Seroprevalence of Leishmania spp. Infection in Cats in Portugal

Leishmania infantum is endemic in Portugal, where dogs are the main reservoir and human visceral leishmaniosis remains a public health concern. Increasing evidence indicates that cats are also susceptible to infection and may contribute to local transmission, although nationwide data remain limited. This study aimed to estimate the seroprevalence of Leishmania spp. infection in cats in Portugal and to identify potential risk factors. Serum samples collected for unrelated clinical purposes and submitted to a veterinary diagnostic laboratory between December 2024 and March 2025, representing all districts of mainland Portugal and the Azores, were analyzed. Anti-Leishmania spp. antibodies were detected using the direct agglutination test, and associations with explanatory variables were evaluated through multivariable logistic regression. The overall seroprevalence was 8.9% (96/1080; 95%CI 7.3–10.7). One cat from Terceira Island (Azores) tested seropositive (1/10). Region was the only independent predictor of seropositivity, with cats from the Algarve showing higher odds of infection than those from other regions (adjusted OR 1.97; 95%CI 1.24–3.13; p = 0.004). These findings demonstrate widespread feline exposure consistent with known canine and human hotspots, and detection in the Azores suggests possible local transmission, supporting the inclusion of cats in multi-host surveillance within a One Health framework.