Journal of Veterinary Diagnostic Investigation最新文献

Mucormycosis is an angioinvasive fungal infection caused by ubiquitous saprophytic fungi of the order Mucorales. In humans, the infection is generally caused by inhalation of spores or traumatic inoculation in cutaneous wounds, typically affecting immunocompromised patients. In animals, Mucorales infection is common in cattle, but is rare in the other species, including felids. No cases of mucormycosis have been reported to date in non-domestic felids, to our knowledge. We describe a case of mucormycosis in a 5-y-old female captive tiger (Panthera tigris). The affected tiger was part of a group of 9 subjects, 7 of which had serohemorrhagic nasal discharge, anorexia, and depression, followed by hemorrhagic diarrhea. Five of the tigers died and organs from one animal were sent for histologic examination, which revealed severe necrohemorrhagic enteritis, with periodic acid-Schiff- and Grocott methenamine silver-positive fungal hyphae. Mucor colonies were cultured from sawdust, which served as litter for the animals, indicating a possible source of infection through inhalation of spores and/or ingestion of contaminated sawdust. Mucormycosis is a possible differential for necrohemorrhagic enteritis in captive felids; careful storage and periodic assessment of the materials used as litter for these animals is recommended.

Pneumothorax is reported infrequently in marine mammals, most often secondary to physical or barometric trauma. We describe tension pneumothorax associated with verminous bronchopneumonia in a juvenile white-beaked dolphin stranded in Québec, Canada. Autopsy findings included a violent escape of air upon opening the pleural cavity, and white nematode-filled cystic nodules extending into the subpleural space and the lung parenchyma. One of these cysts had ruptured on the pleural surface. Numerous nematodes were observed in the lumen of main and secondary bronchi. Mediastinal lymph nodes were also enlarged. Helminths were collected and processed for molecular species identification. Histologically, verminous bronchopneumonia was marked by massive infiltration of the airways by polymorphonuclear and histiocytic cells surrounding adult and larval nematodes. Regional lymph nodes also contained focal infiltrates of polymorphonuclear cells associated with larvae. The nematodes were identified as Halocercus lagenorhynchi according to their morphology and molecular characterization. We attributed the death of this dolphin calf to tension pneumothorax secondary to a massive infection by the lungworm H. lagenorhynchi.

The reliability of assumptions made about prevalence for pooling optimization varies greatly among target pathogens and surveillance strategies. When prevalence is unknown and difficult to anticipate, surveillance programs risk generating additional costs if pooling is suboptimal. Different methods of approximating optimal pool size (OPS) vary in precision of optimization, required sampling information, and the logistical demands placed on a laboratory workflow. Hence, it can be unclear how to assess compatibility between pooling optimization methods and the priorities of a surveillance program, sampling practices for the target population, and infection dynamics of the target pathogen. Our aim was to determine the relative performance in maximizing testing economy and cost reduction in different surveillance programs by simulating different pooling optimization methods on data from 280 submissions for bovine viral diarrhea virus (BVDV) surveillance (Nebraska Veterinary Diagnostic Center) and 111 submissions for Theileria orientalis surveillance (Virginia Tech Animal Laboratory Services). True prevalence, OPS, and historical prevalence were determined for each submission, and different optimization methods using fixed pool sizes, historical prevalence, and prevalence estimation testing were trialed on the data through Monte Carlo simulations. Contrasting results were observed between the 2 target pathogens, with historical prevalence being the most reliable optimization method for BVDV and the least reliable method for T. orientalis, which required significantly more tests than truly optimized pooling (p <0.05). Our results demonstrate the need to consider the interplay of infection dynamics, sampling practices, and surveillance priorities when selecting a pooling optimization approach.

Vitamin D deficiency, defined as low serum 25-hydroxyvitamin D (25D), is a highly prevalent finding in dogs with several disease states. Significant analytical variability between 25D methods of analysis in humans is well-documented; it is unknown if this variability exists in dogs. Our primary goal was to evaluate agreement of 2 chemiluminescent immunoassays (CLIA1, CLIA2); 2 liquid chromatography with tandem mass spectrometry (LC-MS/MS1, LC-MS/MS2) assays, from 3 laboratories; and a point-of-care lateral flow assay (LFA) across a wide range of expected 25D results in dogs. The null hypothesis was that all methods of analysis would have clinically acceptable agreement (<25 nmol/L difference). The tests were assessed for agreement via Bland-Altman analysis, Passing-Bablok regression, and Lin correlation coefficients. In Bland-Altman analysis, all inter-test comparisons exceeded the a priori clinically acceptable ≤25 nmol/L mean difference, except for LC-MS/MS1 vs. CLIA1 (mean difference -7.2 nmol/L). The range of mean bias across all test comparisons was -186% (LC-MS/MS2 vs. CLIA2) to 254% (CLIA2 vs. LFA). Tests of comparable methodology did not produce more similar results. The mean bias between the 2 CLIA assays was 54%, and the mean bias between the 2 LC-MS/MS tests was 125%. The significant analytical variability of canine 25D tests suggest that they cannot be used interchangeably, and caution should be used when comparing 25D results presented in canine studies from different laboratories and methods of analysis.

Feline coronavirus (FCoV) infects both domestic and wild felids and has the potential to cause feline infectious peritonitis (FIP), a progressive and often fatal systemic disease. Although rapid diagnosis and treatment are crucial in cases of FIP, conventional reverse-transcription quantitative real-time PCR (RT-qPCR) requires RNA extraction and specialized equipment, limiting its use for timely testing in general veterinary practice. We evaluated the performance of a direct RT-qPCR method using the PicoGene PCR1100 system (GoFoton, Ibaraki, Japan), which omits the RNA extraction step and delivers results within ~40 min. Compared with FCoV culture supernatants and extracted RNA, we estimated the limit of detection of this direct RT-qPCR method to be 150 copies/reaction-a detection sensitivity equivalent to that of conventional RT-qPCR targeting the FCoV 3'-UTR. We observed no cross-reactivity with other feline viruses or SARS-CoV-2. We subsequently analyzed 28 pleural and abdominal effusions collected from cats suspected of having FIP to compare the direct RT-qPCR method with the conventional approach. The sensitivity of the direct RT-qPCR method was 95.5% (95% CI: [78.2, 99.2]) and the specificity was 100% (95% CI: [61.0, 100.0]), which supports the use of the PCR1100 system as a rapid and user-friendly point-of-care tool for the detection of FCoV RNA in effusion samples.

The genus Salmonella, particularly Salmonella enterica subsp. enterica serovars Choleraesuis and Typhimurium, poses significant challenges to swine production and leads to economic losses from conditions such as septicemia and enterocolitis. We evaluated the effects of experimental infection with Salmonella Typhimurium on clinical signs and anatomopathologic outcomes in pigs. Twenty 90-d-old pigs were divided into 2 groups: G1 received an oral inoculum of 10⁸ cfu of Salmonella Typhimurium; G2 served as a control. Pigs were monitored clinically for 30 d; postmortem examinations and microbiologic analyses were conducted. No significant differences were found in rectal temperature or weight between groups; however, diarrhea episodes were noted in the challenged group starting on day 5 post-inoculation. Isolates of Salmonella Typhimurium were detected intermittently in the challenged group; all positive samples came from pigs without diarrhea. Macroscopic lesions in G1 pigs included button-shaped ulcers in the ileocecal region, enlarged or hemorrhagic mesenteric lymph nodes, and hyperplasia of lymphoid tissue in the colon.

A 3-mo-old domestic shorthair cat was presented with multiple fractures. Bone morphology was normal radiographically, with no long bone deformity or increased bone translucency. A bone biopsy from the ilium was examined histologically, revealing that bone matrix in the trabeculae extended from the growth plate, but cartilage remained in the distal trabeculae. Osteoblasts were observed at the bone surface via immunohistochemical detection with an anti-RUNX2 antibody. Whole-genome sequencing identified a homozygous missense mutation (valine to methionine) in the zinc-dependent metalloprotease domain of BMP1, a gene associated with human osteogenesis imperfecta type 13. In silico analysis predicted that this mutation would disrupt BMP1 protein function, which could affect type I collagen processing. Our findings suggest that a missense mutation in BMP1 may cause feline osteogenesis imperfecta.

Myelolipomas are benign neoplastic lesions composed of adipose and hematopoietic tissue. Excluding dogs and cats, myelolipomas have been extensively described in the spleen of cheetahs (Acinonyx jubatus), the liver of Goeldi's monkeys (Callimico goeldii), and birds in the order Psittaciformes. To better describe the species diversity and the clinical and pathologic relevance of myelolipomas, we conducted a detailed literature review and a retrospective multi-institutional study of myelolipomas, excluding cases diagnosed in dogs and cats. A total of 52 cases from 27 different species were diagnosed or reported (65% mammals and 35% birds) from 8 institutions. Notably, 18 of 27 (67%) of the animal species diagnosed with myelolipoma in our study lacked previous documentation in the literature. In mammals, myelolipomas were diagnosed in the spleen, liver, and adrenal gland, and less commonly in lymph nodes, mesentery, broad uterine ligament, and subcutis; most often, these proliferations were incidental findings at autopsy unrelated to animal death or euthanasia. In birds, the most frequently affected location was the liver, followed by the kidney and celom, occasionally resulting in antemortem clinical disease and adverse outcomes. Myelolipomas had clinical and pathologic relevance in 9 of 52 (17%) cases including birds and mammals. Osseous metaplasia was found within the myelolipomas in 2 of 52 (4%) cases. We conclude that myelolipomas are present in more species than previously documented and most cases are probably underreported. The clinical relevance of a myelolipoma can be determined by postmortem examination, and depends on the species affected, the anatomic location, and the size of the lesion.

Nosemosis, caused by Vairimorpha (Nosema) ceranae or V. (Nosema) apis, is the main fungal disease affecting the Western honey bee (Apis mellifera). We evaluated the use of histology in the diagnosis of disease, identified the histologic patterns, and compared the efficacy of different staining techniques. We sampled 10 hives, collecting ~80 bees per hive. Spore counts were performed on 60 bees per sample using a hemocytometer in accordance with the standard procedure. Slides of whole bees were produced from the remaining bees, stained with 15 different techniques, and observed under a light microscope at 400×. Infection in the ventriculus was graded using hematoxylin-phloxine-saffron stain; prevalence and severity of the infection were determined; and an intra-class coefficient (ICC) was calculated to correlate the histologic results with the standard counting method. Based on contrast, specificity, and sensitivity, we found hot Gram chromotrope and Ziehl-Neelsen stains offered the best approach for highlighting Vairimorpha spores. These stains were optimized to find the ideal staining times for Vairimorpha by testing different immersion durations in key steps to enhance spore contrast. There was a notable association between histologic observations and spore count, with an ICC of 0.74 (95% CI [0.36, 0.91]) and 0.82 (95% CI [0.54, 0.93]) for the percentage of infected bees and histologic grade, respectively. Lesions included distension of ventricular epithelial cells, intracellular microsporidia, reduced ciliation, and disintegration of the peritrophic membrane. No spores were detected in extra-ventricular organs.

A 2-y-old spayed female mixed-breed dog was presented with a 3-mo history of seizures. Coalescing intra-axial complex cystic lesions in the right cerebral hemisphere identified on MRI were suggestive of hydatid cysts; however, PCR testing of a fecal sample for Echinococcus spp. was negative. The dog was euthanized after 3 mo of treatment due to worsening signs and was submitted for postmortem examination. Coalescing 0.5-3-cm cavitations effaced ~20% of the left and 40% of the right cerebral hemispheres, and contained numerous 3-5-mm long ovoid-to-elongate, soft, white-to-clear metacestodes. Similar structures extended into the subarachnoid space. Histology revealed multiple larval cestodes consistent with invaginated cysticerci present in bladder compartments. Cysticerci each had a scolex, convoluted invaginated spiral canal, and spinous tegument with numerous calcareous corpuscles. Within many of the cysticerci, visible armed rostella had refractile hooklets and muscular suckers. Light microscopic evaluation of whole cysticerci preserved in ethanol revealed rostellar hooks with blade-to-guard length and handle-to-guard length that were within RIs for Taenia crassiceps. Sequencing of DNA amplicons obtained via PCR confirmed 100% sequence identity to T. crassiceps. To our knowledge, canine neural cysticercosis attributed to T. crassiceps has not been reported previously. Our case highlights the successful integration of multiple diagnostic modalities in a case of canine neural cysticercosis.