Abstract
Background:
Leptospirosis is a zoonotic disease caused by pathogenic Leptospira spp., which can infect a wide range of mammalian hosts. Transmission to humans occurs not only from rodents and wildlife but also from companion animals, such as cats, living in close contact with humans. The occurrence and clinical expression of leptospirosis in animals vary according to species, age, immune status, and serovar infection. In this context, cats may represent an underrecognized component in the epidemiology of leptospirosis in endemic areas.

Aim:
This study aimed to estimate the seroprevalence of leptospirosis in cats, identify circulating Leptospira serovars, and descriptively characterize clinical signs and selected renal and hepatic laboratory findings in naturally exposed cats in Sleman Regency, Indonesia.

Methods:
A total of 116 pubertal cats from Sleman Regency, Special Region of Yogyakarta, Indonesia, were clinically examined. Three milliliters of blood were collected for the MAT, routine hematology, and biochemical analyses, including renal biomarkers [blood urea nitrogen (BUN), creatinine, symmetric dimethylarginine (SDMA), hepatic biomarkers alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, albumin, globulin], and the inflammatory marker feline serum amyloid A (fSAA). Leptospirosis was diagnosed at a MAT titer ≥1:100 against 14 Leptospira serovars. The seropositivity or infection rate was calculated as the proportion of MAT-positive samples, which represents prior exposure or infection rather than clinical disease.

Results:
Of the 116 cats, 12 (10.34%) were seropositive for leptospirosis. Serovar Bataviae was predominant (83.34%), while Ballum and Icterohaemorrhagiae each accounted for 8.33%. Most seropositive cats (66.67%) were clinically normal at the time of sampling, whereas 25% showed nonspecific signs such as anorexia, fever, icterus, lethargy, vomiting, or diarrhea. One cat (8.33%) presented with clinical signs consistent with renal involvement. The hematological parameters were within the reference ranges in more than half of the seropositive cats (58.33%), whereas leukocytosis indicative of inflammation was observed in 25% and mild anemia in 16.67%. Renal biomarkers (BUN, creatinine) remained within the reference intervals in 91.67% of seropositive cats, indicating minimal renal involvement at the time of sampling. Hepatic alterations were more frequently observed, with elevated ALT and AST levels in 25% of cats and increased total bilirubin or altered albumin-to-globulin ratios in 41.67% of cats. Elevated fSAA concentrations were detected in 33.33% of seropositive cats, indicating subclinical inflammatory responses.

Conclusion:
This study demonstrates the presence of feline leptospiral exposure in Sleman Regency, with a seroprevalence of 10.34%, predominantly associated with L. interrogans serovar Bataviae. Although most infections were subclinical, variation in clinical and laboratory findings among seropositive cats highlights the heterogeneous nature of feline leptospirosis. The detection of pathogenic serovars in outwardly healthy cats indicates an epidemiological role for cats as subclinical carriers, underscoring the need for surveillance and the integration of feline leptospirosis monitoring within a One Health framework.

Key words: Cats, Indonesia, Leptospira interrogans, One Health, Serovar Bataviae.