Leishmaniasis Incidence and Leishmania Species Distribution in the Apurímac, Ene and Mantaro River Valley, a High-Transmission Endemic Area of Peru.

BACKGROUND: Leishmaniasis remains a major public health problem in Peru, and the Apurímac, Ene and Mantaro River Valley (VRAEM) is an endemic area where, despite its epidemiological relevance, information on incidence and circulating Leishmania species remains limited. METHODS: We estimated district-level cumulative incidence of leishmaniasis in the 60 districts of the VRAEM during 2015-2024, using national surveillance data and census population figures. In addition, molecular species typing was performed on 112 Giemsa-stained tissue smears obtained in health facilities located in Ayacucho districts belonging to the VRAEM region. RESULTS: A total of 3589 cases were reported, yielding an estimated annual incidence rate of 80.01 cases per 100,000 inhabitants, which is 4.3-fold higher than the national average. Marked spatial heterogeneity was observed, with districts such as Pangoa, Río Tambo, Llochegua, and Pichari reporting estimated annual incidence rates above 130 cases per 100,000 inhabitants. Furthermore, of 55 samples processed by High-Resolution Melting Analysis, Leishmania braziliensis was found in 54.6% of samples, followed by Leishmania guyanensis in 21.8%. CONCLUSIONS: The VRAEM constitutes a high-transmission endemic focus of tegumentary leishmaniasis with marked inter-district heterogeneity and circulation of multiple Leishmania species, with Leishmania braziliensis as the predominant species. These findings support the need for targeted surveillance and species-informed clinical management strategies.