Ediciones > Año 1956 > Artículo No. 1 2

Studies of Leprosy in the German ethnic group of Colonia Tovar, Venezuela
Jacinto Convit
V. The morbidity rates in BCG vaccined and unvaccined groups during five years. Int. J. of Lep. 24: 269-274, 1956.
REVISTA: Publicaciones - Dr. Jacinto Convit

NUMERO: Año 1956

TITULO: Some observations on borderline Leprosy

AUTORES: Jacinto Convit; Carlos Sisirucá

RESUMEN: This paper is the fifth report of studics madc in the leprosy focus of Colonia To\'ar, settled by pcople of (;ermnn cthnic stock. Onc group in this community was vaccinated with BCG. while the other remained unvaccinated. Both groups were exposcd to thc risk of contagion before and during the period of observation, which covers a period of five years beginning in 1950.

PALABRAS CLAVE:

.- STUDIES OF LEPROSY IN THE GERMAN ETHNIC GROUP OF. COLO~•HA TOV AR, VENEZUELA V. THE MORBIDITY RATES IK BCG-VACCINATED AND UNVACCINATED GROUPS DURING FIVE YEARS JACl:STO CO:S\&#39;IT, !tf. D. CM(( Pll¡¡sieian, l.tpro.~fl /lit·i,.ion .\finú4fry of /lcalth ar.d S<íei11! ll&#39;tr{art Caraca•, \&#39;(&#39;n ~ :utla This paper is the fifth report of studics madc in the leprosy focus of Colonia To\&#39;ar, settled by pcople of (;ermnn cthnic stock. Onc group in this community was vaccinated with BCG. while the other remained unvaccinated. Both groups were exposcd to thc risk of contagion before and during the period of observation, which covers a period of five years beginning in 1950. The first two studies of this series ( 1·3) concerned the epidemiological factors and the immunological findings with the tuberculin and lepromin tests. The ncxt two ( 4, S) de:llt with the clinical f&#39;indings and the changcs in the immunological rcactions after BCG vaccination. The present report is of the occurrence of leprosy in the unvnccinated and vnccinated groups. MATERIAL The age and sex distributions of the two groups nre shown in Table l. Both gt·oups wel&#39;e composecl of persons who showed no signs of infcction TABI.J: 1.-Agll and ¡¡t7 di~ tribution Q{ t&#39;llttiMtCld and amvaccinattd grou¡l:t. a The 3 infcct~ pen;on!O al&#39;e omitted ht-re. b The 25 infec:t~ persons are omitted hcrt-. in 1950, a total of 1,106. Of thesc, 58·1 wcre \&#39;accinatcd and 522 remained as unvaccinated contl-ols. The ages in both g1·oups rangcd f&#39;1·om less than four to more than 50 yc.ars of age. 269 270 lnternational Journal of Leprosy 1956 Both groups were submitted to an initial lepromin tc$t in 1950-1951. The test was repeated in 1954-1955, at the end of the obscrvation pcriod, but the 1\Iitsuda-negative persons were tested annually as previously reported ( 4, 5). Repeated examinations for leprosy were made of both groups, and every suspicious case was submitted to bactcriological, histopathological ~md immunological study to make the diagnosis of leprosy as exact as possible. The lepromin employed was ot the ir.tegn&l type, p~pared at the Cabo Blanco leprosarium by the )fitauda-Ha)·ashi method. The scale u~ ror reading the teats was the one appro,·~ b)&#39; the 11 Pan-American Conferenee on l~prosy (Río de Janciro 194G) . The ncc Wal pre)>ared by lhe National lnstitut.e or Tuberculosis in Caracas. Two intradermal injcetiona we!"e made, cach o! 0.1 ce. containing 0.00075 gm. of baci!!.i. FINDINGS The results of the initial lepromin tests made in 1950-1951, be~ - ·e TABU: 2.- Rtsults of th~ initial (1950-1151) lepr~mi" !eslt Íll tht two group1 before BCG vaccir.ation, ¡,, rtlation to ogt. -- -- - - 1 Oro..rtouh.o1 1 O.,ree DI ¡> .. ith•it)·b ~uwl.ter d IK&#39;t•ou&#39; 1 ·~ lfOUll t&#39;eaaUve l&#39;úti\IVt l+ :1+ 3+ - - - Tow s~t rc&J 1 H•w S&#39;". ( ?.t ~1,). ( ~.) So. <%> So. ( $&#39;.) r\Q. (%) 1 1 ¡ -- -- . - ---- - 1 ()..f 118 61 !·7 24 (42 2) ~3 (~7.8) 27 (11.1) f tlO.I ) 2 (11.1) 6 ·11 121 2& 1 03 30 {32.31 63 (67.1) 52 (3l.t ) 8 (21.6) a o e 11 l()..IU :101 M 1 1~0 t2 (28-0l 1011 (1~ .0) 8& (Jb.5) 13 (35.2) QU<IOI 11)-2!) M 19 u • (8.1) " (ltl.3) 35 (lU) $ (IU) 1 (Ul 3()..J•) ~ 8 u $ (ll.&l 30 (88.~ ) 30 (12 .3) o ( lll.2J 3 t UI.1 ) f()-1&#39;) 19 3 lll 6 (J1&#39;.tl lO (~2.61 9 (3.7) 1 (2.7) o (-) $0 pt,.a 6 &#39; 2 • o (-) • (1001 • (1.6) o {-1 () (-) Total• ---------:l.-lll --&#39;- - --:--------:--- - f09 en.o> ¡ zos c11.1 > 2f3 (100) 37 (100) 18 (100! Group not 1.&#39;CCCil&#39;l4ted. 0-4 ~~~ ¡()..¡&#39;) 10-~ 30 30 f(l-f~ 50 a)hu• T()t-•1• !\} 17 38 • (10.6i 34 \&~. 1} i<l 11 3~ G 0 7 11 ~~~ \&2 .9¡ 1~ :.O&#39;G so 3 t].1 ) &#39;:1 (&#39;#G.l l !12 2$ t-1 1 (1 ~ ) u (~ 8 . 6 ) 71) :10 MI 3 ( ~ . 1 } ., (&#39;/3.1) ) 1\l 20 4 1 o {-) fl (lll(.r) 0:! 4-1 ,~. 4 (S.2 > .:. (91.8) )2~ IG2 :160 21 (8.8) ; 33U (&#39;)4 .2 i 1& (11.6) l l (7.7) 39 (2~.0) ~ (2$ .0) 17 (10.9) 21 (IU) 13 (1 31 l~G UOOJ - - - -:---- ·- ll \10.11) • t7.111 21 !2Ul 16 (1$., 12 (11 .$ ) 9 (8.9) 22 (2 1.~) 8 (~ . 8 ) 9(11.Q) 1~ (1~ . 2 ) ll (13.f ) 15 (2Z.Ol 11 (13.4 ) )(1 (12.:Z) --- -1- -·- 101 (100) 8Z (IQOl -· -- - -- "" & u.: p.:r\:~••wa5..:• u• r...ah.:t o~t:.~"•uu .,e, ..-u a t.u -=:at.:n u&ua~uuuu "Kc KÑilP. 10 &#39;~no\\· the relation of total poaiti\·ity to age. !1 The pereentares in this section ptrtain to each degree-of-positivit)&#39; grou¡>, ht-n~ \&#39;he \ t)\) pel" cent t.o\a)a. e These totals do not inc:lude infe~ petaona in either gl&#39;oup. 24,3 Co111;it: lnfluence of BCG 011 Morbidity Rates 271 BCG vaecination, are shown in &#39;rabie 2, in which the dh·ision of thc two groups by ages is eontinucd. It will be noted that there was a difference in the two groups as regards the number of Mitsuda-negative persona. In the group that was leít unvaccinated there were only 24 negntives, while among those who later were vaccinated a total of 111 wcrc negative. Therefore this group. prior to vaccination, had a far greatcr number than the other of persons who supposedly were more susceptible to infection because of the lack of the resistance evidenccd by lepromin positivity. The difference is also evident when one compares the degrces of positivity in the two groups. In the group that werc vaccinated thc 1 + reactors predominated ovcr those showing 2 ·t- and 3 + reactions, while in the onc that remaincd unvnccinatcd the contrary \&#39;1-&#39;as the case. TARLt~ 3.-lluult ... of the final (U.S4-19$S) leprornirt telt• in the t:M~nat~d IUtd tmvaccít lated grotcp•, in rdotiort to IÍ.ge. ==o_:===-===- -·-===~~==.:====&#39;""&#39;====--=--= -~(;!~.·~~~~···-~- ol p.,.lth ·lty ~ ~umbet of ptnonA ! Pc• ith ·a 1 ... 2+ 3+ &#39; R""d 1 S o. ·- - --- - ( &#39;:&#39;; ) j!&#39;\o. ( ~.) No. ( &#39;7,. ) ¡s a. ( <¡¡ ------~----~·~·- --- VMcirwted group 1 ·-&#39;--- :--- 0-i ~&#39;J 10· 10 20-211 ~0..30 40..40 ~pl\1.0 113 121 ::IOt lit S2 IU ~ ~ • 1 1 1 111 113 lll<l 81 .~1 18 14 (1~ 7 1 3 (2.7 ) t (2.2 ) ~ (3.3) o (· .. :· o(- ~ o (- 1 111 (67 3 ) 1 110 (&7 .3 ) 1116 (117 .8) ~ (!IG.1) ~~ (100) 18 (100) ~ ( 100) ~4 ( II.Sl 31 (23.1 ) ·~ (34.7 ) 10 t1 .7) U (1 1.:•1 3 (2.3) 2 ( 1.~ ) 39 (17.21 30 (1$.3 ) B3 ~.0) 3& (IMJ 19 {UJ 11 {UJ 3 (1.3 ) 3t <ZO. I l 43 12 ) .4 ) ~ (3t.3&#39; 13 (7 .7) ¡¡ (1 11 ¡ ¡ &#39; (2.41 ------- ------ - :, T <>••!o ~~ 3~ ~&!~ Z3 (t .2 J ¡ ~~O (~~.8) 130 <1001 l :n: ooo: &#39; 16~ (1001 - - ---.- - 1 Un~·accin«tf:d oroup o-t ~? J~ l ? 20- ?11 :IO.. ~G 40..9 50 ~&#39;"" Tot.•h ;» 4& 10& ?2 70 01 !&#39;>2 u 11 ;:~ :u 13 14 39 lt! --:-- - •• "&#39; 47 .:.:• - --;·--- - ,...----;-- - - - 8 (20.S) 3 {%2.3) 9 (11 .1) o(-) 4 (7 ) 1 (2.21 3 (~.Al • &#39; 31 (79.SJ 11 <16.1> 1 <U > e (U J 1 :;:1 l77.7 ) 72 (8$.9 ) 10 (9.3) 13 (8.7) t (4.41 20 t24.t) 24 (10 0 ) ~ 2 (: U ; OS \100) 24 (22 .~) U ( ID.OJ 15 (16 1 : M (113-01 1 (0.3) 27 (18.01 1\1 {~ 1 J I 45 {{17.11 ) 10 (11.3) 22 (14.7i U { IH ~ :..o !1H2) ¡_ 12_ (1_1 :r>_ , 28_ (1_8.7•_ -10- {111 : ·,-;u 79!.3> -~ 10: uco1 tso (IOOJ - · w (100¡ - - - -·- 1 1 1 - --- ---- . - ---&#39;- ·- -- - -&#39;---·--- - .. a The percentaa-es in thi& Mlction pertain lo each individual age group, to show the rc:lation of total poaitivity to uge. b The perc:entagea in thia aeetion pertain to eaeh degree-of-~itivity eroup, henc:e the 100 pe" cent totalt. TI1e situation is very different with rcspect to the results of the final lepromin tests, shown in Table 3. In the vaccinated group thcrc was an increase in the numbcr of strong (2 + and 3 +) reaetors, at the expense ·-> .,.. -•) lnte,.national )Qurnal of L1->prosy 195H oC those that were originally neg:ttive or only weakly reactive. In the control group there was also an increase in the degree of Mitsuda-positiveness, but much less thun in the vaccinated group. lt should be tnken into consideration, however, that among the controls there were l·l2 persons whosc lcpromin reactions are unknown, against only :~5 among the Yaccinated persons. The incidcnce of leprosy morl>idity in thc two groups is shown in Table 4. Thcre the persons who wcre found to have contracted the disease in its severa) forms nre tabulated according to the year in which thc diagnosis was made, and in relation to the results of the initial le)WOmin tests made when thcy were without signs of the infection. The persons "not read" at that time are not taken into account in this table. hcc<mse no <&#39;~se of leJH&#39;osy has bcen found among them. &#39;f AllL.: 4.-Co~t:~ of !.,prusv arising in the 1.orucinat.ed and utwaecinated {)roups, in relntion to the rn ults of tlu: iniriallepromin tests. ~»v· year in which l D ~l !U 53 Hl:.-4 l ~ .:-..:.. 1 1 1 . = 1 -= 1 = ~ ·- - &#39; ·- -· - - - - -· the diaquo~i~ U.&#39;as made.• ==;._~· - = = 1 ~ - • - - • - ¡ - -_,1 - - &#39; --- - - - 1 ~. - - - 1 l - &#39; - ._ - &#39; - 1- - _ ¡ 1 . - , - - ¡ - &#39; ..... - -..- - · - ¡&#39;----_,...- - .J. - · - - . - &#39;---- -..----&#39; o 1) 3 o - --- --- l.Jnt·acc:inaled group -:Ú~ l-;-=:: _ .~ - --_-¡-......- -~ --:---·....,....:--:-1-_--=--1 - :-1:-:--·-.,¡- -:-_--c,- -~ l~ -~: ~ 1 1 1 l 1 - . - i - 1 -¡ ·- 1 - &#39; 1 - -1 l -- - 2 l ~ 1 1- 1 !f ~t.:l J!iS• 19~ 1 ~ 1-, - &#39; - ¡ ·1 - 11 - t i • 2 -- ¡&#39; 7 1 2 , ~ 1 - · - - 1- - 1 &#39; - · 1 - . - - 1 l 1- ~----- -J ·-· -~- -- -.........;__-...-- ....J 6 8 ---- --=====- - - ---. - a No case o! lcprosy has becn found among the total o( 177 persons who:se final lc¡¡romin rt"actions were not read. The first striking reature or this table is that only a cases of leprosy dcvcloped amoug 584 persons in the vaccinated groul)-all from among thosc who wcrc originally negative to lepromin-whereas ther~ were 25 cases among the 522 pcrsons of the unvaccinated group. Of these 25, no les:> than 12 carne from the 21 ncgatives (57.2% o( thcm) , whilc> the 13 cases among thc 339 positivcs constitutc only 3.8 per cent of th~t lot. It is of intcrcst that. the G cases among the 156 weak (1 +) reactors nnd the 7 cases among the 186 stronger (2 + and 3 +) reactors represent Pl&#39;<.&#39;<:isely 24,3 Convit: lnfluence of BCG on M orbiditv Rates 273 the same percentage. Also of interest is the fact that in the vaccinated group cases occurred only in the first two years of the period, whereas in the control group a large majority (18 of the 25) were found in the third and fourth years. DISCUSSION We consider the two groups studied to be practicalJy comparable. There were düferences as regards thc numbers of persons in the different age groups, but they are not vcry important, especia11y in the younger groups. They were exposed before and during the period of observation to the same risks of contagion from contact with infectious cases. The difference in morbidity shown in Table 4 may be reduced to morbidity coefficients (cases per thousand) as follows: In tbe vaccinate~ group, with 3 cases out of 687 persona, the coefficient is 6.11. ln tbe other group, with 25 cases among 547 persons, the coefficient is 45.70. The dif ference between these coefficients, 40.59, could oocur by chance only once in 200,000 similar experiments carried out with groups of 567 persona from the same comprehensive system. This means that the reduction of the morbidity coefficient in the vaccinated group can, with all certainty, be attributed to tbe effect of the BCG vaccination. Besides the great difference in the morbidity coefficients, there is also a very clear contrast between the two groups as regards the type of leprosy found, which again is evidence of the protective action of BCG in the vaccinated persons. The 3 cases of infection found in that group were of the tuberculoid type, strongly positive to lepromin, and their lesions disappeared in a very short time. On the other hand, there were 9 infectious cases (lepromatous and dimorphous) in the unvaccinated group, besides 6 of the indeterminate group which could change into the infectious form as their Mitsuda reactions were negative or only weakly positive. BCG vaccination has thus been shown to have a decided preventive effect against leprosy, not only because it was effective in bringing about a radical reduction in the morbidity rate, but also because no infectious forros of the disease were found in the vaccinated group. In addition to this, we have the notable difference between the two groups as regards the number of closed cases (tuberculoid and indeterminate). SUMMARY This report deals with the incidence of leprosy morbidity in the two groups of contacts in Colonia Tovar which have been under observation for five years, of which one (584 persons) was vaccinated with BCG while the other (522 persons) served as a control. All the persons in these groups lived in close contact with infectious forros of the disease. Records were kept of all persons in the two groups starting with 1950, wh~n none as yet showed any evidence of infection. These records included results of clinical examinations and lepromin tests m.ade in 1950-1951. Both groups were again tested with lepromin at the end of the period of 274 Interna.tional Jcrurnal o/ Leprosv 196( observation, in 1954-1956. The examination made of all persons witl: suspicious lesions included bacteriological, histopathological and immunological studies to make the diagnosis of leprosy and the classification of the forms of the disease as accurate as possible. Three infected persons have been found in the vaccinated group, and 25 in the control group, which gives morbidity coefficients of 5.11 for the former and 45.70 for the latter. The probability that such a difference, 40.69, could be produced by chance is only one in 200,000 similar experiments with 667 persons from the same comprehensive system. The great reduction in the morbidity coefficient can thus be attributed, with all certainty, to the effect of BCG vaccination. RESUMEN En esta experiencia se refiere al estudio de la morbilidad por lepra en dos grupos de contactos, uno de ellos vacunado con BCG y no vacunado el otro. Todos viven en un foco lepr6geno en e3trecho contacto con formas h1fectantes de la enfermedad. Todaa eran personas sanas para 1950. El grupo vacunado con BCG esti compuesto en total por 584 personas y por 522 el grupo test.iro. Para las personas componentes de ambos grupos se llev6 un reeord a partir de 1950. En dicho record se reglatr6 los exámenes cUnicos, además prueba. lepromínica en 1950-1961. Una nueva lepromino-reaeci6n ae lea hizo a loe dos grupos al finalizar el periodo de observaci6n en 1954-1956. Durante el curao de la experiencia toda persona sospechosa al exámen clínico se le practicó estudio bacteriológico, histopatológico e inmunológico con objeto de hacer lo ma.s exaetame.nte posible la diagnosis y la clasiticad6n de cada caso de lepra encontrado. El número de enfermos hallados en el grupo vacunado !ué de S, y de 26 en el grupo testigo, lo que da un coeficiente de morbilidad por mil de 6.11 y 45.70 rupeetívamcnte, con una diferencia de 40.59. Esta diferencia y una aún mayor se obllervar!a debido únicamente al azar sólo una vez en cada 200,000 experimentos similares efectuados con grupos de 553 personas provenientes del mismo universo y como consecuencia la reducd6n del coeficiente en el gruPQ vacunado se le puede atribuir con toda seguridad al efecto de la vlicunacl6n BCG. REFERENCES l. CoNvtT, J., Lms GONZÁLEZ, C. and RASSt, E. Estudios sobre lepra en el grupo étnico alemán de la Colonia Tovar, Venezuela. Internat. J . Leproay 20 (1962) 185-193. 2. CONVIT, J., GoNzAI.&Z, C. L. and RAsSJ, E. Estudio sobre. la lepra en la Colonia Tovar. I. Prevalencia en el grupo étnit9 alemán. Rev. San. y Asiat. Soc. (Caracas) 19 (1954) 387·898. S. CoNVIT, J., GONZ.\Lt:Z, C. L. and RASSt, E. Estudio sobre la lepra en la Colonia Tovar. ll. Invest.igaci6n inmuno·alérgica a lepromina y tuberculina en el en el ¡-rupo étnico alemán. Rev. San. y Asist. Soc. (Caracas) 19 (1954) 395-401. 4. CoNVIT, J., Luts GoNzAu:z, C., SIRUCÁ, C. and RASSt, E. Estudios sobre lepra en el grupo étnico Alemán de la Colonia Tovar (Venezuela). (Hallazros clínicos y variAciones de la prueba lcpronúnica en contac~ calmetizados que viven en un foco de lepra.) Mem. VI Congr. lnternae. Leprol., 1953: Madrid, 1954, pp. 629-584; abst. in Internat. J . Leprosy 21 (1953) 587. 5. CoNVIT, J . An investigation o! leprosy in the Gennan ethnie ¡roup of Colonia Tovar in Venezuela. IV. Clinical findinga and variationa in the Mantoux and Mitsuda reactions observed during five years after BCG·vaccination of Mitsudanogative oontacts. Internat. J . Leprosy 14 (1966) 88-44.
  Ediciones > Año 1956 > Artículo No. 1 2
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