Clinicopathological and demographic profile of cats naturally infected with Hepatozoon felis

Hepatozoon spp. is apicomplexan tick‑borne parasites that frequently infect cats, often without overt clinical signs. However, the clinicopathological significance of feline H. felis infection remains poorly understood, particularly in regions where the infection is increasingly reported. This study aimed to investigate Hepatozoon infection in cats and assess its association with hematological and biochemical findings in Iran. Of 103 cats tested, 16 (15.5%) were PCR‑positive for H. felis . Gamonts were detected in buffy coat smears of 6 out of 103 cats (5.8%) and in peripheral blood smears of 3 out of 103 cats (2.9%), with moderate agreement between PCR and buffy coat smears (κ = 0.50). Phylogenetic analysis revealed that the isolates clustered within the H. felis clade, showing close similarity to sequences from Spain and Uruguay. Infection was significantly more prevalent in kittens and younger cats ( P = 0.003). After Bonferroni correction, infected cats had significantly higher red cell distribution width (RDW) and alkaline phosphatase (ALP) than non-infected cats. Both RDW ( P = 0.020) and ALP ( P = 0.024) remained significantly associated with H. felis infection after adjustment for age in multivariable logistic regression. PCR was significantly more sensitive than microscopy, and buffy coat smear improved diagnostic yield. Age was a major confounder affecting hematological parameters. After age adjustment, RDW and ALP emerged as independent biomarkers of infection. However, the lack of molecular testing for potential co-infections limits interpretation, and the associations of RDW and ALP should therefore be interpreted with caution. These findings provide a laboratory baseline for subclinical feline hepatozoonosis and highlight the need for age adjustment. Molecular surveillance combined with buffy coat examination is recommended for accurate diagnosis in endemic regions.