INTERNATIONAL. JOURNAL OF LEPROSY^ Volume 69, Number 2

Primed in the U.S.A.(ISSN 0148-910X)

INTERNATIONAL JOURNAL OF LEPROSYand Other Mycobacterial Diseases

OFFICIAL ORGAN OF THE INTERNATIONAL LEPROSY ASSOCIATION

EDITORIAL OFFICEGillis W. Long Hansen's Disease Center

at Louisiana State UniversityBaton Roug,e, Louisiana 70894, U.S.A.

Voi.uml: 69, NUM13ER 2^

JUNE 2001

EDITORIALEditorial (Onions expressed are those of the writers.

What Strategy Against Leprosy?*

The global plan for the elimination ofleprosy as a public health problem, initiatedin 1991, is at a turning point. By the end ofthe year 2000, several large leprosy-endemic countries had not reached the tar-get prevalence at the national level. Sincethis situation could be anticipated for sometime, during a meeting, convened by theWorld Health Organization (WI-10) at theend of 1999, the year 2005 was decided asthe new target year for the completion ofthe plan. This situation raises questionsabout the validity of the plan itself and, as acorollary, about the actions to be taken overthe next 5 years. In broad terms. this pre-sentation attempts to give some answers tothese questions.

THE ELIMINATION I'LANStarting with the implementation of mul-

tidrug therapy (MDT) in 1982 and followedby the World Health Assembly resolution in1991, the global effort for the "Eliminationof Leprosy as a Public Health Problem . " has

Paper presented at the Asian Leprosy Congress,Agra, India. 9- 13 November 2( 5 )1).

resulted in about 10 million patients beingcured. Such an impact is in itself a strongjustification for having initiated the elimi-nation program.

It has not been possible so far to demon-strate the validity of the fundamental princi-ple on which the elimination plan wasbased at the beginning, i.e., that by reducingleprosy prevalence to less than I case per10,000 by means of making MDT availablefree of charge to all patients, the transmis-sion of Mycobacterium leprae would he re-duced to such an extent that thereafter theprevalence would continue to decreasewithout additional intervention.

Since there are no primary preventiontools available yet of generally acceptedvalue, the MDT strategy remains the onlymethod for controlling leprosy. Experiencehas shown a) the tremendous impact thatthe MDT strategy has had and b) that it isboth feasible under a variety of situationsand affordable, thanks to the current levelof support. Moreover, since it was not pos-sible to complete the elimination programby 31 December 2000, it was fully justifi-able to extend it for a further 5 years, i.e.,until 2005.

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Editorial^ 109

It can be said that the central objective ofthe elimination strategy is to make MDTdrugs available free of charge to all existingleprosy patients. To meet that objective, theelimination strategy has been subjected to anumber of improvements and specific adap-tations to overcome a variety of problemsand difficulties.

THE PROBLEMSThe implementation of the elimination

strategy does not raise difficult problems ofa technical nature:

• MDT regimens are very effective, welltolerated and do not result in the selectionof M. leprae strains resistant to antibi-otics.

• In recent years, the efficacy of severalnew antibiotics and combinations ofthem against Al. leprae have been estab-lished so that alternative regimens are ei-ther already in use or could be put intopractice should the need arise.

• Although sonic problems related to diag-nosis and classification of leprosy resultfrom the characteristics of the disease—which is polymorphous and has an insid-ious onset—it has been possible, at leastpartially, to obviate these difficulties.

Contrary to the technical ones, however,there are many operational problems relatedto the implementation of the eliminationstrategy. These problems tend to be moreand more serious when elimination activi-ties move to areas not yet covered, which isnow generally the case. Of special impor-tance are the problems related to adequateMDT coverage, integration of services, andinformation and education of the groupsconcerned.

Adequate MDT coverage should includethe ability to: a) identify all leprosy cases atan early stage; b) start treatment with MDT;c) deliver the necessary drugs regularly;and d) monitor these activities continuouslyin a given country. The establishment of ad-equate coverage in all endemic areas ismade more difficult by the fact that it is. ingeneral, necessary to implement—simulta-neously and rapidly the integration of lep-rosy services into the general health ser-vices. Informing, educating and motivatingcommunities, patients and health personnel

are crucial for the optimal detection/identi-fication of leprosy cases.

These two series of problems—adequatecoverage and information/education—areamong the most difficult to solve since theyare intimately linked with the cultural andsocioeconomic patterns of the communitiesand groups concerned. It seems that the re-quired changes could be better accom-plished over rather longer periods of time,probably more than the 5- or 10-year inter-vals that planners usually contemplate.

The necessity of integration is, how-ever, being recognized. For example, in In-dia, a country which for decades has had anindependent National Leprosy Control Pro-gramme, leprosy services have been re-cently integrated into the general health ser-vices in several states.

Concerning the information/education/motivation of the various groups, experi-ence with Leprosy Elimination Campaigns(LECs) has shown that education programsof a very short duration ( 1-2 days) can leadto the identification of many leprosy cases.The evaluation of a number of LECs hasalso demonstrated that a proportion of pa-tients (from 10% to 2 5 % ) remains unde-tected even following that activity. One canstill hope, however, that the improvementin antileprosy services resulting from theirintegration with the general health serviceswill significantly improve the level of casedetection.

There are other operational problemssuch as those related to hidden prevalence,regular drug supply, prevention of disabili-ties, training of general health staff, etc. Allof these problems are being addressed byWHO and its partners. Specific options orinitiatives have been undertaken in order toovercome the difficulties presented byLECs, NLECs, SAPELs and other initia-tives. It has generally been recognized thatthe elimination plan should now focus onthe peripheral—or district—level.

Our poor understanding of the transmis-sion of leprosy makes it very difficult tomake accurate projections of' changes inleprosy prevalence at various levels of lep-rosy programs. As a result, in any given epi-demiological and operational context it ishard to predict exactly when the eliminationtarget will he reached. It seems reasonableto assume that the elimination target will be

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International Journal of Leprosy^ 2001

reached at the national level in all countriesby the year 2005. There are serious doubts,however, about the possibility of reachingelimination at the subnational level in sev-eral countries by that date.

At the national level there is a risk thatpolitical problems could also be anticipatedand that the commitment of politicians, ad-ministrators and financial donors could de-crease with time, especially if the numberof leprosy cases decreases sharply as a re-sult of the elimination program, althoughthere is no indication that motivationamong decision-makers has relaxed so far.

Some particular circumstances—disas-ters, natural or otherwise, including civilunrest, warfare, famine and displaced popu-lations—will also delay implementation ofthe elimination plan, at both the nationaland the subnational level, but these situa-tions obviously cannot he overcome by thehealth authorities alone.

At the international level, from 1991 to1999 the implementation of the eliminationplan raised minor conflicts of interest be-tween the various partners involved. Fromnow on, however, the elimination plan willbe implemented under the umbrella of theGlobal Alliance for Elimination of Leprosy.This Global Alliance, which includes somenew partners, was launched in 1999 in acontext of crisis when it was realized thatthe elimination target could not be met bythe year 2000. Since some of the variouspartners in the Alliance have different prior-ities, collaboration will still require furtherstrengthening if its objectives are to beachieved.

WHAT SHOULD BE DONE?

To extend the elimination plan to theyear 2005 was the correct decision. It isnow necessary, however, to proceed withthe following activities:

• To vigorously develop and improve,where necessary, all activities included inthe elimination plan at the national andsubnational levels, as described in TheFinal Push towards Elimination of Lep-rosy: Strategic Plan 2000-2005 (WHO/CDS/CPE/CEE/2000. I ).

• To continuously assess the validity of re-sults of elimination activities and, wherenecessary, to undertake the relevant ac-

lions to correct them. In-depth epidemio-logical and operational evaluations incountries/areas where the elimination tar-get has been reached would also provideinvaluable information.

• To investigate, through operational re-search. all improvements that could beintroduced into ongoing programs and toimplement them as early as possible.

• To vigorously stimulate both basic andapplied research on leprosy in order to de-velop new tools which will be neededwhen the elimination strategy has reachedits objectives—or revealed its limits.a) Recent investigations have opened

some new concepts on the transmis-sion of M. /eprae: the possibility hasbeen raised that healthy carriers play arole in the dissemination of the organ-ism. It is very important therefore tocontinue these investigations untilclear conclusions are reached.

NOther investigations are aimed at de-veloping a test to identify subclinicalinfection during the incubation period.Such a test would he extremely usefulsince it would permit individuals to re-ceive a bactericidal "preventive- treat-ment before they become infectious.

c)The sequencing of the M. Iepraegenome, now complete, opens new andpromising avenues in many disci-plines. These new opportunities shouldbe actively exploited without delay.

The scientific community appears to beready for a "new beginning - in leprosy re-search but coordination of efforts requiresstreamlining in order to achieve maximumresults.

CONCLUSIONS

• At present, the elimination strategy is theonly effective one and therefore remainsthe best strategy for controlling leprosy.

• It is quite gratifying to see that, based onexperience gleaned during the last de-cade, the elimination strategy is feasibleby implementing activities which appearto he acceptable to the partners involvedin the plan (now the Global Alliance forthe Elimination of Leprosy).

• It appears quite feasible that by the year2005 the elimination prevalence at the na-tional level in all endemic countries will

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he reached. In sonic countries, however,the elimination prevalence at the suhna-tional level will not be reached by 2005.

• All efforts to make MDT available free ofcharge to all leprosy patients should hesustained vigorously during the forth-coming years.

• Leprosy research—both basic and ap-plied—should be stimulated.

• Leprosy research requires substantial ef-forts for planning, organization, manage-ment. funding and coordination.

• The implementation of the eliminationstrategy under the auspices of the GlobalAlliance for Elimination of Leprosy re-

quires strengthened collaboration be-tween its various partners.

Dr. Hubert Sansarricq

64160 Saint-Armou, France

—Dr. Denis Daumerie

Leprosy GroupStrategy Development and ivIonitoring

for Eradication and EliminationDepartment of Control, Prevention

and EradicationWorld Health ()rkanizationGenera. Switzerland

Prevalence: a Valid Indicator for MonitoringLeprosy "Elimination"?

In 1991, the World Health Assemblystated that leprosy should he eliminated as apublic health problem by the year 2000(Resolution WHA4-1.9). Elimination wasthen defined as a prevalence rate below Icase per 10,000 inhabitants. Prevalence waschosen rather than case detection becausethe latter was considered as depending toomuch on operational factors. The assump-tion underlying the objective was that, sinceleprosy is an infectious disease directlytransmitted from the patients to the healthypopulation, a reduction of the prevalenceand. thus. of the reservoir would result in areduced transmission of the leprosy bacilli.This would lead, after a number of years. toa decreased incidence of the disease. Sinceelimination was defined in terms of preva-lence, it seemed only logical to use that in-dicator to monitor the achievements of thestrategy. And indeed it was useful. Withmultidrug therapy (MDT), patients could hedeclared cured after a treatment of definedduration: this. accompanied by a systematicreview and cleaning of the leprosy regis-ters, resulted in a dramatic reduction in theregistered prevalence. From more than fivemillion cases registered in 1985, statisticshave L,one down to less than 800,000 cases

in the year 2001. 1 This is undoubtedly agreat achievement: clinics are not congestedany more by large numbers of patients whono longer need any chemotherapy, andhealth workers can better concentrate on themore important issues of detecting andtreating the new cases and on preventingthe occurrence of disabilities.

In spite of its past usefulness, the preva-lence indicator clearly shows its limits now:

• After a dramatic decline. the decrease ofprevalence has been slow for the last 5years.

• Case detection did not decrease as ex-pected: It has indeed increased during thelast 4 years, even if a small decline hasbeen observed in the year 2000. The up-ward trends and the variations observedin the number of newly detected casescan easily be explained by a number ofoperational factors, such as the extensionof geographical coverage by MDT ser-vices and the intensification of detectionactivities through leprosy eliminationcampaigns (LECs) and other special ac-

' W'orld Health Oiltani/ation. Leprosy—y[01)a! situ-ation. Wkly. Hpidentiol. Rec. 7512000) 226-231.