Cutaneous leishmaniosis in a horse from northern Portugal.

The first case of cutaneous leishmaniosis in a horse from the north of Portugal, with a 1.5 cm in diameter ulcerated nodular lesion on the left face, is reported. The skin nodule was surgically excised and assessed by histopathology, including an immunohistochemistry method applied for the first time to equine tissues which clearly demonstrated leishmanial amastigote forms. Two serological determinations with the direct agglutination test performed 13 months apart showed seroconversion specific for Leishmania from a <25 to a 200 antibody titre. Polymerase chain reaction followed by kinetoplast DNA sequencing provided a 116-bp sequence with 98% identity to Leishmania infantum closest sequence deposited in GenBank. No recurrence was observed after complete surgical excision. Leishmaniosis should be included in the differential diagnosis of cutaneous nodular or papular lesions in the equine species in Portugal.