Opening a can of lungworms: Molecular characterization of (Nematoda: Dictyocaulidae) infecting North American bison ().

is a globally distributed genus of lungworms of domestic and wild ungulates. adults inhabit the bronchi, frequently causing subclinical and clinical disease, and that impacts animal health and production. North American bison () and cattle () share various parasitic nematode species, particularly in areas where co-grazing occurs. The current assumption is that North American bison share the lungworm with cattle, but this has not been confirmed on a molecular basis. The aim of this study was to molecularly characterize lungworm isolates from North American plains bison (). Fecal samples were collected from 5 wild conservation bison herds located in Iowa, North Dakota, Oklahoma, Colorado, and Montana in 2019 and 2020, and from ranched and feedlot bison from 2 herds in Oklahoma and Texas. First-stage lungworm larvae (L1) were isolated via Baermann technique. Genomic DNA was extracted from L1s of up to 3 samples per herd and followed by PCR and sequencing targeting the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal DNA and the partial cytochrome oxidase c subunit 1 () of mitochondrial DNA. Phylogenetic analyses were performed in MEGA X 10.1. Sequences of North American plains bison belong to a single, uncharacterized species, clustering in well-supported clades (100% and 100% bootstrap support for ITS2 and , respectively), differing from of cattle in North America and Europe, and European bison (). Our results contradict previous assumptions regarding parasite identity, highlighting the need for characterization of this species through morphological and molecular methods, elucidating its biology and host range, and potential impact on host health. Further investigation into the biodiversity of species infecting bovids and cervids in North America is warranted.