as possible. Worldwide interest in leprosy will soon be diminished, not by design but as a consequence of the laudable success of the MDT programme. The experiment is still underway, but chemotherapy alone, killing bacilli in the detectable human host, does not appear to be the answer to blocking transmission. A number of goals must be addressed while there are still intact national and international leprosy programmes, while there are still leprosy treatment and research centres that can co-ordinate and facilitate the necessary trials for early diagnosis, early detection of reactions, evaluation of immunosuppressive regimens for reactions. A key recommendation is concerned with the means of measuring progress. A clear and explicit means of reporting incidence, prevalence and 'case detection' should be implemented to avoid a distorted picture of worldwide leprosy. These recommendations are non-controversial. What should be done is clear. The uncertainty is in determining who will do the work. Who will fund the laboratories engaged in this work? Look around you. There are fewer scientists attending this Congress but browsing the abstracts and attending our sessions and posters clearly revealed to me that fewer of us are doing far better work than in the past. Alternative sources of funding will help. Tuberculosis research is enticing researchers away from leprosy in the developed countries but is visibly sustaining leprosy research in many centres in developing countries. Formation of alliances was a key goal of this Congress. I asked my colleagues from Carville to identify in their own discipline, dedicated people, committed laboratories that will sustain their leprosy research efforts over the next 5, 10 or more years. These are the people with whom we wish to collaborate, form alliances, share resources and expertise, address the future of worldwide leprosy.