Instrument-Free Point-of-Care Diagnostic for Leishmania Parasites

Leishmaniasis is the second deadliest parasitic disease in the world, after malaria, with an estimated 1.6 million new cases each year. While cutaneous leishmaniasis can result in permanent scars from lesions after treatment, the mucocutaneous and visceral diseases can result in life-altering and life-threatening complications. Mucocutaneous leishmaniasis can lead to permanent facial disfigurement and destruction of airways, while the visceral form is nearly 100% fatal if left untreated, as parasites spread into internal organs. Accurate species diagnosis which can be predictive of future disease is critical for treatment and follow-up. PCR-based diagnostics can provide sensitive detection of parasites and identify the species, but are slow, expensive, and not suitable for low-resource environments. In this publication, we describe our efforts to develop a simple, affordable, and instrument-free leishmania DNA diagnostic that can be used in both high-tech settings and the field. We have developed methods for parasite lysis, RPA amplification of DNA, and CRISPR crRNA detection for all leishmania species as well as specific identification of L. panamensis as a predictor of mucocutaneous disease. We have demonstrated the ability to detect single-digit parasites without compromising the specificity in identifying single species. In tube analysis of individual assays were carried out in succession culminating in un-quenched fluorescent signal quantifiable over negative control. The described work is the foundation which will be implemented into a three-track [all leishmania, mucocutaneous or visceral only, and a human positive control] assay that we plan to utilize in a Funnel Adapted Sensing Tube (FAST) single use, instrument free, and affordable diagnostic.