Further information on the leprosy problem in the world

Bull. Org. mond. Sante' 1972, 46, 523-536Bull. Wld Hith Org. Further information on the leprosy problem in the world L. M. BECHELLI 1 & V. MARTINEZ DOMINGUEZ 2 Information was obtained for the period 1966-70 concerning the number of registered cases, the number of cases that were inactive and released from control, the number of inpatients and of institutions for inpatient care, the proportion of lepromatous, tuberculoid, and indeterminate patients, and the frequency of disabilities. Comparison of the data from different countries was made difficult by non-uniform use of epidemiological terminology. In the circumstances, it would be hazardous to make an appraisal of the leprosy programmes in many of the countries, and it is difficult to determine correctly the trend of the endemics in these countries. The data collected suggest that the total number of estimated cases has not changed substantially in the last 5 years. To obtain further information on trends in the leprosy problem in different countries since the previous survey (Bechelli & Martinez Dominguez, 1966) a questionnaire was prepared and distributed to the public health authorities of the countries concerned. Replies were received from 95 countries. Additional information was obtained from Head- quarters and Regional Office staff of the World Health Organization, consultants, and the literature. The information from the replies received and from some other sources is shown in Table 1 and is summarized in Table 2. In many of the completed questionnaires received the data were incomplete or inconsistent and some appeared not to reflect the true epidemiological situation. Sometimes there were inconsistencies between the data provided and those given in the quarterly reports ofWHO projects or data obtained during visits of consultants or Headquarters staff. There are indications that terms such as " inac- tive " 3, " released from control " 3 and " out of con- trol cases" 4 were interpreted differently, and this renders difficult the comparison of data from dif- 1 Chief Medical Officer, Leprosy, World Health Organiza- tion, Geneva, Switzerland. ' Epidemiologist, Jefatura Provincial de Sanidad, Madrid, Spain (formerly Medical Officer, Leprosy, World Health Organization). " A leprosy patient without any sign of clinical activity and with negative bacteriological examinations should be considered as an' inactive ' case. Once inactivity is achieved, full treatment should be continued for varying periods of time ferent countries and also the assessment of the leprosy programmes. In the circumstances it would be hazardous to make an appraisal of the leprosy programmes in many countries, and it is very difficult to determine correctly the trend of the endemics in these countries and in the world in the last 5 years. In order to improve the value of the information collected, standardization of the collection of data, of the terminology, and of the registration system is essen- tial. It should be pointed out, however, that some countries or areas have provided very useful infor- mation that indicates the magnitude of the problem and the development of leprosy control programmes. Also it is known that in some countries consider- able numbers of patients have been removed from the register. This should obviously occur in the case of misdiagnosis and for patients who have died. However, several countries have removed from the register patients who have not been seen or who have not reported for treatment for a period of 2 or more years. Clearly these patients, especially if they are lepromatous or borderline, or in some instances before the patient is ' released from control ' (r.f.c.). These periods should be 11/2 years for tuberculoid, 3 years for in- determinate and at least 10 years for lepromatous and bor- derline cases." (WHO Expert Committee on Leprosy, 1970). The previous WHO Expert Committee on Leprosy (1966) had indicated 5 years for lepromatous and borderline cases. '"Out of control ", " absentee ", " lost sight of ", and other terms have been used for registered patients who have not been under control for 2 or more years (WHO Expert Committee on Leprosy, 1966). 2828 523- L. M. BECHELLI & V. MARTiNEZ DOMINGUEZ 0 0 M CM co 0 C.)8 U) 0 co C') Lo r- 0 .0 0 LO LO M) Lo NO U) co co c N- N N 0 0) 0 N 0 N 0 U) r-M N N co w U) 0NOwU) M' M' _N U) C'N 0 U) 000U) U) U) U) U000 00 0 N. M (S 0 LUJ C 00 0 E 0 1- co co M '.. 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The above should be taken into account when the total number of patients and prevalence are determined. RESULTS Number of registered cases For many countries it is clear that the figures given for the number of registered cases relate only to patients requiring surveillance and treatment, and therefore do not include those released from control or those who had died or emigrated. For most of the other countries, the total given for the number of registered cases seemed also to correspond to the total number of existing cases (excluding those who had died or had been released from control) but this could not be determined with certainty. The total of 2 887 481 cases registered in 124 coun- tries, according to the information available, exceeds by about 500 000 the total registered for the same countries (2 387 691) given by Bechelli & Martinez Dominguez (1966). The difference would have been greater if the number of patients who had been re- leased from control had not been deducted from the new totals of registered cases for many countries. This was most striking in Africa where 318 402 cases had been released from control (in 17 countries) and the new total number of registered cases is practically the same (1 326 551) as in the previous report (1 314 826). In Asia alone the number of registered cases (1 333 684 in 25 countries) exceeds by 450 511 the previous total (883 173 in the same countries). In these countries, according to the questionnaires, only 41 577 cases (in 10 countries) had been released from control. In some areas where long-term programmes are in progress, the rate of registration of cases seems to be remaining constant or to be declining slightly. How- ever, it is known that several factors, economic, poli- tical, and others, may influence the rate of case- finding and, thus, great caution is required in inter- preting these results. Proportion of lepromatous (L), tuberculoid (T), and indeterminate (I) cases In African tropical countries the proportion of L cases is low, varying from 4% in Upper Volta, 5% in Sierra Leone, to 12% in western Nigeria; the highest rates (18 %) were reported from Tanzania and Madagascar. The proportion of T cases is high, from 40% to 60% and even as high as 83% in one country. It should be mentioned that in the random sample surveys conducted by the WHO Leprosy Advisory Team (LAT) I in Cameroon and in Kat- sina, Northern Nigeria (Bechelli, Martinez Domin- guez & Patwary, 1966) the proportions of L cases were 11.2% and 7.2%, respectively, and those of T cases were 55.6% and 38.5%, respectively. In the Americas the proportions of L cases were generally high, being 55% in Brazil, 57% in Mexico, 61 % in Colombia, and 63 % in Cuba. The propor- tions of T cases were mostly in the range of 20-30% but the proportion was reported to be over 60% in Guyana, Haiti, and Trinidad. The proportion of L cases is higher in Asia than in the African tropical countries: for example, it was 27% for Burma and 35% for Thailand; a WHO LAT found the proportion of L cases to be 37.1 % in Khon Kaen, Thailand. In many countries the pro- portion of lepromatous cases would be lower if case-finding were more intensive, as this would lead to the detection of a greater number of I and T cases. The proportion of T cases reported by Asian countries in general was high, reaching 53% in Thailand and 58% in Burma; the results of the WHO LAT random sample surveys showed propor- tions of T cases of 38.5% in Khon Kaen, Thailand, and of 45.2% and 58.6% for the Shwebo and Myingyan districts of Burma). In Europe, in countries where the endemic is still active, the proportion of L cases is high: Greece, 30 %; Spain, 60 %; Portugal, 72 %; in the same coun- tries the proportions of T cases were 49 %, 26 %, and 19%, respectively. In Belgium and the Netherlands -countries with imported cases-the proportions of L cases were 29% and 40%, and those of T cases 71 % and 60%, respectively. In Oceania, the proportion of L cases varied from 19% to 45 %, and that of T cases from 26% to 74%. The range of variation in the proportion of each form of leprosy would probably have been smaller in all areas if uniform criteria of classification had been adopted. This lack of uniformity makes it difficult to analyse the data on the proportion of I cases. In fact, the proportions varied in Africa as follows: 15%, Kenya; 36%, Upper Volta, Gabon, and northern Nigeria; 43%, Madagascar; 48%, 1 The LAT was later redesignated " Leprosy Epidemio- logical Team " (LET). 532 L. M. BECHELLI & V. MARTiNEZ DOMiNGUEZ Table 2. Summary of data concerning geographical distribution of leprosy Leprosy cases Continent No. Inactive up controldinr196 Out of control at registered to end 1969 contror1969 end of 1968 Africa 1 326 551 488 893 318 402 65 842 Americas 203 749 5 183 6 808 50 150 Asia 1 333 684 40 771 41 577 20 481 Europe 14 516 5 294 1 035 284 Oceania 8 981 4 578 967 289 Total 2 887 481 a 544 719 b 368 789 c 137 046 d a As reported by 124 countries or territories (33 in Africa, 32 in the Americas, 25 in Asia, 22 in Europe, and 12 in Oceania). b As reported by 52 countries (17 in Africa, 9 In the Americas, 7 in Asia, 12 in Europe, and 7 in Oceania). CAs reported by 54 countries (19 in Africa, 11 in the Americas, 10 in Asia, 7 in Europe, and 7 in Oceania). d As reported by 41 countries (8 in Africa, 13 in the Americas, 8 in Asia, 5 in Europe, and 7 in Oceania). Niger; and 49%, Senegal. The findings of the WHO LAT from random sample surveys showed that the proportions of I cases were 52.3 % for males and 36.6% for females in northern Nigeria, and 36.4% for males and 28 % for females in Cameroon. In the Americas it is noteworthy that in Paraguay (20%), Colombia (21 %), Mexico (22 %), and Brazil and Venezuela (24%) the proportions of I cases were similar. In Brazil, Mexico, and Venezuela the proportions of L, T, and I cases reported were similar and this could indicate a common pattern of the disease for Central and South America, with slight variations (perhaps related, at least in part, to the intensity of case-finding activities). In Asia, the proportion of I cases was similar in Burma (15%) and in Thailand (12%). In Khon Kaen, the WHO LAT found about 25% of I cases. In Oceania, the proportion of I cases was high in French Polynesia (31 %) and Northern Caledonia (45%). In some countries or areas the proportion of lepromatous cases is decreasing and only a few such cases are detected even in mass surveys, indicating the efficiency of case-finding. In several African countries the proportion of lepromatous cases seems to be approximately the same in spite of the control measures; the same was also observed in Brazil. Inactive cases and patients released from control (Table 2) In a certain number of countries, the number of patients with inactive disease (544719) and cases released from control (368 789) has considerably increased. In Africa, because of the large number of tuberculoid cases, many patients have been released from some control projects and some of these coun- tries have reported striking decreases in the total number of cases. For this reason this number in Africa has not substantially changed.' Out of control cases Only 41 countries provided information on the number of cases out of control. Many of the figures given are high, even in countries with an apparently satisfactory leprosy programme. This reflects the great difficulty in most countries of keeping all patients under treatment and surveillance for long periods. Disabilities Only a relatively small number of countries sup- plied the relevant information. This is a subject that 1 In 33 countries, there were 1 326 551 registered cases, while in our previous report (Bechelli & Martinez Dominguez, 1966) the number was 1 314 826 in the same countries. FURTHER INFORMATION ON THE WORLD LEPROSY PROBLEM deserves greater attention. Usually only the grade 2 and grade 3 disabilities of the classification proposed by Brand, Bechelli & Martinez Dominguez (1969) were reported, thus excluding the grade 1 disabilities (anaesthesia). The data reported, for continents and countries, are as follows: Africa: Cameroon 7.6%; Reunion 44%; Libya 33%; northern Nigeria 25%; Senegal 8%; Sierra Leone 10%; Tanzania 25%; United Arab Republic 53%; Upper Volta 18%. America: Colombia 29%; Costa Rica 26%; Ecuador 42%; Haiti 36%; Honduras 15%; Mexico 11%; Panama 9%; Trinidad and Tobago 33%. Asia: Burma 35.7%; Ceylon 40%; Taiwan 80%; Kuwait 23 %; Syria 24%; Thailand 21 %; West Malaysia 39 %; Venezuela 18 %; Yemen 19 %. Europe: Belgium 26%; Portugal 25%; Romania 24%; Spain 31 %; Turkey 25 %. Oceania: Australia 41 %; French Polynesia 22%; Tonga 17%; Western Samoa 9%. To facilitate a better appraisal of the data supplied, the percentage of disabilities (including anaesthesia) found by a WHO Leprosy Advisory Team (Bechelli & Martinez, 1966) are reproduced below: Argentina Burma Cameroon Nigeria Philippines Thailand (1964) (1963) (1961) (1960) (1963) (1962) 35.8% 48.7% 35.6% 23.4% 32.2% 41.5% In general, it may be said that in countries where case-finding is very active the number of early cases diagnosed is high and, as a result of treatment, the proportion of cases with disabilities becomes smaller than in similar areas with poor case-finding pro- grammes. Thus, in countries with an abnormally high proportion of disabilities, it is most probable that the great majority of registered cases are ad- vanced cases. Number of inpatients and number of institutions or units caring for inpatients Many countries did not provide the relevant in- formation. The data available are summarized in Table 3. An analysis of the data is difficult because the information is not complete. In general terms, the proportion of inpatients is small in Africa and Asia compared with that in America and Europe. In all continents, outpatient care is now given Table 3. Summary of data available on inpatients Continents No. of inpatients Noitsfostitupatiensor Africa 13 239 (13 countries) 140 Americas 20 728 (17 countries) 62 Asia 28 053 (17 countries) 125 Europe 3 599 (13 countries) 17 Oceania 783 (11 countries) 10 greater emphasis than inpatient care, which is being reduced more and more as the years go by. The per- centage of inpatients in relation to the number of registered cases is still high, however, in several countries (Indonesia 10.4%, Brazil 15.9%, Iran 16.5%, Spain 16.5 %, Japan 16.7%, Ceylon 17.1 %, Australia 18.7%, Korea (Republic) 22.7%, Taiwan 23.3 %, Portugal 23.7%, West Malaysia 52.3 %). Most of these countries had developed their leprosy control projects on the basis of inpatient care, as re- commended in the past; after the shift in emphasis from inpatient to outpatient care a great number of patients refused to leave the institutions. In contrast to this, those countries in which con- trol projects were started in the last 15 years have only a very small proportion of inpatients (for in- stance, Burma 1.5 %). The number of institutions in Africa and Asia includes a high proportion of " segregation villages ". In the Americas the number of sanatoria for leprosy patients is high. Prevalence and lepromatous rates From the data collected, it appears that the maximum prevalence rate does not exceed 50 per 1 000, and this is confirmed by the information obtained by the WHO Leprosy Advisory Team in random sample surveys in some of these areas- Burma (Shwebo and Myingyan), northern Nigeria, and Cameroon-and by the WHO Leprosy BCG Trial in a mass survey in Singu, Burma. In small villages or foci the prevalence rate may be as high as 82 per 1 000 but the rates for larger areas do not exceed 50 per 1 000. This observation should be considered in connexion with the statement made by Doull et al. (1942) that the average incidence of L leprosy was strikingly low and less than 0.5 per 1 000 each year. Later, Newell (1966) noted that, " In no survey or study published . . ., even in 533 534 L. M. BECHELLI & V. MARTINEZ DOMINGUEZ Table 4. Prevalence of leprosy by continent, 1965-70 No. of N oofcss Etmed No.of cases No. of cases Continents estimated epestmated No. of cs E ate released from of leprosyleprosy cases 1965-70 1965-70 a 1965r70 estinm1970din 1965 16-0b 90 Africa 3 868 000 312 000 352 600 318 402 3 509 000 Americas 358 000 26 000 32 500 6 808 344 700 Asia 6 475 000 650 000 612 000 41 577 6 471 400 Europe 52 000 3 000 4 700 1 035 49 300 Oceania 33 000 4 000 3 200 967 32 800 Total 10 786 000 995 000 1 005 000 368 789 10 407 200 a Annual mortality rates for L (22 per 1000) and non-L cases (17 per 1000) were estimated on the basis of data of average mortality rates during a 1 0-year period among leprosy patients in an African country. These rates have been applied to Asia and Oceania. For Europe and America the rates of 15 per 1000 for non- L cases and 20 per 1000 for L cases were used. The proportion of L cases was estimated at about 10 % in Africa, 20 % in Asia, 55 % in America and Europe and 25 % in Oceania. b As reported by 51 countries. c Number approximated to the nearest hundred. ' epidemic ' situations, has a lepromatous leprosy prevalence rate in a population been reported that was greater than 15 per 1 000 persons. . . ". It should be pointed out that in some villages the lepromatous rate may go up to 27 per 1 000, and in the Nauru epidemics (Wade & Ledowsky, 1952) it reached 22.7 per 1 000 (only 1 365 inhabitants in 1929). However, when larger populations are con- sidered, Newell's statement is valid. The statement that the point prevalence rate does not exceed 50 per 1 000, even in the most endemic countries, does not indicate that only 5% of the population is to some degree susceptible to leprosy. In the usual living conditions only a certain proportion of the susceptible inhabitants are, in fact, exposed to in- fectious cases. Thus the maximum point prevalence does not exceed 50 per 1 000 and the maximum lepromatous rate does not exceed 10 per 1 000. In special circumstances this proportion may be greater as is shown by the data of Lara & Nolasco (1956) and Lara 5 and the data from the Nauru epidemics (Wade & Ledowsky, 1952).2 The data of Lara, 1 Lara, C. B. (1961) Unpublished working paper WPR/ Leprosy/24, prepared for the WHO Western Pacific Region Post-graduate Leprosy Training Course, Philippines, 1961. ' According to Lara, the attack rate in continuously exposed children aged 3-6 years, repeatedly observed for different periods of time, was 36.2%; apparent complete healing occurred in more than three-quarters (77.7 %) of all cases (Lara & Nolasco, 1956). In the Nauru epidemics, the most important in the world, 30 per cent of the population (about 1500 natives) showed signs of leprosy (Wade & Ledow- sky, 1952). however, refer to children exposed to high risk because they were living in a sanatorium for leprosy patients, the majority of whom were lepromatous. Estimated number of leprosy cases In the 1965 estimate (Bechelli & Martinez Domin- guez, 1966) the total number of cases was 10 786 000; it was realized at that time that the figure could well be an underestimate. Also, according to a WHO estimate referred to in that paper, the number of leprosy cases expected between 1965 and 1970, in countries with a prevalence rate of 0.5 per 1000 or higher, was 995 000, with the following distribution: Africa 312 000 America 26 000 Asia 650 000 Europe 3 000 Oceania 4 000 Taking into account on the one hand the estimated number of patients in 1965 and the expected number of cases in the subsequent 5 years, and on the other hand the number of deaths and releases from control (Table 4), it is probable that the total number of cases in 1970 is not greatly different from the 1965 estimate. Allowing for the shortcomings of the data, however, it would appear that approximately the same level of endemicity was maintained in most countries in 1970 as was found in 1965, as indicated by the yearly detection rate, by the proportion of L FURTHER INFORMATION ON THE WORLD LEPROSY PROBLEM 535 cases still being detected, and by other data. This is as would be expected in view of the limitations of the antileprosy drugs and the characteristics of the disease, which may take decades to control with present methods. In some countries or areas the pro- gress of the campaign is impressive, but its effect on the trend of the disease cannot be seen in such a short period as 5 years. RESUME INFORMATIONS COMPLEMENTAIRES CONCERNANT LE PROBLtEME DE LA LEPRE DANS LE MONDE Dans le present rapport, les auteurs exposent un certain nombre de donnees recentes relatives a la situation de la lepre dans le monde. D'apres les renseignements regus en reponse a un questionnaire ou en provenance d'autres sources, le nombre des cas de lepre recenses dans 124 pays est de 2 887 481, en augmentation d'environ 500 000 sur le chiffre obtenu pour ces memes pays lors d'une prece- dente evaluation (1965). Cette difference aurait ete plus forte encore si, dans beaucoup de pays, on n'avait defalque du total des cas enregistres les malades liberes des controles. Dans certaines regions oii des programmes de longue haleine sont en cours d'execution, le taux des cas nouveaux enregistres semble rester stationnaire ou decliner legerement. La proportion des cas lepro- mateux est faible dans les pays d'Afrique tropicale (10% environ), plus elevee en Asie (27% en Birmanie; 35% en Tha-lande) et habituellement forte dans les Am6riques (plus de 40 %). Dans les pays d'Europe oii l'endemie persiste, on note une forte proportion de cas lepromateux (Grece: 30 Y.; Espagne: 60%; Portugal: 72 %). En Oceanie, on compte 19 a 45% de cas lepro- mateux et 26 a 74% de cas tuberculoides. Il est probable que, dans chaque continent, les variations en pourcen- tages de chaque forme de lepre seraient de moindre amplitude si l'on avait adopte des criteres de classifi- cation uniformes et si le d6pistage avait atteint partout le meme niveau d'efficacite. Il convient de signaler que la proportion des cas ind6termines est tres voisine au Paraguay (20%), en Colombie (21 %), au Bresil et au Venezuela (24 %). D'apres des statistiques portant sur un certain nombre de pays, le nombre des cas inactifs (544 719) et des malades liberes des contr6les (368 789) s'est consid6- rablement accru. Quarante et un pays seulement ont foumi des renseigne- ments sur les malades perdus de vue. Leur nombre est frequemment eleve, et cela meme dans des pays oui, ap- paremment, la lutte antilepreuse est convenablement organisee. Les donnees relatives aux invaliditds sont relativement peu nombreuses et gendralement limitees aux invalidites des degres 2 et 3, a l'exclusion du degre 1 (anesthesie). Les pourcentages varient fortement de pays a pays dans un meme continent. La raison de ces diffdrences reside probablement dans le degre de precocite du diagnostic. Il est vraisemblable que dans les pays qui signalent une proportion importante d'invalidites la plus grande partie des cas enregistres sont des cas avances. II est difficile d'analyser les donnees relatives au nombre de malades traites dans les h6pitaux et au nombre d'etablissements qui leur dispensent les soins; les ren- seignements disponibles sont tres incomplets et ne con- cement qu'un petit nombre de pays. D'apres une eva- luation approximative, la proportion des malades hospi- talises est moins elevee en Afrique et en Asie que dans les Ameriques et en Europe. Des informations recueillies, il ressort que dans les pays ou l'endemicite est la plus forte la prevalence maximale n'excede pas 50 pour 1 000, si on la mesure a l'echelon de la commune, du district, de la province ou du pays. Dans des petits villages ou dans des foyers limites, elle peut atteindre jusque 82 pour 1 000. Si l'on considere d'une part le nombre estime des malades en 1965 et le nombre prevu de nouveaux cas pendant les 5 annees suivantes et d'autre part les deces et les cas liberes des contr6les, il est probable que le nombre total des cas en 1970 n'est pas tres different du nombre obtenu lors des evaluations de 1965. REFERENCES Bechelli, L. M. & Martinez Dominguez, V. (1966) Bull. Wld Hlth Org., 34, 811-826 Bechelli, L. M., Martinez Dominguez, V. & Patwary, K. M. (1966) Int. J. Leprosy, 34, 223-243 Berkeley, J. S. & Berkeley, M. I. K. (1970) Int. J. Leprosy, 38, 78-82 Brand, P. W., Bechelli, L. M. & Martinez Dominguez, V. (1969) Bull. Wid Hlth Org., 40, 609-612 536 L. M. BECHELLI & V. MARTINEZ DOMiNGUEZ Coffari, V. (1969) Acata Leprol. (Geneve), No. 34-35, 5-8 Doull, J. A. (1951) Ann. N.Y. Acad. Sci., 54, 134-141 Doull, J. A., Guinto, R. S., Rodriguez, J. N. & Bancroft, H. (1942) Int. J. 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