First report of treatment and short-term follow-up of a European mink (Mustela lutreola) with leishmaniosis in Spain.

Leishmania infantum causes disease endemic in the Mediterranean Basin that affects humans and various mammals, including mustelids. Clinical leishmaniosis has been documented in domestic ferrets (Mustela putorius furo) and in a captive Eurasian otter (Lutra lutra). The European mink (Mustela lutreola), one of the world's most endangered mammals, is experiencing severe population declines linked to habitat degradation, climate change, the introduction of non-native species, and diseases. This report presents the first documented case of clinical leishmaniosis in a captive European mink, detailing its clinical presentation, anti-Leishmania therapy, and follow-up. The affected animal showed weight loss, pyogranulomatous blepharitis, and enlarged popliteal lymph nodes. Haematological and biochemical analyses revealed anaemia, hypergammaglobulinaemia, and elevated renal parameters. Diagnosis was supported by clinical signs, pathological findings, moderate anti-Leishmania antibody levels, and cytological detection of amastigotes in skin and lymph node samples, further confirmed by parasite culture. An initial oral regimen of miltefosine and allopurinol produced limited clinical improvement, likely due to inadequate drug intake. Subsequently, treatment with meglumine antimoniate and allopurinol resulted in a marked clinical response and resolution of the main signs. These findings underscore the need for screening for L.infantum and prompt therapeutic intervention to protect Mustela lutreola populations.