Phylogenetic and histopathological characterization of putative Hepatozoon ophisauri-like lineages in rodents from Italy.

PURPOSE: The aim of this study was to describe the occurrence and phylogenetic diversity of Hepatozoon spp. in small mammals from the Emilia-Romagna region, northern Italy, and to assess their genetic relationships with previously described lineages.

METHODS

Tissue samples (spleen and ear) from wild animals belonging to eight small mammal species were examined. Molecular screening was performed using PCR targeting the 18 S rRNA gene of Hepatozoon spp. Positive amplicons were sequenced and analyzed using phylogenetic methods to determine their taxonomic placement, and one positive fresh sample was additionally subjected to histopathological characterization.

RESULTS

Hepatozoon DNA was detected in two rodent species, the brown rat (Rattus norvegicus) and the European edible dormouse (Glis glis). Sequences showed high identity (98.9-100%) with Hepatozoon sp. previously reported in rodents from Spain and Tanzania, and 98.32-98.9% identity with Hepatozoon ophisauri. Phylogenetic analysis placed the sequences from R. norvegicus within a rodent-associated clade, whereas those from G. glis formed a distinct lineage related to Hepatozoon detected in a great gerbil. Histopathological analysis in a European edible dormouse revealed multifocal pulmonary granulomatous inflammatory lesions associated with intracytoplasmic parasitic zoites and developmental stages consistent with type I and type II meronts.

CONCLUSION

This study provides molecular evidence of distinct Hepatozoon lineages in European rodents, potentially representing undescribed taxa, and highlights the need for integrative studies combining molecular, morphological, and ecological data.