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Open Access Research

Factors affecting deer ked (Lipoptena cervi) prevalence and infestation intensity in moose (Alces alces) in Norway

Knut Madslien1*, Bjørnar Ytrehus1, Hildegunn Viljugrein14, Erling J Solberg2, Kent Rudi Bråten3 and Atle Mysterud4

Author Affiliations

1 Norwegian Veterinary Institute, Oslo, Norway

2 Norwegian Institute of Nature Research, Oslo, Norway

3 Hedmark University College, Campus Evenstad, Evenstad, Norway

4 Centre for Evolutionary and Ecological Synthesis, University of Oslo, Oslo, Norway

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Parasites & Vectors 2012, 5:251  doi:10.1186/1756-3305-5-251

Published: 12 November 2012

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.

Keywords:
Bogs; Deer ked; GIS; Habitat; Latitude; Longitude; Moose density; Prevalence; Infestation intensity; Scots pine