Distribution of large lungworms (Nematoda: Dictyocaulidae) in free-roaming populations of red deer (L.) with the description of n. sp.

Lungworms of the genus are causative agents of parasitic bronchitis in domestic and wild ungulates. This study investigates the distribution, morphology and genetic diversity of and a new lungworm species, n. sp. infecting red deer , fallow deer and moose in Poland and Sweden. The study was conducted on 167 red deer from Poland and on the DNA of lungworms derived from 7 fallow deer, 4 red deer and 2 moose collected in Sweden. The prevalence of and n. sp. in dissected red deer in Poland was 31.1% and 7.2%, respectively. Moreover, n. sp. was confirmed molecularly in 7 isolates of fallow deer lungworms and 1 isolate of red deer lungworms from Sweden. n. sp. was established based on combination of their distinct molecular and morphological features; these included the length of cephalic vesicle, buccal capsule (BC), buccal capsule wall (BCW), distance from anterior extremity to the nerve ring, the width of head, oesophagus, cephalic vesicle, BC and BCW, as well as the dimensions of reproductive organs of male and female. Additionally, molecular analyses revealed 0.9% nucleotide sequence divergence for 1,605 bp rDNA, and 16.5–17.3% nucleotide sequence divergence for 642 bp mitochondrial B between n. sp. and , respectively, and 18.7–19% between n. sp. and , which translates into 18.2–18.7% amino acid sequence divergence between n. sp. and both lungworms.