Journal of Veterinary Diagnostic Investigation最新文献

Phenobarbital is a common antiseizure medication that has a relatively narrow therapeutic window. Therapeutic drug monitoring (TDM) is a helpful tool to guide dose adjustments for phenobarbital and avoid its toxicity. We investigated the agreement among 3 methods of quantifying phenobarbital in canine plasma: high-performance liquid chromatography (HPLC), point-of-care (POC) testing, and the FDA-approved immunoassay analyzer. We randomly selected 45 plasma samples obtained by the TDM service (College of Veterinary Medicine, Auburn University, Auburn, AL, USA). Passing-Bablok regression and Lin concordance correlation coefficients (CCCs) were used to determine the agreement of the results obtained for the 3 methods; Bland-Altman plots were used for bias analysis using the results from the HPLC method as a reference. The FDA-approved immunoassay analyzer and POC immunoassay method results agreed with the HPLC. The results from the FDA-approved immunoassay analyzer were better correlated than those from the POC method, with Lin CCCs of 0.96 (95% CI: 0.93-0.98) and 0.94 (95% CI: 0.90-0.97), respectively. The average biases of the FDA-approved and the POC immunoassay analyzers were 0.80 and -0.64 µg/mL, respectively. Based on the CIs of Lin CCCs, the commercial POC phenobarbital test is a good screening tool and agrees with the HPLC method. However, the FDA-approved immunoassay analyzer method allows for more accurate quantification of phenobarbital concentrations, which is required for appropriate dose adjustment of phenobarbital.

Tumoral macrocysts (grossly observable cysts) are common in human pilocytic astrocytomas but are rarely reported in canine astrocytomas. Here we describe 7 canine astrocytomas with macrocysts. The median age of affected patients was 9.6 y, and 2 dogs were brachycephalic. Clinical signs reported in 6 cases included head tilt (4 cases), falling (4 cases), and ataxia (3 cases). Gross changes consisted of well (5 cases) or poorly demarcated (2 cases), tan-to-pale-yellow masses with distinct, 2-10-mm fluid-filled cysts that expanded the cerebellum (4 cases) or telencephalon (3 cases). Histology and immunohistochemistry revealed low-grade astrocytoma in 6 cases and high-grade astrocytoma in 1 case. Neoplastic cells were elongate, formed bundles embedded in an eosinophilic fibrillary stroma, and had oval-to-elongate nuclei. Gemistocytic differentiation was common (4 cases). Cystic areas were lined by neoplastic astrocytes and were either apparently empty or contained scant, eosinophilic, proteinaceous material and a few neoplastic astrocytes, foamy macrophages, and occasionally other leukocytes. The mitotic activity was absent or low across cases. Cytoplasmic immunolabeling for glial fibrillary acidic protein was detected in 6 cases. Our findings indicate that canine cystic astrocytomas are rare (our cases span several decades) and are located mainly, but not exclusively, in the cerebellum.

Feline meningiomas typically arise on the surface of the brain but can occur in the third ventricle. Meningiomas in the fourth ventricle have not been reported in cats, to our knowledge. Here, we describe the clinical and pathologic findings of meningioma in the fourth ventricle in 2 cats. Both affected patients (1 castrated male, 1 spayed female) were 15-y-old. Case 2 had neurologic signs, including absent menace response, head tilt, and ataxia. Grossly, both tumors were well-demarcated and firm, expanded the fourth ventricle, and compressed the adjacent neuroparenchyma. Cytology of the ventricular mass in case 1 revealed a spindle-cell neoplasm. Based on histology, the neoplasms were classified as WHO grade 1 fibrous meningioma (case 1) and transitional meningioma (case 2). Immunohistochemistry revealed diffuse, robust cytoplasmic E-cadherin and vimentin immunolabeling in both cases and multifocal, weak cytoplasmic pan-cytokeratin AE1/AE3 immunolabeling in case 2. Our findings indicate that meningiomas should be included as a differential diagnosis for tumors of the fourth ventricle in cats.

Spontaneous intoxication by Astragalus arequipensis was diagnosed in a flock of 300 sheep in Jujuy province, northwestern Argentina, that grazed an area heavily invaded by this plant. The main clinical signs were intention tremors, ataxia, and progressive loss of condition. Autopsy of 2 affected animals revealed loss of body condition. The main microscopic changes were fine cytoplasmic vacuolation of cells in the cerebrum, cerebellum, thyroid and adrenal glands, kidney, liver, pancreas, urinary bladder, and lymph nodes, and swollen axons in the cerebellum. Ultrastructurally, the cytoplasmic vacuoles consisted of dilated secondary lysosomes. Composite leaf and stem samples of A. arequipensis analyzed by high-performance liquid chromatography contained 0.05% swainsonine. The diagnosis of intoxication by A. arequipensis was made based on the clinical history and signs; gross, microscopic, and ultrastructural changes; and detection of swainsonine in the plant.

Aspergillosis is the most commonly and widely reported fungal infection in birds. Disease development is often secondary to stressors that cause immunocompromise, and it is typically regarded as a disease of captivity. We retrospectively evaluated data from 133 birds diagnosed with aspergillosis at the Southeastern Cooperative Wildlife Disease Study from 2001-2023 to assess diversity and relative frequency across avian taxa, gross and histologic lesion patterns, and comorbidities. Of 10 taxonomic orders represented, Charadriiformes (shorebirds; n = 35) and Accipitriformes (raptors; n = 32) were most common. Among them, the laughing gull (Leucophaeus atricilla; n = 20) and bald eagle (Haliaeetus leucocephalus; n = 14) were infected most commonly. Gross lesions were most frequent in lung (n = 80), air sac (n = 71), or celomic cavity lining (n = 42). Four distinct gross lesion patterns were identified: 1) tan caseous plaques (n = 106), 2) hollow masses lined with mold (n = 26), 3) red pulmonary nodules (n = 15), and 4) necrotic brown plaques (n = 3). Histologically, fungal hyphae were most common in lung (n = 107) and air sac (n = 49). Comorbidities were diagnosed in 67 birds with a spectrum of viral (n = 19), bacterial (n = 11), parasitic (n = 6), other fungal (n = 4), and non-infectious (n = 50) causes. Six birds each were diagnosed with highly pathogenic avian influenza or salmonellosis. Twenty-two birds were emaciated. Free-ranging birds are susceptible to myriad stressors that can predispose them to the development of aspergillosis.

An 8-y-old, spayed female Bernese Mountain Dog was presented to a referral center for evaluation of right thoracic limb lameness and previously suspected Evans syndrome that had been poorly responsive to immunosuppressive therapy. Based on review of examination findings and laboratory data, Evans syndrome was deemed unlikely and hemophagocytic histiocytic sarcoma (HHS) was strongly suspected. On blood smear evaluation, atypical, histiocytic cells were noted, some of which exhibited siderophagia. Considering that circulating cells are not typically observed in dogs with HHS, additional diagnostic investigation was performed. Autopsy and histopathology revealed that the dog had a mixed form of HS (dendritic-cell origin HS in the lung, and HHS in the spleen, liver, and bone marrow), and immunocytochemical characterization of cultured cells derived from blood suggested that the cells were of dendritic HS origin, rather than HHS origin, as originally suspected. Whole-exome sequencing revealed genetic similarity between cell lines derived from lung tissue and blood, providing additional evidence of the relatedness of these 2 cell populations. Our case highlights the rare entity of mixed HS and typifies the inherent challenges in classifying rare, atypical, circulating neoplastic cells.

Peste-des-petits-ruminants (PPR) is primarily a disease of small ruminants caused by peste-des-petits-ruminants virus (PPRV; Paramyxoviridae, Morbillivirus caprinae), formerly the small ruminant morbillivirus. PPRV can cause significant morbidity and mortality in small ruminants and a significant economic impact. Conventional reverse-transcription PCR (RT-PCR), and probe-based and SYBR Green-based RT quantitative real-time PCR (RT-qPCR), are employed for the molecular detection of PPRV. Here we describe a SYBR Green-based RT-qPCR for rapid and sensitive detection of PPRV. We designed the specific primers from the conserved region of the fusion gene (F) of PPRV. The standard curve of the established RT-qPCR assay had a good linear relationship. The developed assay was also 3 log units more sensitive than the conventional RT-PCR, with a detection limit of 13.6 copies and an efficiency of 98.2%. There was no cross-reactivity with other caprine respiratory viruses, namely bluetongue virus, goatpox virus, and orf virus. The positive detection rate of clinical samples was 11 of 64 (17.2%) versus 10 of 64 (15.6%) by conventional RT-PCR. We confirmed our results by sequencing the full F and N genes of the isolates. Our SYBR Green RT-qPCR can be used as a fast, economical, and sensitive alternative to RT-PCR for the detection of PPRV.

Ossifying fibroma (OF) is a slow-growing, expansive, and benign fibro-osseous neoplasm that is rare in cattle. It mainly affects the craniofacial bones, especially the mandible. Here, we report 2 cases of mandibular OF in Nelore and mixed-breed steers with enlarged masses in the rostral portion of the mandible. Radiographic analysis of case 1 revealed an oval, lobed mass with the radiopacity of bone tissue that displaced the incisors laterodorsally. Histologically, both masses were composed of a proliferation of spindloid-to-stellate cells, supported by a dense fibrovascular stroma, with bony trabeculae surrounded by stroma and covered by a single layer of osteoblasts. Cellular pleomorphism was low, anisocytosis and anisokaryosis were negligible, and mitotic figures were not observed. The clinical, radiologic, gross, and histologic changes are compatible with OF. The primary differential diagnoses of OF are fibrous dysplasia and osteoma; their differentiation can be difficult. Fibroma, low-grade osteosarcoma, and multilobular sarcoma of bone are also differential diagnoses, with striking features that facilitate their exclusion.

An apparent outbreak of fenugreek forage toxicosis occurred in a beef cattle herd near Moose Jaw, Saskatchewan in February-May 2022. The herd had consumed fenugreek hay from late fall to early winter. Clinical signs included various degrees of weakness, ataxia, knuckling, walking on hocks, and recumbency. All adult cattle in the herd eventually died or were euthanized. Feed analysis did not reveal nutritional deficiencies or mycotoxin contamination. Liver mineral and vitamin status of affected animals did not indicate any consistent abnormality. The last live cow in the herd was presented to a veterinary teaching hospital for evaluation and subsequent postmortem examination. Major postmortem findings included emaciation, and sciatic nerve and spinal cord axonal degeneration. Histologic examination of the sciatic nerve showed Wallerian-like axonal degeneration, increased Schwann cell nuclei, and endoneurial fibrosis. Histologic examination of the spinal cord showed infrequent myelin sheath dilation and digestion chambers within white matter. These results are consistent with other reports of natural and experimental outbreaks of fenugreek poisoning in livestock. To our knowledge, fenugreek toxicosis has not been reported previously in Canada. We conclude that caution should be taken when feeding fenugreek hay to cattle.