Volume 4 | Issue 1 | January-March 2019
51
TREATMENT FOR TB
Active TB infections are treated with a
standard 6-9 months treatment regimen
involving four antibiotics: rifampin,
isoniazid, ethambutol and pyrazinamide
for varying durations. This treatment
duration is one of the longest for a
bacterial infectious disease, second only
to the treatment of leprosy. Side effects like
itching, rashes, fever, nausea, diarrhoea
and reddish/orange discolouration of
body fluids including urine, tears and
A third technique, which involves the
detection of TB DNA using polymerase
chain reaction (PCR) and named
Xpert MTB/RIF promises results of
sample positivity within 2 hours and
is currently the gold standard in PCR
based TB diagnosis. However, this
system suffers from high costs per assay
and the requirement for infrastructure
and constant electricity, which are not
available in many cases.
DETECTION AND DIAGNOSIS OF TB
One of the main challenges in the
fight against TB is the very first step
of diagnosis. Millions of TB cases go
undetected and unrecorded all over
the world due to the shortcomings
of technology. Conventional TB
diagnosis is performed by sputum
smear microscopy, wherein the
sputum of the patient is examined
under a microscope for TB bacilli.
However, this approach is only 36-
43% sensitive which means that many
Sputum smear microscopy also suffers
from false positives, as some non-TB
bacilli may also pick up the TB specific
stain. Therefore, a positive sputum smear
needs to be confirmed by culturing the
bacilli obtained from the sputum in the
lab, which can then be tested to confirm
TB. Unfortunately, growing patient strains
and analysing them requires resources and
technical expertise that are not available
in most of the high prevalence countries.
In addition, growth-based confirmation
of TB positivity takes a minimum of 21
days since the growth rate of the bacilli is
extremely slow.
RISK FACTORS FOR TB
Being primarily a respiratory disease, TB
is disseminated by airborne infection as
the bacteria is exhaled from an infected
individual and inhaled by another. This
often happens in poorly ventilated and
over-crowded settings typically seen in
crampedhousing where the disease can
spread like wildfire. Indeed, earlier TB
was thought to be hereditary as it used to
wipe out entire households. Weakening
of the body’s immune system due to age,
substance abuse, air pollution, diabetes,
HIV infection and malnutrition, among
others, play a major role in increasing
susceptibility to TB. Its spread is seen
across the socio-economic strata. As
Dr. Zarir Udwadia, one of the world’s
leading pulmonologists puts it, “TB
does not distinguish between the
chauffer driving the Mercedes and the
CEO sitting at the back!”
cases of TB infection are missed by
this method.
patient’s stomach. However, the cost of
such technology is yet to be estimated and
given WHO and Govt. of India goals to
reduce the economic burden of TB, cost
effective ingestible sensors may remain
only a distant possibility.
Several technological innovations have
facilitated easier and improved patient
monitoring, such as 99DOTS which is a
low-cost solution for improving patient
compliance during TB treatment. Patients
using 99DOTS receive medication
in specially packaged blister packs.
Dispensation of a dose reveals a hidden
and unique phone number that the
patients can call for free and confirm
that the medication has been taken. In
this way, remote monitoring of patient
compliance has been made possible.
Several digital adherence technologies
have also been developed as an electronic
way to monitor medication and provide
reminders. These include digital pill boxes
(evriMED, Wisepill etc.) that are given to
patients with their medication inside. The
digital boxes provide visual cues such as
coloured LED lights which turn on and
remind the patient of the dose and the
medicine that is due. These boxes can also
record medication events in real time by
logging the opening of the box for each
dose, allowing for real time monitoring of
patient compliance. Pilot studies are also
underway in US for ingestible sensors
that are embedded inside each pill, which
transmits information that the pill was
consumed upon activation inside the
Indian TB research has made recent headway in
TB diagnosis, with a research group at the All India
Institute for Medical Sciences (AIIMS) developing
a rapid and portable aptamer (a DNA molecule that
can bind to a specific target) based diagnostic test
which is capable of detecting TB with a sensitivity of
93% compared to the 22% sensitivity of Xpert MTB/
RIF, the current gold standard.
intensify research and innovation in the
field of TB treatment, prevention and
diagnosis. The Government of India has
instituted a similar strategy, the Revised
National Tuberculosis Control Program
(RNTCP). RNTCP involves adopting
WHO guidelines of Direct Observation
Therapy (DOT) to the Indian scenario
and includes direct monitoring and
administration of anti-TB drugs to the
patient, rapid TB diagnosis and treatment,
and increased partnership between public
and private healthcare systems. RNTCP’s
objective is to eliminate TB by 2025. The
plan outlines four directives – Detect,
Treat, Prevent and Build and includes
system for free and sensitive diagnostic
tests for TB, screening of high-risk
population, free TB drugs for all patients,
implementation of uniform treatment
regimen, increased social support and
monitoring and treatment of latent
TB. Finally, the plan will work towards
translation of political commitment to
action through strengthening support
structures for surveillance, research and
innovation.