Feline Leishmania infections have been observed all over the world, caused by the species commonly found in other animals in that region; the prevalence in cats is usually lower than that in dogs in the same area. L infantum is most likely transmissible from cats to sand flies, because sand flies have been shown to feed on cats and to be infected after feeding on naturally infected cats. To date, nonvectorial transmission has not been described in cats, but blood transfusion may be a source of infection in cats similar to humans and dogs. Host factors predisposing to susceptibility include immunocompromise secondary to feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV) infection, immunosuppressive therapies, or debilitating concomitant diseases.
Feline leishmaniosis is a chronic disease with clinical signs and clinicopathologic abnormalities mirroring those found in dogs. FeLV/FIV testing is warranted in potential cases, because approximately 50% of reported cases have been positive for one of these viral infections. The two most common clinical findings are skin and/or mucocutaneous lesions and lymphadenopathy, and the most common clinicopathologic abnormality is hypergammaglobulinemia.
Cats with clinical signs consistent with leishmaniosis should have their diagnosis confirmed via quantitative serology. If serology is negative but the clinical picture is highly suggestive, particularly if the cat is FeLV or FIV positive, cytology, histology, quantitative PCR, or culture should be considered, because immune compromise may inhibit the ability to produce specific detectable antibodies.