Leprosy is a chronic infectious disease that results in nerve damage, muscle weakness and atrophy, and permanent disability and disfigurement, causing sufferers to be stigmatized and isolated by their communities. Provision of multidrug therapy and follow-up care has resulted in a dramatic decline in the prevalence of leprosy; however, there are close to 200,000 new cases of this curable disease each year, often diagnosed after permanent disability has already developed.

The World Health Organization (WHO) 2020 goal is to eliminate leprosy as a public health problem (defined as prevalence <1 case per 10,000). The WHO set a number of goals for the Neglected Tropical Diseases (NTD) to be achieved by 2020, and the London Declaration on NTDs backed these goals with commitments from public and private institutions, notably for leprosy Novartis committed to donate antibiotic drugs to treat leprosy in endemic countries. The 3rd progress report of the London Declaration indicated that “priorities for progress” towards reaching leprosy goals include an urgent need for fieldfriendly diagnostic tests for leprosy.

In support of the London Declaration goals, PATH aims to catalyze engagement of the diagnostics industry and product development efforts. As part of this work, PATH assessed needs and landscaped potential solutions to improve diagnostic tools used to support leprosy elimination efforts. We conducted literature reviews, a product development landscape, and interviews with key stakeholders in the leprosy community to identify use cases for leprosy diagnostics, understand current practices, and analyze progress toward more robust diagnostics. The findings were used to develop recommendations to improve availability, access, and adoption of leprosy diagnostic tools.

PATH identified four use cases for leprosy diagnostics: diagnosing subclinical infection, diagnosing symptomatic infection including paucibacillary (PB) and multibacillary (MB) disease, and treatment monitoring. We found that current diagnostic tools and practices for leprosy are unlikely to support achievement of elimination goals. There are no POC tools commercially available for leprosy diagnosis. Tools currently in late-stage development are not applicable to all symptomatic leprosy infections and there is growing interest in new tools that can detect subclinical infections and monitor treatment outcomes. Based upon these findings, we have developed the following recommendations:

1. Bring to market antibody-detecting rapid tests to aid health workers in the confirmation of MB infections. Prototypes are in late-stage development and would identify the most transmissible and debilitating infections. Implementation and market research may be needed to support optimal uptake and use of these tools.
2. Develop new diagnostic tools that identify all symptomatic leprosy infections. These tools are necessary to ensure prompt treatment and cure of all leprosy cases.
3. Support further research to understand feasibility and utility of diagnostic tools for subclinical infections and post-treatment monitoring of immunologic reactions and relapse.