There are 3 main categories of diagnostics for leprosy, each with their own strengths and challenges in application and field feasibility. The first that often comes to mind is for early detection of new leprosy – which could significantly impact global leprosy transmission, disability and discrimination.
However, diagnostics are also needed for early detection of reactions and/or neuropathy as well as treatment monitoring for those conditions and MDT. There is also need for differential diagnosis.
Our team in Bangladesh is currently working in partnership with Professor Annemieke Geluk on a finger-prick test that can diagnose leprosy within minutes (watch the webinar).
This is the first study that will simultaneously test for six different biomarkers in the blood. The biomarkers that the team are testing show whether or not a person has asymptomatic leprosy; so, while they are testing for these biomarkers, they are also testing different forms of PEP (Post-Exposure Prophylaxis) treatment to see which is better at preventing a leprosy development in contacts.
With funding from the NTD Innovation Prize, The Leprosy Mission Nepal are working on a project that would allow us to diagnose leprosy using a smartphone equipped with spectral imaging technology.
Humans can only see things in the visual light spectrum, which is around 400-600 nanometres. Spectral imaging allows us to see up to 900 nanometres. This will allow us to analyse skin for leprosy-specific lesions.
Spectral imaging is being used with skin cancers currently and could be used to help us diagnose leprosy in the field within minutes.
The Leprosy Mission's Indian labs are working on a PCR test for leprosy.
Over a number of years, our team in India have been testing one gene marker of leprosy at a time to determine which of these genes have the most sensitivity to tests. In October 2021, the Stanley Browne Research Laboratories were in a position to combine three of the most sensitive gene markers into one multiplex PCR test.
This test is 90 percent successful at diagnosing cases of leprosy, including the really early cases of PB leprosy. By 2024, it could be ready for a global rollout.