Veterinary Pathology

Four cases of canine blastomycosis are described. Biopsy specimens were examined in two of the cases. Typical granulomas and microabscesses containing yeast forms of Blastomyces dermatitidis were seen in the testicle, prostate, kidney and bladder. Complete necropsies are described in two dogs with granulomas in the lung, eyes, prostate, testicle and meninges. The distribution of the lesions indicates a systemic infection.

A capillary hemangioma in the gastrocnemius muscle of a Rhesus monkey is reported. It is believed to be the fourth vascular neoplasm described in Rhesus monkeys and the first to have developed in skeletal muscle. The tumor was a firm, hemorrhagic mass 5.0 × 6.5 cm. It was composed of a benign bed of proliferating capillaries. No distinct capsule separated the mass from the adjacent muscle, but collagenous trabeculae subdivided the tumor into packets of capillaries.

Spontaneous gross and microscopic lesions were studied in 82 perinatal and neonatal monkeys of various species. Ninety-seven lesions were found in the body systems examined. The system at greatest risk was the respiratory system (33 lesions), at the least risk, the cardiovascular system (four lesions). Lesions were inflammatory, degenerative, vascular, and of other types, such as intrauterine aspiration and congenital anomalies. Differences in the type and distribution of lesions in the various systems were found between premature and mature infants.

The causes of death were studied in 82 perinatal and neonatal monkeys. Forty-three of the 82 neonatal deaths were caused by inflammatory diseases (mainly pneumonia), intrauterine distress, and trauma. In 28 of the 82 monkeys, a major disease process could not be demonstrated. Intrauterine distress and antepartum death with maceration were commoner causes of death in premature infants; trauma and inflammatory disease occurred more often in mature infants. Forty-nine of the 82 neonatal deaths occurred before the second day of life. During the last 3 weeks of the neonatal period, the majority of deaths were caused by infection.

Lesions induced by a bovine coronavirus-like agent were studied in gnotobiotic and colostrum-fed calves using gross, histologic and electron microscopic procedures. Lesions in gnotobiotic calves were present in the colon, mesenteric lymph nodes and in all segments of the small intestine. Calves killed 4 h after the onset of diarrhea had immunofluorescent epithelial cells on the villi of the small intestine and surface of the colon. Calves killed at 44 h had shortened intestinal villi and cuboidal epithelial cells. The villus-to-crypt ratio in the lower small intestine averaged 1.0 compared with 5.3 in a control calf. Immunofluorescent cells were present at the tips of the villi, and at the surface and in the crypts of the colon. Colostrum-fed calves that had serum-neutralizing antibody titers for the coronavirus-like agent developed diarrhea when inoculated orally with the agent. There was good correlation between histologic, immunofluorescent and electron microscopic findings.

A 5-year-old male Golden Retriever was examined because of a chronic localized loss of hair and elevated, multiple white nodules 2–8 mm in diameter that coalesced in several areas on the right side of the neck. The principle change was marked hyperplasia of the dermal collagen. The lesion is compatible with the connective tissue nevus described in man.

The sequential pathology of canine nephrotoxic glomerulonephritis was studied by light microscopy, immunofluorescence and electron microscopy. The disease was induced by intravenous administration of antiglomerular basement membrane serum, and experimental animals were examined from 4 h up to 60 days after administration of nephrotoxic serum. During the first few days there was extensive glomerular capillary necrosis and infiltration by neutrophils. This was followed by mesangial proliferation and glomerular scarring. Using immunofluorescence, nephrotoxic (rabbit) serum and host IgG and complement (C3) were detected in damaged glomeruli.