A previously unidentified Chorioptes species infesting outer ear canals of moose (Alces alces): characterization of the mite and the pathology of infestation

<p>Abstract</p> <p>Background</p> <p>During the past decade, <it>Chorioptes </it>mites occupying the outer ear canals have been a common finding at routine necropsies of moose (<it>Alces alces</it>) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. In this study, the mites are characterized by morphological and molecular techniques, and the histopathology of the skin of the outer ear canal is described.</p> <p>Methods</p> <p>External auditory meatuses from 53 necropsied moose were examined for the presence of <it>Chorioptes</it>, and samples from outer ear canals were taken for histopathological and microbiological examination. A proportion of the mites from each moose was identified to species. The DNA was extracted from mites from three moose, and their ITS-2 sequences were determined; these sequences were compared phylogenetically to sequences from other <it>Chorioptes </it>taxa.</p> <p>Results</p> <p><it>Chorioptes </it>mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of <it>C. texanus </it>and <it>C. bovis</it>, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as <it>C. crewei</it>, <it>C. mydaus </it>or <it>C. panda</it>. On histopathology, lesions were characterized by a hyperplastic perivascular to interstitial dermatitis with epidermal hyperkeratosis and crust formation. Dermal inflammatory infiltrates were composed of mixed T- and B-lymphocytes, plasma cells and macrophages, whereas eosinophils were notably uncommon. <it>Staphylococcus aureus </it>was grown from the infested epidermis of five of 14 examined moose.</p> <p>Conclusion</p> <p><it>Chorioptes </it>mite infestation was frequently detected in the outer ear canals of moose in Sweden. The mites were evidently pathogenic, being associated with inflammatory lesions of the external auditory meatus. Our studies indicate infestations with a previously undescribed <it>Chorioptes </it>species.</p

Sealing the new home

Peer reviewed: NoNRC publication: Ye

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

<p>Abstract</p> <p>Background</p> <p>The deer ked (<it>Lipoptena cervi</it>), 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 (<it>Alces alces</it>) 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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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 (<it>Pinus sylvestris</it>) 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.</p> <p>Conclusions</p> <p>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.</p