Published in the Hindu on October 12, 2006
The discovery of a highly virulent strain — extremely drug resistant tuberculosis (XDR-TB)–in KwaZulu-Natal province in South Africa, and presented last month at the XVI international AIDS conference in Toronto, has dramatically changed our perception of the way tuberculosis can create havoc for humanity. According to the data presented at the conference, of the 536 patients tested, 53 were found infected with XDR-TB; 52 of the these, many of whom tested positive for HIV, had fallen prey to the new strain within 25 days. This is not the first time that such strains have been identified. A survey carried out between 2000 and 2004 by the World Health Organisation and the Atlanta based Centers for Disease Control and Prevention, which identified these strains in all regions of the world, conforms their prevalence. As an editorial in a recent issue of the British Medical Journal points out, the emergence of such strains was only to be expected, given the poor control practices. If the global incidence of tuberculosis is estimated to be growing at one per cent a year, about 4.5 lakh new cases are caused by multi-drug resistant tuberculosis (MDR-TB)—clearly the result of the failure of all stakeholders to adhere to correct strategies for fighting TB despite the directly observed treatment, short-course (DOTS) being widely adopted.
While treating multi-drug resistant TB is possible by using at least four second-line drugs, treating patients suffering from extremely drug-resistant TB is currently not possible as the bacilli are resistant to three or more of the six classes of second-line drugs. That the possibility of developing a new class of TB drugs is at least four years away further compounds the tragedy. Though “… a strain resistant to so many drugs is not virulent enough to make healthy people seriously ill,” as reported in Nature, is comforting, it can prove lethal to those who are HIV positive, estimated to number over five million in India. The only recourse, therefore, is to ensure that the incidence of multi drug resistant TB is reversed. Adoption of incorrect prescription practices by many private practitioners is one of the biggest contributing factors. Despite the DOTS programme being in place throughout the country, and the prevalence of multidrug-resistant TB well known, estimates on a national scale are not available. With the emergence of XDR-TB, the original roadmap to have these estimates by 2010 covering nearly 50 per cent of the population has to be revisited. Concerted efforts are needed to make the DOTS-Plus programme, to address the management of multi drug resistant TB, operational quickly. In the wake of XDR-TB there is no room for complacency.