Drug resistance in leprosy
The need to monitor drug resistance
The emergence of drug resistance is a cause for concern and a threat for any infectious disease intervention programme. For leprosy, a chronic disease with social stigma, drug resistance poses a serious impediment especially at the stage where a dramatic decline in prevalence and new case detection has been achieved due to intensive and concerted chemotherapy interventions made by the national programmes and its global partners.
Recent reports and publications have, however, indicated instances of rifampicin resistance in several endemic areas. Since rifampicin is the backbone of multi-drug therapy (MDT), it is important to monitor the emergence of rifampicin-resistant mutants. Resistance to dapsone has been reported since the late 1960s but convincing data supporting the existence of clofazimine resistant strains of M. leprae have not been reported.
To meet the challenge of containing the disease and to sustain the on-going declining trend of leprosy in endemic countries, it is essential to monitor drug sensitivity patterns in vulnerable settings.
Two-pronged strategy for monitoring drug resistance
- To closely monitor trends in occurrence of relapses after treatment with MDT due to drug resistance, particularly to rifampicin
- To promote research on developing new drugs for nonrifampicin containing regimens to limit and treat patients who relapse after completing one or more courses of MDT due to resistant strains of M. leprae (secondary resistance) and those new patients who are not responding to standard MDT regimen (primary resistance)
Global surveillance of drug resistance
The establishment of a network for global surveillance of drug resistance in leprosy is primarily to keep a close vigil on the drug resistance scenario at many vulnerable settings. To accomplish this, WHO has developed a simple guidelines to carry out sentinel surveillance and this initiative is expected to be conducted annually on a routine basis.
This initiative will be coordinated by the WHO-Global Leprosy Programme with support and collaboration from national programmes and major research institutes around the world. The research institutes have offered to provide free-of-cost testing of samples sent to them from the sentinel sites in several endemic countries.