Absence of Leishmania infantum in cats with dermatological signs in an endemic area

INTRODUCTION. Leishmania infantum is increasingly reported in cats living in endemic areas (Morelli et al., 2020 Front Vet Sci. 7: 616566). Nevertheless, reports of clinical illness due to feline leishmaniosis (FeL) are still rare. The most common clinical signs compatible with FeL include mucocutaneous or skin lesions (e.g. ulcerative, crusting, exfoliative or nodular dermatitis) and lymph nodes enlargement (Pennisi et al., 2015 Parasit Vectors. 8: 302). However, FeL remains poorly characterized (Savioli et al., 2021 Parasit Vectors. 14: 217) and the role of L. infantum in the etiopathogenesis of feline dermatopathies is still unclear. This study evaluated the exposure to L. infantum in cats with dermatological lesions in an endemic area of Italy (Adriatic coast, Abruzzo region). MATERIALS AND METHODS. Thirty-nine cats with dermatological clinical signs were included in the study. All cats were clinically examined and sampled for blood and sera. Sera were subjected to an immunofluorescent antibody test (IFAT) for the detection of specific IgG against L. infantum, with a dilution of 1:80, as previously described (Morelli et al., 2020 Front Vet Sci. 7: 616566). Cytological examinations from skin lesions were also performed. RESULTS AND CONCLUSIONS. Alopecia, crusting dermatitis, nodular skin lesions and furfuraceous dermatitis were reported in 16 (41.02%), 14 (35.89%), 7 (17.94%) and 4 (10.25%) cats, respectively. Only one cat was seropositive for L. infantum (2.56%). This was a 14-years-old female cat showing a single ulcerated nodule on the thorax. Amastigotes were not found at cytological examinations of the nodule while the histopatology was compatible with a squamous cell carcinoma (SCC). The cat died after the diagnosis without the possibility of more in-depth studies. FeL is commonly associated with impaired immunocompetence as in case of retroviral co-infections and malignant neoplasia (Pennisi et al., 2015 Parasit Vectors. 8: 302). Indeed, amastigotes of Leishmania were previously found in neoplastic tissues of two cats with SCC (Grevot et al., 2005 Parasite. 12: 271-75). Although the sample size is limited, the present study further demonstrates that cats living in endemic areas are at risk to be infected by L. infantum. Nonetheless, it is still not clear to what extent FeL should be considered in the differential diagnosis of feline dermatopathies.