|TUBERCULIN SENSITIVITY IN YOUNG CHILDREN (0-4 YEARS
OLD) AS AN INDEX OF TUBERCULOSIS IN THE COMMUNITY.
|NL Bordia, Anton Geser, J Maclary, I Mundt & Kul
Bhushan: Indian J TB 1960, 8, 25-43.
The purpose of this study was to find out whether
the prevalence of infection in young children might be used as an
index of the tuberculosis problem in a population. Tuberculin testing
was done in a random sample of 2,883 children (0-4 years) in Bangalore
city, of those 2,589 (89.8%) actually completed testing. A total
of 4340 children were registered in 59 villages and of these 4090
(94.2%) were tuberculin tested. The villages were from Bangalore,
Kolar and Mandya as these districts were within 100 miles from Bangalore
city. The team went from house to house and made a complete registration
of the children 0-4 years in the selected houses. Information on
socio-economic status, density of population etc., was also collected
before giving tuberculin 1 TU RT 23 with Tween 80.
The results of the study showed that prevalence
of infection in 0-4 years age group of cantonment area was 1.6%
and in the crowded city area 4.1% at 14mm induration level. In the
rural population, the prevalence of tuberculosis infection was 2%.
In the city, a positive correlation between tuberculosis infection
and socio-economic condition was obtained while it was not seen
in rural areas. It was not possible to establish any correlation
between tuberculosis disease and infection either in rural or urban
areas, as the population was not examined for the prevalence of
|KEY WORDS: PREVALENCE, INFECTION, CHILDREN,
RURAL, URBAN, COMMUNITY.
|SIZE & EXTENT OF TB PROBLEM IN URBAN & RURAL
|Raj Narain: Indian J TB 1962, 9, 147-50 & also
in Proceed Natl TB & Chest Dis Workers Conf 1962, 155-68.
The aim of modern Public Health Programmes, is
a reduction in the total amount of disease in the community. The
unit for treatment and cure is not an individual but a sick community.
With this new aim, it becomes essential to know the size and extent
of tuberculosis in the community as it will be helpful not for purposes
of planning only but essentially for the assessment of their effect
on the problem. An attempt is made to review the important features
of the available knowledge about infection, morbidity and mortality
through various surveys. (i) Prevalence of Infection: Tuberculosis
infection is widespread in both urban and rural areas of almost
all parts of the country. Nearly 40% of the population are infected.
To avoid the effect of non- specific allergy and get a more reliable
demarcation, tuberculin reactions of 14mm and more were considered
as positive by National Tuberculosis Institute. (ii) Prevalence
of morbidity: The prevalence of radiologically active tuberculosis
in the population is likely to be 1.5%, Prevalence of bacteriologically
confirmed diseases is 0.4%. Based on single sample of sputum examination,
the prevalence of infectious cases in the country is probably an
under estimate. About two million are infectious at any one point
of time. (iii) Mortality: Deaths from tuberculosis in the
country is not definitely known. The impression of clinicians that
death due to tuberculosis have fallen sharply may not be true. Half
a million deaths will appear an underestimate. About 250 per 1,00,000
persons i.e., one million deaths due to tuberculosis per year seems
to be a reasonable estimate. (iv) Bovine Tuberculosis: Only
a few cases in man caused by the bovine tubercle bacillus have been
reported although 2.75% to 25% of cattle have been found tuberculin
To put in a nut shell, the problem of tuberculosis
in India is a gigantic one and our means of fighting it with the
single tool of BCG, do not even touch the fringe of the problem.
|KEY WORDS: INFECTION, SUSPECT CASE, CASE, MORTALITY,
|SOME ASPECTS OF A TB PREVALENCE SURVEY IN A SOUTH
|Raj Narain, A Geser, MV Jambunathan & M Subramanian:
Bull WHO 1963, 29, 641-64 & Indian J TB 1963, 9, 85-116.
The objective was to establish the prevalence rates
for tuberculosis infection, radiologically active pulmonary tuberculosis
and bacteriologically confirmed diseases for different age and sex
groups. Tumkur District in Mysore State consisting of 2,392 villages,
10 towns of was selected for the study. The district headquarter
town Tumkur was excluded from the survey. Random sample of 62 villages
and 4 town blocks having a population of 34,746 persons constituted
the study population. All the individuals available in the registered
population were given a Mantoux test with 1 TU RT 23 with Tween
80. Longitudinal diameter of induration was read 3-4 days after
the test. At the time of tuberculin test, all persons aged 10 years
and above were offered a single 70mm photofluorogram. For each picture
read as abnormal, a spot specimen of sputum of the individual concerned
was collected at the time of reading the tuberculin test. Age and
sex distribution of infection and disease were studied.
Various parameters concerning the prevalence of
infection and disease in the community were reported. Prevalence
rate of infection in all ages and both sexes of the population was
found to be 38.3%, radiologically active tuberculosis 1.86% and
0.41% sputum positive disease. The infection and disease increased
with age; of the total diseased, half were in age group 40 years
and more and about 2/3 among males.
|KEY WORDS: SURVEY, PREVALENCE, INFECTION, DISEASE,
CASE, COMMIUNITY, RURAL, URBAN.
|PROBLEMS CONNECTED WITH ESTIMATION OF THE INCIDENCE
OF TUBERCULOSIS INFECTION
|Raj Narain, SS Nair, P Chandrasekhar & G Ramanatha
Rao: Indian J TB 1965, 13, 5-23.
The incidence of infection with mycobacterium tuberculosis
is an index of the risk of infection to which a community is exposed.
An accurate estimation of incidence rate is of considerable importance
in understanding the epidemiology of tuberculosis in organising
control measures. A new method of estimating incidence of infection
is discussed. The material from 3 studies of National TB Institute
has been utilized. Study I: is a part of a survey of a random
sample of 134 villages. No previous tuberculin testing or BCG vaccination
had been carried out in the area, but each person was examined for
BCG scar in order to exclude persons vaccinated probably from other
areas. After a complete census, a Mantoux test with 1 TU of PPD
RT 23 with Tween 80 given on two occasions (Round I and II). Those
with reaction of 13mm or less at Round I were offered a test with
20 TU with Tween 80 within a week of 1 TU test. The interval between
the rounds was about 18 months. From the analysis of the data from
the first 50 villages for which complete information for both rounds
was available, it was seen that there was a general increase in
the size of reactions elicited in the second round. Study 2:
tuberculin testing was carried out with 1 TU and 20 TU among
selected control groups which provided the data regarding
the enhancing of tuberculin allergy seen in repeat tuberculin
tests. Study 3: in the course of the longitudinal survey
reader assessments were carried out periodically to judge
the standards of the tuberculin test readers. Inter & intra-reader
comparisons were made. The findings have been used to estimate the
magnitude of reader variation. The data was also used to study variations
in the technique of testing and reading.
It was estimated that on an average inter &
intra-reader variations between the rounds were unlikely to exceed
6mm or more in more than 5% of the observations. The reading errors
have an equal chance of being positive or negative except at extreme
ends of the distribution where zero readings of Round I can only
show an increase, and the very large reactions had a greater chance
of showing only a decrease at a subsequent round. The study mainly
concerns with the problems of estimating the incidence of tuberculous
infection in a community. Calculations based on age-specific prevalence
rates or on rates of tuberculin conversion or both subject to gross
error, leading to unreliable epidemiological conclusions. For estimating
the newly infected, a new approach has been suggested based on the
drawing of a curve for the distribution of differences in reaction
size from one round of tuberculin testing to another. It is assumed
that if new infection causes a distinct rise in the degree of tuberculin
sensitivity which is greater than the combined rise due to enhancement
and reader variation, the distribution of differences between the
rounds should indicate the newly infected. It is shown that the
newly infected probably constitute a homogeneous group with an increase
in mean reaction size of about 24mm and standard deviation of 4mm.
Accordingly, 98% of the newly infected show an increase in reaction
size of 16mm or more.
|KEY WORDS: RISK OF INFECTION, TUBERCULIN ALLERGY,
ENHANCEMENT, INCIDENCE, INFECTION.
|DISTRIBUTION OF INFECTION AND DISEASE AMONG HOUSEHOLDS
IN A RURAL COMMUNITY
|Raj Narain, SS Nair, G Ramanatha Rao & P Chandrasekhar:
Bull WHO 1966, 34, 639-54 & Indian J TB 1966, 13, 129-46.
Studies on the distribution of tuberculous infection
and disease in households have mostly been restricted to the examination
of contacts of known cases. Clinical experience has lead to a strong
belief that tuberculosis is a family disease and contact examination
is a must for case-finding programmes. A representative
picture of the distribution of infection and disease in households
can be obtained only from a tuberculosis prevalence survey.
This paper reports an investigation, based on a
prevalence survey in a rural community in south India. The survey
techniques and study population have been described in an earlier
report. Briefly, the defacto population was given a tuberculin test
with 1 TU of PPD RT 23 with Tween 80 and those aged 10 years and
above were examined by 70mm photofluorography. All the X-ray pictures
were read by two independent readers. Those with any abnormal shadows
by either of the two readers were eligible for examination of a
single spot specimen of sputum by direct smear and culture. The
defacto population numbered 29,813 and tuberculin test results were
available for 27,115. After excluding BCG scars, the study population
of 24,474 was distributed over 5,266 households which were further
classified as bacillary case household with atleast
one bacteriologically confirmed case, X-ray case household
with atleast one radiologically active case but with no bacillary
cases and non-case household with neither a bacillary
nor an X-ray case. Total bacillary cases were 77 and were distributed
in 75 household. 74 households had one case each and one household
had 3 bacillary cases.
The findings of the study have thrown considerable
doubt on the usefulness of contact examination in tuberculosis control;
(1) over 80% of the total number of infected persons, in any age
group, occurred in households without cases, (2) cases of tuberculosis
occurred mostly singly in households, and the chance of finding
an additional case by contact examination in the same household
is extremely small, (3) a common belief has been that prevalence
of infection in children in 0-4 age group is a good index of disease
in households, but in this study about 32% of households with cases
of tuberculosis had no children in this age group, (4) in houses
with bacteriologically confirmed case only 12% of the children in
0-4 age group showed evidence of infection, a possible explanation
of such a low intensity of infection could be that there is resistance
to infection. It is well known that some children even after repeated
BCG vaccination do not become tuberculin positive. It is felt that
a large number of children do inhale tubercle bacilli, but a primary
complex does not develop or even if it develops, the children remain
tuberculin negative. A hypothesis has been made that in addition
to resistance to infection, there is something known as resistance
to disease. Otherwise, it is difficult to explain why under
conditions of heavy exposure in infection, only some individuals
develop evidence of infection and very few develop disease thereafter.
|KEY WORDS: PREVALENCE, INFECTION, DISEASE,
CONTACT EXAMINATION, HOUSEHOLD, RURAL COMMUNITY.
|SOME EPIDEMIOLOGICAL ASPECTS OF TUBERCULOUS DISEASE
AND INFECTION IN PAEDIATRIC AGE GROUP IN A RURAL COMMUNITY
|GD Gothi, SS Nair & Pyare Lal: Indian Paediatrics
1971, 8, 186-94.
The prevalence and incidence rates of tuberculous
infection and disease in the community are known in the age group
10 years and above from several surveys carried out so far. The
present paper provides various parameters of tuberculosis in particular
in the pediatric age group. A random sample of 119 villages in 3
taluks of Bangalore district were surveyed 4 times from May 1961
to July 1968 at intervals of 18 months, 3 years and 5 years of the
initial survey. Tuberculin test was done for the entire available
population with 1 TU PPD RT 23 with Tween 80, and 70mm X-ray for
all available persons aged 5 years and above. Two samples of sputum
were obtained from the X-ray abnormals, and examined by smear and
It was found that prevalence of infection increased
with age from 2.1% at 0-4 year age group to 16.5% at 10-14 year
age group, compared to 47% at 15 years and above age group. Prevalence
of disease in 5-14 year age group was considerably lower than in
age group 15 years or more. Tuberculosis morbidity increased with
the size of tuberculin reaction and it was high among children with
reaction 20mm or more. Incidence of infection increased with age
from 0.9% per year in age group 0-4 years to 2.8% per year among
that of 15 years and above. Incidence of disease also showed the
same phenomenon-, rising from 0.5% in age group 5-9 to 4% per year
in the age group 15 years and above. There were 10 sputum positive
cases in 5-14 years of age in first survey, of them, 8 became negative
and one died. While from among 152 cases in 15 years and above age
group, 48 became negative, 72 died and 32 remained positive. The
fate of cases of pulmonary tuberculosis in 5-14 years age was not
as serious as in 15 years and above age group. The survey had no
means of examining miliary and meningeal tuberculosis.
Children as well as adults with larger reaction
of 20mm or more to tuberculin test had higher mortality. This could
be considered due to tuberculous infection after taking into account
death due to non- tuberculous reasons in both the infected and uninfected
groups. Use of chemoprophylaxis might be considered for those who
give history of contact with open cases and have tuberculin reaction
size 20mm or more.
|KEYWORDS: CHILDREN, RURAL COMMUNITY, PREVALANCE,
INCIDENCE, INFECTION, DISEASE, TUBERCULIN, INDURATION SIZE, MORTALITY,
|DISTRIBUTION OF TUBERCULOUS INFECTION AND DISEASE
IN CLUSTERS OF RURAL HOUSEHOLDS
|SS Nair, G Ramanatha Rao & P Chandrasekhar: Indian
J TB 1971, 18, 3-9.
Data from 62 randomly selected villages in a district
of south India, which formed part of a prevalence survey carried
out by the National Tuberculosis Institute, Bangalore, during 1960-61,
has been made use of. The survey covered 29,813 persons in 5,266
households. There were 70 cases with bacilli demonstrable either
in smear or culture and 300 suspect cases. Using the village map
(prepared by survey staff), case clusters were formed
first, with each case household as nucleus and adjacent households
within a maximum distance of about 20 meters on either side of the
case households. Households closest to the nucleus household on
either side have been called as 1st neighbourhood and those coming
next in proximity on either side as a 2nd neighbourhood and so on.
The case household and its four neighbourhood together was called
a cluster. If another case household was found within 4th neighbourhood
of the first case the cluster was extended by including the 4th
neighbourhood of the new case also. Such clusters were called composite
case clusters and clusters with only one case household as simple
case clusters. Similarly, suspect case clusters were formed and
differentiated as simple suspect clusters or composite suspect clusters.
Further, to serve as a control group, non-case clusters were constituted
from a systematic sample of 10% households that were not included
in case or suspect case clusters.
Out of 60 case clusters formed, only 7 have multiple
cases showing that there was no evidence of high concentration of
disease in case clusters. While the percentage of child contacts
(0-14 years) infected was considerably higher in case clusters (25.8%),
there was not much difference between suspect case clusters (14.9%)
and non-case clusters (9.8%). Similarly, there was not much difference
between simple and composite clusters. Infection among child contacts
was higher in case households as compared to their neighbourhoods.
To get some idea of the zone of influence of a case or suspect case,
prevalence of infection was studied for 10 neighbourhoods, in simple
clusters to avoid the influence of multiple cases. It appeared that
the zone of influence of a case may extend at least upto the 10th
neighbourhood. It was also noted that there was very little difference
between zones of influence of suspect cases and non-cases. Case
clusters in which the nucleus case had shown activity of lung lesion
(evident on X-ray reading) or had cough showed significantly higher
infection among child contacts. Clusters around cases positive on
both smear and culture did not show higher infection than those
around cases positive on culture only. (This may be due to sputum
examination of single specimen only).
Out of the total infected persons in the community,
only 2% were in case households and 7% in suspect case households,
over 90% being in non-case households. The zone of influence of
a case extending at least upto the 10th neighbourhood and the overlapping
of such zones of influence of cases, present and past, seems to
be the most probable explanation for the wide scatter of infection
in the community. Prevalence of infection among child contacts was
definitely higher in case clusters. But, the significance of this
could be understood only from a study of the incidence of disease
during subsequent years in different types of clusters. It is significant
that only 10% of the total infected persons in the community were
found in case clusters. The case yield in general population, cluster
contacts, household contacts and symptomatics attending general
health institutions have been also compared. The case yield in the
last group (10%) is much higher than the case yield from both types
of contacts (0.7% and 0.6%) which where only slightly higher than
the case yield from the general population (0.4%).
|KEYWORDS: RURAL, HOUSEHOLDS, CLUSTERS, CASE,
SUSPECT CASE, CONTACT, PREVALENCE, INFECTION, DISEASE, SURVEY.
|TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA:
A FIVE YEAR EPIDEMIOLOGICAL STUDY
|National Tuberculosis Institute, Bangalore: Bull
WHO 1974, 51, 473-88.
A rural population of 65,000 belonging to 119 randomly
selected villages of Bangalore district was repeatedly examined
four times during 1961 to 1968, by tuberculin test, X-ray and sputum
examinations, to study the epidemiology of tuberculosis without
any active anti-tuberculosis measures. The interval between the
first and the fourth examination was 5 years. The coverage of various
examinations at different surveys were very high.
The main findings of the study are: Prevalence
rate of tuberculous infection in the population was about
30% (among females 25% and males 35%). The overall prevalence
rates of infection were fairly constant at all the four surveys,
but a steady decrease in the prevalence of infection was observed
in the age group 0-24 years. Annual incidence rate of infection
on the average was about 1%. During the study period,
the incidence of infection showed a decline from 1.63% to 0.8% for
all ages combined. Prevalence rate of disease ranged from
337 to 406 per 1,00,000 population during the study period,
the highest being at the time of first survey and lowest at the
time of third survey. For the younger age group of 5-34 years, the
rates showed continuous decrease during the study period. Annual
incidence rate of disease ranged from 79 to 132 per 1,00,000
population, highest being between first and second surveys and lowest
between second and third surveys. The incidence rate in younger
age groups below 35 years showed a decline during the study period.
Those with tuberculin test induration of 20mm or more had highest
annual incidence rate of disease. The annual incidence rate
of bacteriologically confirmed disease in the three radiological
groups of population was (i) 185 per 1,00,000 with normal X-rays,
(ii) 958 per 1,00,000 with abnormal shadows judged as inactive
tuberculous are non-tuberculous and (iii) 4,530 per 1,00,000 with
abnormal shadows judged as active or probably active tuberculous
but bacteriologically not confirmed. The third group constituted
1% of the total population and contributed 34% of the total incidence
cases. In each of the above three radiological groups, the incidence
of disease was highest among those with tuberculin test induration
of 20mm or more to 1 TU RT 23 with Tween 80. Those with 20mm or
more tuberculin test induration in the third radiological group
constituted 0.45% of the total population but contributed 27% of
the total incidence cases. Incidence rate for males was nearly double
that of females. More than half of the new male cases were 35 years
of age, whereas more than half the females were below the age of
35 years. Out of 126 cases followed up at three subsequent surveys
over a period of 5 years, 49.2% died, 32.5% got cured and 18.3%
continued to remain sputum positive. Both death and cure rates
were highest during the first one and a half year period.
About 30% of newly detected cases come from population
uninfected at an earlier survey. Both infection and disease showed
a decline in the younger age group. There was no evidence of an
increase in drug resistance among newly diagnosed cases. Incidence
of cases showed a higher natural cure. These findings indicate that
tuberculosis cases are not a uniform entity. There can be different
gradations from the point of view of diagnosis and ability to benefit
from treatment. The differences between male and female patients
with regard to death and cure rates support this view
|.KEY WORDS: TREND, RURAL POPULATION, PREVALENCE,
INCIDENCE, INFECTION, DISEASE, LONGITUDINAL SURVEY.
|INCIDENCE OF TUBERCULOSIS AMONG NEWLY INFECTED POPULATION
AND IN RELATION TO THE DURATION OF INFECTED STATUS
|VV Krishnamurthy, SS Nair, GD Gothi & AK Chakraborty:
Indian J TB 1976, 23, 3-7.
Some of the parameters relating to duration of
infected status and incidence of disease have been measured by analysing
the data collected from the five year study. Between 1961-68, 119
villages in Bangalore district with total average population of
about 62,000 were surveyed at intervals of 1, 3 and 5 years from
the first survey. All persons were tuberculin tested with 1 TU RT
23 and those aged 5 years or more were X-rayed. Sputum of those
persons showing any X-ray abnormality were collected and examined
for AFB. Persons with X-ray abnormality but bacteriologically negative
or with normal X-ray in all the preceding surveys, and who became
culture positive with X-ray abnormality in the current survey were
termed as "New cases". New cases who had shown 10 mm or
more reaction to 1 TU RT 23 at I Survey were considered infected
previously. New cases, tuberculin negative at I survey but who showed
an increase of 16 mm or more between two consecutive surveys were
considered infected midway between the two surveys.
Of the 42 new cases diagnosed from among the newly
infected during 5 years, 81% came from those infected within one
year. Incidence rate of cases among those who were infected within
one year was about 5 times more than those infected earlier than
one year. Incidence of cases steadily decreased with the increase
in the duration of infection. Further, it was found that one fourth
of all newly diagnosed cases came from the newly infected persons.
However, the size of the pool of previously infected persons in
a community being much larger, at least 72% of the new cases came
from the reservoir of previously infected persons. The incidence
of disease among the newly infected was almost the same in the three
age groups i.e., 5-14, 15-34 and 35 years or more. But, the ratio
of the incidence rates for the newly infected and the previously
infected decreased from 13 for the age group 5-14 to 3 for the age
group 35 years and above. In other words, the incidence of disease
among the newly infected in the age group 5-14 was thirteen times
more than for the previously infected in the same age-group whereas
in the age-group 35 years and above, the incidence among newly infected
was only thrice that among the previously infected.
Out of the 160 new cases diagnosed during the three repeat surveys,
21 per cent cases came from among those who were infected on the
average for one year or less. This is almost in conformity with
the hypothesis that one-fourth of all new active cases come from
new infections less than a year old.
|KEY WORDS: INCIDENCE, INFECTION, CASE, TUBERCULIN
|PREVALENCE OF NON-SPECIFIC SENSITIVITY TO TUBERCULIN
IN A SOUTH INDIAN RURAL POPULATION
|AK Chakraborty, KT Ganapathy, SS Nair & Kul Bhushan:
Indian J Med Res 1976, 64, 639-51.
The data from a tuberculosis prevalence survey
carried out in three taluks of Bangalore district in south India
during 1961-68 were analysed to study (i) the prevalence of non-specific
sensitivity in the community i.e., prevalence of infection with
mycobacteria other than M.tuberculosis, as found by testing the
population with tuberculin RT 23 of a lower strength (1 TU) and
higher strength (20 TU), both with Tween 80 and (ii) additional
boosting if any, resulting from testing with higher dose of tuberculin,
immediately following a test with 1 TU RT 23.
The level of demarcation between infected and uninfected
with 1 TU was 0-9 mm induration size and this negative group tested
with 20 TU dose induration of 8 mm or more was considered positive.
Prevalence of infection with M.tuberculosis in the community were
2.1% in 0-4 years, 7.9% in 5-9 years, 16.5% in 10-14 years, 33.2%
in 15-24 years and overall 14.5% in 0-24 years of age group. Infection
rate with other mycobacteria were 12.9%, 44.9%, 66.2%, 62.4% and
45.7% respectively in the above stated different age groups.
Testing the population with 20 TU RT 23 following
a 1 TU test was found not to boost the tuberculin reactions over
that observed on a single test with 1 TU only.
|KEY WORDS: NTM, PREVALENCE, INFECTION, BOOSTING,
TUBERCULIN REACTION, RURAL POPULATION.
|TUBERCULOSIS IN CHILDREN IN A SLUM COMMUNITY
|GD Gothi, Benjamin Isaac, AK Chakraborty, R Rajalakshmi
& Sukant Singh: Indian J TB 1977, 24, 68-74.
A study was conducted in a slum area of Bangalore,
to get information on the prevalence of all forms of tuberculosis
in 0-4 year age group, respiratory tuberculosis in 5-14 year age
group and the proportion of respiratory tuberculosis among total
respiratory diseases in 0-14 year age group. Entire population in
a slum area was investigated. Children aged 0-9 years were given
tuberculin test and their nutritional status assessed. All persons
were X-rayed. Sputum specimens were collected from those having
radiological abnormality in chest, chest symptoms of one week or
more in 0-4 years, in addition from those with any kind of sickness,
malnutrition and tuberculin reactors.
In 0-9 year age group, 5.5% were tuberculin positive
(without BCG lesions), in 0-4 years, 1.8% and 5-9 years, 11.3%.
Among the X-rayed children, 47.4% had some kind of sickness, the
proportion being significantly high in 0-4 year age group. The respiratory
sickness is the commonest among children of all ages followed by
malnutrition (21%). Among children with chest symptoms, upper respiratory
infections were 33%. Chest X-ray abnormalities were present in 4.5%
of children and of these 82.5% had non-specific pneumonitis. Of
71 persons with respiratory disease, about 7% were tuberculous.
Out of 1408 children, only 5 had active primary tuberculosis, giving
a prevalence of 0.35%. None in 0-4 year age had sputum positive
disease or extra pulmonary tuberculosis.
It has been highlighted that non-tuberculous chest
diseases are common in pediatric age group and many of these may
be wrongly classified as active tuberculous in practice. It is concluded
that tuberculosis in the pediatric age group in this community is
not a serious public health problem.
|KEY WORDS: CHILDREN, SLUM COMMUNITY, PREVALENCE,
INFECTION, PEDIATRIC TUBERCULOSIS.
|PREVALENCE OF INFECTION AMONG UNVACCINATED CHILDREN
FOR TUBERCULOSIS SURVEILLANCE
|AK Chakraborty, KT Ganapathy & GD Gothi: Indian
J TB 1980, 72, 7-12.
A survey was carried out among 12,535 children
in the age group 0-9 years of 90 villages in Doddballapur sub-division
of Bangalore district to study the possible variation in the prevalence
of tuberculous infection among the unvaccinated children in a village
depending upon the varying prevalence of BCG scars in the same population.
In each village, all the children in the age group of 0-9 years
were registered and examined for the presence or absence of the
BCG scar. Of the 12,535 children, 6269 (50%) who did not have BCG
scars were eligible for tuberculin test, while 6045 were actually
tested. Each child without BCG scar was tuberculin tested with 1
TU RT 23 with tween 80 and the reaction read between 72 and 96 hours.
Two proportions were calculated in each village viz., a) the proportion
with BCG scars and b) that of infected children among those without
scar and the villages were distributed by these two proportions.
On the basis of distribution of tuberculin reactions,
10 and 12 mm induration was the demarcation between positive and
negative reactors. Prevalence of infection among 0-9 years was 4.9%,
2.6% among 0-4 years and 8.9% among 5-9 years. Distribution of villages
according to two variables i.e., prevalence of BCG scars and prevalence
of infection among unvaccinated children did not show any correlation
with the prevalence of infection among the unvaccinated in the same
It is seen from the study that exclusions of various
proportions of children with BCG scars did not have any correlation
with the prevalence of infection among the unvaccinated in the same
In non-e of the villages any association was seen
between these two. In view of this finding, it is felt that the
simple method of periodic tuberculin testing of the population in
younger age groups could be developed into a method of tuberculosis
surveillance even in areas where direct mass BCG vaccination is
given. This would appear to be the cheapest, practicable and technically
appropriate method of studying the overall tuberculosis situation.
|KEY WORDS: PREVALENCE, INFECTION, BCG SCAR,
|EFFECT OF NUTRITIONAL STATUS ON DELAYED HYPERSENSITIVITY
DUE TO TUBERCULIN TEST IN CHILDREN OF AN URBAN SLUM COMMUNITY
|AK Chakraborty, KT Ganapathy & R Rajalakshmi: Indian
J TB 1980, 27, 115-19.
Prevalence of tuberculous infection in young children
is an important surveillance measure. However, the hypersensitivity
may be depressed by malnutrition and thus interfere with the interpretation
of tuberculin test leading to underestimation of the infection rate.
Objective of this investigation was to study the relationship between
tuberculin reaction with 1 TU RT 23 and nutritional status of children.
The study was carried out in 1974 among children aged 1-9 years
of age living in an urban slum area of Bangalore city and who were
not given BCG vaccination.
Of the 1151 registered children aged 0-9 years,
482 in the age group 1-4 and 526 in 5-9 years formed the study group.
Of these 1008 children, 980 had both clinical evaluation and anthropometric
measurement for nutritional status and 963 had both tuberculin test
readings and anthropometric measurements carried out for them. Of
the 482 children aged 1-4 years, 230 were classified as suffering
from Protein Calorie Malnutrition (PCM) and of the 498 in the 5-9
years of age, 227 were classified as suffering from PCM. Distribution
of tuberculin test indurations in mm among the normals and the undernourished
were compared; no significant difference in the mean size of tuberculin
indurations as well as in the distributions of these indurations
was observed, regardless of the method used for arriving at the
|KEY WORDS: NUTRITIONAL STATUS, TUBERCULIN REACTION,
SLUM COMMUNITY, INFECTION.
|TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA:
REPORT ON FIVE SURVEYS
|AK Chakraborty, Hardan Singh, K Srikantan, KR Rangaswamy,
MS Krishnamurthy & JA Steaphen: Indian J TB 1982, 29, 153-67.
The trend of tuberculosis in a sample of 22 villages
of Bangalore district observed over a period of about 16 years (1961-77)
is reported. Distribution of tuberculin indurations did not show
a clear cut demarcation between infected and non-infected. The method
adopted to demarcate the cut off point has been described herewith:
Distribution of tuberculin induration size of 0-14 years was attempted
and extrapolated to higher age groups. Even in these younger age
groups the antimodes were not clearly defined, so the antimode was
arrived by fitting two normal curves as two likely modes.
The choice of demarcation level, therefore, is
somewhat arbitrarily made on the basis of the distributions and
these varied from survey to survey; between 10 mm at survey I and
16 mm at survey V. The actual and standardized infection rates showed
more or less declining trend in 0-4 years, 5-9 years and 10-14 years
age groups. The prevalence of cases was not significantly different
from survey to survey (varying from 3.96 to 4.92 per thousand from
first to fifth survey). However, there was a shift in the mean age
of cases, and better survival rate of cases diagnosed at later surveys.
|KEY WORDS: TREND, CASE, INFECTION, PREVALENCE,
TUBERCULIN READING METHOD, LONGITUDINAL SURVEY.
|INCIDENCE OF TUBERCULOSIS INFECTION IN A SOUTH INDIAN
VILLAGE WITH A SINGLE SPUTUM POSITIVE CASE: AN EPIDEMIOLOGICAL CASE
|MS Krishna Murthy, R Channabasavaiah, AV Nagaraj &
P Chandrasekhar: Indian J TB 1991, 38, 123-30.
During a longitudinal survey, carried out in 119
randomly selected villages of Bangalore district for studying the
time trend of tuberculosis, the average infectivity of a case over
a period of one and a half years was found to be six. In 1986 i.e.,
25 years after the start of I survey, 61 persons belonging to one
village called Nunnur who were found newly infected between I &
II surveys, were interviewed. Further, a general study of the layout
of the houses and public facilities in the village was made. However,
in Nunnur, there was just a single bacteriological case (index case)
identified at the I survey. This index case was resident of household
numbered 80 in the main village. This case study investigates the
background of the observed high infectivity. The incidence rate
of infection in Nunnur was 9.5% in 1½ years which is higher
than the overall average rate of 4% as well as rate for 30 other
single case villages i.e., 3.5%. The investigation reveals that
at least 21 persons., found newly infected at II survey, had varying
levels of contact with the index case. The remaining 40 infected
persons could not be linked, either directly or indirectly, to any
other known bacteriological case including the index case in the
village. All the persons identified as infected at II survey were
distributed throughout the village, beyond the likely zone of infection
of the index case.
|KEY WORDS: SINGLE CASE STUDY, INFECTIVITY, INCIDENCE,
INFECTION, RURAL POPULATION.
| TUBERCULIN TESTING IN A PARTLY BCG VACCINATED POPULATION
|National Tuberculosis Institute, Bangalore: Indian
J TB 1992, 39, 149-58.
To obtain precise information for computing the
indices of tuberculosis situation in a community, with passage of
time, reliance has been placed on tuberculosis infection rates obtained
by carrying out tuberculin surveys. In most developing countries,
covered extensively by BCG vaccination without prior tuberculin
testing, the tuberculin test has problems of interpretation for
demarcating the infected persons from the uninfected. To overcome
the problem, therefore, the test results are analysed among persons
who do not show a BCG scar and are, thus, considered as normal population.
In this paper, an attempt is made to show that BCG vaccination not
always lead to the formation of a scar, and also that the scar resulting
from BCG vaccination may fade away with time and the person, thus,
may be wrongly included in the unvaccinated group. It has also been
found that there is greater fading of scars in the younger age groups:
in children 0-2 years of age, upto 52% of the scars faded away within
21 months of vaccination. This proportion steadily decreased to
about 8% in the 10-14 years age group.
The implication of the finding is that the demarcation line between
uninfected and infected persons may require to be shifted from survey
to survey, based on the distributions among the 'no scar' population.
Moreover, in a totally vaccinated community, the differences of
reactions may provide the answer to the problem of identifying the
newly infected persons.
|KEY WORDS: TUBERCULIN TEST, BCG SCAR, INFECTION,