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

• Published in: International Journal for Parasitology: Parasites and Wildlife
• Main Authors: Hannah A.Danks, Caroline Sobotyk, Meriam N.Saleh, Matthew Kulpa, Joe L.Luksovsky, Lee C Jones, Guilherme G. Verocai
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2022
• Subjects: Bison bison; dictyocaulosis; Nearctic fauna; Phylogenetic relationships; Verminous pneumonia; Lungworm; Zoology; QL1-991; Bison bison bison; Plains Bison
• Online Access: https://doi.org/10.1016/j.ijppaw.2022.04.011; https://doaj.org/article/01587d275ea54f41b8099ce065f38d06

Dictyocaulus is a globally distributed genus of lungworms of domestic and wild ungulates. Dictyocaulus adults inhabit the bronchi, frequently causing subclinical and clinical disease, and that impacts animal health and production. North American bison (Bison bison) and cattle (Bos taurus) share various parasitic nematode species, particularly in areas where co-grazing occurs. The current assumption is that North American bison share the lungworm D. viviparus with cattle, but this has not been confirmed on a molecular basis. The aim of this study was to molecularly characterize Dictyocaulus lungworm isolates from North American plains bison (Bison bison 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 (cox1) of mitochondrial DNA. Phylogenetic analyses were performed in MEGA X 10.1. Sequences of North American plains bison Dictyocaulus belong to a single, uncharacterized species, clustering in well-supported clades (100% and 100% bootstrap support for ITS2 and cox1, respectively), differing from D. viviparus of cattle in North America and Europe, and European bison (Bison bonasus). 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 Dictyocaulus species infecting bovids and cervids in North America is warranted.