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018 |
A COMPARISON BETWEEN LONGITUDINAL AND TRANSVERSE
DIAMETERS OF TUBERCULIN TEST INDURATIONS |
Kul Bhushan, MN Mukherjee, SP Chattopadhya & KT
Ganapathy: Indian J Med Res 1972, 60, 1724-30. |
In the epidemiological surveys carried out by the
National Tuberculosis Institute (NTI), Bangalore, instead of reading
the tuberculin reactions (indurations) by measuring their transverse
diameters as is done conventionally, the longitudinal diameters
were read. Later on, as the longitudinal diameters were observed
to be larger than the transverse diameters, an investigation was
carried out to study whether this difference would affect the estimation
of infection rates. Out of 1,240 tuberculin tested persons, for
1,189 both transverse and longitudinal diameters were read by each
of two readers, one accustomed to read the longitudinal diameter
and the other, the transverse diameter. All care was taken to avoid
bias on the part of the readers. All four reading were available
for 1,075 persons (87%).
It was found that longitudinal diameters were larger
than the transverse diameters for all ranges (of sizes) of reactions
when either diameter for each reader was taken as standard. The
prevalence of infection, considering 10mm+ reactions as the minimum
level for those infected, were almost the same for both the diameters
and for both the readers. Analysis according to age sex gave similar
results. Variations between the readers are known to be of much
higher magnitude than those observed between the diameters in this
study. The levels of post-vaccination allergy calculated on the
basis of longitudinal diameters, however, will be larger than those
for transverse diameters. In view of the above results, the findings
of the NTI epidemiological surveys wherein longitudinal diameters
of tuberculin reaction are read, will not only be comparable with
other studies conducted by NTI but also with studies done by other
organizations-national or international.
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KEY WORDS: TUBERCULIN, INDURATION SIZE, TRANSVERSE
DIAMETER, LONGITUDINAL DIAMETER. |
028 |
FIVE YEAR INCIDENCE OF TUBERCULOSIS AND CRUDE MORTALITY
IN RELATION TO NON SPECIFIC TUBERCULIN SENSITIVITY |
GD Gothi, SS Nair, AK Chakraborty & KT Ganapathy:
Indian J TB 1976, 23, 58-63. |
The study was undertaken in a sample of 103 villages
of 3 sub-divisions of Bangalore district as a part of the 5 year
study of epidemiology of tuberculosis between 1961-68. The follow
ups were done at 1.5, 3 & 5 years after the first survey.
The entire population was offered tuberculin test with 1 TU RT 23,
a second test with 20 TU RT 23 to those persons who were having
reactions of 0-13 mm to 1 TU. All aged 5 years or more were offered
70mm photofluorograms at each survey. Two specimens of sputum were
collected from persons having abnormal X-ray shadows for examination
of tubercle bacilli. Procedures were uniform at each survey. The
population was divided into three groups on the basis of their tuberculin
reactions: (a) reactors to 1 TU (infected with M.tuberculosis),
b) non-reactors to 1 TU but reactors to 20 TU (infected with atypical
mycobacteria), c) non-reactors to both 1 TU & 20 TU (not infected
with either M.tuberculosis or other mycobacteria). Incidence of
disease and crude mortality were studied separately among these
groups.
The five year incidence of culture positive disease
was the highest among 1 TU reactors and the least among reactors
to 20 TU. In the younger age group (5-14 years) the five year incidence
of culture positive disease among reactors to 20 TU was significantly
lower compared with that among 20 TU non-reactors. The reduction
of incidence of culture positive cases in the former group over
that in the latter was 75% for culture positive cases and 61% for
combined culture positive and negative disease. As regards crude
mortality, the overall rate was significantly lower among 20 TU
reactors compared with non-reactors. Even if the significance of
the finding on crude mortality is debatable, it could be concluded
that non-specific infection provides some protection against development
of tuberculosis, at least in younger age groups.
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KEY WORDS: INCIDENCE, DISEASE, MORTALITY, NTM,
RURAL POPULATION. |
029 |
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.
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KEY WORDS: NTM, PREVALENCE, INFECTION, BOOSTING,
TUBERCULIN REACTION, RURAL POPULATION. |
033 |
USE OF 20 TU RT 23 AND 5 TU BATTEY ANTIGEN FOR ESTIMATION
OF PREVALENCE OF NON-SPECIFIC TUBERCULIN SENSITIVITY |
GD Gothi, AK Chakraborty, MJ Jayalakshmi & KT Ganapathy:
Indian J Med Res 1977, 66, 389-97. |
Estimates of prevalence of non-specific tuberculin
sensitivity in south Indian population are based on studies using
large doses of tuberculin prepared from Mycobacterium tuberculosis.
In the present study, comparison of tuberculin test done on 2168
children aged 0-9 years with 20 TU RT 23 and 5 TU Battey antigen,
belonging to rural areas, have been done. The distribution of induration
to 20 TU RT 23 test has been compared to that of 5 TU Battey test,
to see whether estimates of prevalence of non- specific tuberculin
sensitivity based on the former could be compared with those based
on tests with antigen derived from other mycobacteria.
It was seen that distributions of reactions, mean
size of indurations as well as percentages of positive reactors
to either test were not significantly different in the two randomly
selected groups i.e., one tested with Battey antigen and the other
with 20 TU RT 23. The prevalence of non-specific sensitivity in
0-4 years age group based on Battey test was 18.4 per cent and that
with 20 TU test, 16.6 per cent. In the age group 5-9 years corresponding
rates were 54.2 and 60.1 per cent. From these observations, it is
suggested that if other antigens are not available, 20 TU RT 23
could be used for estimation of non-specific sensitivity.
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KEY WORDS: BATTEY ANTIGEN, PREVALENCE, NON SPECIFIC
INFECTION. |
042 |
EFFECT ON TUBERCULIN ALLERGY OF TUBERCULIN TESTS
GIVEN 18 MONTHS EARLIER |
Raj Narain, GD Gothi, KT Ganapathy & CV Shyama
Sunder: Indian J Med Res 1979, 69, 886-92. |
Enhancing effect of tuberculin allergy as a result
of repeat tests with 1 TU RT 23 on groups tested with I TU, 20 TU
and placebo was studied by random allocation among population not
vaccinated with BCG in 8 villages. In all, 2357 persons were tested
with 1 TU and 759 with normal saline at first round. Based on testing
at three rounds the study population could be divided into eight
different groups and were labelled with alphabets 'a' to 'h' having
been tested once, twice or thrice. The groups 'a', 'c', 'e' &
g' were tested at 2 months, round two with 1 TU RT 23 and
remaining half were not tested. However, all available persons in
the 8 groups were retested at the third round, 18 months after the
initial test. Thus, eight groups cannot be treated as independent
samples but representative of the whole population.
The study did not show enhancing effect due to
previous tuberculin test with 1 TU alone among groups tested once,
twice or thrice after an interval of 18 months. Part of population
was tested with 20 TU at round one; boosting effect was seen at
2 months when test was repeated. However, it was not seen after
18 months but when exactly the boosting effect disappeared was not
known. Thus, there was no increase in reaction even among those
who were tested with a higher dose of 20 TU earlier after 18 months.
The groups provided the largest number for comparison between tested
and the control groups. It is inferred from the study that boosting
with high dose or repeat tests with the same dose does not persist
after 18 months. Hence, for classifying positive tuberculin reactors,
no correction is required to the same individuals/population after
an interval of 18 months or more, as no boosting effect after 18
months has been observed, on the basis of this analysis.
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KEY WORDS: TUBERCULIN TEST, TUBERCULIN ALLERGY,
BOOSTING. |
043 |
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
villages.
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
villages.
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.
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KEY WORDS: PREVALENCE, INFECTION, BCG SCAR,
SURVEILLANCE. |
046 |
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
classification.
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KEY WORDS: NUTRITIONAL STATUS, TUBERCULIN REACTION,
SLUM COMMUNITY, INFECTION. |
050 |
DOES MALNUTRITION AFFECT TUBERCULIN HYPERSENSITIVITY
REACTION IN THE COMMUNITY |
KT Ganapathy, AK Chakraborty: Indian J Pediatrics
1982, 49, 377-82 |
Distribution of tuberculin test indurations were
studied in relation to nutritional status of 930 rural children
aged 1-4 years and 796 aged 5-9 years. Using Quetlet's Index, it
has been observed that the distribution of indurations were similar
in normal and malnourished children. By following Jelliffe's criteria
of grading nutrition, no correlation was observed between the size
of induration and degree of malnutrition. It is concluded that malnutrition
in the community may not influence the prevalence rates of tuberculin
infection based on such testing.
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KEY WORDS: MALNUTRITION, TUBERCULIN REACTION,
COMMUNITY. |
053 |
ARE THE ABSENTEES FOR EXAMINATIONS IN THE EPIDEMIOLOGICAL
SURVEY OF TUBERCULOSIS DIFFERENT FROM THOSE EXAMINED? |
VV Krishna Murthy & KT Ganapathy: NTI Newsletter
1989, 25, 15-21. |
It is a common observation that in epidemiological
surveys all those eligible for various examinations (tuberculin,
X-ray and sputum examinations) do not attend them. If the 'non-attenders'
differ from the 'attenders' the true situation of the problem may
not be known. In this paper, the prevalence of infection, bacillary
cases and suspect cases at II survey for both attenders and non-attenders
of the I survey from longitudinal study conducted by National Tuberculosis
Institute, Bangalore, are compared.
It was observed that in spite of repeated attempts,
nearly 1/5th of the population did not attend examinations. The
non- response group during I survey was examined at the subsequent
survey and both response and non- response groups at the preceding
survey were compared. It was found that in respect of prevalence
of infection and bacillary disease, the two groups did not differ,
but the mortality and emigration was higher among the non- response
group. Higher mortality among non-attenders may be due to the fact
that the group contained more sick people. The higher emigration
among non-attenders due to small error even to the extent of 0.5%
at the stage of census taking by registering a non-resident as permanent
resident of the village would highly boost the rate of emigration
among non- attenders. The difference in the indices of crude mortality
and emigration rates becomes narrower and narrower as coverages
for examinations increase. The analysis indicates that every attempt
should be made to obtain as high a coverage as possible in order
to obtain valid estimates of epidemiological indices in a population
survey.
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KEY WORDS: SURVEY, ABSENTEES, CRUDE MORTALITY,
EMIGRATION. |
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