Outbreak of Leishmania tropica amongst militia members in a non-endemic district under conflict in the lowlands of Somali Region in Ethiopia

Abstract Following the emergence of a conflict, an outbreak of cutaneous leishmaniasis (CL) occurred in a non- endemic lowland area in the Somali Region in Ethiopia, raising public health concerns. All 1050 patients were militia members, immunologically naïve and displaced into a conflict area with a likely sylvatic transmission cycle. We identified Leishmania tropica as the causative species, challenging the previous assumption that L. aethiopica was Ethiopia’s primary agent of CL. Notably, over 77% of patients had more than 10 lesions, a presentation atypical for L. tropica elsewhere. Phlebotomus orientalis and P. sergenti , vectors for visceral leishmaniasis (VL) and CL in North Africa respectively, were captured. Further research is needed to explore the eco-epidemiology of the outbreak and the patient’s treatment responses. Insights will help develop management strategies to control this newly emerging form of CL, prevent its spread to other regions, and hybridize with Leishmania strains causing VL endemic.