Genetic diversity and spatial distribution of Hepatozoon spp. in domestic cats from Argentina.

This study reports the first molecular detection of Hepatozoon spp. in domestic cats from central Argentina, expanding current knowledge of its distribution and genetic diversity in South America. Blood samples (n = 257) from domestic cats in Santa Fe, Esperanza, and San José del Rincón were analyzed by PCR targeting the 18S rDNA gene of Hepatozoon spp. Four samples (1.6%) tested positive for Hepatozoon spp. Phylogenetic analyses revealed two distinct lineages: two sequences clustered with Hepatozoon canis, typically found in dogs and transmitted by Rhipicephalus sanguineus, and two were closely related to a rodent-associated Hepatozoon lineage. Spatial analysis identified a significant cluster in the northern area of Esperanza (p = 0.003), suggesting that local environmental conditions may facilitate parasite transmission at the urban-natural interface. All positive cats had outdoor access, supporting the role of environmental exposure and potential trophic transmission. No gamonts were observed in blood smears, consistent with the subclinical nature and low parasitemia characteristic of feline hepatozoonosis. Although the small number of positive cases limited statistical analysis, this study provides baseline molecular and spatial epidemiological data on feline Hepatozoon in Argentina. The coexistence of H. canis and a rodent-related Hepatozoon lineage indicates complex, multi-host transmission dynamics at the domestic-wildlife interface.