562^ International Journal o/ Leprosy^ 1998

TAKING HOME LESSONS FROM THE15TH INTERNATIONAL LEPROSY CONGRESS

Prof. Michel F. Lechat

For the last 5 years, lince the I4th Con-gress in Orlando, work on leprosy has beendominated by the continuation of what Iwou Id cal1 the Great Chemotherapeutic Ini-tiative, multiple drug therapy (MDT), in thecontext of the 1991 Resolution of the WorldHealth Assembly on the "elimination ofleprosy as a public health problem."

The rationale underlying this approach isthat the clinicai patient is the only reservoirof Mycobacterium leprae and the onlysource of infection for secondary cases.Therefore, by effectively treating these pa-tients, transmission should be gradually re-duced and ultimately interrupted. Incidenceshould thus, in the long term, be reduced tozero. MDT, as recommended by a WHOStudy Group in 1981, has prover to be aneffective treatment, with the major advan-tage that it prevents the emergence of drug-resistant strains of the bacillus. It shouldtherefore be asked to do the job.

This strategy was made possible by theconfluence of several orders of opportunity:not only the scientific opportunity (the nat-ural history of the disease at the presentstate of knowledge), but also technological(MDT and the blister pack), political (com-mitment of the governments) and financial(support from a number of NGOs) opportu-nities.

Under the leadership of WHO, full usehas been made of this unique window ofopportunity. Objectives were defined interras of targets (prevalence) and time-frames. Guidelines were developed. Effi-cient systems for the analysis of epidemio-logical trends and the monitoring of drugdistribution were set isto place. Imaginativeand innovative approaches were devised inorder to reinforce or supplement currentleprosy control activities centered on MDT,such as the Leprosy Elimination Campaigns(LEC) and the Special Action Projects(SAPEL).

As made clear at the Congress, the elim-ination program as defined has proven

highly successful. Prevalence of registeredcases has been considerably reduced world-wide, the elimination threshold of 1 per10,000 population lias already been at-tained in many countries. In a number ofcountries, however, including large ones,some leadtime should be given after thedeadline of the year 2000 to allow for thefali implementation of the program.

The ongoing elimination program alsohas an important added value: It helps de-veloping capacity building and managerialskills at the country levei, as shown througha large number of reports from national lep-rosy programs. It is also stirring communityparticipation. It promotes a culture of part-nership between ali these parties concerned,that is, national governments, internationalorganizations, nongovernmental organiza-tions, as wel 1 as the constituency of the per-sons affected by the disease, referred to to-day as the stakeholders. In addition, for alarge part due to the success of MDT, thestigmatization of the persons affected withleprosy has considerably diminished. Theseencouraging signs would have been un-thinkable even 20 years ago.

In many countries, however, as reportedat the Congress, in spite of the dramatic faliin prevalence, the number of newly de-tected cases reported each year does notshow a marked decline. A number of oper-ational reasons could be invoked to explainthis apparent epidemioiogical paradox. Alithe same, it suggests that transmissionmight possibiy be maintained at a leveihig,her than expected. Could it be that theuntreated or relapsing clinicai patients donot constitute the sole source of transmis-sion of the disease? To what extent couldpeople with subclinical infection serve as asource of transmission? Would an extra-hu-man reservoir of M. leprae exist and, in thatcase, what, where, and how does it operate?

These are questions that have resistedelucidation for ages. They neverthelesshave inmportant implications. Will transmis-

66, 4^Transactions of the Fifteerntlr I nternational Leprosv Congress^563

sion be maintained in some countries at alow levei with no pope for further progress,at least for a while? Should we learn to livewith leprosy as a rare disease, and concen-trate ou the prevention of disability in orderto render it, in a way of speaking, "but aminimal skin inconvenience"? Should webe worried that, if large-scale MDT isstopped, incidence will resume? If so, whatother strategy should already be envisagedand worked out to counteract this possiblebacklash?

It is too early to say. The next 5 yearswill provide a crucial test to vindicate thebasic assumptions regarding transmission.Nevertheless, it is not too early to preparefor unpleasant surprises, however unlikelythey may seem.

New investigative tools are being devel-oped which may help to solve these issues.By comparing the gene sequences of M.lepras and M. tuberculosis, synthetic pep-tide skin tests can be designed that wouldidentify individuais infected with or ex-posed to M. leprae. Actual proteins andproducts of genes have also been obtainedfrom armadillos and tested for their im-munogenicity. The prevalence of PGL-I an-tibodies has been correlated with the preva-lence of clinicai cases in endemic arcas.Regarding the possible existence of an ex-tra-human reservoir, using the polymerasechain reaction (PCR), DNA of M. lepraehas been found in the water supply of ruralcommunities that have a high prevalence ofleprosy.

PCR is opening the door to the study ofthe epidemiology of leprosy infection. Hy-potheses regarding an animal and/or envi-ronmental reservoir are becoming testable.In a large international cooperative researchproject conducted in a number of endemiccountries, PCR is used to study the preva-lence of subclinical infection, the risks as-sociated with exposure to positive PCRindividuais, the infection rates, the cell-me-diated immunity in the nasal mucosa, andthe role of the nose as the primary site andportal of entry for the bacillus. A pattern forthe pathogenesis of early leprosy infectionstarts to emerge.

Although it may at times look as thoughnew technologies are utilized to revisit oldideas, much can be expected from thesestudies in the years to come, and could have

significant implications to face possible set-backs and make room for the need to adjustthe post-elimination control measures.

As a parenthesis, though this is perhapsnot the right piace, a word should be said onthe importance of the M. leprae genome se-quencing project, now Glose to its comple-tion. It will in some way substitute for thislong sought for and never attained goal ofits cultivation in Nitro. A number of epi-demiologic as well as more fundamental re-search undreamed of until recently will be-come possible. Matches and mismatchesbetween the genetic sequences of M. lepraeand M. tuberculosis will olfer new insightsinto the respective distastes or gustos ofthese microorganisms, as well as help in de-signing drugs, especially targeted for spe-cific metabolic pathways. It could also leadto the engineering of a synthetic vaccine.

It is amazing to think that, while for along time attempts were made, often withlittle success, to combine the field activitiesagainst leprosy and tuberculosis, the twobacilli will now be companions in the labo-ratory together with a panoply of othermycobacteria.

Having considered these current worries,and turning resolutely to the future, what isto be done?

It is obvious that a prevalence of 1 per10,000 as the target of elimination, and theyear 2000 as the deadline, are not goals perse. They are nothing but milestones on theway to having the "final word" against lep-rosy. I deliberately use the terra "finalword," because it is vague enough and pre-cludes a firm defìnition. According to theepidemiological context of each countryand its sociocconomic conditions, the aimcould be to make leprosy a rare disease, ul-tinritely eradicating it.

It should be clear for everybody thatelimination programs should be continuedafter the year 2000 to achieve what shouldhave been achieved by then. Conversely, itwould be absurd to wait for the millenniumto initiate, develop or expand needed activ-ities not directly related to the program.

The question is: can we go along withthe same objectives, the same strategy, thesame methods, once the prevalence goals ofelimination have been achieved. The an-swer, 1 think, is clearly "No." The programof elimination of leprosy as a public health

564^ Internntionul Journal of Lepros.v^ 1998

problem was and still is linked to thetremendous opportunity offered by chemo-therapy, which has allowed us to strive afull-fledged b1ow, knocking out M. leprueinside the human reservoir. But there ismore to leprosy than MDT, and more to thefight against leprosy than mere decimal dig-its. The next patients below 1 per 10,000and ali those that follow will still be pa-tients in need of treatment. After popula-tions have been effìciently dealt with, theindividuais are still there.

This being said, what has definitelyemerged from the Congress is a strong con-sensus that the future will be different. Newchallenges will need new approaches.

What will be different?A preliminary remark to start with.

Changes will not be achieved overnight. Itwill be a long process requiring patience,flexibility and determination. The key com-ponents as summarized by the Coneress readas follows: a comprehensive patient-orientedapproach, relevance to those affected, part-nership, sustainability, and training.

What will be different though?First, to the extent that the elimination

program is successfully completed, andthere is every chance that it will be, the epi-demiological situation will show differentpatterns than at present.

Second, the political commitment islikely to evaporate as the elimination pro-gram becomes increasingly successful.

Third, the general evolution of society,together with reforms in the health sector,will bring with it threats as well as opportu-nities.

Let us start first with the changed epi-demiological context. In low-endemic situ-ations, that is, where the disease is becom-ing rire, patients will become harder tofind. They could also show up at a laterstage, with an increased risk to present im-pairment of some sort.

The activities will have to focus on sus-tained detection and early case finding. Thesurveillance of cured cases will become ofmajor importance. With leprosy being insome way now defined as, and classifìed ac-cording to, "eligibility for a treatment offixed duration," there has been some ten-dency toward complacency, i.e., a tendencyto overlook follow up after completion oftherapy. At times it looks as though patients

are not supposed to relapse. There is, how-ever, a set of post-treatment complications,such as neuritis, eye lesions, problems asso-ciated with sensory loss and deformities, re-actions, which need to be watched closelyfor several years after treatment has beenstopped. Such surveillance is particularlyimportant in view of the recently introducedshortening of MDT in multibacillary pa-tients, possibly bringing with it an in-creased risk of relapse. This is one morereason for reinforcing surveillance, becausethe occurrence of small outbreaks or clus-ters of secondary cases cannot be excluded.

It should be kept in mind that low en-demicity, however it is defined, refers totwo contrasting situations: "natural low en-demicity" on the one hand, in those arcaswhere leprosy has been tailing off for manydecades, and "induced low endemicity," en-gineered by the great chemotherapeutic ini-tiative, on the other. One of the basic postu-lates of the MDT elimination program hasbeen that by reaching low leveis of preva-lence, the transmission of the disease willautomatically plug roto the natural low en-demicity dynamics, rendering further sur-veillance somewhat redundant. Such an as-sumption should now be revised in view ofthe persistence of relatively high detectionrates. Incidentally, reports on the trends ofleprosy in those arcas where it has been onthe way of disappearing for a long period oftime are particularly valuable to test the va-lidity of this postulate.

Secondly, priorities. There are so manyhealth issues requiring attention and com-peting for resources that it would be naiveto expect political commitment to be main-tained at the present levei while leprosywould have vanished as a public healthprobiem. There are such things as challengefatigue.

Many issues will still be facing the dis-case orce elimination as a public healthprobiem has been achieved. One should,therefore, strive to keep leprosy on theagenda even if, as one participant put it, nolonger with capital letters. Just as high pri-ority does not mear exclusivity, reducedpriority should not be taken as absence ofpriority.

Among the issues for the future, nodoubt the most important is the disabiementleprosy causes among a large proportion of

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the affected persons. Leprosy is said to beone of the four main causes of disability inthe Third World. Statistics presented at theCongress were eloquent in this respect. Ithas even been proposed that early detectionbe defined as "detecting a case of leprosybefore disability sets in."

As the number of patients detected low-ers, the proportion of disabled among themcould increase. There is a danger thatstigtnatization and exclusion would againset in, as is already suspected in some coun-tries. Good programs for the prevention andmanagement of disabilities should help inconvincing governments and funding agen-cies that leprosy still constitutes a problemdeserving careful attention.

Finally, leprosy activities in the years tocome will likely have to be carried out in acontext of accelerating reforms of thehealth sector, including increasing privat-ization of services.

In low-endemic situations, vertical pro-grams are no longer effective or justilied.There will be a need to dismantle verticalleprosy programs and shift to a policy ofsuspicion at the periphery, and referral tospecialized leveis for diagnosis and themanagement of complications. Detectionand referral will have to be integrated rotogeneral health services, which supposestraining and the capacitating of healthworkers. Private practitioners, and espe-cially dermatologists, as well as the tradi-tional sector whenever appropriate, shouldalso be involved in referring suspect cases.Public awareness of the disease should bepromoted. Self-help groups can be veryuseful in this respect. The importance of ed-ucating patients and families in recognizingthe early symptoms of the disease cannot beoveremphasized. In addition, quality of carewill be essential to enhance the credibilityof the program and to sustain the collabora-tion of the patients.

Thus, apart from surveillance for earlydetection and follow up, activities will haveto concentrate on the prevention and man-agement of deformities and disablement.There is an ongoing debate on the respec-tive importance of cure and care. Worldthere be care or cure? Cure after cure? Orwould no more care be needed after cure'?While it is true that the best way of prevent-ing disabilities remains early diagnosis plus

MDT, the untreated patients of today arethe mutilated ones of tomorrow, yet a largenumber of individuais survive and newones will appear who are or will be victimsof late detection or inappropriate treatmentin the past. There is, therefore, no conflictbetween cure and care. One or the othermay take precedence according to needs,resources and opportunities.

As mentioned by the participants, the so-cial and economic integration of persons af-fected by leprosy is an important means forpromoting human dignity, reducing stigma,increasing economic independence and effi-ciently using community resources. Thismust be a priority of leprosy programsalong with cure and prevention of disabili-ties.

I was personally impressed by one con-cern that persisted alI through the discus-sions: that people with impairments are notnecessarily in need of rehabilitation. This isimportant. Concerned individuais are theonly ones who should judge their degree ofautonomy, self-dependence, and aspirationsaccording to their own concepts of what is asatisfying life. Rehabilitation should neverbecome a goal per se, no more than preva-lence, institutional program, or even theleprosy image itself should.

It remains that life in ali its fullness, thatis, the integration and empowerment of per-sons affected by leprosy, goes through theprevention of disabilities, and the preven-tion of disabilities goes through research.Research on the pathogenesis of nerve le-sions and the mechanisms of protective im-munitv for nerve damage should, therefore,be very high on the agenda of priorities. Itwas orce said that eliminating leprosy as apublic health problem will possibiy beachieved before the epidemioiogy of itstransmission is elucidated. I think that iscorrect. By contrast, large-scale preventionof deformities will certainly not beachieved as long as so little is known abouttheir mechanism.

There is a great shortage of knowledgeregarding the actual size of the disabilityproblem in leprosy, its trends, its age andsex distribution, and its associated risk fac-tors. A large cohort study is being carriedout in Bangladesh, the results of which areexpected to be the determinant for the pian-ning of prevention and management of de-

566^ Intcrnationul Journul of Leprosv^ 1998

formities. New insights are also opened bya molecular approach to cha acterizing theinteraction between M. leprnc and the pe-ripheral nerves, which could throw light ona variety of questions, such as why does thebacillus target lhe nerve and how does it in-vade the Schwann cell, how often are thenerves infected at the latent stage or do theyshelter bacilli responsible for later relapses.Such research could ultimalely lead to moreeffective prevention in the future.

The relationship between lhe most ah-struse pathological phenomenon and thedaily life of persons affected by leprosy waswell stated by one of the speakers: "If Mv-cobacteriunr leprae is denied entry to the

nerves, and effective chemotherapy kills thebacteria harbored in other sites, then thestign uitizing cfeformities associated withnerve clamages in leprosy could be elimi-nated. ,,

That would be elimination at its best.Facing the new challenges, meeting the

needs for change, grasping the opportuni-lies, all require a spirit of partnership. Atthe Congress, it was referred to as an al-liance of all parties concerned.

In Chis respect, the full participation ofpersons affected with leprosy at chis 15thCongress refìects a major change of per-spective as well as a message of encourage-ment for all of us.

CONCLUDING REMARKSDr. S. K. Noordeen

It is a great pleasure for me to be able tospeak at chis concluding session and to ex-press my deep appreciation for lhe success-ful conclusion of the Congress. 1 would alsolike to take this opportunity to express myadmiration for the excellent organization ofthe Congress by our Chinese hosts. In everyway this Congress is an important landmarkin our light against leprosy. The theme ofthe Congress, namely, "Working Toward aWorld Without Leprosy," itself exemplifieswhat we are aiming at, and the presenta-tions and discussions at the Congress havebeen able to give us an insight finto theprogress we are making toward our goal.

The scientific contributions made at chisCongress reflected very well the develop-ments in the various fields of leprosy. Thestructure of the Congress sessions itself fa-cilitated excellent interaction between par-ticipants and opportunities for consensus

building. The participation of scientists,clinicians, field workers and others wasvery well balanced and so, too, was lhe par-ticipation of ',copie from difficult geo-graphic arcas. A particular mention shouldalso be made of the substancial participationof the leprosy-affected persons at chis Con-gress.

In light of the 100-year history of the In-ternational Leprosy Congresses, this Con-gress can easily be identified as one of thebest, particularly in rel a tiou to highlightingthe progress we are making in our lightagainst leprosy and in addressing the chal-lenges for the future. With regard to the fu-ture, what is most important for all of us isto recognize the important opportunity wehave to see a world free from leprosy. Thiscalls for further intensified and coordinatedefforts by all concerned so that we canreach our goal.