Contents lists available at ScienceDirect Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar Research paper Pathological lesions in the lungs of red deer Cervus elaphus (L.) induced by a newly-described Dictyocaulus cervi (Nematoda: Trichostrongyloidea) Anna M. Pyziel a, ⁎ , Izabella Dolka b , Joanna Werszko c , Zdzisław Laskowski c , Żaneta Steiner-Bogdaszewska c , Jan Wiśniewski a , Aleksander W. Demiaszkiewicz c , Krzysztof Anusz a a Department of Food Hygiene and Public Health Protection, Faculty of Veterinary Medicine, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland b Department of Pathology and Veterinary Diagnostics, Faculty of Veterinary Medicine, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159c, 02-776 Warsaw, Poland c W. Stefański Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland ARTICLE INFO Keywords: Dictyocaulosis Large lungworm Histopathology 18S rRNA (SSU) Poland ABSTRACT The large lungworms of the genus Dictyocaulus are causative agents of parasitic bronchitis in various ungulate hosts, including red deer. Recently, the red deer-derived lungworm D. cervi was described and separated from D. eckerti. Little is known of the transmission patterns, epidemiology, geographical distribution and pathogenicity of D. cervi. Histological examinations were performed on 22 formalin-fixed lung tissue samples of hunted red deer. Exclusively, D. cervi adults were derived from 15 red deer and confirmed molecularly (GenBank accession: MH183394). Dictyocaulus cervi infection was associated with various degrees of lung pathology, including in- terstitial pneumonia, bronchitis and bronchiolitis with an influx of eosinophils, lymphocytes, plasma cells and macrophages; massive hyperplasia of lymphoid follicles within bronchiolar tissue, and hyperplasia of the bronchial and bronchiolar epithelium. Furthermore, emphysema, atelectasis and lung tissue congestion were noted. Interestingly, interstitial and subpleural fibrosis was seen in adult Dictyocaulus-negative samples, sug- gesting either a prepatent phase of Dictyocaulus infection or infection/coinfection with protostrongylid nema- todes. 1. Introduction Large lungworms from the genus Dictyocaulus Railliet and Henry, 1907 (Nematoda: Trichostrongyloidea) are causative agents of parasitic bronchitis (dictyocaulosis, husk) in various ungulate hosts, including domestic and wild ruminants (Eysker, 1994; Divina et al., 2002; Mahmood et al., 2014; Pyziel, 2014). The life cycle of Dictyocaulus lungworms is direct, with adults being present in the small and large airways of a host, where they produce embryonated eggs that hatch in the airways or in the large intestine. First stage larvae (L1) are passed in the faeces of the host into the environment to develop into infective L3 (Panuska, 2006). A new host can be infected orally, and the ingested larvae migrate through the body to reach the lungs as L4 at the seventh day after infection (Panuska, 2006). According to Corrigall et al. (1982) the main clinical signs of parasitic bronchitis, which include coughing and dyspnea, occur during the prepatent phase, between days seven and 25 of infection (Panuska, 2006). They result from the immunological reaction to the appearance of larvae within the alveoli and to their migration towards the bronchiole and bronchi. During the patent phase, between days 25 and 55 of infection, clinical signs es- calate; intense coughing, loss of condition, harsh respiratory sounds with rhonchi, and emphysematous crackling can be diagnosed (Panuska, 2006). Dictyocaulosis is a potential threat to the biodiversity and also to the development of the game industry (Gortázar et al., 2006; Hoffman and Wiklund, 2006). According to the first systematic revision of the genus (Skrjabin et al., 1954), D. eckerti was described as a collective species infecting various cervid hosts including red deer. However, this classification had to be revised following the morphological and molecular description of D. capreolus Gibbons and Höglund (2002) from roe deer and moose (Höglund et al., 1999) and D. cervi Pyziel et al. (2017) from red deer (Pyziel et al., 2015). During this revision, the D. cervi lungworm of red deer with unique ribosomal SSU, ITS2 and mitochondrial cox1 and cox3 sequences (Pyziel et al., 2018), was separated from D. eckerti. https://doi.org/10.1016/j.vetpar.2018.08.003 Received 30 May 2018; Received in revised form 6 August 2018; Accepted 7 August 2018 ⁎ Corresponding author. E-mail address: anna_pyziel@sggw.pl (A.M. Pyziel). Veterinary Parasitology 261 (2018) 22–26 0304-4017/ © 2018 Elsevier B.V. All rights reserved. T