Impact of MDT on leprosy with a special reference to monolesions and smear positivity among the new cases

Introduction

St Joseph′s Leprosy Hospital, a unit of Fr Muller′s Charitable Institutions started the Leprosy control programme in an area of 1 lakh population near Mangalore, South India in 1986. This population was found to have increased to 1,35,000 in 1993-94. All the cases in the project area were brought under MDT as per Government of India Guidelines.[1] In the study we are presenting the impact of MDT as observed through various epidemiological indices. We have given a special emphasis on the proportion of new cases presenting as monolesional cases and the proportion of smear positive cases.

Materials and Methods

All the cases detected in the area were registered and a detailed clinical and bacteriological examination was done. The records had been maintained meticulously which enabled us to go through it and get the necessary statistical details. The following details were obtained from the records.

1. Number of existing cases on treatment at the end of the reporting year (1st April to 31st March)

2. Number of new cases detected during the reporting year.

3. Clinical details like number of lesions and smear status.

4. Number of new cases detected in a completed survey and the clinical details of such cases.

Observation and Result

The prevalence rate showed a gradual decline from 23 per 10,000 in 1986-87 to 1.33 per 10.000 in 1999-2000.

The incidence rate is calculated on the basis of the number of new cases detected in a year provided one full round of survey should have been completed in that year. As it took us about 3 years to complete a round of survey, we are giving the number of new cases detected from 179 in 1986-87 to 23 in 1999-2000. This decline is also seen in [Table - 2] where 366 new cases detected in the first survey has come down to 91 in the fourth survey, and then to 30 in the fifth incompleted survey which covered 64,731 people.

The number of cases with monolesions among the newly detected cases shows some variations [Table - 1] [Figure - 1]. It ranges from 63.69% in 1986-87 to 26.09% in 1999-2000.

The number of cases with smear positivity though initially has shown a decline from 3.91 % in 1986-87 to nil in 1988-89 has then slowly ascended from 1.52% in 1989-90 to 25% in 1995-96 and descended to 4.35% in 1999-2000. [Table - 1], [Figure - 2]. This gradual increase in the smear positive cases is also seen in [Table - 2] where it has gone up from 2.19% in the 1st survey to 8.79% in the 4th survey.

Discussion

The shorter duration of treatment with MDT has shown its effect on the prevalence rate. It has declined gradually from 23 per 10,000 in 1986-87 to 1.33 per 10,000 in 1999-2000. The number of cases- detected every year also shows a similar trend being 179 in 1986-87 and 18 in 1999-2000. The same pattern is seen in the 4 completed surveys. 366 new cases detected in the first survey has come down to 91 in the fourth survey.

We are giving a special emphasis on the monolesions and smear positive cases among the newly detected cases. The number of cases the leprosy control with MDT progresses.[2] In our study the percentage of newly detected cases in a year presenting with monolesions has come down slowly from 63.69% in 1986-87 to 60.78% in 1990-91 and then shows a sudden fall to 32.08% in 1991-92 and then gradually reaching 26.09% in 1999-2000. This trend is also seen in the completed surveys where the percentage has come down from 55.46% in first survey to 34.07% in the fourth survey.

The percentage of smear positive cases is known to decrease with the advancement of MDT programme.[3],[4] In our study the percentage of new cases with smear positivity showed a gradual ascent from 3.91 % in 1986-87 to 25% in 1995-96 and a fall to 4.35% in 1999-2000. The sudden rise in the percentage from 11.54% in 1994-95 to 25% in 1995-96 is difficult to explain. This trend is also seen in the completed surveys. From 2.19% in the first survey the percentage has gone up to 8.79% in the fourth survey.