title: Resurrection and redescription of Varestrongylus alces (Nematoda: Protostrongylidae), a lungworm of the Eurasian moose (Alces alces), with report on associated pathology.
abstract: BACKGROUND
  Varestrongylus alces, a lungworm in Eurasian moose from Europe has been considered a junior synonym of Varestrongylus capreoli, in European roe deer, due to a poorly detailed morphological description and the absence of a type-series.
  
  
  METHODS
  Specimens used in the redescription were collected from lesions in the lungs of Eurasian moose, from Vestby, Norway. Specimens were described based on comparative morphology and integrated approaches. Molecular identification was based on PCR, cloning and sequencing of the ITS-2 region of the nuclear ribosomal DNA. Phylogenetic analysis compared V. alces ITS-2 sequences to these of other Varestrongylus species and other protostrongylids.
  
  
  RESULTS
  Varestrongylus alces is resurrected for protostrongylid nematodes of Eurasian moose from Europe. Varestrongylus alces causes firm nodular lesions that are clearly differentiated from the adjacent lung tissue. Histologically, lesions are restricted to the parenchyma with adult, egg and larval parasites surrounded by multinucleated giant cells, macrophages, eosinophilic granulocytes, lymphocytes. The species is valid and distinct from others referred to Varestrongylus, and should be separated from V. capreoli. Morphologically, V. alces can be distinguished from other species by characters in the males that include a distally bifurcated gubernaculum, arched denticulate crura, spicules that are equal in length and relatively short, and a dorsal ray that is elongate and bifurcated. Females have a well-developed provagina, and are very similar to those of V. capreoli. Morphometrics of first-stage larvae largely overlap with those of other Varestrongylus. Sequences of the ITS-2 region strongly support mutual independence of V. alces, V. cf. capreoli, and the yet undescribed species of Varestrongylus from North American ungulates. These three taxa form a well-supported crown-clade as the putative sister of V. alpenae. The association of V. alces and Alces or its ancestors is discussed in light of host and parasite phylogeny and host historical biogeography.
  
  
  CONCLUSIONS
  Varestrongylus alces is a valid species, and should be considered distinct from V. capreoli. Phylogenetic relationships among Varestrongylus spp. from Eurasia and North America are complex and consistent with faunal assembly involving recurrent events of geographic expansion, host switching and subsequent speciation.
authors.affiliation: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada. gverocai@gmail.com.
authors.forename: Guilherme G
authors.initials: GG
authors.lastname: Verocai
authors.affiliation: US Department of Agriculture, United States National Parasite Collection, Agricultural Research Service, BARC East No. 1180, 10300 Baltimore Avenue, Beltsville, Maryland, 20705, USA. eric.hoberg@ars.usda.gov.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Hoberg
authors.affiliation: Norwegian Veterinary Institute, Ullevålsveien 68, N-0454, Oslo, Norway. turid.vikoren@vetinst.no.
authors.forename: Turid
authors.initials: T
authors.lastname: Vikøren
authors.affiliation: Norwegian Veterinary Institute, Ullevålsveien 68, N-0454, Oslo, Norway. kjell.handeland@vetinst.no.
authors.forename: Kjell
authors.initials: K
authors.lastname: Handeland
authors.affiliation: Norwegian Veterinary Institute, Ullevålsveien 68, N-0454, Oslo, Norway. bjornar.ytrehus@nina.no.|Present address: Norwegian Institute for Nature Research, P.O. box 5685, Sluppen, N-7485, Trondheim, Norway. bjornar.ytrehus@nina.no.
authors.forename: Bjørnar
authors.initials: B
authors.lastname: Ytrehus
authors.affiliation: Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada. amrezans@ucalgary.ca.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rezansoff
authors.affiliation: Norwegian Veterinary Institute, Ullevålsveien 68, N-0454, Oslo, Norway. bekidavidson@hotmail.com.|Present address: Norwegian Defence Research Institute, Postboks 25, 2027, Kjeller, Norway. bekidavidson@hotmail.com.
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: Davidson
authors.affiliation: Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada. jsgillea@ucalgary.ca.
authors.forename: John S
authors.initials: JS
authors.lastname: Gilleard
authors.affiliation: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada. skutz@ucalgary.ca.|Canadian Wildlife Health Cooperative - Alberta Node, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada. skutz@ucalgary.ca.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Kutz
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005260:Female; D008168:Lung / Q000469:parasitology; D008297:Male; D008681:Metastrongyloidea / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009664:Norway; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012418:Ruminants / Q000469:parasitology*; D017422:Sequence Analysis, DNA; D017206:Strongylida Infections / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*
chemical_list: D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer