|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.
|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.
|EXAMINATION OF MULTIPLE SPUTUM SPECIMENS IN A TUBERCULOSIS
|P Chandrasekhar, SS Nair, K Padmanabha Rao, G Ramanatha
Rao & Pyare Lal: Tubercle, 1970, 51, 255-62.
Prevalence surveys are useful for estimating the
tuberculosis problem in different countries. Three techniques are
commonly used in surveys, tuberculin test, mass miniature radiography
and sputum examination. Each has its own limitations. A limitation
of sputum examination is that all the sputum positive cases in the
community cannot be diagnosed when only one sample of sputum is
examined from each eligible person. Multiple sputum examinations
are not often possible under field conditions of surveys covering
the whole community. It would be worthwhile to have some idea of
the extent of under-diagnosis in sputum examination. For this purpose,
during an epidemiological survey, four specimens of sputum were
collected within seven days of X-ray examination from each person
with an abnormal chest X-ray in 30 villages of a district of south
India. Each specimen was examined by Fluorescent Microscopy (FM),
Ziehl Neelson (ZN) technique and culture.
There were 34 culture positive cases among 2,164
persons for whom all the four culture examination results were available.
Of them, 21 (62%) were found positive on one specimen. The second
specimen increased the positivity to 32 (95%). Thus, for detecting
both smear and culture positive cases two specimens are adequate.
A third specimen is helpful for detecting cases positive by culture
alone. An estimate of prevalence obtained from one sputum specimen
can be estimated for the prevalence obtained from many specimens
by applying correction factor of 1.67 and estimates based on two
specimens by applying 1.26. Of the remaining 37 smear positive cases
detected by one specimen, 20 were smear positive and culture negative.
Of the remaining 17 smear positive and culture positive, 14(82%)
were detected by one smear examination only.
ZN positives not confirmed by culture (mostly with
less than four bacilli reported in the smear) increased from 7 from
the first specimen to 18 from all four specimens, while positives
confirmed by culture method showed only a marginal increase from
13 to 15. FM did not have this disadvantage as only two were culture
negative among the 18 smear positive results by FM method. Examination
of two specimens by FM detected about 95% of cases demonstrable
by this method. But with the ZN technique additional specimens may
add more false positives. Thus, for detecting cases
both smear and culture-positive two specimens appear adequate. A
third specimen is helpful for detecting cases positive on culture
|KEY WORDS: SPUTUM EXAMINATION, MULTIPLE SPUTUM
SPECIMEN, SURVEY, RURAL, ZIEHL NEELSON, FLUORESCENT, CULTURE.
|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.