Issues involved in the rapid assessment of the leprosy problem

Sample surveys for estimation can prove very expensive and time-consuming because of the enormous sample sizes usually required. Where sample surveys have to be undertaken, diagnoses should be limited to detecting a case of leprosy, without attempting skin smears etc. in order to classify by types. Usually enough knowledge is available on the approximate proportion of multibacillary (MB) cases in most communities, and this knowledge could be utilized for estimating the caseload by types of leprosy. Again intensive tracing of nonrespondents could be limited to either males or females depending on convenience, and well-known sex ratios among patients utilized for deriving estimates for the other sex. The type of rapid methods of estimation depend on three types of situations: (1) before multidrug therapy (MDT); (2) 5 years or more after MDT; and (3) less than 5 years after MDT. In the first situation one or more of the following methods are suggested: (i) extrapolation from registered cases; (ii) extrapolation from child prevalence; and (iii) conducting rapid village surveys. In situations where MDT has been introduced for 5 years or more the registered cases plus a small number, depending on local experience, would seem to be adequate. When MDT was introduced less than 5 years before, it is suggested that the prevalence rates be obtained by statistical interpolation drawing on the experience from areas which have had more than 5 years of MDT.