Human immunodeficiency virus type 1 can occasionally be detected as a cryptic or latent infection in seronegative, asymptomatic patients. To develop an animal model of host latency, cats were mucosally challenged with 10(2)-10(6) feline immunodeficiency virus (FIV)-infected T cells. Although high-dose exposure (10(4)-10(6) T cells) resulted in progressive infection, no evidence of infection was seen in 5 of 6 cats exposed to 10(2) or 10(3) T cells. However, after ex vivo CD8(+) T cell depletion and phorbol myristate acetate treatment, FIV could be reactivated in tissues from 4 cats. Thus, latent tissue viral reservoirs can be induced by low-dose cell-associated mucosal challenge, providing a model to dissect the mechanisms that control reservoir establishment.

No single treatment provided an optimal method to evaluate freshwater mussel hemolymph. Maximal hemocyte counts were obtained following formalin treatment. l-cysteine reduced clumping and maintained hemocyte morphology for performing a cytologic differential. These techniques provide a standardized approach for the hematologic evaluation of freshwater mussels.

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A 6-year-old, male castrated, mixed-breed dog was referred to the James L. Voss Veterinary Teaching Hospital at Colorado State University for bicavitary effusion. On examination, the dog was tachycardic and tachypneic with bilaterally decreased lung sounds. Thoracic and abdominal ultrasonic examination revealed pleural and peritoneal effusions, which were aspirated and submitted for fluid analysis and cytology. Both cavity fluids were classified as exudates with a large population of vacuolated mononuclear cells. Multiplex immunocytochemistry (ICC) for cytokeratin and vimentin demonstrated exclusively cytokeratin expression, indicating these cells were of epithelial origin. A full diagnostic evaluation was performed, including CBC, clinical chemistry, a pet-side test for heartworm disease, ehrlichiosis, Lyme disease, and anaplasmosis, imaging modalities of thorax, abdomen, and heart, urinalysis, and fine-needle aspirations of spleen, liver, and popliteal lymph nodes. The dog was diagnosed with pleural and peritoneal carcinoma with presumed carcinomatosis. A single dose of intracavitary carboplatin was administered before discharge, and over a period of 2 weeks, 5 thoracocenteses were performed. A subcutaneous mass was noted at a thoracocentesis site one week after initial presentation. Cytology of the mass was consistent with carcinoma, and neoplastic seeding of the tumor cells from the thoracocentesis was suspected. The dog was euthanized 15 days after the first visit, and a necropsy was performed. Findings were consistent with carcinomatosis secondary to anaplastic pulmonary carcinoma with transient subcutaneous seeding of neoplastic cells during routine thoracocentesis. This case demonstrates the utility of multiplex ICC in the clinical setting.

Gamna-Gandy (GG) bodies are non-infectious, hyphal-like structures associated with siderotic nodules in lymphoid tissue; GG bodies are very rarely reported in veterinary cytologic samples. Cytologically, GG bodies can be misidentified as hyphae or plant material. Seven canine lymphoid tissue aspiration cases that contained GG bodies were investigated for morphologic variability and staining characteristics. Available archived cytology slides containing GG bodies were stained with reagents known to show positive results (Prussian blue, Alizarin red S, Von Kossa) and negative results (Gomori methenamine silver) in histologic samples. Calcofluor white staining was also performed. GG bodies in Wright-Giemsa-stained cytology samples displayed considerable variability but were generally 2-5 µm diameter, 10-35 µm long, refractile, clear, pale-tan or pale-yellow, wavy or straight, tubular structures. Six cases allowed for cytochemical staining; staining properties were similar to histology samples. The bodies did not stain with calcofluor white; this stain may be helpful in distinguishing GG bodes from fungal hyphae.