Each year an estimated 86 lakh tuberculosis (TB) cases are reported worldwide. India accounts for nearly one-fourth of the global TB burden, recording approximately 23 lakh new cases annually and nearly 1,000 TB deaths every day. The economic loss of this burden to the country is immense, amounting to around INR 1.3 lakh crores per annum, as an estimated 17 crore workdays are lost to TB annually. India's annual expenditure on TB control averages around INR 500 crores, however, the country's requirement to effectively combat TB is significantly larger at an estimated INR 3,240 crores .
Although much remains to be done, the Government of India's Revised National Tuberculosis Control Programme (RNTCP) has made good progress over the years. Population coverage has risen from 14 crore in 1999 to 125 crore by 2013 , and the Directly Observed Treatment Short-course (DOTS) strategy for TB control has achieved a high treatment success rate of over 80%. Despite these efforts and expanded reach, the public sector alone cannot fight India's TB epidemic, which is becoming increasingly complex due to many challenges that lie outside its direct control.
Drug-resistant TB is one such major challenge. Poor awareness, private sector malpractices as well as drug pressures have greatly contributed to the emergence and growing severity of drug-resistant TB. Drug resistance is thought to develop if an incorrect drug regimen is administered or when patients fail to complete their full course of medication. Additionally, the germ too has developed novel and rapid ways to resist anti-TB drugs become more virulent. Drug-resistant TB cases are much harder to diagnose and treat, with protracted time to recovery. Patients often discontinue treatment due to experience of several severe side effects. Furthermore, poorly treated cases of drug-resistant TB can worsen from partial resistance against existing anti-TB drugs to extensive resistance against nearly all TB medication.
Given that TB patients potentially infect another 10-15 people annually , drug-resistant TB patients put others at risk of their deadlier TB strains directly via transmission. The potential of drug-resistance in most TB suspects goes undetected on their first visit for diagnosis. Consequently, most drug-resistant TB patients remain unaware of their condition until they complete the six-month treatment for regular TB, during which time their condition further worsens and others in proximity to them are at risk of exposure.
The age-old practice of sputum smear microscopy continues to be the primary method of TB diagnosis in India, however, it has limitations. It cannot detect drug resistance, TB-HIV co-infection and TB disease in other body sites apart from the lungs. These shortcomings have allowed for the continued spread of TB infection in all its forms.
The GeneXpert MTB/RIF assay is a new World Health Organization-endorsed test for initial TB diagnosis that detects both regular and drug-resistant strains. It is highly accurate, with a turnaround time of two hours and requires minimal training. However, the test itself is relatively costly. Each GeneXpert machine costs between INR 8-28 lakh , with each disposable test-cartridge costing between INR 540 and INR 5400. If diagnostic capacity for drug resistant TB is to be strengthened throughout India, cost control interventions such as reduced import duties on test-cartridges are necessary. Tie-ups between development organizations and the government could also be explored to facilitate adoption, as in the case of South Africa where the rapid scale-up of GeneXpert coverage is underway to control its TB-HIV burden, which is the highest in world.
Given its dangerous implications, curbing transmission-generated drug-resistant TB in India is the need of the hour. This is only possible if every suspected patient undergoes drug susceptibility testing during their initial TB diagnosis to guide an appropriate, timely and effective treatment regime suited to their individual needs. This will rapidly reduce transmission of severe disease and prevent needless deaths.
Transmission-generated drug-resistant TB is a serious concern, particularly in big cities like Mumbai due to high population density driven by rapid urbanization. The Municipal Corporation of Greater Mumbai (MCGM) has shown great leadership by proactively confronting Mumbai's challenge of TB and emerging drug-resistant forms in this way. Through focused urban TB control strategies directed towards the most vulnerable segments of its population the MCGM's 'Mumbai Mission for TB Control' has improved the detection of multi-drug resistant cases (MDR TB-resistant to the two most common first-line anti-TB drugs) from 16 cases in 2010 to 2,383 cases in 2013 . This can be attributed in large part to the Mission's ongoing roll-out of GeneXpert machines across municipal hospitals in Mumbai.
The MCGM has also taken the lead in generating public awareness about TB in India, with the launch of its Mumbai Mission for TB Control campaign, featuring Mr. Amitabh Bachchan as its brand ambassador for maximised impact. Following Mumbai's lead, public awareness and innovation in diagnostic technology must be utilized as the critical tools that will keep India's battle-plan relevant to the country's evolving TB challenges. Awareness generation must go hand-in-hand with scientific and technological advances to ensure effective, swift and widespread implementation of new and improved TB control measures. These measures need to be adequately and reliably funded so that gaps in diagnosis and drug availability do not occur.
However, efforts must not stop with this. Ending tuberculosis in India in its most comprehensive form will require the involvement of non-medical sectors such as nutrition, education, sanitation, engineering, urban planning and judicial. This is a historical lesson that India can ignore only at its peril.