Chronic Eosinophilic Dermatitis Associated with Persistent Feline Herpes Virus Infection in Cheetahs (Acinonyx jubatus)

Abstract

Abstract:A chronic ulcerative and eosinophilic dermatitis occurred in 20 captive cheetahs (Acinonyx jubatus) with persistent feline herpes virus 1 (FHV1) infection. Affected animals had erythematous, ulcerated plaques primarily on the face and forelegs in sites of contact with lachrymal and salivary secretions. The dermatitis was characterized by dense infiltrates of eosinophils and plasma cells and pseudoepitheliomatous hyperplasia. Rare keratinocytes within the lesions had nuclei with marginated chromatin and small eosinophilic inclusions composed of herpes virus nucleocapsids. Virus isolated from lesions was confirmed to be FHV1. Lesions persisted and progressed unless removed by cryoexcision. The occurrence of this unusual reaction to FHV1 in approximately 5% of captive North American cheetahs suggests a species propensity for a Th2-dominant response to herpes virus infection. This atypical immune reaction may indicate a heritable trait or modulation of the immune response by other factors such as chronic stress.Key words: Acinonyx jubatus; cheetahs; dermatitis; eosinophils; feline herpes virus 1; pseudoepitheliomatous hyperplasia.In 1991, a chronic ulcerative dermatitis developed in two cheetah cubs (Acinonyx jubatus) with feline herpes virus 1 (FHV1) infection. 10 Although at that time this cutaneous manifestation of FHV1 infection was considered unusual, 20 cheetahs in nine zoos (approximately 5% of the captive North American [NA] population) have now been confirmed with this condition, and additional cheetahs with similar lesions have been reported but not confirmed. In most cases, the cutaneous lesions first occurred as plaquelike edematous swellings at the medial canthus of the eye and on the palpebra that progressed to nonhealing ulcers. Lesions then extended across the nasal planum or ventrally to the nasal philtrum and skin beneath the eyes (Table 1, Fig. 1). Lesions also occurred commonly at the commissures of the lips, top of the head, distal forelegs, flank, tail, and footpads (Fig. 2). Three cheetahs had concurrent ulcerative keratitis, and one affected cheetah had a lingual ulcer.The skin lesions were typically firm irregular plaques with a raised rim and central ulceration. A white, eosinophil-rich exudate was present in many cases. Over time, these plaques expanded centrifugally, and the epidermis became thickened and verrucous, resembling squamous cell carcinomas. The histopathologic appearance was similar in all cases and was characterized by dense dermal infiltrates of eosinophils, mast cells, plasma cells, and lymphocytes and by pseudoepitheliomatous hyperplasia (Fig. 3). Approximately 40% of the inflammatory cell infiltrates were eosinophils and 30% were plasma cells. In some cases, eosinophilic pustules occurred in the epidermis, and aggregates of eosinophils were associated with degenerate collagen in the dermis. The hyperplastic epithelium formed raised plaques and had prominent rete ridges. Within the stratum spinosum, there were individual necrotic keratinocytes and swollen, degener...

Extrinsic Factors Significantly Affect Patterns of Disease in Free-Ranging and Captive Cheetah (Acinonyx Jubatus) Populations

“…Lower premolars were categorized by cementum aging, and these results correlated with other age estimates (Marker and Dickman, 2002). Only those cheetahs that were 24 or more months old (approximate age of sexual maturity) were included in the study because the diseases prevalent in captive animals occur principally in adults (Munson, 1993;. The Namibian study animals ranged from 2 to 10 yr old (median ageϭ6 yr) with only one animal Ͼ8 yr old.…”

“…Veno-occlusive disease (VOD), glomerulosclerosis, and gastritis were graded by one author (L.M.) using previously published criteria (Munson, 1993;Munson et al, 1999). Lymphoid aggregates in the deep lamina propria of the stomach were considered normal and were not included in gastritis grading (Stolte and Meining, 2001).…”

“…A subset of this data has been published previously. (Munson, 1993;Papendick et al, 1997;Bolton and Munson, 1999). b Prevalences are expressed as the proportion (%) of tissues available.…”

“…The NA and SA animals died between 1988 and 2002; a subset of this data was previously reported (Munson, 1993;Munson et al, 1999). All histopathology was performed by the same pathologist (L.M.)…”

“…The propensity for cheetahs to maintain persistent viral infections and develop atypical immune responses to common pathogens (Evermann et al, 1988;Junge et al, 1991;Eaton et al, 1993;Steinel et al, 2000;Munson et al, 2003) may also have a genetic basis, although modulation of the immune response by chronic stress has also been proposed . In light of these suspected inherent vulnerabilities to viral agents, we were surprised to find that morbidity and mortality in North American (NA) cheetahs were principally due to chronic degenerative diseases, such as veno-occlusive disease, glomerulosclerosis, and amyloidosis, rather than infectious disease (Munson, 1993;Papendick et al, 1997;Bolton and Munson, 1999). Furthermore, the prevalence and severity of these diseases in both captive populations differed among facilities, suggesting an environmental effect.…”