Tubercle !I8 (1977) 91-96
OCCULT TUBERCULOUS
INFECTION
IN CHILDREN
T. G. Fox Children’s Hospital, Auckland,
New Zealand
Summary Three hundred and fifty New Zealand children with occult tuberculous reviewed. Ninety four had received BCG vaccine previously.
infection
are
Three hundred and forty were admitted to hospital and 3 gastric aspirations were obtained from each child and cultured for tubercle bacilli. Mycobacterium tuberculosis was isolated from 1 or more aspirates in 29 (8.5 %) of the children. Excluding those who had received BCG the isolation rate was 10.9 %. Mycobecrerium bows was not cultured from any child. X-rays of the chest which were initially in 73 (20.8%) cases.
normal showed calcification
after 2 to 5 years
The 350 children were treated with 2 drugs, during the early years isoniazid and PAS and in the past 3 years isoniazid and rifampicin in standard dosage for either 12 or 18 months. The reasons for treating these children are discussed.
350 enfants NBo-Zelandias porteurs d’infection tuberculeuse latente ont et6 etudies. 94 avaient anterieurement recu le vaccin BCG. 340 ont et6 admis a I’hbpital et pour chaque enfant, on a pratique 3 aspirations gastriques et pro&de B la recherche des bacilles tuberculeux. Mycobacterium tuberculosis a et6 isok B partir d’un ou de plus d’un Bchantillon de liquide d’aspiration gastrique chez 29 soit 8.5 % des enfants. Si I’on exclue ceux qui ont recu le BCG le taux d’isolement du bacille a et6 de 10.9 %. Chez aucun des enfants on n’a mis en evidence Mycobacterium bovis. Les radiographies du thorax (elles Btainet initialement normales) ont revel6 la presence de calcifications apres 2 B 5 ans chez 73 soit 20.8 % des cas. Les 350 enfants ont et6 trait& avec 2 medicaments (isoniazide et PAS) au tours des premieres ant-tees de l’etude et par isoniazide et rifampicine lors des trois recentes an&es, aux doses standards, soit pendant 12 mois soit pendant 18 mois. L’auteur discute les raisons qui ont motive le traitement de ces enfants.
Resumen Se han revisado trescientos cincuenta nirios de Nueva Zelandia con una infeccitk tuberculosa oculta. Noventa y cuatro habfan recibido BCG previamente. Se hospitalizaron trescientos cuarenta y a cada uno se le efectuaron 3 lavados gktricos para realizar cultivos en busca de bacilos. Se aislaron Mycobacterium tuberculosis en uno o mas lavados gktricos en 29 niiios (8.5 %). Si se excluyen 10s que habfan recibido BCG el indice de aislamiento fue de 10.9 %. No se hall6 Mycobacterium bovis en ningun nifio. Las radiograffas de t&ax, que eran normales al inicio, mostraron calcificaciones cabo de 2 a 5 adios en 73 cases (20.8 %).
al
92
Fox Los 350 nirios fueron tratados con dos drogas, al comienzo isoniazida y Bcido para-aminosalicilico, y en 10s ljltimos 3 aiios, isoniazida y rifampicins en las dosis corrientes, durante 12 6 18 meses. Se discuten 10s fundamentos del tratamiento de estos nirios. Introduction
Occult tuberculous infection is the term used here to classify be infected with M. tuberculosis or M. bovis and who have a or more to the 5TU Mantoux test performed on the flexor surface method, the child being free of symptoms and having a normal
children who are thought to reaction of 10 mm induration of the forearm by the standard chest x-ray.
New Zealand had a population of 3 130 083 in 1976. The economy is based primarily on farming but with an increasing industrial content. Auckland is the largest city in the country with a population of 150000. The Auckland Hospital Board area from which the patients have come has a present population of 798 000 (1976). The racial distribution at the 1971 census was European 609 503, Maori 50 958, Pacific Islanders 27 589 and others 10 350 (total 698 400). During the 1961-71 period the European population in the Auckland area increased 35.5 %, the Maori 156 96 and the Pacific Islanders 218 %. The incidence of tuberculosis in the Maori and Pacific estimated as from 14 to 20 times that in the European.
Island
population
is variously
The eradication of tuberculosis from dairy and beef herds has been actively pursued for some years. In the area from which the patients have been drawn all town supply herds are tuberculin negative. In the early years it was frequently difficult or impossible to find the source of tuberculous infection in both the rural and city communities, while no information was available regarding the frequency of childhood infection by M. tuberculosis, Ad. bovis or opportunist mycobacteria. The major portion of the bacteriology reported has been carried out in the Auckland Mycobacterial Reference Laboratory which was established some 10 years ago. The management of children with positive Mantoux reactions has caused concern in New Zealand and in other countries in the absence of an internationally agreed policy. Some physicians rely on supervision only, others use one drug, usually isoniazid (INH), for varying periods of time, while others use two drugs such as rifampicin and INH for 12 to 18 months. Method Three hundred and fifty children with a diagnosis of occult tuberculous infection have been reviewed. They are part of a series of 1294 tuberculous children studied and managed by the author. Of these, 383 were reviewed retrospectively in 1965 while the remainder have been studied prospectively since 1965. There have been no exclusions. Ninety-four, 13 European and 81 Polynesian, of the 359 children had received BCG vaccination from one to 13 years previously. The reasons for their inclusion are discussed later. All have had 5TU Mantoux and Heaf tests on different limbs performed by experienced senior public health nurses or hospital medical staff and read by the writer after 48-72 hours. Three hundred and forty of the 350 children were admitted to the Children’s Hospital for initial assessment including three gastric aspirations on successive mornings performed by senior ward sisters. The aspirates were cultured and sensitivities performed at the Auckland Mycobacterial Reference Laboratory. Where necessary the Heaf and Mantoux tests were repeated on the thighs or other sites if the tests had been done on the forearms in the previous 4 weeks.
Occult tuberculous
infection
in children
93
X-rays of the chest were read by the paediatric radiologists and the author. If, for instance, the hilar shadows were considered by the radiologist to be doubtfully normal, the patient was excluded from this study. When the laboratory specimens were taken and clinical examination completed treatment was commenced. From the outset two drugs had been used, initially INH and PAS, and in the past two years rifampicin and INH in standard dosage. As a matter of policy following the report of the Medical Research Council (1953) one drug treatment has not been used. After discharge from hospital the patients have been followed up by the author at the Children’s Tuberculosis Clinic where they have been seen 6-weekly for clinical review and for the provision of drugs. X-rays have been performed every 3 months except in the case of the occasional pregnancy. After the termination of drug treatment, for 18 months in the earlier series and more recently for 12 months, the policy has been to see the patients 3-monthly for 1 year, 6-monthly for a second year and thereafter annually until the age of 21 years. Results The 350 children with occult tuberculous infection were 27.4 % of a total of 1294 tuberculous child patients. The type and frequency of the disease in the patients from whom the 350 were selected are shown in Table I, compiled in 1975. Since that time a further 164 patients, making a total of 1294, have been seen with a comparable range of diagnoses including a further 99 with occult infection, bringing the total patients in the occult category to 350. Their mode of presentation is given in Table II. The racial distribution is shown in Table III and as with other types of tuberculosis the Polynesians, including Maoris and Pacific Islanders together, constitute the major part (69.7 %) of the total. The Polynesians constitute approximately 11 .l % of the total population of the area served. Three gastric aspirates for culture and sensitivities were taken from 340 of the 350 patients. The 10 patients from whom gastric aspirates were not taken belonged to a very small number
Table I.
1268 diagnoses made in 1130 patients in 1975
Occult infection Hilar node enlargement Hilar node enlargement and pulmonary lesions Moderate pulmonary disease Extensive pulmonary disease Miliary disease Pleural effusion Other pulmonary lesions e.g. calcification
Table II.
Mode of presentation
251 314 284 111 17 56 54 37
of 350 children with occult infection Number
Routine school or pre-BCG surveys Siblings of positive reactors in school surveys Household contacts of infectious adults Routine tuberculin testing in hospital Other ways Total
Tuberculous meningitis Bone and joint disease Extrathoracic lymphadenitis Peritonitis En/theme nodosum Genito-urinary disease Other extrapulmonary forms
Per cent
79 20 222 15 14
22.6 5.7 63.4 4.3 4.0
350
100.0
35 10 51 10 8 1:
94
Fox
Table III.
Racial distribution
of 350 infected children
Race
European
Maori
Pacific Islanders
Others
Total
Patients Percentage
97 27.7
131 37.4
113 32.3
9 2.6
350 100.0
Table IV.
Occult tuberculous
All patients Positive aspirate No. Percentage
infection : positive gastric aspirates and race
European
Maori
Pacific Islanders
97 4 4.1
131 15 11.5
113 8 7.1
of families whose parents objected to hospital admission. of the parents.
Others 9 2 22.2
Total 350 29 8.3
The source case was usually one
M. tuberculosis was cultured from 1 or more of the gastric aspirates from 29 (8.3 %) of the 350 children. M. bows was not isolated in this group of patients and in fact was isolated from only four of the 1130 patients whose diagnoses are outlined in Table I. Two of the 29 patients with positive gastric aspirates had been vaccinated with BCG. If the 94 children who had received BCG are exluded from the series there remain 27 (10.9 %) with positive gastric aspirates in the remaining 246 patients. The rate of isolation by race is shown in Table IV. The age distribution of the 29 positive children was not remarkable; the numbers of patients in the three age groups O-5, 5-9, and 1O-l 4 years were similar as were the rates of isolation. The mode of presentation of those with positive aspirates was mainly as contacts of known infectious adults and 24 of the 29 presented in this way. Pulmonary calcification occurred in 73 (20.8 %) of the 350 children with an initial diagnosis of occult infection and in 8 (27.6 %) of the 29 with positive gastric aspirates. In these patients calcification has appeared from 2 to 5 years after diagnosis and frequently 1 to 2 years after drug treatment has been completed. The appearance of calcification in the absence of other recognised causes has been taken as a further indication that the original tuberculous infection was pulmonary rather than a!imentary (due for instance to infected milk). Discussion It had been suspected that bovine infection from infected milk may have been responsible for a proportion of infections. This suspicion has not been confirmed. The small number of bovine isolations, 4 from the total series of 1294 cases, is almost certainly due to a very small number of adults known to have bovine pulmonary disease. M. tuberculosis infection in domestic animals is exceptionally rare in New Zealand (D. D. Cordes, personal communication). The rate of isolation of M, tuberculosis from gastric aspirates (8.5 %), the absence of bovine isolates in the occult group and the incidence of calcification (20.8 %) has been taken to indicate that in Auckland the lungs are the primary site of infection and that adults with pulmonary disease are the primary source. This is particularly important for our rural communities
Occult tuberculous
infection
in children
95
where every effort has been made to find the source, though the efforts have sometimes been unrewarding. The rates of calcification, similar in the 3 age groups, is a further indication of unseen active disease, though slight, in the lungs and the desirability of treatment with 2 drugs of all infected individuals in the paediatric age group. Calcification may indicate healing of a tuberculous lesion at the particular site but the possibility of other small, active, but invisible lesions is not excluded. There is a case to be made for treating children with large Mantoux reactions to 5TU, a history of contact and showing pulmonary calcification, as some at least of this group of children will have positive gastric aspirates. The patients have all been treated with two drugs, formerly PAS and INH and more recently rifampicin 15 mg/kg and INH 15-20 mg/kg, for 18 months in the case of contacts and for 1 year in the case of children found in school or pre-BCG surveys and with a more remote history of family contact. No significant complications of drug treatment or extension of tuberculosis have been encountered. The use of 2 drugs has been a matter of policy following the report of the Medical Research Council (1953) that bacillary resistance to isoniazid was found in 64% of patients remaining culture-positive on isoniazid alone at 3 months and in 93 % at 6 months. The report further observed that over a 3 month period after stopping treatment with isoniazid there was no evidence of reversion of isoniazid-resistant strains either to a lower level of resistance or to sensitivity. So-called prophylactic treatment with INH has not been used. Regrettably there have been no control studies in New Zealand. No attempt has been made to select patients for, on the one hand, observation only, or on the other for drug treatment on social, economic or racial grounds, for in the writer’s opinion such is impossible in this particular community, though it may be considered possible elsewhere. The high incidence of tuberculosis in the Polynesian community, the rate of integration and intermarriage, the rate of immigration from the Pacific Islands and the movements of the native Maori population to the city, together would seem to indicate the need for treatment of detected infection. While there is a good deal of information (Ferebee, 1970 ; Joint Tuberculosis Committee, 1973) from other countries regarding the rates of tuberculosis developing in untreated Mantoux positive children, no such information is available regarding the breakdown rates for Maoris and Polynesians in whom it may be about impossible to distinguish endogenous exacerbations from exogenous reinfection. These factors, together with the life style and the cultural pattern of the Polynesians generally, have determined the policy of treating these children in the hope of reducing the incidence of tuberculosis in the foreseeable future. The inclusion of the 94 children, 13 European and 81 Polynesian, who had received BCG requires explanation. They were a particularly difficult group and in no case was it possible to exclude recent infection. All had strongly positive, 20-40 mm reactions to 5TU. In many the BCG had been given in the Islands with no prior or post vaccination Mantoux testing. There were many instances where, on historical grounds, recent infection was extremely likely just before or soon after BCG vaccination. In many families adult cases of tuberculosis had resulted in younger unvaccinated siblings being infected. Investigation and treatment of this group was not undertaken lightly and many children from tuberculous families who had received BCG and gave positive reactions of less than 20 mm induration were not treated but were recommended for further surveillence. Co-operation from parents has generally been good and drug treatment has been regular in 90.7 % of Europeans, 63.8 % of Maoris, 74.9 % of Islanders and 94.7 % of other races.
96
Fox References
Ferebee, S. H. (1970). Controlled chemoprophylaxis trials in tuberculosis. A general review. Advances Research, 17, 28. Joint Tuberculosis Committee (1973). Chemoprophylaxis against tuberculosis in Britain. Tubercle, 54, Medical Research Council (1953). Emergence of bacterial resistance in pulmonary tuberculosis. Under isoniazid, streptomycin plus P.A.S., and streptomycin plus isoniazid. (M.R.C. lsoniazid Trial : Report 2, 217.
in Tuberculosis 309. treatment with No. 4). Lancer.
OCCULT TUBERCULOUS
INFECTION
IN CHILDREN
T. G. Fox Children’s Hospital, Auckland,
New Zealand
Summary Three hundred and fifty New Zealand children with occult tuberculous reviewed. Ninety four had received BCG vaccine previously.
infection
are
Three hundred and forty were admitted to hospital and 3 gastric aspirations were obtained from each child and cultured for tubercle bacilli. Mycobacterium tuberculosis was isolated from 1 or more aspirates in 29 (8.5 %) of the children. Excluding those who had received BCG the isolation rate was 10.9 %. Mycobecrerium bows was not cultured from any child. X-rays of the chest which were initially in 73 (20.8%) cases.
normal showed calcification
after 2 to 5 years
The 350 children were treated with 2 drugs, during the early years isoniazid and PAS and in the past 3 years isoniazid and rifampicin in standard dosage for either 12 or 18 months. The reasons for treating these children are discussed.
350 enfants NBo-Zelandias porteurs d’infection tuberculeuse latente ont et6 etudies. 94 avaient anterieurement recu le vaccin BCG. 340 ont et6 admis a I’hbpital et pour chaque enfant, on a pratique 3 aspirations gastriques et pro&de B la recherche des bacilles tuberculeux. Mycobacterium tuberculosis a et6 isok B partir d’un ou de plus d’un Bchantillon de liquide d’aspiration gastrique chez 29 soit 8.5 % des enfants. Si I’on exclue ceux qui ont recu le BCG le taux d’isolement du bacille a et6 de 10.9 %. Chez aucun des enfants on n’a mis en evidence Mycobacterium bovis. Les radiographies du thorax (elles Btainet initialement normales) ont revel6 la presence de calcifications apres 2 B 5 ans chez 73 soit 20.8 % des cas. Les 350 enfants ont et6 trait& avec 2 medicaments (isoniazide et PAS) au tours des premieres ant-tees de l’etude et par isoniazide et rifampicine lors des trois recentes an&es, aux doses standards, soit pendant 12 mois soit pendant 18 mois. L’auteur discute les raisons qui ont motive le traitement de ces enfants.
Resumen Se han revisado trescientos cincuenta nirios de Nueva Zelandia con una infeccitk tuberculosa oculta. Noventa y cuatro habfan recibido BCG previamente. Se hospitalizaron trescientos cuarenta y a cada uno se le efectuaron 3 lavados gktricos para realizar cultivos en busca de bacilos. Se aislaron Mycobacterium tuberculosis en uno o mas lavados gktricos en 29 niiios (8.5 %). Si se excluyen 10s que habfan recibido BCG el indice de aislamiento fue de 10.9 %. No se hall6 Mycobacterium bovis en ningun nifio. Las radiograffas de t&ax, que eran normales al inicio, mostraron calcificaciones cabo de 2 a 5 adios en 73 cases (20.8 %).
al
92
Fox Los 350 nirios fueron tratados con dos drogas, al comienzo isoniazida y Bcido para-aminosalicilico, y en 10s ljltimos 3 aiios, isoniazida y rifampicins en las dosis corrientes, durante 12 6 18 meses. Se discuten 10s fundamentos del tratamiento de estos nirios. Introduction
Occult tuberculous infection is the term used here to classify be infected with M. tuberculosis or M. bovis and who have a or more to the 5TU Mantoux test performed on the flexor surface method, the child being free of symptoms and having a normal
children who are thought to reaction of 10 mm induration of the forearm by the standard chest x-ray.
New Zealand had a population of 3 130 083 in 1976. The economy is based primarily on farming but with an increasing industrial content. Auckland is the largest city in the country with a population of 150000. The Auckland Hospital Board area from which the patients have come has a present population of 798 000 (1976). The racial distribution at the 1971 census was European 609 503, Maori 50 958, Pacific Islanders 27 589 and others 10 350 (total 698 400). During the 1961-71 period the European population in the Auckland area increased 35.5 %, the Maori 156 96 and the Pacific Islanders 218 %. The incidence of tuberculosis in the Maori and Pacific estimated as from 14 to 20 times that in the European.
Island
population
is variously
The eradication of tuberculosis from dairy and beef herds has been actively pursued for some years. In the area from which the patients have been drawn all town supply herds are tuberculin negative. In the early years it was frequently difficult or impossible to find the source of tuberculous infection in both the rural and city communities, while no information was available regarding the frequency of childhood infection by M. tuberculosis, Ad. bovis or opportunist mycobacteria. The major portion of the bacteriology reported has been carried out in the Auckland Mycobacterial Reference Laboratory which was established some 10 years ago. The management of children with positive Mantoux reactions has caused concern in New Zealand and in other countries in the absence of an internationally agreed policy. Some physicians rely on supervision only, others use one drug, usually isoniazid (INH), for varying periods of time, while others use two drugs such as rifampicin and INH for 12 to 18 months. Method Three hundred and fifty children with a diagnosis of occult tuberculous infection have been reviewed. They are part of a series of 1294 tuberculous children studied and managed by the author. Of these, 383 were reviewed retrospectively in 1965 while the remainder have been studied prospectively since 1965. There have been no exclusions. Ninety-four, 13 European and 81 Polynesian, of the 359 children had received BCG vaccination from one to 13 years previously. The reasons for their inclusion are discussed later. All have had 5TU Mantoux and Heaf tests on different limbs performed by experienced senior public health nurses or hospital medical staff and read by the writer after 48-72 hours. Three hundred and forty of the 350 children were admitted to the Children’s Hospital for initial assessment including three gastric aspirations on successive mornings performed by senior ward sisters. The aspirates were cultured and sensitivities performed at the Auckland Mycobacterial Reference Laboratory. Where necessary the Heaf and Mantoux tests were repeated on the thighs or other sites if the tests had been done on the forearms in the previous 4 weeks.
Occult tuberculous
infection
in children
93
X-rays of the chest were read by the paediatric radiologists and the author. If, for instance, the hilar shadows were considered by the radiologist to be doubtfully normal, the patient was excluded from this study. When the laboratory specimens were taken and clinical examination completed treatment was commenced. From the outset two drugs had been used, initially INH and PAS, and in the past two years rifampicin and INH in standard dosage. As a matter of policy following the report of the Medical Research Council (1953) one drug treatment has not been used. After discharge from hospital the patients have been followed up by the author at the Children’s Tuberculosis Clinic where they have been seen 6-weekly for clinical review and for the provision of drugs. X-rays have been performed every 3 months except in the case of the occasional pregnancy. After the termination of drug treatment, for 18 months in the earlier series and more recently for 12 months, the policy has been to see the patients 3-monthly for 1 year, 6-monthly for a second year and thereafter annually until the age of 21 years. Results The 350 children with occult tuberculous infection were 27.4 % of a total of 1294 tuberculous child patients. The type and frequency of the disease in the patients from whom the 350 were selected are shown in Table I, compiled in 1975. Since that time a further 164 patients, making a total of 1294, have been seen with a comparable range of diagnoses including a further 99 with occult infection, bringing the total patients in the occult category to 350. Their mode of presentation is given in Table II. The racial distribution is shown in Table III and as with other types of tuberculosis the Polynesians, including Maoris and Pacific Islanders together, constitute the major part (69.7 %) of the total. The Polynesians constitute approximately 11 .l % of the total population of the area served. Three gastric aspirates for culture and sensitivities were taken from 340 of the 350 patients. The 10 patients from whom gastric aspirates were not taken belonged to a very small number
Table I.
1268 diagnoses made in 1130 patients in 1975
Occult infection Hilar node enlargement Hilar node enlargement and pulmonary lesions Moderate pulmonary disease Extensive pulmonary disease Miliary disease Pleural effusion Other pulmonary lesions e.g. calcification
Table II.
Mode of presentation
251 314 284 111 17 56 54 37
of 350 children with occult infection Number
Routine school or pre-BCG surveys Siblings of positive reactors in school surveys Household contacts of infectious adults Routine tuberculin testing in hospital Other ways Total
Tuberculous meningitis Bone and joint disease Extrathoracic lymphadenitis Peritonitis En/theme nodosum Genito-urinary disease Other extrapulmonary forms
Per cent
79 20 222 15 14
22.6 5.7 63.4 4.3 4.0
350
100.0
35 10 51 10 8 1:
94
Fox
Table III.
Racial distribution
of 350 infected children
Race
European
Maori
Pacific Islanders
Others
Total
Patients Percentage
97 27.7
131 37.4
113 32.3
9 2.6
350 100.0
Table IV.
Occult tuberculous
All patients Positive aspirate No. Percentage
infection : positive gastric aspirates and race
European
Maori
Pacific Islanders
97 4 4.1
131 15 11.5
113 8 7.1
of families whose parents objected to hospital admission. of the parents.
Others 9 2 22.2
Total 350 29 8.3
The source case was usually one
M. tuberculosis was cultured from 1 or more of the gastric aspirates from 29 (8.3 %) of the 350 children. M. bows was not isolated in this group of patients and in fact was isolated from only four of the 1130 patients whose diagnoses are outlined in Table I. Two of the 29 patients with positive gastric aspirates had been vaccinated with BCG. If the 94 children who had received BCG are exluded from the series there remain 27 (10.9 %) with positive gastric aspirates in the remaining 246 patients. The rate of isolation by race is shown in Table IV. The age distribution of the 29 positive children was not remarkable; the numbers of patients in the three age groups O-5, 5-9, and 1O-l 4 years were similar as were the rates of isolation. The mode of presentation of those with positive aspirates was mainly as contacts of known infectious adults and 24 of the 29 presented in this way. Pulmonary calcification occurred in 73 (20.8 %) of the 350 children with an initial diagnosis of occult infection and in 8 (27.6 %) of the 29 with positive gastric aspirates. In these patients calcification has appeared from 2 to 5 years after diagnosis and frequently 1 to 2 years after drug treatment has been completed. The appearance of calcification in the absence of other recognised causes has been taken as a further indication that the original tuberculous infection was pulmonary rather than a!imentary (due for instance to infected milk). Discussion It had been suspected that bovine infection from infected milk may have been responsible for a proportion of infections. This suspicion has not been confirmed. The small number of bovine isolations, 4 from the total series of 1294 cases, is almost certainly due to a very small number of adults known to have bovine pulmonary disease. M. tuberculosis infection in domestic animals is exceptionally rare in New Zealand (D. D. Cordes, personal communication). The rate of isolation of M, tuberculosis from gastric aspirates (8.5 %), the absence of bovine isolates in the occult group and the incidence of calcification (20.8 %) has been taken to indicate that in Auckland the lungs are the primary site of infection and that adults with pulmonary disease are the primary source. This is particularly important for our rural communities
Occult tuberculous
infection
in children
95
where every effort has been made to find the source, though the efforts have sometimes been unrewarding. The rates of calcification, similar in the 3 age groups, is a further indication of unseen active disease, though slight, in the lungs and the desirability of treatment with 2 drugs of all infected individuals in the paediatric age group. Calcification may indicate healing of a tuberculous lesion at the particular site but the possibility of other small, active, but invisible lesions is not excluded. There is a case to be made for treating children with large Mantoux reactions to 5TU, a history of contact and showing pulmonary calcification, as some at least of this group of children will have positive gastric aspirates. The patients have all been treated with two drugs, formerly PAS and INH and more recently rifampicin 15 mg/kg and INH 15-20 mg/kg, for 18 months in the case of contacts and for 1 year in the case of children found in school or pre-BCG surveys and with a more remote history of family contact. No significant complications of drug treatment or extension of tuberculosis have been encountered. The use of 2 drugs has been a matter of policy following the report of the Medical Research Council (1953) that bacillary resistance to isoniazid was found in 64% of patients remaining culture-positive on isoniazid alone at 3 months and in 93 % at 6 months. The report further observed that over a 3 month period after stopping treatment with isoniazid there was no evidence of reversion of isoniazid-resistant strains either to a lower level of resistance or to sensitivity. So-called prophylactic treatment with INH has not been used. Regrettably there have been no control studies in New Zealand. No attempt has been made to select patients for, on the one hand, observation only, or on the other for drug treatment on social, economic or racial grounds, for in the writer’s opinion such is impossible in this particular community, though it may be considered possible elsewhere. The high incidence of tuberculosis in the Polynesian community, the rate of integration and intermarriage, the rate of immigration from the Pacific Islands and the movements of the native Maori population to the city, together would seem to indicate the need for treatment of detected infection. While there is a good deal of information (Ferebee, 1970 ; Joint Tuberculosis Committee, 1973) from other countries regarding the rates of tuberculosis developing in untreated Mantoux positive children, no such information is available regarding the breakdown rates for Maoris and Polynesians in whom it may be about impossible to distinguish endogenous exacerbations from exogenous reinfection. These factors, together with the life style and the cultural pattern of the Polynesians generally, have determined the policy of treating these children in the hope of reducing the incidence of tuberculosis in the foreseeable future. The inclusion of the 94 children, 13 European and 81 Polynesian, who had received BCG requires explanation. They were a particularly difficult group and in no case was it possible to exclude recent infection. All had strongly positive, 20-40 mm reactions to 5TU. In many the BCG had been given in the Islands with no prior or post vaccination Mantoux testing. There were many instances where, on historical grounds, recent infection was extremely likely just before or soon after BCG vaccination. In many families adult cases of tuberculosis had resulted in younger unvaccinated siblings being infected. Investigation and treatment of this group was not undertaken lightly and many children from tuberculous families who had received BCG and gave positive reactions of less than 20 mm induration were not treated but were recommended for further surveillence. Co-operation from parents has generally been good and drug treatment has been regular in 90.7 % of Europeans, 63.8 % of Maoris, 74.9 % of Islanders and 94.7 % of other races.
96
Fox References
Ferebee, S. H. (1970). Controlled chemoprophylaxis trials in tuberculosis. A general review. Advances Research, 17, 28. Joint Tuberculosis Committee (1973). Chemoprophylaxis against tuberculosis in Britain. Tubercle, 54, Medical Research Council (1953). Emergence of bacterial resistance in pulmonary tuberculosis. Under isoniazid, streptomycin plus P.A.S., and streptomycin plus isoniazid. (M.R.C. lsoniazid Trial : Report 2, 217.
in Tuberculosis 309. treatment with No. 4). Lancer.
