Leishmaniasis

The leishmaniases are poverty-related parasitic diseases transmitted by sandflies. Up to 20 Leishmania species are human pathogens. The clinical outcome depends on the host as well as on the Leishmania species and ranges from latent carriership to fatal disease. There are three clinical syndromes: visceral (VL), cutaneous (CL), and mucocutaneous leishmaniasis (MCL). VL is the fatal syndrome, CL the most common, and MCL is a late complication of CL. The global incidence of leishmaniasis is declining. In 2017, World Health Organization (WHO) estimated there are about 700 000 to 1 million new cases of leishmaniasis around the world, a decline from the 2 million estimate 10 years earlier. VL now causes an estimated 50 000–90 000 cases per year, mostly in East Africa, the Indian subcontinent, and Brazil, showing a downward trend from previous estimates at 500 000. CL is common in South America, Africa, and Asia and is also regularly seen in travel clinics around the world. MCL is limited to South America. Leishmaniases are poverty-related diseases, belonging to the group of Neglected Tropical Diseases. Until recently R&D on diagnostics and therapies was largely neglected, but diagnostic and therapeutic breakthroughs have now greatly facilitated access to care. This, together with the WHO-supported regional elimination initiatives, has probably contributed to the declining global incidence of VL and CL.