Morphological and molecular detection of Hepatozoon species in amphibians and reptiles from Mato Grosso, Midwest Brazil.

The Hepatozoon genus is composed of hemoparasites widely distributed, though their diversity and phylogeny remain poorly understood in the Brazilian herpetofauna. We aimed to characterize Hepatozoon species infecting the blood and spleen of amphibians and reptiles in Mato Grosso, Midwestern Brazil, using morphological and molecular tools. In total, 146 animals from 19 species (8 amphibians and 11 reptiles) were evaluated. Giemsa-stained blood smears revealed Hepatozoon-like inclusions in 35 individuals (8 amphibians and 27 reptiles), including new infection records in the anurans Boana raniceps and Trachycephalus typhonius, and the snake Eunectes notaeus. Morphological analysis revealed diverse morphotypes. Molecular analysis of the 18S rRNA gene identified six haplotypes in Rhinella diptycha, Ameiva ameiva, Boa constrictor, Epicrates crassus, E. notaeus, and Caiman yacare. Phylogenetic analyses revealed clustering with clades linked to H. musa and H. caimani, suggesting the presence of potentially novel lineages. These findings highlight the high genetic diversity of Hepatozoon in the region and emphasize the value of integrative approaches in parasitological research.