Pneumatosis intestinalis in an SIV‐infected rhesus macaque (Macaca mulatta)

Pneumatosis intestinalis (PI) has been described as an incidental finding in domestic animals and humans where it is associated with human immunodeficiency virus infection among other comorbidities. This report describes emphysematous changes consistent with PI in a simian immunodeficiency virus (SIV)‐infected rhesus macaque (Macaca mulatta).     

Spontaneous telangiectatic osteosarcoma in a rhesus macaque (Macaca mulatta)

Osteosarcoma (OS) is the most common type of bone cancer, especially in young. Telangiectatic osteosarcoma (TO) is a rare variant of OS, and hence, its occurrence, presentation, and prognosis are poorly understood. A 4‐year‐old female rhesus monkey presenting lameness and swelling was examined for a mass on the right humerus. Radiography revealed fracture and disorganized structure of bone tissue. Histopathological examination revealed malignant neoplasm composed of anaplastic osteoblasts, which invaded the bone marrow and surrounded blood‐filled cysts in the epiphysis and diaphysis forming septa. Cytogenetic analysis showed aneuploid cells, supernumerary AgNORs, and a marker fragment. The neoplasm was diagnosed as TO. To our knowledge, the occurrence of TO and its cytogenetic analysis were reported for the first time in non‐human primates.     

Cerebral cysts of ependymal or ventricular origin in a juvenile rhesus macaque (Macaca mulatta) with neurologic signs

Naturally occurring neurologic disease in non‐human primates may be attributable to a wide‐range of causes, including infectious agents, congenital or acquired malformations, degenerative diseases, and, rarely, neoplasia. We report a case of ataxia and paresis in a juvenile rhesus macaque with ependymal‐lined cerebral cysts.     

Fatal pulmonary acariasis in an aged indoor rhesus macaque (Macaca mulatta)

Pulmonary acariasis is a sporadic, incidental finding in colony‐raised rhesus macaques (Macaca mulatta). Prophylactic treatment in indoor‐raised and indoor‐housed macaques is not routine due to low prevalence, lack of clinical significance, and potential risk of toxicosis. This case is an unusually severe infestation of Pneumonyssus simicola in an indoor‐housed rhesus macaque, which ultimately resulted in this animal's death.     

Generalized convulsive seizures are associated with ketamine anesthesia in a rhesus macaque (Macaca mulatta) undergoing urodynamic studies and transcutaneous spinal cord stimulation

A female rhesus macaque developed two episodes of generalized convulsions during transcutaneous spinal cord stimulation (TSCS) and urodynamic studies under ketamine anesthesia. The seizures took place in the absence of active TSCS and bladder pressure elevation. Ketamine anesthesia remains the primary risk factor for the convulsions during these experimental procedures.     

Immune-mediated interface dermatitis in a rhesus macaque

BACKGROUND: Autoimmune dermatitis, specifically interface dermatitis, is rarely reported in nonhuman primates. RESULTS AND CONCLUSIONS: This report describes a case of idiopathic immune-mediated dermatitis clinically manifesting as palmoplantar hyperkeratosis in a rhesus macaque, successfully controlled with the use of long-term oral corticosteroid therapy.     

Subcutaneous hemangiosarcomas in a rhesus macaque (Macaca mulatta)

Hemangiosarcoma is a malignant tumor of vascular endothelial cell origin. The occurrence of hemangiosarcoma in nonhuman primates has been rarely documented. An adult male rhesus monkey was reported having a firm subcutaneous swelling, approximately 4.5 cm in diameter, on the ventral midline of the abdomen. Fine-needle aspiration, microbial culture, biopsy, radiographs, exploratory laparotomy, histopathology, immunohistochemistry, hematology, and serology were performed. A second subcutaneous mass approximately 4.5 x 4.0 x 2.7 cm developed on the ventral midline several weeks later. A fine-needle aspirate of the first mass consisted of numerous erythrocytes with few polymorphonuclear cells and lymphocytes. Histopathology showed foci of spindle-shaped cells surrounding the vascular spaces. Many spindle-shaped cells had prominent nucleoli, and mitotic figures could occasionally be seen. Immunohistochemical staining of the masses for Factor VIII-related antigen, an endothelial cell and tumor marker, yielded positive results. Both masses were consistent with hemangiosarcoma.     

Real‐time telemetric monitoring in whole‐body 60Co gamma‐photon irradiated rhesus macaques (Macaca mulatta)

Background Animals undergoing experimental manipulations, such as exposure to radiation, may exhibit physiologic and behavioral signs of pain and distress. Telemetry permits close monitoring of these parameters for early and effective management during procedures. Methods Radiotelemetric units were surgically implanted into 24 Macaca mulatta before 6.5‐Gy cobalt‐60 γ‐photon irradiation. Each unit transmitted electrocardiogram, intrathoracic pressure, and body temperature leads. Primate irradiation‐restraint boxes and housing cages were modified to collect telemetric signals before, during, and after irradiation. Results Differences in respiratory rate, heart rate, or body temperature in telemetric‐collected recordings, which were observed during non‐irradiation and irradiation sessions, were statistically insignificant. Conclusions Insignificant changes in the physiological parameters during monitoring suggest that the animals experienced no detectable pain or distress during irradiation.     

Microbial translocation in simian immunodeficiency virus (SIV)‐infected rhesus monkeys (Macaca mulatta)

Background Chronic immune activation is a hallmark of HIV infection and has been postulated as major factor in the pathogenesis of AIDS. Recent evidence suggests that activation of immune cells is triggered by microbial translocation through the impaired gastrointestinal barrier. Methods To determine the association between microbial translocation and disease progression, we have retrospectively analyzed microbial products, viral load and markers of immune activation in a cohort of 37 simian immunodeficiency virus‐infected rhesus monkeys, divided in two groups with distinct disease courses. Results As seen in HIV‐infected patients, we found elevated levels of lipopolysaccharide (LPS) in infected animals. However, LPS levels or LPS control mechanisms like endotoxin core antibodies or LPS‐binding protein did not differ between groups with different disease progression. In contrast, neopterin, a metabolic product of activated macrophages, was higher in fast progressors than in slow progressors. Conclusion Our data indicate that translocation of microbial products is not the major driving force of immune activation in HIV infection.     

Two cases of cryptococcus gattii infection in the rhesus macaque (Macaca Mulatta)

Cryptococcus gattii was diagnosed in two female indoor‐housed rhesus macaques. Gross and histopathologic findings included an isolated pulmonary cryptococcoma in a non‐SIV‐infected macaque and disseminated disease centered on the lungs of an SIV‐infected macaque. Fungal yeast were positive with special stains, and the diagnoses were confirmed with a lateral flow assay and PCR.