NOVEL SIMPLEXVIRUS (SIMPLEXVIRUS DOLICHOTINEALPHA1) ASSOCIATED WITH FATALITY IN FOUR PATAGONIAN MARA (DOLICHOTIS PATAGONUM).

Four of seven Patagonian maras (Dolichotis patagonum) at a zoological institution developed acute neurologic signs that progressed to tetraparesis and death. All affected were young adult females (10 mon-5 yr old) that presented over 11 d. Clinical signs were rapidly progressive and unresponsive to supportive therapies. Two of the four individuals were found deceased 4 d after hospitalization. Two individuals were euthanized due to poor prognosis and decline after 6 and 8 d, respectively. Simultaneously, an additional mara developed mild and self-resolving clinical signs, including a kyphotic gait and paraparesis. On gross examination, there were widespread petechiae and ecchymoses of the skeletal muscle, myocardium, skin, pericardium, urinary bladder mucosa, and spinal cord. On histopathology, all animals had necrotizing myelitis and rhombencephalitis, with intranuclear viral inclusions in three individuals. Electron microscopy confirmed herpesviral replication and assembly complexes in neurons and oligodendrocytes. Consensus PCR performed on spinal cord, brainstem, or cerebellum revealed a novel Simplexvirus most closely related to Simplexvirus leporidalpha 4. The virus was amplified and sequenced and is referred to as Simplexvirus dolichotinealpha1. It is unknown whether this virus is endemic in Patagonian mara or whether it represents an aberrant host species. Clinicians should be aware of this virus and its potential to cause severe, rapidly progressive, life-threatening disease in this species.

Septicaemic Listeriosis in a White-Faced Saki (Pithecia pithecia).

A 27-year-old female white-faced saki (Pithecia pithecia) died following an onset of vomiting and ptyalism. Necropsy revealed lesions of suppurative ventriculitis, choroid plexitis, periventricular encephalitis and meningitis with intralesional gram-positive coccobacilli and paired rods. The saki also had suppurative to mononuclear hepatitis, mild intestinal crypt necrosis, proliferative glomerulonephritis, aortic arteriosclerosis, pulmonary interstitial fibrosis, chronic mild epicarditis, ovarian medullary arteriopathy and a focal superficial cerebral fibrotic nodule with surrounding chronic mixed cell inflammation. Listeria monocytogenes was cultured from liver and spinal cord. Intralesional Listeria bacteria were immunolabelled in brain sections and real-time polymerase chain reaction of brain tissue detected L. monocytogenes. Whole genome multilocus sequence typing characterized the cultured bacterial isolates as sequence type 6 and clonal complex 6. A database search for related clinical and food listerial outbreaks identified genetically related isolates but, because these isolates were more than 20 alleles distant from the saki isolates, they were not a related cluster. Reports of listeriosis in non-human primates are infrequent, and when infections do occur, they tend to be haematogenous with the propensity to cause meningoencephalitis. This saki likely ingested environmental L. monocytogenes, which resulted in disease that may have been facilitated by pre-existing co-morbidities and age.

Oral Methylene Blue Treatment in A Dog with Cytochrome B5 Reductase Deficiency And 78, XX Testicular Disorder of Sex Development.

A 6-month-old mixed breed dog was referred for evaluation of a potential disorder of sex development (DSD) and lower than expected energy level. Genitourinary examination revealed ambiguous external genitalia, hypospadias, and a subtle pouch of skin that resembled an empty scrotum. Corrective surgery was planned and subsequently aborted after cyanosis was identified preoperatively and an arterial blood gas analysis by co-oximetry identified increased methemoglobin (MetHb) concentration (35%, normal <2%) with normal arterial oxygen tension. Ensuing investigations confirmed hereditary methemoglobinemia caused by cytochrome b5 reductase (CYB5R) deficiency via molecular genetic (Arg219Pro homozygous variant in CYB5R3 gene) and biochemical (cytochrome b5 reductase enzyme activity of 8% [normal, 100% activity] testing. Karyotyping and molecular analysis of sex chromosomes revealed the dog was genetically female with a normal female karyotype (78,XX), and was negative for the Y-linked SRY gene and positive for the X-linked androgen receptor gene. Methylene blue (MB, 3.3 mg/kg per os [PO] q24 h) was administered and the MetHb concentration decreased to 9% within 14 days. Urogenital revision surgery proceeded without complication and the dog was maintained on MB (3-4 mg/kg PO q24 h) long-term without adverse effects. This is the first report to describe the use of PO MB to decrease MetHb concentrations in a dog with CYB5R deficiency in preparation for anesthesia and highlights its potential as a viable alternative to the intravenous formulation for elective procedures. In addition, this report describes the clinical, molecular, imaging, surgical, and macroscopic and microscopic pathological features of a dog with SRY-negative, 78,XX testicular DSD.

Oral histiocytic sarcoma in a cat with mandibular invasion and regional lymph node metastasis.

CASE SUMMARY: An 11-year-old female spayed domestic medium-hair cat presented for dental prophylaxis, at which time no oral mass was appreciated. Fifteen days after a dental cleaning, a mass expanding the oral mucosa of the rostral mandible was identified. An incisional biopsy revealed that the oral mucosa was infiltrated by neoplastic round-to-spindloid mesenchymal cells arranged in streams and small, dense aggregates consistent with an undifferentiated sarcoma. The patient was managed medically for approximately 6 months following the diagnosis, but, owing to declining health, euthanasia was elected and a post-mortem examination was performed. On post-mortem examination, the previously described neoplastic cells were infiltrating the rostral mandible and had metastasized to the right submandibular lymph node. Immunohistochemistry performed during the postmortem examination found that neoplastic cells were positive for Iba-1, CD18 and CD204, and negative for MUM-1, S100, Melan-A and E-cadherin, favoring a diagnosis of oral histiocytic sarcoma. Although recently recognized in cats, feline oral histiocytic sarcoma is rare, the tumor's immunohistochemical profile is unstandardized, and the tumor's behavior and prognosis are unclear. The diagnosis is challenging if small incisional biopsies are submitted and the neoplasm is poorly differentiated. This case report discusses the clinical, macroscopic, microscopic and immunohistochemical features of oral histiocytic sarcoma in a cat with mandibular invasion and submandibular lymph node metastasis. RELEVANCE AND NOVEL INFORMATION: Feline primary oral histiocytic sarcoma is rare and tumor behavior and prognosis are unclear. This report broadens the immunohistochemical features of the tumor and recognizes mandibular invasion and submandibular lymph node metastasis.

STREPTOCOCCUS EQUI SSP. ZOOEPIDEMICUS MENINGOENCEPHALOMYELITIS IN A SOUTHERN TAMANDUA (TAMANDUA TETRADACTYLA) ASSOCIATED WITH A RAW HORSEMEAT DIET.

A 1-y-old female southern tamandua (Tamandua tetradactyla) presented with vomiting, hyporexia, and neurologic signs. Magnetic resonance imaging revealed contrast-enhancing material within the lateral and fourth ventricles and a T2 hyperintense cerebellar lesion, consistent with meningoencephalitis. The tamandua rapidly declined and was euthanatized. On gross postmortem exam, the tamandua had diffusely injected leptomeninges, opaque fluid in the fourth ventricle, and subdural brainstem and spinal cord hemorrhage. Histologically, there was regionally hemorrhagic and multifocal fibrinosuppurative meningoencephalomyelitis, ventriculitis, choroid plexitis, cerebellar folia necrosis, ependymitis, radiculoneuritis, and abundant intralesional gram-positive cocci. Streptococcus equi ssp. zooepidemicus was cultured from brain, cardiac blood clot, and multiple samples of horsemeat collected from the animal's diet. This is the first report of streptococcal meningoencephalomyelitis in a southern tamandua. The route of infection was likely gastrointestinal inoculation, which may have implications for the routine practice of feeding diets containing raw meat to insectivores.

Meningoencephalitis, Vasculitis, and Abortions Caused by Chlamydia pecorum in a Herd of Cattle.

A cow dairy (n = 2000) in close proximity to a sheep flock had third-trimester abortions and fatalities in cows and calves over a 14-month period. Eighteen of 33 aborted fetuses (55%) had multifocal random suppurative or mononuclear meningoencephalitis with vasculitis. Seventeen of these affected fetuses had intracytoplasmic bacteria in endothelial cells, and 1 fetus with pericarditis had similar bacteria within mesothelial cells or macrophages. Immunohistochemistry for Chlamydia spp. or polymerase chain reaction (PCR) for Chlamydia pecorum or both, performed on brain or pooled tissue, were positive in all 14 tested fetuses that had meningoencephalitis and in 4/4 calves and in 3/4 tested cows that had meningoencephalitis and thrombotic vasculitis. In 1 calf and 11/11 fetuses, C. pecorum PCR amplicon sequences were 100% homologous to published C. pecorum sequences. Enzootic chlamydiosis due to C. pecorum was the identified cause of the late term abortions and the vasculitis and meningoencephalitis in fetuses, calves, and cows. C. pecorum, an uncommon bovine abortogenic agent, is a differential diagnosis in late-term aborted fetuses with meningoencephalitis, vasculitis, and polyserositis.

Diagnostic evaluation of fatal Balamuthia mandrillaris meningoencephalitis in a captive Bornean orangutan (Pongo pygmaeus) with identification of potential environmental source and evidence of chronic exposure.

A female Bornean orangutan (Pongo pygmaeus) aged 11 years and 6 months was examined by veterinarians after caretakers observed lethargy and facial grimacing. Within 72 h the primate had left-sided hemiparesis that worsened over the next week. An MRI revealed a focal right-sided cerebral mass suspected to be a neoplasm. Ten days after onset of clinical signs, the orangutan died. On postmortem exam, the medial right parietal lobe was replaced by a 7 × 4 × 3.5 cm focus of neuromalacia and hemorrhage that displaced the lateral ventricle and abutted the corpus callosum. Histopathology of the cerebral lesion revealed pyogranulomatous meningoencephalitis with intralesional amoeba trophozoites and rare cysts. Fresh parietal lobe was submitted to the Centers for Disease Control and Prevention lab for multiplex free-living amoebae real-time PCR and detected Balamuthia mandrillaris DNA at a high burden. Mitochondrial DNA was sequenced, and a 760-bp locus 19443F/20251R was compared to several human infections of B. mandrillaris and shown to be identical to the isolates from four human cases of encephalitis: 1998 in Australia, 1999 in California, 2000 in New York, and 2010 in Arizona. Indirect immunofluorescent antibody testing of stored serum samples indicated exposure to B. mandrillaris for at least 2 years prior to death. Within 1 week of the orangutan's death, water from the exhibit was analyzed and identified the presence of B. mandrillaris DNA, elucidating a possible source of exposure. B. mandrillaris, first reported in a mandrill in 1986, has since occurred in humans and animals and is now considered an important emerging pathogen.

Case Report: Successful Management of a Compressive Intraspinal Coccidioides Species Granuloma in a Cat.

A 9-year-old, neutered male, domestic shorthair cat from Arizona, was presented for evaluation of a 7-day history of hind limb paraparesis that progressed to paraplegia. There was no history of respiratory abnormalities. Neurologic examination supported localization of a T3-L3 myelopathy. Computed tomography (CT) revealed an expansile widening of the spinal canal dorsal to L4 associated with a strongly contrast-enhancing mass. Moreover, CT series of the thorax revealed a diffuse miliary pulmonary pattern, as well as tracheobronchial, sternal, and cranial mediastinal lymphadenomegaly. Transthoracic lung lobe and sternal lymph node fine needle aspiration revealed pyogranulomatous inflammation with Coccidioides spp. spherules and endospores. A suspected diagnosis of spinal coccidioidomycosis was made; fluconazole (10.9 mg/kg PO q12h) treatment was initiated, and decompressive neurosurgery was performed. The granuloma was removed en bloc and histopathology revealed marked, chronic-active, pyogranulomatous myelitis with intralesional Coccidioides spp. spherules with endosporulation. Serum anti-Coccidioides spp. antibody titer results revealed a negative IgM and a positive IgG (1:4). The cat was treated with fluconazole for 445 days and examined at various time points, with the last examination 2 years after initial presentation. The cat returned to full ambulation with only mild functional deficits of the right hind limb. In conclusion, this report documents the diagnosis, treatment, and long-term follow up of a cat with a compressive Coccidioides spp. spinal cord granuloma. This case highlights the importance of including coccidioidomycosis as a differential diagnosis for cats with peracute hindlimb paraplegia that have lived in or traveled to regions where Coccidioides spp. is endemic, and demonstrates the potential for a good long-term outcome with decompressive neurosurgery and antifungal therapy.

Gastrinoma and Zollinger-Ellison syndrome in canids: a literature review and a case in a Mexican gray wolf.

Gastrinoma, an infrequent diagnosis in middle-aged dogs, occurs with nonspecific gastrointestinal morbidity. Laboratory tests can yield a presumptive diagnosis, but definitive diagnosis depends on histopathology and immunohistochemistry. We describe a malignant pancreatic gastrinoma with lymph node metastases and corresponding Zollinger-Ellison syndrome in a Mexican gray wolf ( Canis lupus baileyi) and review this endocrine neoplasm in domestic dogs. A 12-y-old, captive, male Mexican gray wolf developed inappetence and weight loss. Abdominal ultrasonography revealed a thickened duodenum and peritoneal effusion. Two duodenal perforations were noted on exploratory celiotomy and were repaired. Persisting clinical signs led to a second celiotomy that revealed a mesenteric mass, which was diagnosed histologically as a neuroendocrine carcinoma. During the following 16 mo, the wolf received a combination of H2-receptor antagonists, proton-pump inhibitors, gastroprotectants, and anti-emetics, but had recurrent episodes of anorexia, nausea, acid reflux, and remained underweight. Worsening clinical signs and weakness prompted euthanasia. The antemortem serum gastrin concentration of 414 ng/L (reference interval: 10-40 ng/L) corroborated hypergastrinemia. Autopsy revealed a mass expanding the right pancreatic limb; 3 parapancreatic mesenteric masses; duodenal ulcers; focal duodenal perforation with septic fibrinosuppurative peritonitis; chronic-active ulcerative esophagitis; and poor body condition. The pancreatic mass was diagnosed histologically as a neuroendocrine carcinoma and the parapancreatic masses as lymph node metastases. Immunohistochemistry of the pancreatic mass was positive for gastrin and negative for glucagon, insulin, pancreatic polypeptide, serotonin, somatostatin, and vasoactive intestinal peptide.