Evidence Gaps and Global Patterns in Leishmaniasis Control: A Scoping Review of Clinical, Diagnostic, and Treatment...

Leishmaniasis is a neglected tropical disease with diverse clinical forms, heterogeneous geographical distribution, and persistent diagnostic and treatment challenges. Although substantial primary research exists, evidence remains fragmented, limiting integrated and context-specific control strategies. This scoping review synthesizes global evidence on disease distribution, diagnostic performance, and treatment outcomes, and identifies critical evidence gaps.

A scoping review was conducted in accordance with the Arksey and O'Malley framework and PRISMA-ScR guidelines. Four electronic databases were searched for studies published between January 2000 and January 2026. Data were synthesized narratively. A total of 118 studies were included in the review, of which 75 were analyzed to assess the geographical distribution of Leishmaniasis, while the remaining 43 studies were used to evaluate diagnostic tools and treatment outcomes.

Seventy-five studies from 53 countries were included. Cutaneous leishmaniasis was reported in 58 studies (77.3%) and was the most geographically widespread form, whereas visceral leishmaniasis was reported in 26 studies (34.7%) and showed marked focality, particularly in East Africa, South Asia, and Brazil. Molecular diagnostics demonstrated superior performance, with PCR and qPCR sensitivities ranging from 89% to 100% and specificities from 57% to 100%, depending on target gene and sample type. Loop-mediated isothermal amplification showed sensitivities of 89.7%-95% and specificities of 63.6%-100%. In contrast, microscopy showed lower sensitivity (32.8%-80.8% for cutaneous and 44%-67% for visceral leishmaniasis) but high specificity (> 95%). Serological tests and rapid diagnostic tests performed well for visceral leishmaniasis, with rK39-based assays showing sensitivities of 78-96.4% and specificities of 93%-97%, and direct agglutination tests achieving sensitivities of 97.3%-99.1% and specificities of 97.5%-98.8%. Fewer than one-third of studies evaluated operational feasibility. Liposomal amphotericin B achieved the highest cure rates for visceral leishmaniasis, whereas antimonials remained the most frequently used treatment for cutaneous disease. Relapse was predominantly reported in visceral leishmaniasis.

Leishmaniasis exhibits substantial global heterogeneity, with molecular diagnostics offering high analytical accuracy but limited real-world deployment. Addressing operational constraints and integrating emerging technologies are critical priorities for strengthening global leishmaniasis control. Molecular and antigen-based diagnostics offer improved accuracy but remain underutilized in resource-limited settings. Effective treatment is complicated by toxicity, cost, and relapse. Expanding diagnostic capacity, optimizing treatment protocols, and strengthening surveillance systems are critical for effective global leishmaniasis control and elimination.