|FATE OF CASES DIAGNOSED IN A SURVEY
|Raj Narain, G Ramanatha Rao, G Chandrasekhar &
Pyare Lal: Proceed Natl TB & Chest Dis Workers Conf,
The report describes the changes that occurred
during second survey carried out after an interval of one and half
years in the cases diagnosed at the first survey done during 1961-62
from among a total population of about 62,000 in 119 villages in
Bangalore District. It was observed that (1) Of the 62 sputum smear
positive cases also having suggestive chest X-ray shadows, 34% had
died, 35% were sputum positive and 31% had become culture negative
after 1½ years. Of the 10 smear positive cases who were X-ray
normal, non-e was culture positive at the start and 7 were negative
by culture and smear after 1½ years. Of the 67 scanty smear
positive cases (1 to 3 bacilli seen), only 3 were sputum positive,
10 were having X-ray shadows and half were tuberculin negative after
1½ years. (2) Of the 88 culture only positive cases (20 or
more colonies and with X-ray evidence of disease) 31% had died and
47% continued to be sputum positive after 1½ years. A much
smaller proportion of these changes occurred among culture positive
cases with less than 20 colonies. (3) There were 457 persons having
radiologically active tuberculosis on the basis of interpretation
of a single X-ray picture by two independent readers but whose sputum
were negative for AFB (suspect cases). Of these, 38% were tuberculin
negative also. Of those suspect cases who were tuberculin positive,
9% become sputum positive after 1½ years, while only 2% of
the tuberculin negative suspect cases became sputum positive.
It is concluded that there is a lot of variation
in fate among the different categories of cases of pulmonary tuberculosis.
Further, attention has been drawn to the possibility of self healing
in about 30% of the bacillary cases after 1½ years.
|KEY WORDS: FATE, CASE, SUSPECT CASE, NATURAL
|PREVALENCE, FATE, SOURCE AND INFECTIVITY OF RESISTANT
IN MYCOBACTERIUM TUBERCULOSIS
|Raj Narain, P Chandrasekhar, Pyare Lal and RA Satyanarayanachar:
Proceed Natl TB & Chest Dis Workers Conf, Hyderabad,
The material on resistant strains of mycobacterium
tuberculosis is derived from the longitudinal survey conducted from
1961-68 in a random sample of 133 villages of 3 taluks of Bangalore
district. About 54,000 persons aged five years or more were surveyed
3 times at an interval of 18 months, two samples of sputum were
collected from persons whose chest X-rays were judged to have abnormal
shadows. The sputum specimens were examined by direct smear and
culture and sensitivity tests were performed.
An attempt is made to study prevalence, fate, source
and infectivity of resistant mycobacterium tuberculosis in three
rounds. PREVALENCE: In the 3 rounds, 199, 194 and 176 cases
respectively yielded positive cultures; Of them, 30, 36 and 53 cases
were having resistant strains. At round III, the number of culture
positive cases has not fallen significantly, but the number of strains
resistant to INH alone has sharply increased (13, 18 & 35).
Both findings are likely to be due to the treatment with INH alone
offered at round II and also due to the fact that treatment was
taken very irregularly. FATE: Over period of 3 years, of
the cases with INH resistant strains, more than 1/3rd were dead,
1/4th continued to remain positive and resistant, and 1/4th became
culture negative. Whereas, of the cases with strains sensitive to
INH, less than 1/3rd were dead, 1/3rd became negative and the remaining
were positive, 1/2 with sensitive strains and 1/2 with resistant
strains. SOURCE OF CASES: The prevalence of cases with resistant
strains at any one round is not due to the persistence of such cases
from previous rounds but by development of new cases with such strains
at each round. INFECTIVITY: The incidence of infection among
contacts with sensitive strain was significantly more than among
the contacts of cases with resistant strain. It is inferred that
the infectivity of sensitive strains is more than that of the resistant
|KEY WORDS: M.TUBERCULOSIS, SENSITIVE STRAINS,
RESISTANT STRAINS, CASE, FATE, PREVALENCE, INFECTIVITY.
|SOME ASPECTS OF CHANGES IN RURAL POPULATION AND
FATE OF TB CASES AFTER AN INTERVAL OF TWELVE YEARS
|MS Krishnamurthy, KR Rangaswamy, AN Shashidhara &
GC Banerjee: NTI Newsletter, 1974, 11, 1-7.
During second epidemiological survey carried out
in 1972-73, special efforts were made in 21 of 62 villages belonging
to first survey (1961-62) to study the demographic changes and fate
of TB cases after an interval of 12 years.
The findings were: The increase of dejure population
was about 20% over a period of 12 years i.e., an annual increase
of 1.7%. The age structure had altered mainly due to significant
increase in the age group 60 years and above 51% to 64% indicating
aging of population. The loss of original population after 12 years
was 44%, of which 33% was due to migration and 11% due to death.
The overall migration was more among females. The migration rate
was higher in younger age group, being highest in 10-19 years (49%),
next in 0-9 years (38%). Thus, overall migration in 0-19 years was
43%. The death rate was highest in 60 years and above (58%). It
varied from 4-9% in age group 0-39 years. Original population available
after 12 years for re-examination was 56%. Distribution in different
age groups were; 0-9yr = 57%, 10-19yrs = 47%, 20-49yrs = 66%, 50-59yrs
= 44%, 60yrs and more = 28%.
Out of 88 X-ray suspect cases of earlier survey,
87 could be identified and present status of 72 were known. Of them,
16 were normal, 12 and 4 found to be suspect cases and bacillary
cases respectively and 40 had died. Of the remaining fifteen, 11
migrated and 4 not examined. Out of 14 bacillary cases, 13 could
be identified. Of them, 3 were sputum negatives (2 normal and 1
suspect case) 9 had died and 1 migrated.
|KEYWORDS: FATE, CASE, SUSPECT CASE, MORTALITY,
MIGRATION, RURAL POPULATION, DEMOGRAPHIC CHANGES, SURVEY.
|INTERPRETATION OF PHOTOFLUOROGRAMS OF ACTIVE PULMONARY
TB PATIENTS FOUND IN EPIDEMIOLOGICAL SURVEY AND THEIR FIVE YEAR FATE
|GD Gothi, AK Chakraborty & GC Banerjee: Indian
J TB 1974, 21, 90-97.
In this study the material from Five year
study of Epidemiology of Tuberculosis (1961-68) has been analysed
to find out an improved method of interpretation of chest X-rays
to get accurate estimation of prevalence of suspects
in the community. The population of a random sample of 119 villages
from the three taluks of Bangalore district was surveyed four times
with intervals of 1½ to 2 years by tuberculin testing, 70mm
chest photofluorography and sputum bacteriology. Out of 45,434 persons
X-rayed during the first survey, 590 were read as active pulmonary
tuberculosis on the basis of single picture interpretation by two
independent readers. Of them, 460 being sputum culture negative
were classified as initial suspects and these were reviewed
in this study by the panel of three readers together by the method
of joint reading. The interpretation was done comparing
the serial X-rays of individuals taken at intervals along with other
available examination results and personal data. Out of 460 initial
suspects only 110 (23.9%) were confirmed as suspects,
the remaining were judged as non-tuberculous and/or inactive tuberculous
(62.2%) and normals (13.9%).
Fates on five year follow up were compared between
85 confirmed suspects and 385 initial suspects.
The mortality and sputum positive status were found more among the
former group i.e., 23.5 and 25.5 and 14% and 7.2% respectively.
Radiologically, 48.7% of the confirmed suspects and only 10% of
the initial suspects could be classified as suspects at 5th year
follow up. Incidence of bacillary disease among the confirmed suspects
was also found higher. On the basis of joint reading
and five year follow up study, the limitations of single picture
interpretation resulting in considerable over diagnosis were clearly
seen. The comparative reading of serial X-rays along with other
examination results did help in the better assessment of etiology
and activity status of disease. Of the X-rays read as non-tuberculous
and inactive tuberculous when reviewed by joint reading
method, about 67 more suspects could be added. Even then the estimates
of prevalence of suspects based on single film interpretation
which are widely used in India appear to be about 3 times the actual
|KEY WORDS: FATE, SUSPECT CASE, X-RAY, JOINT
READING, SINGLE PICTURE, OVER DIAGNOSIS.
|PREVALENCE AND INCIDENCE OF SPUTUM NEGATIVE ACTIVE
PULMONARY TUBERCULOSIS AND FATE OF PULMONARY RADIOLOGICAL ABNORMALITIES
FOUND IN A RURAL POPULATION
|GD Gothi, AK Chakraborty, VV Krishnamurthy & GC
Banerjee: Indian J TB 1978, 25, 122-31.
A study was carried out mainly to find out the
prevalence and incidence of sputum negative active pulmonary tuberculosis
(suspect cases) among 35,876 persons aged 5 years and above in rural
areas of Bangalore district during 1968-72. Two surveys (I &
II) at an interval of 3 months, succeeded by a follow up examination
of the X-ray abnormals of the earlier surveys, were conducted in
the same villages. Examinations at each survey consisted of tuberculin
test, X-ray and sputum examinations. X-rays were interpreted individually
at the time of each survey by single picture interpretation method
and subsequently by Joint Parallel Reading (JPR) method to
arrive to a diagnosis. In the JPR method X-ray readings and their
comparison was done by a panel of three X-ray readers with full
knowledge of age, sex, result of sputum examination and tuberculin
test of each person with chest abnormality at any of the three surveys.
On a single picture interpretation the overall
prevalence rate of suspect disease was found to be 5.4 per thousand
at I survey and 4.59 per thousand at II survey. There was no significant
difference in the overall age and sex specific prevalence rates
of suspect disease between I & II surveys. Incidence of suspect
disease at the end of 3 months was 2.24 per thousand. By JPR method
the prevalence rates of suspect disease was 3.2 per thousand at
I survey and 3.6 per thousand at II survey. The prevalence rates
by single picture method were overestimated to the extent of 38%
at I survey and 19% at II survey when compared with those found
by JPR method. At I survey prevalence rates on JPR method was significantly
lower than by single picture method. This was not so at II survey.
Similarly, incidence rate of 0.2 per thousand of suspect disease
on JPR was about 1/10th of that found by single picture method.
The incidence of bacteriologically positive cases
in 6 months from among suspect cases on JPR was found to be 28%.
Majority (76%) of non-tuberculous or inactive tuberculous shadows
continued to remain as such after 6 months and about a quarter (23%)
became normal. Incidence of bacteriologically positive cases from
this group was minimal. Of 19,640 persons with normal X-rays 134
(0.7%) developed new shadows in 3 months; 103 (0.5%) cleared after
2-12 weeks (fleeting shadows). Mis-interpretation of the latter
as active tuberculous may falsely boost the estimates of suspect
disease to the extent of about 5%.
|KEY WORDS: SUSPECT CASE, PREVALENCE, INCIDENCE,
RURAL POPULATION, FATE.
|INCIDENCE OF PULMONARY TUBERCULOSIS AND CHANGE IN
BACTERIOLOGICAL STATUS OF CASES AT SHORTER INTERVALS
|GD Gothi, AK Chakraborty, K Parthasarathy & VV
Krishnamurthy: Indian J Med Res 1978, 68, 564-74.
The incidence rates of sputum positive pulmonary
tuberculosis (cases) from the five year follow ups of a rural population
done by National Tuberculosis Institute were reported on the basis
of studies at intervals of one and a half to two years. Information
on fate of cases was also likewise reported. These parameters appear
to be imprecise since incidence and fate of cases at shorter intervals
were not taken into account. Thus, the information on incidence
of pulmonary tuberculosis in India is meager as compared to that
on prevalence of disease. Therefore, a study mainly to find out
the incidence and fate of cases at shorter intervals of 3-6 months
was undertaken in 87 randomly selected villages of Nelamangala sub-division,
Bangalore district which was one of the 3 sub-divisions where repeated
epidemiological surveys had been conducted between 1961-68. The
sample of villages in the present investigation was other than that
included in the earlier report. Organized Case-finding, anti-tuberculosis
treatment and BCG vaccination neither existed nor could be provided
in the area till the completion of the study. The present study
was conducted between 1968-1972.
This study conducted among 30,576 persons has shown
that incidence of cases over a period of three months was 0.99 per
thousand and was not much different from the annual rate of 1.03
per thousand reported on the basis of repeated surveys at longer
intervals. That the three months rates were not a quarter of the
annual rates meant that the procedure of calculating incidence rates
on the basis of surveys done at varying intervals after adjusting
for the interval had to be used with great caution. The study of
fate of cases showed that cases converted or reverted even at shorter
intervals and this appeared to be going on continually in the community.
However, incidence of cases and cure and death from among the existing
as well as the fresh cases kept on balancing each other so that
the prevalence rates of cases studied at shorter or at longer intervals
did not show variations.
|KEY WORDS: INCIDENCE, FATE, CASE, RURAL POPULATION,
SURVEY, SHORTER INTERVALS
|PREVALENCE, INCIDENCE AND FATE OF SUSPECT CASES
OF TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA
|VV Krishna Murthy: NTI Newsletter 1982, 19, 75-80.
The data from a longitudinal survey conducted in
Bangalore district from 1961-1968 by National Tuberculosis Institute
was analysed to find out the prevalence, incidence and fate
of suspect cases. In brief, the survey was conducted in 119
randomly selected villages in three taluks of Bangalore district
and repeated within the next five years. At each survey, eligible
population was subjected to tuberculin, X-ray & sputum smear
and culture examinations.
The overall prevalence rate of suspect cases among
persons aged five years and more was 1.06% at I survey, 0.68%, 0.49%
and 0.43% at II, III and IV survey respectively. In males, the prevalence
rate was 1.19% at I survey & 0.62% at IV survey corresponding
figures for females were 0.94% and 0.24% respectively. A decline
of prevalence of suspect cases from 1.06% at I survey to 0.43% at
IV survey was observed. The overall incidence of suspect cases was
0.16% between I & II surveys, 0.10% between II & III, and
0.06% between III & IV surveys. The overall as well as age specific
annual incidence rates between III & IV surveys were significantly
less than that between I & II surveys. At all the three intervals
the incidence increased with the age. Incidence of suspect cases
in males was more than that in females. Change in disease status
over a period of time is termed as "fate". The
disease status was classified as (i) cure (ii) continued to be suspect
case (iii) converted into bacillary cases and (iv) dead. The percentage
of cure (51.9%, 53.2% and 50.3%) and conversion into bacillary cases(7.2%,5.8%
and 5.4%) were almost the same at all the three intervals. But the
percentage of those who remained suspect cases reduced from 33.5%
at the end of 18 months to 17.5% at the end of 60 months. On the
other hand, the death rate increased from 7.4% at the end of 18
months to 26.8% at the end of 60 months. The decreasing trend of
continuing to be suspect cases at the rate of 10% between two observations,
appears to be corresponding to the increasing trend in the death
rate as seen from the observations made at the three intervals.
|KEY WORDS: PREVALENCE, INCIDENCE, FATE, SUSPECT
CASE, RURAL COMMUNITY, LONGITUDINAL SURVEY.