title: Factors affecting deer ked (Lipoptena cervi) prevalence and infestation intensity in moose (Alces alces) in Norway.
abstract: BACKGROUND
  The deer ked (Lipoptena cervi), a hematophagous ectoparasite of Cervids, is currently spreading in Scandinavia. In Norway, keds are now invading the south-eastern part of the country and the abundant and widely distributed moose (Alces alces) is the definitive host. However, key factors for ked abundance are poorly elucidated. The objectives of our study were to (i) determine deer ked infestation prevalence and intensity on moose and (ii) evaluate if habitat characteristics and moose population density are determinants of deer ked abundance on moose.
  
  
  METHODS
  In order to identify key factors for deer ked abundance, a total of 350 skin samples from the neck of hunted moose were examined and deer keds counted. Infestation intensity was analyzed in relation to moose age and sex, moose population density and landscape characteristics surrounding the killing site.
  
  
  RESULTS
  Deer ked infestation prevalence was 100%, but infestation intensity varied from 0.001 to 1.405 keds/cm². Ked intensity was highest in male yearlings (~1.5 years) and positively associated with longitude and Scots pine (Pinus sylvestris) dominated habitat and negatively associated with bogs and latitude. Moose population density during autumn showed a tendency to be positively associated, while altitude tended to be negatively associated with ked intensity.
  
  
  CONCLUSIONS
  Deer keds exploit the whole moose population within our study area, but are most prevalent in areas dominated by Scots pine. This is probably a reflection of Scots pine being the preferred winter browse for moose in areas with highest moose densities in winter. Ked intensity decreases towards the northwest and partly with increasing altitude, probably explained by the direction of dispersal and reduced temperature, respectively. Abundant deer ked harm humans and domestic animals. Moose management authorities should therefore be aware of the close relationship between moose, deer ked and habitat, using the knowledge as a management tool for locally regulating the ked burden.
authors.affiliation: Norwegian Veterinary Institute, Oslo, Norway. knut.madslien@vetinst.no
authors.forename: Knut
authors.initials: K
authors.lastname: Madslien
authors.forename: Bjørnar
authors.initials: B
authors.lastname: Ytrehus
authors.forename: Hildegunn
authors.initials: H
authors.lastname: Viljugrein
authors.forename: Erling J
authors.initials: EJ
authors.lastname: Solberg
authors.forename: Kent Rudi
authors.initials: KR
authors.lastname: Bråten
authors.forename: Atle
authors.initials: A
authors.lastname: Mysterud
mesh_terms: D000367:Age Factors; D000818:Animals; D004175:Diptera / Q000254:growth & development*; D017753:Ecosystem; D004478:Ectoparasitic Infestations / Q000453:epidemiology / Q000662:veterinary*; D005260:Female; D008297:Male; D009333:Neck / Q000469:parasitology; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D012418:Ruminants / Q000469:parasitology*; D012737:Sex Factors; D012867:Skin / Q000469:parasitology