This paper reflects on the current emphases in the domain of prevention of disability (POD). A review of literature is presented and issues relating to the challenges that affect POD, in the changing scenario of services for leprosy-affected people are considered. A notable conclusion is that the preservation of peripheral nerve function is primarily dependent on early detection; due to challenges that may compromise that essential service, it is suggested that a sharper focus needs to be given to interventions that prevent secondary disabilities. The paradox of pragmatic and simple interventions is that they are difficult to implement. The main issue is that there is a requirement for a commitment to a fundamental change in the relationship between health providers (at all levels) and recipients.

In 1991 the World Health Assembly decided to ‘eliminate leprosy as a public health problem’ by the year 2000. Elimination was defined as reducing the global prevalence of the disease to less than 1 case per 10,000. In 2000 the World Health Organization (WHO) announced that elimination was reached globally.

Conventionally control of disease is defined as the reduction of disease burden to a locally acceptable level. Elimination of disease is defined as the reduction to zero of the incidence in a defined geographical area, and eradication is defined as the permanent reduction to zero of the worldwide incidence of infection caused by a specific agent. In leprosy however, WHO limited elimination to control instead of transmission, by using prevalence instead of incidence of disease.

Leprosy statistics usually report on prevalence and new case detection. Prevalence is linked to length of treatment, which has changed over time. Trends in new case detection rates only reflect trends in incidence rates when no changes occur in case detection, but in the past 25 years case detection in leprosy has been determined strongly by operational factors.

For the leprosy elimination strategy it was assumed that MDT would reduce transmission of M. leprae, but there is no convincing evidence for this. Data for evaluating the impact of MDT on transmission are not readily available because leprosy has a long incubation period. Also declines in case detection may have other causes, such as BCG vaccination. Mathematical modelling of the transmission and control of leprosy showed that the elimination strategy reduces transmission slowly, with a predicted annual decline in incidence ranging from 2% to 12%. Early case finding was the key factor to attain this decline. Future projections of the global leprosy burden indicated that 5 million new cases would arise between 2000 and 2020, and that in 2020 there would be 1 million people with WHO grade 2 disability.

It is concluded that substantial progress has been made to control leprosy, but when elimination of disease is defined as the reduction to zero of the incidence, leprosy is definitely not eliminated. To attain elimination of leprosy it is necessary to find effective interventions to interrupt transmission of M. leprae and practical diagnostic tools to detect levels of infection that can lead to transmission. This requires extensive research in the areas of epidemiology and microbiology.

The magnitude of drug resistance in Mycobacterium leprae to dapsone, rifampicin, and ofloxacin was studied in three Southeast Asian countries with a high prevalence of leprosy.

M. leprae from the skin of leprosy patients was collected in North Maluku and North Sulawesi in Indonesia, Yangon in Myanmar, and Cebu in the Philippines. Mutations in the drug resistance determining regions in the folP1, rpoB, and gyrA genes, which have been proven to confer resistance, were analysed. In addition, samples from 51 newly diagnosed cases and 13 patients with leprosy relapse in Cebu were submitted for susceptibility testing in the mouse footpad.

Of 252 isolates obtained from new cases, 3% were dapsone resistant and 2% were rifampicin resistant. In samples taken from patients with relapsed leprosy (n = 53), significantly more resistance mutations were detected: 15% had dapsone resistance mutations, and 8% had rifampicin resistance mutations. Two patients with relapsed leprosy had mutations for both dapsone and rifampicin resistance. No mutations conferring quinolone resistance were detected. No mutations were detected in the folP1 gene of M. leprae isolates with a low degree of resistance to dapsone.

Detection of drug-resistant cases by mutation detection in the drug resistance determining region of the genome is a practical method for monitoring resistance. A comparison of the results obtained in this study with previous data obtained prior to the use of multidrug therapy (MDT), does not indicate clearly whether the magnitude of drug resistance has changed. Larger studies of resistance mutations in M. leprae isolated from patients with relapsed leprosy are needed to confirm our results.

We recommend monitoring the magnitude of drug resistance globally, by testing M. leprae DNA from relapse cases and a representative sample of new cases.