The proliferative response of peripheral blood mononuclear cells (PBMC) stimulated with caprine arthritis-encephalitis virus (CAEV) surface glycoprotein (SU) was depressed 4- to 20-fold in Saanen goats with chronic CAEV-induced arthritis compared with asymptomatic goats. Phytohemagglutinin-stimulated responses were not depressed. Complement depletion of PBMC with anti-CD4 or anti-CD8 monoclonal antibodies identified CD4+ T lymphocytes as the antigen-responsive cells in both high-responder asymptomatic goats and low-responder arthritic goats. Serum antibody titers to CAEV SU were 8- to 32-fold higher in goats with chronic arthritis. Increased anti-CAEV SU titers as early as 3 months after infection predicted the eventual development of clinical arthritis. Thus, CAEV-induced arthritis is associated with chronic B cell activation resulting from dominant type 2 immune responses to viral antigen. The clinical outcome of CAEV infection may be determined by differential activation of type 1 or 2 T lymphocyte phenotypes at or near the time of initial exposure to CAEV.

Abstract. Tumors of the perianal area of dogs are common and include multiple tumor types. Whereas perianal adenomas occur often, adenocarcinomas of the apocrine glands of the anal sac occur less frequently. A review of the literature revealed no reports of squamous cell carcinomas arising from the epithelial lining of the anal sac. Squamous cell carcinomas originating from the lining of the anal sac were diagnosed in five dogs. Microscopically, the tumors consisted of variably sized invasive nests and cords of epithelial cells displaying squamous differentiation. Four of the five dogs were euthanatized because of problems associated with local infiltration by the tumors. In the fifth dog, there was no evidence of tumor 7 months after surgical removal, but further follow up was not available.

Abstract. The primary causes of mortality were identified in postmortem examination of 339 (90.9%) of 373 farmed mink (Neovison vison; syn. Mustela vison) from January 2009 through June 2014 at the Utah Veterinary Diagnostic Laboratory (Logan, Utah). Mink were raised under farm conditions in the Intermountain West in North America, except for 1 submission of mink from Wisconsin. In the 339 mink where cause(s) of death were established, 311 (91.7%) died from a single disease or condition, whereas 28 (8.3%) had 2 diseases or conditions contributing to death. Where cause(s) of death were evident, 11 diseases accounted for 321 (94.7%) of the diagnoses: bacterial pneumonia (67, 18.8%), Aleutian mink disease (61, 17.7%), mink viral enteritis (56, 16.2%), hepatic lipidosis (28, 8.1%), nutritional myopathy (24, 7%), bacterial enterocolitis (17, 4.9%), bacterial septicemia (16, 4.6%), starvation (15, 4.3%), epizootic catarrhal gastroenteritis of mink (14, 4.1%), pancreatitis (13, 3.8%), and bacterial metritis (10, 2.9%). In 34 (9.1%) animals, a cause of death was not evident. In an additional 16 (4.3%) of the mink, botulism was suspected from clinical history but could not be confirmed by laboratory testing. Control measures for the most common causes of death in farmed mink include testing and removal of positive animals (Aleutian mink disease), vaccination (Pseudomonas aeruginosa pneumonia, mink viral enteritis), avoidance of obesity in mink (hepatic lipidosis), and environmental management, including maintaining clean water cups, floors, feed troughs, cages, feed silos, feed truck tires, workers' shoes, dining areas for farm personnel, leather mink handling gloves, street clothes, and coveralls.

Persistent vitelline duct remnants, with the exception of Meckel's diverticulum in pigs and horses, are rare in animals. During an ovariohysterectomy of an 8-month-old Labrador Retriever, multiple fibrous nodules with cystic centers were found attached to the ileal serosa and in a mesodiverticular band attached to the abdominal wall. Histologic and ultrastructural evaluation revealed that the cysts were composed of well-differentiated intestine with mucosa, submucosa, and muscularis layers surrounded by a thick layer of fibrous connective tissue. The morphology and arrangement of lesions were consistent with multiple persistent vitelline duct cysts, a distinct condition related to Meckel's diverticulum. This case in a dog represents a unique presentation of this congenital anomaly in domestic animals.

Characteristic dermatologic lesions of naturally occurring and iatrogenic canine hyperglucocorticoidism have been well documented, and include any combination of bilaterally symmetric alopecia, thinning of the epidermis, skin hyperpigmentation or depigmentation, comedones, phlebectasia, and calcinosis cutis. 20 Other generalized signs reported in affected animals include polydipsia, polyuria, muscle weakness, hepatomegaly, and myopathies. Although calcinosis cutis in its broadest definition can encompass all forms of calcium deposition, it is most commonly used to denote the specific pattern of dystrophic calcification associated with hyperadrenocorticism or iatrogenic hyperglucocorticoidism. 8 The mechanism of this process has not been completely elucidated, but it involves phase transformation of calcium and phosphate ions from solution into crystalline aggregates, with deposition upon the matrices of dermal collagen and elastin under the influence of cellular factors. 3,8 The collagen fibers in these cases are variably mineralized, and root sheaths may also be affected. 8,20 The deposition of minerals in calcinosis cutis is often not associated with areas of inflammation and, when observed, typically consists of a histiocytic foreign-body-type reaction. In contrast, several dermatologic conditions of humans known as metaplastic ossification, primary or secondary osteoma cutis, plate-like osteoma, and acquired cutaneous osteomatosis are characterized by metaplastic bone formation in the dermis, where osteoid formation occurs with or without collagen mineralization. 2,4,7,10,12,15,18 Some of these syndromes are idiopathic, while others have been associated with a variety of predisposing factors, including acne vulgaris, systemic metabolic illness, dermal surgery, and chronic irritation. 1,12,15,17,18 Reported here are 2 cases of widespread dermal osseous metaplasia in dogs with evidence of iatrogenic hyperglucocorticoidism that share histologic features with human cases of metaplastic ossification.An 8-year-old male Rottweiler had a 4-year history of chronic skin disease that was only partially responsive to antibiotic and corticosteroid therapy and was becoming progressively worse. The dog was minimally pruritic. On physical examination, moderate multifocal areas of alopecia and lichenification were observed on the dorsal topline with extension to the neck, shoulders, hips, and proximal limbs. Six separate, oozing, variably sized dermal ulcers were present along the back from the shoulder blades to the area near the base of the tail. Numerous pustules, macules, and papules were distributed along the skin of the back, and the skin was noticeably thickened. Multiple skin scrapings and dermatophyte cultures were negative, and complete blood counts were within normal limits. Serum chemistry abnormalities Received for publication May 13, 1997.(normal ranges given in parentheses throughout) included 901 U/liter (Ͻ141 U/liter) alkaline phosphatase and 258 U/ liter (Ͻ85 U/liter) ALT. The urine specific gravity was 1.0...