Journal of Veterinary Diagnostic Investigation最新文献

In 2021, bovine polyomavirus 1 (BoPyV1; Polyomaviridae, Epsilonpolyomavirus bovis) was associated with nephritis in an aborted bovine fetus in Uruguay, with renal lesions resembling those typical of polyomavirus-associated nephropathy of humans. Given that little is known about the epidemiology of BoPyV1 infection in cattle, we screened for BoPyV1 in urine samples collected in 2015-2017 from beef and dairy herds from 12 of the 19 departments in Uruguay. We tested for BoPyV1 by PCR in 156 urine pools and 249 individual urine samples from 42 herds. We detected BoPyV1 in 33 of 42 (79%) farms across 100% of the departments studied, in similar proportions in beef (22 of 30; 73%) and dairy (11 of 12; 92%) herds. At the animal level, BoPyV1 was detected in 80 of 249 (32%) animals; this frequency was significantly higher in dairy (51 of 119; 43%) than beef (29 of 130; 22%) cattle, and in cows (36 of 81; 44%) than heifers (32 of 121; 26%). BoPyV1 strains circulating in Uruguay have a high degree (98.7-100%) of sequence identity at the major capsid protein VP1, which is slightly lower (96.2-99.7%) than for strains from other countries. We conclude that shedding of BoPyV1 in the urine of dairy and beef cattle is prevalent and geographically widespread in Uruguay.

Confirmation of extracellular amyloid deposition across various animal species and tissue types has been a long-standing challenge in veterinary diagnostic pathology. Transmission electron microscopy (TEM) has historically been used to advance the understanding of amyloid fibril morphology and confirm amyloid fibril deposition when histologic methods provide unclear results. We assessed the feasibility of utilizing TEM for routine confirmation of amyloidosis as an addition to histology. We analyzed ex situ amyloid fibrils with direct, negative-contrast TEM and in situ amyloid fibrils with aldehyde-fixed, plastic-embedding TEM to confirm amyloidosis in a variety of cases in which amorphous extracellular amyloid deposits had been identified by H&E and Congo red staining. We compared the 2 TEM methods and documented amyloid fibril morphology and morphometry in 7 species (goat, guinea pig, kudu, fox, sheep, flamingo, and duck). Ex situ fibrils had helical morphology and widths of 15-18 nm across all species. Fibril crossover distances had more interspecies variation of 60-130 nm, and species could be grouped based on pitch (twist size). Twisting patterns of in situ fibrils could not be visualized, but in situ widths of 10 nm were measured across all species. In 4 different chicken cases, fibrils differing morphologically from amyloid were consistently detected via both TEM methods, suggesting the possibility of a non-amyloid deposit that is commonly diagnosed as amyloidosis based on its histologic appearance. When available, we recommend routine confirmation of amyloid fibril deposition by TEM.

Sarcocystis pinnipedi is an apicomplexan protozoal parasite that was first recognized during a mass mortality event in juvenile grey seals (Halichoerus grypus) in the northwest Atlantic Ocean. Since its identification, this parasite has been reported in various pinniped species and has been associated with fatal necrotizing hepatitis. Little is known of the host range of S. pinnipedi. Here we report 2 cases of California sea lions (Zalophus californianus) in managed care that died following an 8-d history of inappetence, vomiting, diarrhea, and progressive lethargy with elevated hepatic enzyme activities. Postmortem examination identified hepatitis and icterus. Sarcocystis schizonts and zoites were identified in regions of necrosis. Molecular and ultrastructural findings demonstrated the close relatedness of this Sarcocystis to S. canis, which produces a similar lesion in bears.

Bovine herpesviral meningoencephalitis (BHM) is an infectious disease of cattle caused by bovine alphaherpesvirus 1 (BoAHV1; Orthoherpesviridae, Varicellovirus bovinealpha1) or 5 (BoAHV5; Orthoherpesviridae, Varicellovirus bovinealpha5). Cases are frequent in South America, but the disease is sporadic in other countries. Infection typically leads to fatal necrotizing meningoencephalitis that most often affects calves <1-y-old and yearlings under stressful situations, including weaning, large concentrations of animals, transport, and introduction of cattle from other locations into a herd. Clinical disease lasts from 1-10 d and often leads to typical gross and histologic lesions that are more prominent in the frontal lobes of the brain. This particular neuroanatomic distribution of lesions results from retrograde viral infection from the nasal mucosa along the olfactory nerves and bulbs with subsequent spread to the rostral cerebrum. Because of its particular geographic distribution, many aspects of BHM are still poorly documented in the English language veterinary literature, and thus a comprehensive review of the disease is warranted. Here we review the main aspects of BHM, including its historical timeline, etiology, pathogenesis, epidemiology, clinical and pathologic findings, diagnosis, and control and prophylaxis.

Campylobacter spp. can cause gastroenteritis, hepatitis, bacteremia, and abortions in domestic animals and humans. Some Campylobacter spp. are zoonotic. To our knowledge, hepatitis caused by Campylobacter jejuni has not been reported in horses. Here we present a case of acute necrosuppurative hepatitis caused by C. jejuni infection in a 3-y-old gelding, and we review the literature on C. jejuni infections in various animal species. The horse had a one-week history of weight loss and weakness before becoming recumbent and dying. Grossly, the liver had rounded edges and was mottled. There were ecchymoses on the gastric serosa, and a large amount of mucoid, pale, green-to-yellow content adhered to the mucosa of the small and large intestines. Microscopically, random areas in the liver were necrotic and infiltrated by large numbers of neutrophils, and fewer lymphocytes and plasma cells. Other changes in the liver included neutrophilic cholangitis with bile duct hyperplasia in portal areas, canalicular cholestasis, and mild portal fibrosis. The lamina propria, and occasionally the submucosa, of the small intestine and colon was infiltrated by large numbers of lymphocytes and plasma cells, and there was multifocal crypt necrosis. C. jejuni was recovered in pure culture from the liver.

Bovine respiratory disease complex (BRDC) is a multi-etiologic disease that significantly impacts the cattle industry. Nasopharynx-associated lymphoid tissue (NALT) is the nasal mucosal immune system that protects against various pathogens; however, reports on its pathology are limited. We compared the pathologic impact of BRDC-related viruses on the NALT and lungs of 10 pneumonic and 3 negative control Japanese black (JB) calves. Three bovine viral diarrhea virus (BVDV) persistently infected Holstein calves were examined as positive control; all 3 calves had BVDV in situ hybridization (ISH)-positive signals in NALT follicular macrophages and lymphocytes, suggesting viral replication in these cells. NALT and lungs of pneumonic JB calves had weak-positive BVDV results in PCR and negative results in ISH, indicating late-stage transient BVDV infection. The finding of BVDV in unvaccinated pneumonic JB calves confirmed the involvement of a BVDV field strain. PCR detection of bovine coronavirus (BCoV) and bovine respiratory syncytial virus (BRSV) in NALT along with ISH BCoV-positive signals in NALT epithelial cells confirms infection by those viruses. Pneumonic JB calves had nasopharyngitis and pneumonia, with the same bacteria present in nasopharyngeal swabs and lungs, indicating that, in these animals, the bacteria proliferating in the nasopharynx probably migrated to the lungs via inhalation. BVDV transient infection in the NALT may induce local immunosuppression; BCoV and BRSV infections are thought to damage epithelial cells, facilitating bacterial infection of the NALT and lungs. Our results confirm that bovine NALT is a location for viral replication and may be associated with BRDC development in cattle.

A sudden mass mortality involving 44 fallow deer (Dama dama) occurred in September 2020 at a game management area near Budapest, Hungary. The die-off affected both sexes and all age classes equally. On postmortem examination of 2 subadults and 1 fawn, we found average body condition, diffuse subcutaneous edema, swelling of peripheral lymph nodes, marked hemorrhages in lymph nodes along the esophagus and trachea, and left ventricular dilation. We isolated Pasteurella-like colonies from spleen, liver, small intestine, lung, and brain samples of 7 animals, and identified them as P. multocida serotype B:2 by amplifying kmt1, toxA, and hyaC-hyaD genes, capsular typing by PCR, and serotyping by agar gel diffusion precipitation test, which established the diagnosis of hemorrhagic septicemia as the cause of the outbreak. By further analysis, we determined that all of our P. multocida isolates encoded ptfA, fimA, hsf-2, nanH, hgbA, and pfhA, but we did not detect genes encoding toxA, hsf-1, tbpA, or tadD. We identified our strains by RIRDC MLST as sequence type (ST)122, characteristic for strains causing hemorrhagic septicemia, while using multi-host MLST analysis we assigned these strains to ST64 clustering with P. multocida strains from the 2015 hemorrhagic septicemia outbreak of saiga antelopes in Kazakhstan. We concluded that increased population density and aggregation due to limited drinking water availability played a role in initiating the outbreak.

Virginia opossums (Didelphis virginiana) are the only native marsupials in the United States of America and Canada. Females have a reproductive tract consisting of a complex duplex (bifurcated) reproductive system, with 2 ovaries, 2 uteri and uterine tubes, and a vaginal complex composed of 2 lateral vaginae, vaginal sinuses, and a urogenital sinus. Few conditions of the reproductive tract have been described in these marsupials. A 2-y-old, female Virginia opossum was presented because of hematuria and was found dead shortly after admission. The autopsy revealed left lateral vaginal torsion and pyovagina. Streptococcus didelphis was isolated and identified from the lateral vaginal exudate, blood, and liver using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Histologic examination confirmed suppurative and lymphoplasmacytic vaginitis, endometritis, cystitis, pyelonephritis and interstitial nephritis, portal hepatitis with fibrosis, myocarditis, and adrenalitis with intralesional gram-positive cocci. These results suggest ascending S. didelphis infection of the lateral vagina with subsequent torsion, bacterial translocation, bacteremia, and sepsis as the cause of death.

Primary neoplastic diseases of the CNS in livestock are rare compared to companion animals. Here we describe the clinical, pathologic, and genetic findings in an adult sheep with a high-grade cerebral astrocytoma. Clinically, apathy, ataxia, bilateral amaurosis, and horizontal resting nystagmus were observed. The signs were suggestive of a space-occupying lesion affecting the vestibular and ascending reticular activating systems. The CSF had high total protein, hypercellularity, and pleocytosis. Macroscopically, a friable, gray-pink, ovoid mass (6 × 3 × 4 cm) was observed within most of the right parietal, occipital, and temporal cerebral subcortical areas, extended into the thalamus, hippocampus, and the cerebral peduncles, and reached the ipsilateral choroid plexus and the lateral ventricles. Histologically, the well-delimited, unencapsulated lesion consisted of proliferating neoplastic spindloid-to-polygonal cells mainly arranged in streams and bundles supported by minimal fibrous stroma, and random areas of coagulative necrosis and hemorrhages without pseudopalisading in the center of the mass. Immunohistochemistry revealed strong immunolabeling of spindle cells for S100, vimentin, and glial fibrillary acidic protein. Immunolabeling for neuron-specific enolase was restricted to trapped neurons; oligodendrocyte transcription factor 2 (OLIG2), pan-cytokeratins, and SOX10 were immunonegative. TP53 gene sequencing of the neoplasm did not demonstrate any point mutations involving exons 2-11.

Salmonella spp. are important pathogens of foals, causing clinical enterocolitis and sepsis. We characterized the resistance, virulence, and stress response genes in Salmonella isolates from foals with or without diarrhea. Salmonella isolates (n = 23) recovered from fecal samples of 16 diarrheic and 7 non-diarrheic <1-y-old foals were subjected to whole-genome sequencing. The most common serovars detected in diarrheic foals were S. enterica subsp. enterica serovars Infantis and Minnesota. Multidrug resistance was observed in 9 of 23 isolates, with 8 of the 9 from diarrheic foals. All of the isolates contained at least 2 resistance genes, with most of the genes related to the multidrug efflux pump complex. Among the 9 isolates shown to be resistant to β-lactam antimicrobials, at least one antimicrobial resistance gene (ARG) related to the inactivation of these antimicrobials was observed (bla_TEM-1, bla_CMY-2, bla_CTX-M-8). Among the 7 isolates resistant to the quinolone class, 3 contained ARGs (qnrB19, qnrB6). The occurrence of multidrug-resistant isolates, particularly among foals with diarrhea, and the zoonotic potential of Salmonella species, highlight the importance of implementing biosecurity measures on the studied farms.