Molecular epidemiology of M. leprae infection in high prevalence, distinct geographical areas in Maharashtra, western India.
Principal Investigator Dr. Nerges F Mistry
Collaborators Colorado State University (Dr. Vara Visa)
Project team Ms. Sanjana Kuruva and Dr.Vanaja P Shetty
Funder Corpus grant to FMR by Jamsetji Tata trust
Duration 2010 – 2011
Studies on the M. leprae genome have revealed a large degree of conservation making strain differentiation difficult. Limited understanding of the transmission patterns of leprosy along with a prolonged incubation period make assessment of control measures difficult. A number of Variable Number Tandem Repeats (VNTR) have been identified which have proven to be suitable for tracking short term transmission of leprosy. A high number of child cases and their familial contacts diagnosed through an active case detection drive reported by us (Shetty et al., 2008) provide an ideal situation to study recent transmission events and identify M. leprae strain composition in defined areas. The patterns of 9 VNTR’s were studied in order to detect the transmission pattern if any and to establish a molecular database of M. leprae in hyper-endemic areas.
A pilot study is being carried out using archived skin biopsies of leprosy patients from rural and urban areas of Panvel to assess VNTR patterns across 9 loci. Patterns are being identified on the basis of number of repeat units observed at each locus after PCR amplification and subsequent fluorescent fragment length analysis of the amplicon on a sequencer. Out of 64 rural and 41 urban biopsies collected, 35 and 14 samples respectively were found to be positive for M. leprae DNA whose patterns are being identified (Kuruwa et al., 2012).
Standardization of this analysis using slit skin smears as sample is also in progress, which would eliminate the need of biopsies in order to obtain M. leprae DNA and further carry out genomic analysis.
This study will be extended to hyper-endemic areas of western Maharashtra viz. Karjat and Gadchiroli where patterns across these 9 loci and other VNTRs, if identified, will be carried out.