Ongoing outbreak of cutaneous leishmaniasis in northwestern Yemen: clinicoepidemiologic, geographic, and taxonomic study.

Background: Cutaneous leishmaniasis (CL) is widespread in Yemen but has not been fully documented.

Objectives: This study aimed to investigate the clinicoepidemiologic and geographic aspects of CL in northwest Yemen and the taxonomic profile of the causative Leishmania species.

Methods: All CL cases diagnosed at the Dermatology Clinic of the Saudi Hospital at Hajjah during 1997-2012 were reviewed. Diagnoses were based on clinical, microscopic and, occasionally, histopathologic examinations. Leishmania species identification was carried out in 712 microscopically positive samples by multi-locus enzyme electrophoresis and polymerase chain reaction-restriction fragment length polymorphism.

Results: During the surveillance period, 1343 cases of CL were diagnosed. Lesions per patient ranged from one to 71, but most patients had a single facial lesion, classified as representing the "dry type" in 1315 (97.9%) and "wet type" in 28 (2.1%) patients. Leishmania typing in 576 cases identified Leishmania tropica as the main species responsible (n = 529), followed by Leishmania infantum (n = 20), Leishmania donovani (n = 11), and members of the L. donovani complex (n = 8). Atypical molecular patterns were observed in eight CL cases diagnosed in areas in which the three Leishmania species were found sympatrically.

Conclusions: Cutaneous leishmaniasis appears to be endemic in northwest Yemen, where its incidence has recently increased abruptly. The disease presents clinically as the "dry type" and is caused mainly by L. tropica and occasionally by L. infantum, L. donovani, and L. donovani complex species. A sympatric diffusion of the three species is present in some governorates.