Published in The Hindu on march 20, 2008
If globally containing tuberculosis, the incidence of which is estimated to be growing at one per cent a year, is proving to be a big challenge, the spread of multi-drug resistant tuberculosis (MDR-TB) — caused by a bacterial strain that is resistant to at least two of the best first-line drugs — is not making things easy. According to the latest report of the World Health Organisation on anti-tuberculosis drug resistance surveillance, the fourth by the world body, the number of drug resistant TB cases that had emerged in 2006 was about 4.9 lakhs. That translates to 4.8 per cent of the global population affected by drug resistant TB. Sadly, India and China alone account for half the global burden of multi-drug resistant TB. The percentage of people affected by MDR-TB is likely to increase in India as the DOTS Plus programme to treat such cases was started only in August last year. Unlike detecting TB, diagnosing MDR-TB can be done only by specialised laboratories and not clinically. Though the plan is to have 24 regional laboratories (one for each State) capable of identifying such cases and managing 5,000 cases annually by 2010, in reality only five laboratories are now equipped to undertake testing and three more will be ready by the end of the year. “Insufficient laboratory capacity is seen as the primary limitation in implementation of these plans,” notes the report. This is of great concern as “…unless MDR-TB management develops rapidly in the public sector, an increasing number will be managed by the unregulated private sector.”
Though tuberculosis is endemic in the country, which is one of the high TB burden countries in the world, it was only two years ago that the Revised National TB Control Programme succeeded in achieving population coverage of directly observed treatment, short-course (DOTS) in all districts. Despite a detection rate of 61 per cent and treatment success rate of 86 per cent, the prevalence of drug resistance in new cases is about 3 per cent and over 17 per cent in the previously treated cases. Apart from the well known reason of patients not completing the full course of treatment, the indiscriminate use of second-line drugs by private practitioners is a major factor in the increasing number of drug resistant patients. More efforts have to be directed at educating healthcare providers on correct prescribing methods as some of the MDR-TB cases would eventually become drug resistant to three or more of the six classes of second-line drugs leading to extremely drug resistant TB (XDR-TB). Though estimates are not available, extremely drug resistant cases have already been reported in the country. A multi-pronged strategy is imperative to tackle MDR, lest the number of extremely drug resistant forms, for which there is no treatment at present, escalates.