Metabarcoding reveals rodents as exclusive hosts of Hepatozoon hemoparasites among synanthropic small- to medium-sized mammals in suburban New Jersey, USA.

Alveolate protozoan parasites in the genus Hepatozoon infect a wide range of wild animals and pose a significant health threat to companion animals, mainly dogs and cats. Aiming to create a baseline description of Hepatozoon sp. in wild animals in the northeastern USA, we used 18S rDNA metabarcoding to screen blood from 243 small- and medium-sized wild mammals from 11 species sampled in New Brunswick, NJ, USA. To the best of our knowledge, this is the first use of metabarcoding to examine community-level Hepatozoon prevalence and diversity in North American wildlife. We analyzed amplicon sequence variants (ASVs) using phylogenetic and haplotype network approaches. We detected Hepatozoon DNA in 17.3% of individual mammals but only rodents were positive, with no positive carnivores, lagomorphs, marsupials, or shrews. Thin blood smears from three gray squirrels showed leukocyte parasitemia ranging from 1.5 to 6.9%. We identified 130 distinct ASVs, most of which had a top pairwise identity to Hepatozoon griseisciuri A or B or Hepatozoon sp. DB2220. In the phylogenetic analysis, all ASVs grouped with sequences from rodents and reptiles, separate from the clade containing sequences of parasites known to infect dogs and cats. Contrary to other studies, we found no evidence of Hepatozoon sp. in carnivores such as raccoons and did not detect Hepatozoon species known to infect domestic animals, suggesting the synanthropic mammals examined are not current reservoir hosts for these parasites in the study region.