Dermatophilus is a skin disease caused by the bacterial parasite Dermatophilus congolensis. It affects a wide range of animal species including man.1,2,9 This zoonotic disease is worldwide in distribution but more prevalent in the humid tropical and subtropical regions.
Dermatophilosis has been described in many wild ungulate species including antelope, eland, gazelle, kudu, buffalo, giraffe1, white-tailed deer3,7 and kafue lechwe6. In chamois, the disease sporadically occurs in the European Alps; it was diagnosed for the first time in 1967.5
A 2-mo-old male free-ranging roe deer was found dead in the vicinity of Berne, Switzerland. The skin showed severe lesions and because of suspicion of mange, the animal was sent for necropsy to the Institute of Animal Pathology, University of Berne.
The lesions were characterized by thickening of the skin and coalescing crusts which could be easily detached, leaving a moist hair loss patch on the skin covered with a yellowish sticky exudate. Almost all parts of the body were affected. In addition, the animal was infested with a high number of ticks (Ixodes ricinus).
The direct examination with KOH revealed neither mites nor mycotic organisms. The bacterial culture showed an infection with Staphylococcus sp. Histologically, there was diffuse acanthosis with hydropic degeneration in the upper spinous layer and marked palisading ortho- and parakeratotic hyperkeratosis alternating with inflammatory exudate. Characteristic large ramified filaments with compartmented structures resembling “rolls of coins,” positive with Grocott stain, were found in the crusts as well as in the follicles and identified as D. congolensis. Aggregates of coccoid bacteria were also present.
A diagnosis of dermatophilosis was made, based on the characteristic morphology of the etiologic agent revealed by histological examination. The infection with Staphylococcus sp. was considered to be secondary. According to Morrow & Compton4 and Walker & Lloyd8, the tick infestation was a predisposing factor in the pathogenesis of the D. congolensis dermatitis. The exceptional wet weather in the summer of 1996 may have favored the infection as well.
To our knowledge, this is the first reported case of dermatophilosis in roe deer.
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