Abstract
BackgroundDuring the past decade, Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) 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.MethodsExternal auditory meatuses from 53 necropsied moose were examined for the presence of Chorioptes, 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 Chorioptes taxa.ResultsChorioptes mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of C. texanus and C. bovis, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as C. crewei, C. mydaus or C. panda. 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. Staphylococcus aureus was grown from the infested epidermis of five of 14 examined moose.ConclusionChorioptes 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 Chorioptes species.
Highlights
During the past decade, Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated
Infested moose were found in all parts of the study area, covering the mid and south regions of Sweden
As judged from post-mortem records, the panorama of necropsy diagnoses did not differ between infested and non-infested animals, and was similar to that found in the material of Swedish moose necropsied at SVA 1986–1991 [15]
Summary
Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. Ectoparasites of the genus Chorioptes (Acari: Psoroptidae) are distributed worldwide, infesting domestic as well as wild herbivores [1,2] These non-burrowing mites are commonly found on cattle, sheep, goats, horses and the New World camelids, where they are a common cause of mange and have considerable veterinary importance. Chorioptes bovis (Hering, 1845) and Chorioptes texanus Hirst 1924 are generally accepted [1,4], based on morphology and genetic differentiation, while the existence of three further species, Chorioptes crewei Lavoipierre 1958, Chorioptes mydaus Fain 1975 and Chorioptes panda Fain and Leclerc 1975, is still questionable [2,5] Both C. bovis and C. texanus are ubiquitous mites with a low degree of host specificity. Reported hosts of C. bovis include wild and domestic Bovidae, Cervidae, Equidae and Camelidae [4]
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