Epidemiological trends of leprosy elimination in CLTRI rural field operation area, Tamil Nadu, India.

The analysis of computerized data of patients in our Rural Field Operation Area (Kunrathur Taluk, Kancheepuram District, Tamil Nadu) from the start of MDT in 1986 has shown a decrease of leprosy prevalence from 275/10000 in 1986 to 0.7/10000 in 2005. Leprosy has been eliminated as a public health problem after 19 years of MDT implementation. Although the control programme was started in 1962, MDT implementation began only in 1986. The new case-detection rate has declined significantly from 27.3 in 1987 to 2.4/10000 in 2005 (y = -1.6x + 2325.1, p = < 0.05). The age-specific cumulative detection rates calculated showed highest case-detection at 10-14 years for total, 10-14 years for PB, 50-54 for MB, and 10-14 for both males and females. MB percentage was more among new cases in the last three years as compared to the initial three years, and this difference was found to be statistically significant, but there was no significant difference between the first three and the last three-year periods in child, male and disability rates (grade +/-2) among new cases. Thus, the declining trend in NCDR has not reflected any change in sex and age-groups of new cases. This analysis strengthens the hypothesis of sub-clinical cases possibly transmitting the disease and MB cases accruing after long incubation period.

A study on trend of relapse in leprosy and factors influencing relapse.

A retrospective analysis of data pertaining to the rural field operation area of the Central Leprosy Teaching and Research Institute, Chengalpattu, Tamil Nadu, was carried out to determine the magnitude of relapse after MDT and its significance with other variables. The study included 3248 leprosy patients who have successfully completed treatment during 1987-2003, of whom 2892 were PB and 356 MB cases. A total of 58 cases of relapse was reported which gives a crude cumulative relapse rate of 1.78% for the 16-year period of follow-up and the rates for PB and MB were 1.9% and 0.84% respectively. With respect to PB cases, 68% of relapses were reported in the first 3 years of RFT. The person-year relapse rate was highly significant with regard to the number of skin lesions (p<0.0002) and nerve involvement (p<0.0002). The person-year relapse rate did not differ significantly between PB and MB leprosy, male and female, and child and adult cases. RFT year cohort relapse rate reveals that the introduction of MB-MDT regimen for PB leprosy had resulted in the reduction of relapses among PB cases after 1998. The relapse rate with reference to the time gap after RFT reveals that relapse declines with passage of time after RFT. The risk of relapse was very low in both PB and MB leprosy which fact emphasizes that proper counselling about signs and symptoms of relapse during RFT is adequate to combat the problem. A majority of relapses occurred in the first three years after RFT. The number of skin lesions and involvement of nerves were the main risk factors for relapse.

Leprosy situation in endemic states of India and prospects of elimination of the disease.

In India there is a dramatic fall in the prevalence rate (PR) of leprosy, but the new case-detection rate (NCDR) has not been reduced concomitantly. It is the operational efficiency of the National Leprosy Eradication Programme (NLEP) that has led to a significant reduction in the NCDR in Andhra Pradesh and Tamil Nadu. The ratio of PR to NCDR has been declining in these two states and it reveals that elimination could be reached even with the high NCDR level of 3 to 4 per 10000 population, particularly if single skin lesion (SSL) cases are discharged through single dose treatment of rifampicin, ofloxacin and minocycline (ROM). On the other hand, the significant number of cases detected in Bihar and Orissa during modified leprosy elimination campaigns (MLECs) reveals that there are lacunae in operational activities in new case-detection resulting in a large number of undetected cases in the community. Only one-third of the cases are reporting voluntarily. Awareness of leprosy is not adequate to motivate the patients to report voluntarily and complete their treatment, thus underscoring the need for relying on active case-detection so that transmission can be broken and elimination of leprosy achieved. In addition, the influence of socio-economic factors on continued occurrence of leprosy cannot be ruled out. The establishment of a sentinel surveillance system along with a computerized simplified information system to gain in-depth knowledge on the functioning of the NLEP will ensure operational efficiency. In view of this situation, the NLEP should adopt a more realistic approach towards reaching the elimination goal.