Genomic Characterisation of Canis Familiaris Papillomavirus Type 24, a Novel Papillomavirus Associated with Extensive Pigmented Plaque Formation in a Pug Dog.

Numerous large dark plaques developed over the ventrum, legs and head of a 9-year-old pug dog over a 4-year-period. Histology confirmed a diagnosis of viral pigmented plaque and a short section of a novel papillomavirus (PV) type was amplified using consensus PCR primers. Taking advantage of the circular nature of PV DNA, 'outward facing' PCR primers allowed amplification of the full sequence. As this is the 24th PV known to infect dogs, the novel PV was designated canine papillomavirus (CPV) type 24. The CPV24 genome contained putative coding regions for 5 early proteins and 2 late ones. The CPV24 open reading frame L1 showed the highest (78.2%) similarity to CPV4 and phylogenetic analysis showed that CPV24 clustered with CPV4 and CPV16 suggesting CPV24 is the third species 2 Chipapillomavirus type identified in dogs. This is the third report of extensive pigmented plaques covering a high proportion of the skin. Both previous cases were caused CPV4 and, considering the high genetic similarity between CPV4 and CP24, infection by these CPV types may predispose to more severe clinical disease. In addition, as plaques caused by CPV16 appear more likely to progress to neoplasia, the detection of a species 2 Chipapillomavirus within a pigmented plaque may indicate the potential for more severe disease.

Feline atopic dermatitis: a retrospective study of 45 cases (2001-2012).

BACKGROUND: Atopic dermatitis (AD) is recognized as a common cause of pruritus in cats, but it remains incompletely characterized. HYPOTHESIS/OBJECTIVES: The aim of the study was to evaluate cases of confirmed feline AD. ANIMALS: Fourty-five cats from a dermatology referral practice (2001-2012). METHODS: A retrospective case record review was carried out using strict diagnostic criteria, including exclusion of flea-bite hypersensitivity and adverse food reaction. RESULTS: Disease prevalence was 12.5%, with domestic mixed (n = 24), Abyssinian (n = 6) and Devon rex (n = 3) cat breeds predisposed. Median age of onset was 2 years (62% <3 years; 22% >7 years; range 3 months to 12 years). Common presentations were severe (82%), nonseasonal (82%), waxing/waning (36%) pruritus, with alopecia/crusting/excoriations and/or erosions/ulceration (73%). Miliary dermatitis (20%) and eosinophilic granuloma complex lesions (27%) occurred. The face/head (71%), ventral abdomen (51%), neck (51%), limbs (38%), pinnae (31%), dorsum/rump (31%) and feet (16%) were frequently affected sites; lesions were restricted to the head/neck in only five cats (11%). Concurrent otitis externa (16%), superficial bacterial pyoderma (49%), Malassezia dermatitis (7%), flea-bite hypersensitivity (24%) and adverse food reaction (13%) occurred. Strong reactions on intradermal allergen testing were common (68%; 19 of 30), most frequently to pollens (61%) and/or insects (46%). Good response to ciclosporin (100%; 10 of 10), systemic glucocorticoids (55%; 22 of 40) and allergen-specific immunotherapy (57%; 13 of 23) and good/partial response to antihistamines (67%; 22 of 33) were reported. CONCLUSIONS AND CLINICAL IMPORTANCE: The prevalence of feline AD was higher than previously suggested, and breed predispositions were confirmed. Severe nonseasonal pruritus was most common, with a varied spectrum of lesions affecting a range of body areas.

Papillomavirus-associated multicentric squamous cell carcinoma in situ in a cat: an unusually extensive and progressive case with subsequent metastasis.

BACKGROUND: Multicentric squamous cell carcinoma in situ (MSCCIS) is an uncommon cutaneous disease of middle-aged to older cats, with some cases being linked to papillomavirus infection. The disease course is usually benign. Initial eruption of multifocal, pigmented, hyperkeratotic plaques is typical, with gradual progression to thickly crusted ulcerative lesions. ANIMAL: A 5-year-old male neutered Devon rex cat in apparent good health was initially presented with a 16 month history of over 40 nonpruritic dorsally distributed hyperpigmented patches. Lesions progressed gradually over 2 years to larger, more pigmented, crusted plaques and ulcerated nodules. At 7 years of age the cat developed neurological signs and systemic illness and was euthanized. METHODS AND RESULTS: Initial skin histopathology revealed discrete regions of epidermal and follicular epithelial hyperplasia, with moderate numbers of apoptotic keratinocytes, and mild focal epithelial dysplasia. A diagnosis of erythema multiforme was considered; feline herpesvirus-1 immunohistochemistry was negative. Repeat histopathology 22 months after initial presentation confirmed MSCCIS with foci of invasive squamous cell carcinoma (SCC). Postmortem examination 1 month later revealed SCC within the thoracic wall, lungs and vessels of the thoracic spinal cord and heart base, presumed to be metastases from skin lesions. Fluorescent in situ hybridization of initial and later histopathology samples was positive for Felis domesticus papillomavirus type 2. Immunoreactivity of p16 was prominent within early and late cutaneous lesions and internal SCCs. CONCLUSIONS: This case represents an unusual presentation of papillomavirus-associated MSCCIS with extensive lesions, atypical initial histopathology and progression to SCC with distant metastases.