A methodology in brief about conducting Classical
Tuberculosis Sample Survey and Tuberculosis Surveillance is given
below:
I. CLASSICAL TUBERCULOSIS SAMPLE SURVEY
A tuberculosis prevalence survey to measure the problem of tuberculosis
in the community is a challenging assignment especially so when
it is to be conducted by an organisation not created with the specific
objectives of carrying out research work e.g., the District Tuberculosis
Centre, State Tuberculosis Centre, etc. However, following procedure
is described in brief: (1) Selection of district for the study,
(2) Collection of basic data like size and distribution of population,
number of towns and villages, (3) Selection of sample population
for survey by valid statistical methods, (4) Census enumeration
of study population by trained census takers - preparation of cards
for all the individuals, (5) Tuberculin testing & reading of
all subjects under study, (6) BCG scar survey, (7) X- ray examination
of the eligible population (> 10 years or > 15 years). Interpretation
of X-rays by standard readers, (8) Collection of sputum from chest
symptomatics and X-ray abnormal individuals, (9) Transportation
of sputum to central laboratory (necessary precaution to be taken
during storing and transportation), (10) Sputum to be examined by
trained staff, (11) Compilation, analysis and interpretation of
data. Number of working teams with full complement of staff depends
upon the size of the study population and the time frame of the
study. An average survey team may have the following personnel on
its strength: Medical Officer - One, Census Takers - Three, Tuberculin
Tester & Reader (one each) - Two, Lab Technician - One, Lab
Asst. - One, X-ray Technician. - One, Dark room attender - One.
Equipment required: Mobile X-ray unit - mounted on a jeep along
with the generator mounted on another jeep, Laboratory infrastructure,
Vehicles preferably jeep.
Apart from the above, the team may need part time
assistance of a Statistician and a few Statistical Computers. In
case a state is interested to carry out an epidemiological survey,
it may need to create the above infrastructure. Once arranged, it
may request the National TB Institute (NTI) to train the required
staff on standard survey techniques under field situations which
is very essential.
II. TUBERCULOSIS SURVEILLANCE
In contrast to the more complex methodology involved in a classical
survey described above, an alternative, much simpler and indirect
method to assess the problem of tuberculosis in the community is
by finding out the infection rate, through tuberculin surveys. It
may be possible to estimate the prevalence of sputum smear positive
disease from infection rate. Such survey is conducted by subjecting
the age-specific unvaccinated population to tuberculin test periodically.
For carrying out the work, one to two teams composed of three to
four properly trained tuberculin testers and readers are needed
along with at least two vehicles and a standby vehicle per team.
Budgetary support for petrol, travelling and daily allowance of
staff, and for minor miscellaneous expenditure like stationery,
spirit, etc., may be required to be provided. Training could be
imparted to such personnel at NTI and their services utilised exclusively
for carrying out tuberculin surveys as a regular ongoing surveillance
activity. If this methodology is found suitable, one may take action
to create posts of tuberculin testers and readers in suitable scales
and draft them for training in tuberculin survey methodology. The
Institute will be happy to train the required personnel for the
purpose, as well as analyse the data so collected for use by the
states.
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