Journal of Veterinary Diagnostic Investigation最新文献

The rapid geographic spread of chronic wasting disease (CWD) in white-tailed deer (WTD; Odocoileus virginianus) increases the need for the development and validation of new detection tests. Real-time quaking-induced conversion (RT-QuIC) has emerged as a sensitive tool for CWD prion detection, but federal approval in the United States has been challenged by practical constraints on validation and uncertainty surrounding RT-QuIC robustness between laboratories. To evaluate the effect of inter-laboratory variation on CWD prion detection using RT-QuIC, we conducted a multi-institution comparison on a shared anonymized sample set. We hypothesized that RT-QuIC can accurately and reliably detect the prions that cause CWD in postmortem samples from medial retropharyngeal lymph node (RPLN) tissue despite variation in laboratory protocols. Laboratories from 6 U.S. states (Michigan, Minnesota, Missouri, New York, Pennsylvania, Wisconsin) were enlisted to compare the use of RT-QuIC in determining CWD prion status (positive or negative) among 50 anonymized RPLNs of known prion status. Our sample set included animals of 3 codon 96 WTD genotypes known to affect CWD progression and detection (G96G, G96S, S96S). All 6 laboratories successfully identified the true disease status consistently for all 3 tested codon 96 genotypes. Our results indicate that RT-QuIC is a suitable test for the detection of CWD prions in RPLN tissues in several genotypes of WTD.

Neoplasia is a common disease in guinea pigs (Cavia porcellus); however, few studies have evaluated the prevalence of neoplasia in all organ systems. We retrospectively analyzed the tumor prevalence in pet guinea pigs and the frequency of metastasis in a multi-institutional study population of 2,474 autopsy cases. Tumors were found in 508 guinea pigs (prevalence: 20.5%), of which 95 cases had >1 tumor, resulting in a total of 627 tumors. The tumor prevalence increased from 1.4% in animals <0.5-y-old to 53.6% for guinea pigs >5-y-old. The most common tumor type was lymphoma or leukemia, affecting 174 guinea pigs (tumor prevalence: 7.0%). Lymphomas or leukemias were disseminated to various organs and/or lymph nodes in 146 (83.9%) cases and localized to 1 organ or 1 lymph node in 28 (16.1%) cases. Primary non-lymphoid tumors were most frequent in the female genital tract (62 of 1,235 cases, mostly uterus), respiratory system (116 of 2,474), skin including mammary gland (81 of 2,474), endocrine system (66 of 2,474, mostly thyroid gland), and alimentary tract (35 of 2,474). Tumors of the alimentary tract were dominated by gastrointestinal stromal tumors. Metastasis was detected in 42 of 453 non-lymphoid tumors (9.3%), with a surprisingly low frequency for pulmonary carcinoma and splenic hemangiosarcoma compared to other species. Our postmortem study demonstrates a high prevalence of disseminated lymphoma or leukemia in pet guinea pigs at the time of death or euthanasia. Additional studies are needed to further characterize these tumors.

Schwannosis is a rare, non-neoplastic, perivascular proliferation of aberrant Schwann cells within the CNS with simultaneous partial myelination of axons. A single report exists in veterinary medicine of schwannosis in the spinal cord of 3 foals and 1 calf. Here we describe a case of schwannosis in the brain of a 1-d-old Holstein-Friesian calf, submitted for autopsy due to arthrogryposis and premature death, with no other gross abnormalities observed. Histologically, the brain had multifocal, mainly perivascular, spindle-cell proliferations within the white matter of the medulla oblongata and focally within the gray matter of the midbrain. These cells immunolabeled with periaxin, myelin protein zero, SOX10, S100, and equivocally for vimentin, indicating Schwann cell origin. No changes were identified within other organs. Ancillary tests did not support an infectious etiology. Schwannosis should be considered as a differential diagnosis when investigating cases of arthrogryposis in calves with negative ancillary tests for infectious conditions.

A 2-y-old, intact male roan antelope (Hippotragus equinus) was submitted for routine postmortem investigation after a prolonged history of diarrhea and weight loss. The abomasal mucosa was diffusely thickened and corrugated. Abomasal gland hyperplasia was associated with abundant apical organisms consistent with Cryptosporidium spp. Genomic DNA was extracted from abomasal and intestinal contents and subjected to PCR using primers specific for the 18S rRNA gene of Cryptosporidium spp., followed by Sanger sequencing. The sequence was >99% homologous to Cryptosporidium andersoni. C. andersoni-associated proliferative abomasitis has not been reported previously in a captive hippotraginid, to our knowledge.

Pituitary pars intermedia dysfunction (PPID) is a neurodegenerative disease of senior horses. Loss of dopaminergic inhibition of the melanotropes of the pars intermedia leads to increased concentrations of pro-opiomelanocortin (POMC)-derived peptides. Diagnosis is challenging due to pre-analytical variables, such as sample storage, handling, and time to analysis. Our objective was to develop an ELISA for ACTH measurement, which could ultimately form the basis for a stall-side equine ACTH test. We selected 2 ACTH-specific monoclonal antibodies, CBL57 and EPR20361-248, based on the recognition of separate epitopes, strong and rapid color change, and minimal background interference, including no cross-reactivity with themselves, each other, and the test reagents. CBL57 was chosen as the detection antibody (or secondary antibody). EPR20361-248, functionalized on superparamagnetic iron oxide beads, was chosen as the capture antibody (or primary antibody) to bind ACTH in plasma. The incorporation of magnetic beads marks the initial stage in establishing a platform that could potentially be utilized in the field, similar to other stall-side tests. The concentrations of antibodies, magnetic beads, and incubation durations were optimized. Our immunoassay detected unglycosylated rat recombinant ACTH. Further studies are ongoing to optimize and validate our assay using equine plasma and serum samples.

Bacillary hemoglobinuria (BH) is an infectious disease, mostly affecting cattle, caused by Clostridium haemolyticum (C. novyi type D), with acute hepatic necrosis and intravascular hemolysis. Cattle are typically predisposed to BH by liver injury caused by Fasciola hepatica, although cases have been reported in cattle without evidence of this parasite. Here we describe a cluster of 14 BH cases from 7 counties in north-central to central Missouri submitted to a veterinary diagnostic laboratory between December 2020 and April 2023. Postmortem examination in all cases revealed hemoglobinuria and acute hepatic necrosis with large numbers of gram-positive bacilli with terminal-to-subterminal spores. Flukes, fluke ova, and/or fluke pigment consistent with Fascioloides magna were identified in 12 of 14 cases. Sequences of the nuclear ribosomal internal transcribed spacer 1 (ITS1) from one fluke had 100% identity to F. magna. C. novyi was detected by fluorescent antibody testing of liver impression smears (11 of 12 cases) and by immunohistochemistry of liver sections (7 of 7 cases). PCR on formalin-fixed, paraffin-embedded tissues amplified the C. haemolyticum beta toxin gene in each of the 7 cases tested. To our knowledge, a confirmed cluster of BH associated with F. magna has not been reported previously in cattle.

An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0.5-2.5-cm, firm, tan nodules. Histologically, the lungs, spleen, liver, kidneys, adrenal glands, omentum, left eye, and femur were infiltrated by bundles and nests of pleomorphic polygonal-to-spindloid cells intermixed with frequent multinucleate cells. Lymphatic vessels in the affected tissues were frequently distended with tumor emboli. Neoplastic cells were diffusely positive for vimentin, desmin, sarcomeric actin, myoblastic differentiation protein 1, and myogenin, supportive of the diagnosis of rhabdomyosarcoma (RMS), which is a rare neoplasm in horses. Cross-striations were not evident with H&E or phosphotungstic acid-hematoxylin stains. Markedly pleomorphic neoplastic cells, multinucleate cells, and lack of cross-striations suggested the subclassification of pleomorphic RMS.

Viscoelastic testing methods, including thromboelastography (TEG) and rotational thromboelastometry, have an advantage over traditional tests of coagulation due to their ability to reflect in vivo hemostasis and predict need for transfusion of blood products more accurately. TEG in clinical settings is most often performed on citrated whole blood samples that are recalcified at the time of analysis, with or without the addition of an activator of coagulation. To date, superiority of the use of an activator in canine patients with abnormal hemostasis has not been demonstrated. We compared the use of tissue factor-activated (TF) TEG with citrated native (CN) TEG in dogs with suspected hemostatic abnormalities. Forty-five of 79 enrolled dogs with suspected abnormal hemostasis had an abnormal MA value. There was very high correlation between CN samples and TF-activated samples for alpha, K, MA, and R; there was a high correlation for LY30 and LY60. Categorical agreement for CN- and TF-activated TEG classification of hypercoagulable and hypocoagulable cases based on MA was good to very good, with 91% and 97% categorical agreement, respectively. No difference was found in the variance for any TEG variable between the 2 methods of analysis. For canine patients with suspected abnormal hemostasis, use of CN or TF-activated TEG appears acceptable. Monitoring of coagulation should be done with the same method; methods may not be used interchangeably.

Lingual biopsies are a common type of sample submission at the Athens Veterinary Diagnostic Laboratory (AVDL). Here we describe the pathology diagnoses of 793 canine and 406 feline lingual biopsies submitted to the AVDL in a 10-y period. Non-neoplastic lesions accounted for 450 diagnoses (57%) in dogs and 239 diagnoses (59%) in cats. Canine non-neoplastic lesions consisted of inflammatory lesions (286 cases; 64% of non-neoplastic lesions) and tumor-like proliferative lesions (164 cases; 36% of non-neoplastic lesions). Feline non-neoplastic lesions consisted of inflammatory lesions (228 cases; 95% of non-neoplastic lesions) and tumor-like proliferative lesions (11 cases; 5% of non-neoplastic lesions). The most common canine neoplasms were melanocytic neoplasms (103 cases; 30% of neoplasms) and epithelial neoplasms (102 cases; 30% of neoplasms), followed by mesenchymal neoplasms (90 cases; 26% of neoplasms) and round cell neoplasms (48 cases; 14% of neoplasms). Approximately 43% of melanocytic neoplasms affected Chow Chows and Labrador Retrievers, and 20% of epithelial neoplasms affected Labrador Retrievers. In cats, most tumors were epithelial (158 cases; 94% of neoplasms), followed by mesenchymal (8 cases; 5% of neoplasms) and round cell neoplasms (1 case; 1% of neoplasms). Over 50% of neoplasms of cats affected domestic shorthair cats. Although the percentage of lingual biopsies that had a neoplastic diagnosis was roughly the same between species, the diversity of neoplasms was much greater in dogs than in cats.