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September 1996 |
ELIMINATION OF LEPROSY IN THE AMERICAS
In 1990 the World Health Assembly adopted a Resolution to achieve the global elimination of leprosy as a public health problem by the year 2000, defining elimination as "the reduction of prevalence to a level below one case per 10,000 population." This target, therefore, does not signify the eradication of the disease or the interruption of transmission, but rather, a reduction in prevalence to very low levels in which the potential for transmission is considered very slight.
This Resolution is of enormous significance, however, considering that for many years leprosy was regarded as a disease that little could be done about, with very limited possibilities for action and little hope of its control.
This radical reversal of the strategy was made possible by the advent of multidrug therapy (MDT/WHO), an appropriate and robust treatment technology that has proven highly effective and feasible. The treatment scheme combines two or three drugs, depending on the clinical form of the disease, thus avoiding the development of resistant strains of M. leprae while eliminating the patient as the source of infection as soon as the first dose is administered. This treatment was recommended by the WHO Study Group on Chemotherapy of Leprosy for Control Programmes in 1981 and made it possible for the first time to state, with solid scientific backing, that leprosy is curable and that control activities can be managed and executed, like most communicable diseases, by the general health services.
One very important aspect is that leprosy ceased to be viewed as "a skin problem" and began to be considered a communicable disease. The strengthening of programs and increase in activities spurred by the advent of MDT, moreover, have prevented disabilities in more than 1 million patients through early diagnosis and timely treatment.
WHO took advantage of this technical and epidemiological opportunity to propose a concrete and feasible goal to the Member States, which the vast majority of endemic countries adopted, thus indicating the political will to tackle the problem. Activities to
combat leprosy have increased and intensified worldwide, and significant progress has been made toward that goal.
Five years ago, the situation in the Region of the Americas was similar to that of the rest of the world. Therefore, grounded
in the resolution of the World Health Assembly, the Hemispheric Conference on the Control of Leprosy was held in Mexico City in
1991, bringing together specialists from the countries with higher rates of endemicity. The Conference adopted the technical recommendations, obtaining a political commitment and defining the PAHO mandate to draft the Regional Plan of Elimination.
The central strategy of this Plan, which was launched in 1992, was mass application of the MDT/WHO treatment, associated with early detection of the disease. Its support strategy places emphasis on strengthening managerial capacity at the national and subnational level, through epidemiological and operational stratification, to ensure the preparation, execution, and evaluation of national and intermediate-level elimination plans and the supply of the specific drugs for MDT by WHO to all the countries that have requested it.
Once the countries' political commitment to the goal of elimination was obtained and a continuous supply of drugs for MDT guaranteed, achieving a rapid response to the Regional Plan
demanded strategies to strengthen the programs at the various levels, through:
- Managerial training of the team at the various levels through utilization of the WHO Modules and the training of multipliers. Some 29 courses have been offered, one regional
course in Buenos Aires and the rest at the national or intermediate level, which have trained over 600 multipliers.
- Preparation and execution of elimination plans (national, state, and at the current time, nicipal as well), leading to the improvement and broadening of the stratification process for leprosy. At this time national elimination plans are being executed in all the countries that have yet to meet the target (Argentina, Bolivia, Brazil, Colombia, Paraguay, and Venezuela), while in Brazil, Colombia, Cuba, and Mexico plans are being executed at the subnational levels. The countries of Central America, the English-speaking Caribbean, Brazil, Cuba,
the Dominican Republic, Ecuador, Mexico, and Uruguay are also developing post-elimination strategies.
- Promotion of decentralization (municipalization) of control
measures and of their integration into the general health services--activities in which significant advances have also been made in most of the countries.
In the five years since the conference in Mexico, there have been significant positive changes have taken place as a result of the efforts to meet the goal of eliminating leprosy as a public health problem in the Americas.
At the Hemispheric Conference on the Elimination of Leprosy, held last May in Brasilia, the results of country efforts in the Region to meet this goal were presented. The table below shows the prevalence and incidence rates, as well as the MDT/WHO coverage achieved in the Latin American countries by the end of 1995.
The prevalence rate (see map), which in 1991 was 8.1 per 10,000 population, was reduced to 3.6 by the end of 1995, a reduction of 55.6%. In the period analyzed, three countries (Cuba, the Dominican Republic, Mexico) were added to the list of those whose rates were already below 1 per 10,000 population (Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Peru, and Uruguay); considerable reductions in the prevalence rate were observed in the rest of the countries, with most of them also approaching elimination (see table). Brazil, which accounts for 80% of the problem in the Region, also experienced a significant reduction in prevalence, which fell from 18.2 per 10,000 population to 8.5, a reduction of more than 50%.
It is important to point out that the results with regard to prevalence refer only to the subregion where the disease is considered endemic (Latin America). If the prevalence rate for the Americas as a whole is calculated, the figurei is 2.2 per 10,000 population.
TABLE 1
Lepra: Prevalence, Cases Detected, and Multidrug Therapy (MDT)
Coverage in the Latin American Countries - 1995
Country |
Registered
Cases |
Prevalence
x 10,000 |
Cases
with MDT |
MDT Coverage
(%) |
New
Cases |
Detection
x 10,000 |
| Argentina |
3,797 |
1.10 |
3,649 |
96.1 |
509 |
0.15 |
| Bolivia |
864 |
1.17 |
859 |
99.4 |
86 |
0.12 |
| Brazil |
137,806 |
8.52 |
101,358 |
73.6 |
35,906 |
2.22 |
| Colombia |
4,738 |
1.35 |
4,738 |
100.0 |
692 |
0.20 |
| Costa Rica |
195 |
0.57 |
142 |
72.8 |
15 |
0.04 |
| Cuba |
684 |
0.62 |
648 |
94.7 |
252 |
0.23 |
| Dominican Republic |
528 |
0.67 |
486 |
92.0 |
229 |
0.29 |
| Ecuador |
518 |
0.45 |
518 |
100.0 |
115 |
0.10 |
| El Salvador |
21 |
0.04 |
17 |
81.0 |
0 |
--- |
| Guatemala |
106 |
0.10 |
25 |
23.6 |
7 |
0.01 |
| Haiti |
... |
... |
... |
... |
... |
... |
| Honduras |
83 |
0.15 |
83 |
100.0 |
3 |
0.01 |
| Mexico |
6,106 |
0.67 |
4,725 |
77.4 |
523 |
0.06 |
| Nicaragua |
82 |
0.18 |
53 |
65.0 |
36 |
0.08 |
| Panama |
54 |
0.21 |
14 |
25.9 |
0 |
--- |
| Paraguay |
828 |
1.66 |
817 |
98.7 |
401 |
0.81 |
| Peru |
240 |
0.10 |
240 |
100.0 |
90 |
0.04 |
| Uruguay |
118 |
0.37 |
101 |
85.6 |
20 |
0.06 |
| Venezuela |
3,954 |
1.81 |
3,285 |
83.1 |
490 |
0.22 |
| Latin America |
160,722 |
3.60 |
121,758 |
75.8 |
39,374 |
0.88 |
... No data
Source: Morbidity and MDT: SIL/OPS; Population: UN-World Population Prospects, 1994 revision.
MDT coverage rose from 23.9% to 75.8%, representing a 51.9% increase for the period. In many countries the figure is over 90% (see map and table). Only in two countries is coverage less than 50% and in each of them the number of cases is limited. The 74% achieved by Brazil represents a 56% increase over 1991.
With regard to new case-finding, rates tended to be stable in this period, both in countries that have already achieved elimination and those currently working toward this goal. The reason for this is still not clear, but it may be the result of a complex set of epidemiological and operational factors in each local situation. During 1995, 39,374 new cases were detected, a rate of 0.9 per 10,000 population, 91% of which were diagnosed in Brazil.
To strengthen the activities geared toward the elimination of leprosy, brief targeted interventions are also being carried out in critical areas where access to MDT is difficult, among population pockets in urban and metropolitan areas where health care is lacking, and in areas considered to have hidden prevalence. Similarly, new technologies in information science are being employed, such as computerized geographical information systems (GIS) and drug inventories. Subregional initiatives are also being promoted in Central America, the Southern Cone, the English-speaking Caribbean, and the countries of the Amazon region.
In light of the above, the proposal to eliminate leprosy in the Americas by the year 2000 is considered to be absolutely feasible. Even taking into account only the Latin American subregion, a rate of 1 per 10,000 population (or approximately 52,000 cases) will be achieved with the projected population growth. At that point the prevalence rate for the Region of the Americas as a whole should be 0.6 per 10,000 population.
Thus, to reach the goal of eliminating leprosy in Latin America by the year 2000 it would be enough for Brazil to reduce its prevalence rate by 13% annually, a rate similar to that already observed during the past four years, and for the rest of the countries of the subregion to reduce their rates by 15% a year, a figure lower than that observed for the period 1991-1995.
Work is currently
under way not only to eliminate leprosy in
the countries that have yet to meet that goal but also to reduce
prevalence rates in countries where the rates are already under 1
per 10,000 population (that is, countries in the post-elimination
stage). Activities are being carried out to verify and consolidate
the results obtained and continue advancing toward new objectives.
Under
this strategy, in addition to maintaining and
strengthening the current lines of technical cooperation aimed at
reducing prevalence, PAHO/WHO is supporting and cooperating in
evaluation and monitoring initiatives, with a view to:
- Validating the
state of elimination achieved
- Consolidating the process and making
it sustainable
- Evaluating and incorporating technologies that can
lead in the
not too distant future to a new objective in the struggle
against leprosy: interruption of transmission.
The successes of the
leprosy elimination strategy around the world make it possible to foresee the
eradication of this disease
through interventions that could include:
- Differentiated activities targeted
to persistent pockets of
the disease even in countries in which elimination has already
been achieved.
- Identification of areas in which endemicity was once
high and
residual cases may appear, in order to establish intensive
surveillance that will permit early detection and treatment of
the disease.
- Detection of people with subclinical infections that
could
maintain the transmission, in order to take preventive action.
Here adequate tools for identifying such individuals are of
the utmost importance.
At this time there is a need to evaluate
and validate the
available techniques that could permit diagnosis of the infection
and to develop new techniques. However, there is a conviction that
advances can continue in the struggle against leprosy, with the
ultimate goal of definitively eradicating the disease.
For further information contact:
Dr. Clovis Lombardi;
E-mail: lombardi@opas.org.br
Dr. Reinaldo E. Gil Suárez;
E-mail: suarezrg@opas.org.br
Tel (061)
312-6532;
Fax (061) 321-1922
Bibliography
- Organización Panamericana de la Salud, OPS/OMS.
Informe de la
Conferencia para el control de la Lepra de las Américas, Mexico
1991, PNSP-9213.
- Organización Panamericana de la Salud. OPS/OMS.
Lepra al día,
Boletín de la Eliminación de la Lepra de las Américas, Vol.
1 No.
1, November 1993.
- Organización Panamericana de la Salud, OPS/OMS.
Lepra al día,
Boletín de la Eliminación de la Lepra de las Américas, Vol.
1 No.
2, November 1994.
- World Health Organization. Report of the International
Conference
on the Elimination of Leprosy, Hanoi-Viet Nam 1994,
WHO/CTD/LEP/94.5.
- Organización Mundial de la Salud. Quimioterapia
de la lepra.
Informe de un Grupo de Estudio de la OMS, Serie de Informes
Técnicos 847, Geneva 1994.
- Organización Panamericana de la
Salud, OPS/OMS. Lepra al día,
Boletín de la Eliminación de la Lepra de las Américas, Vol.
1 No.
3, Noviembre 1995.
- Organización Panamericana de la Salud, OPS/OMS.
Guía para la
Eliminación de la Lepra como Problema de Salud Pública, First
Edition WHO/LEP/95.1.
- Noordeen,S.K. Eliminating leprosy as a public health
problem - is
the optimism justified?, World Health Forum, Volume 17, Number 2,
1996.
- Organización Mundial de la Salud, OPS/OMS. Informe de la
Conferencia sobre la Eliminación de la Lepra de las Américas,
Brazil 1996, (in publication)
Source: Division of Disease Prevention and Control, Communicable
Diseases Program, HCP/HCT, PAHO.
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