A bacteriological assessment of multibacillary cases in leprosy colonies after 4 1/2 years of multidrug therapy

In this presentation we have devised a novel way of calculating the total bacterial quantum in 100 (78 LL and 22 BL) multibacillary leprosy patients living in leprosy colonies. The calculation is based on Ridley's logarithmic scale. We have also attempted to assess the reduction in the bacterial quantum as a result of intervention through multidrug therapy (MDT). 53% of the patients rendered bacteriologically negative within two years of treatment of MDT and 94% at 54th pulse dose i.e. at 54th month. The bacterial quantum in human source as leprosy patients was calculated thus--Average BI of the group X Number of patients in each group X Multiplication factor devised as per Ridley's Bacterial Index (BI). By applying this purely arithmetic formula, it was found that 99.8% of the bacterial load is harboured in leprosy patients having BI more than 3. The introduction of MDT initiated the reduction in total bacterial quantum "based on above arithmetic scale" was achieved very fast i.e., from 100% to 5% at 12 months and to 0.4% at 24 months. We believe that if one wants to achieve leprosy control through a reduction in total bacterial quantum within a specific period, leprosy cases with BI more than 3 should be treated on priority basis.