Cat Skin: Cowpox Dermatitis
Animal: Cat, 6 yr old, neutered female, Domestic Short Hair.
Submission history: a week’s history of an ulcer on the right side of the face which was non responsive to broad-spectrum antibiosis. Further ulcerative lesions developed, after one week of initial onset of clinical signs, to the right foreleg. Biopsy was performed on leg lesions and submitted for histologic examination.
Cowpox virus is member of the orthopoxvirus group in the family Poxviridae. Reservoir hosts in Europe include voles, wood mice, ground squirrels and gerbils. Cutaneous clinical signs include an initial erythematous ulcerated plaque or macule (often head, neck and forelimbs). Secondary lesions can develop within 10 days following viraemia. Ulcers within the oral cavity can occur. Development of a systemic infection is rare but can include a necrotising bronchointerstitial pneumonia.
H&E (2x obj)
H&E (20x obj)
Classical lesions include highly acidophilic, variably sized, predominantly single and globular intracytoplasmic inclusion bodies. Cutaneous lesions usually are centrally ulcerative and display peripheral epidermal hyperplasia and ballooning of keratinocytes.
Diagnosis: Cowpox dermatitis.
Photo by: Richard Fox, Finn Pathologists, UK