We report on a 66-year-old patient originating from Greece and living in Germany with a prosthetic mitral valve because of a combined vitium following juvenile rheumatic fever. The patient fell ill with acute fever, splenomegaly, and pancytopenia. After unsuccessful antibiotic therapy because of presumed endocarditis or sepsis with unknown focus, visceral leishmaniasis was suspected because of recent travel to Greece. Subsequently, this diagnosis was confirmed by serology. Considering thrombocytopenia and concurrent anticoagulation after prosthetic mitral valve replacement, we avoided a bone marrow biopsy usually required for definite proof of leishmania infection. Instead, infection with Leishmania infantum was diagnosed by PCR of a peripheral blood sample. After treatment with liposomal amphotericin B the patient recovered fully.