A study of relapse after MDT in a district in West Bengal, India.

A study was undertaken to estimate the magnitude of the problem of relapse and to identify factors responsible for relapse in leprosy units that were delivering MDT in Purulia District of West Bengal. From records patients were classified as "Relapse" or "Not relapse". "Not relapse" patients were selected by simple random sampling from the Surveillance Register and were matched according to age, sex, and the leprosy control unit. 128 cases ("Relapse") and 128 controls ("Not relapse") were interviewed in the clinic using a pre-tested questionnaire. Details of methods to identify and confirm relapse were circulated to all reporting units for ensuring uniformity and reliability. NGOs covered 42% of the population, while the State Government covered the remaining. The patients had been followed up after completion of treatment for a period of two years in PB leprosy and for five years in MB leprosy. The study revealed that the relapse rate was 1.71/1000 person-years for original PB cases and 0.76/1000 person-years for original MB cases. The study also showed that history of contact with an active leprosy patient and irregular treatment led more PB cases to relapse than control cases. All patients with an initial BI of 3+ relapsed with a BI of 1+ or 2+.

Role of paucibacillary leprosy in the transmission of disease.

The objective of this study was to establish that paucibacillary leprosy also carried increased risk of infection to the community. All members of 100 families with an index paucibacillary case were clinically, bacteriologically and immunologically examined. The "comparison" group was sampled from suspect register. Fifty-six cases occurred among 944 contacts of index paucibacillary cases; of these, four were multibacillary and 52 were paucibacillary. In the "comparison" group, two contacts out of 760 developed paucibacillary leprosy. This difference, between the two groups, was statistically significant. All the 56 cases in the index case families were under 20 years of age; and 50 of them were aged under 15 years. Male/female ratio was 2.1:1. Of the 56 cases, 28 shared the same bed with the index patient, 20 shared the same room and eight lived in the same house. Lepromin positivity rate was higher in "comparison" families (92.2%) than in index case families (74.6%), the difference being statistically significant (x = 6.09, P < 0.001). Contacts of index case families, therefore, were immunologically at higher risk than contacts of "comparison" families.