Need and strategy for sentinel surveillance for drug resistance in leprosy in India.

In the fight against leprosy drug resistance poses a serious impediment at a stage when there is dramatic decline in prevalence due to intensive and concerted chemotherapy intervention. Drug resistance in leprosy has been reported since 1964 for dapsone, 1976 for rifampicin and 1996 for ofloxacin. Recent reports and publications have indicated few instances of rifampicin resistance in several endemic areas. In light of reporting drug resistance in leprosy, the National Leprosy Eradication Programme (NLEP) in India has started collecting information on relapse cases from peripheral institutions. The data show quite significant number of relapse cases (328 in year 2008-09) reported from few endemic states. Comprehensive data on the magnitude of drug resistance are crucial to evaluate the efficacy of MDT and to maintain the effectiveness of the current leprosy control strategy. It has become a necessity to develop a surveillance system to keep a close vigil on drug resistance. PCR based assays have convincingly demonstrated that detection of rifampicin resistance by this method is a feasible and practical alternative to the mouse foot pad (MFP) assay and has practical application in India. Surveillance of drug resistance in leprosy can be carried out based on a sentinel surveillance model. Certain district hospitals and tertiary institutions can be identified as sentinel sites in endemic states where tissue samples can be collected and transported to the identified reference laboratories. Based on the suspected and confirmed relapsed cases reported, 12 states have been identified for inclusion under the surveillance of drug resistance in leprosy. These are Andhra Pradesh, Bihar, Chhattisgarh, Karnataka, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Tamilnadu, Uttar Pradesh, West Bengal and Delhi. Four reference laboratories have already been identified, one each in the states of Uttar Pradesh, Andhra Pradesh, Tamilnadu and Delhi. Tissue samples from sentinel sites would be sent to designated laboratories for conducting the DNA sequencing tests to confirm rifampicin resistance.