Journal of Veterinary Diagnostic Investigation最新文献

We describe here a case of the sinus roundworm, Skrjabingylus chitwoodorum, found incidentally in a rabies-positive striped skunk (Mephitis mephitis) in Texas, USA. Skunks serve as a natural definitive host for this metastrongylid nematode in North America, in which infections result in observable damage to the host cranium, where adult parasites reside. Additionally, skunks are considered the primary reservoir of rabies in Texas. In November 2022, the animal was discovered in northern Texas displaying neurologic signs before euthanasia and submission to the Oklahoma Animal Disease Diagnostic Laboratory for rabies testing. Direct fluorescent antibody testing indicated that the animal was rabies-positive, and, upon tissue collection, numerous adult nematodes were recovered from the cranium and identified as S. chitwoodorum by morphology and amplification of the mitochondrial cytochrome c oxidase subunit I gene. Histologically, we found lymphohistiocytic meningitis in several loci and chronic sinusitis rostral to the cribriform plate. Due to behavioral abnormalities, we additionally tested for Toxoplasma gondii via PCR, but no parasite DNA was detected. Concurrent infection by S. chitwoodorum and rabies virus may contribute to neurologic signs in skunks.

In 2018, a new virus, named equine parvovirus-hepatitis (EqPV-H), was discovered in a biologic product that had been administered to horses that subsequently developed clinical signs of equine serum hepatitis (Theiler disease). Further correlation of the virus with the disease sparked federal requirements that all equine biologics be free of EqPV-H. The initial quantitative real-time PCR (qPCR) test for EqPV-H has proved to be sensitive to co-extracted PCR inhibitors in template nucleic acids, causing false-negative results. We investigated the use of digital PCR (dPCR) as a more robust test. Examination of 227 equine biologic product lots available for purchase both before and after regulatory implementation using both detection methods indicated that dPCR is a more reliable platform. Nevertheless, use of the qPCR method for product screening had reduced the fraction of serials with EqPV-H detected from 39.6% prior to regulation to 6.8% after regulatory implementation. Adoption of dPCR testing is an opportunity to further decrease the prevalence of EqPV-H in equine biologics.

Postmortem examination of deceased production animals with appropriate ancillary testing is fundamental to determining causes of morbidity and mortality. Reaching a definitive diagnosis is crucial to evidence-based herd management and treatment decisions that safeguard animal health and welfare, food safety, and human health. However, for a range of reasons, carcasses sometimes cannot be examined in a veterinary diagnostic laboratory. As a result, postmortem examinations of farmed animals, including cattle, are often performed on-farm by the referring veterinarian (rVet) with tissue samples submitted to a veterinary diagnostic laboratory for ancillary testing. For various reasons, field postmortems can be associated with lower diagnostic rates. We investigated real-time pathologist-assisted field postmortem examination (rtPAP) assistance to beef cattle rVets to gauge any improvement in attaining a final diagnosis. We found that rtPAPs improved the success of reaching a final diagnosis compared to unassisted field postmortem examinations. Both the participating bovine rVets and the pathologists saw benefits to the rtPAPs, with bovine rVets indicating that they would utilize this service in the future if available. Our proof-of-concept study demonstrated the positive role of rtPAPs in diagnosing beef cattle disease and speaks to the need for telepathology services supporting food animal rVets and producers.

Cerebellar granule cell layer conglutination is a tissue artifact associated with postmortem autolysis that causes cerebellar granule cell changes once thought to be caused by degeneration and necrosis. Granule cell layer conglutination has been reported mainly in humans and cattle and rarely in other animal species, but its frequency remains vastly unknown in veterinary medicine, mostly because this postmortem change is typically not recorded in autopsy reports. Pathology trainees should be aware of autolytic tissue changes that may mimic pathologic changes in the CNS, particularly when those changes are highly selective for a specific cell population within the cerebellar cortex. Here we provide a brief historical perspective on the evolution of cerebellar granule cell layer conglutination from "enzootic cerebellar necrosis," a presumed necrotic lesion affecting granule neurons in humans and cattle, to a tissue change associated with postmortem autolysis and increased tissue acidity in the cerebellum. We also provide an update on the animal species in which cerebellar granule cell layer conglutination has been observed during our diagnostic pathology routine.

Neurolisteriosis, a common disease of small ruminants, is most often caused by Listeria monocytogenes. Here we describe 25 cases of caprine neurolisteriosis diagnosed in our laboratory over a 5-y period and compare our fluorescent antibody test (FAT) results with immunohistochemistry (IHC) and polymerase chain reaction (PCR) testing for diagnostic confirmation. Neurohistologic changes consistent with neurolisteriosis affected the pons in all cases, extending rostrally to the mesencephalon in 6 cases, caudally to the medulla oblongata in 6 cases, and/or dorsally to the cerebellum in 4 cases. Acute inflammatory changes were observed in 17 cases, and included neuroparenchymal microabscesses, neuronal necrosis and neuronophagia, axonal swelling, microgliosis and astrogliosis, and perivascular neutrophils with macrophages, lymphocytes, and plasma cells that occasionally extended to the leptomeninges. Subacute-to-chronic changes (8 cases) consisted of neuroparenchymal and perivascular clusters of macrophages with rare neutrophils, lymphocytes, and plasma cells admixed with glial nodules. Bacterial bacilli were observed within neutrophils or macrophages in H&E-stained tissue sections in 4 cases. Gram stain highlighted gram-positive bacilli in 13 cases. Neurolisteriosis was confirmed by FAT in 2 cases, by IHC in 19 cases, and by PCR in 20 cases.

The rostral cranial fossa (RCF) consists of the sphenoid and ethmoid bones, which accommodate the olfactory bulbs and nerves along the recesses of the cribriform plate. Neoplasms located in the vicinities of the RCF can compress and/or invade the cribriform plate. Here we describe the clinical and pathologic findings of neoplasms involving the cribriform plate in 32 dogs and 17 cats autopsied over a 13-y period. The average ages of affected dogs and cats were 9.2 y and 9.7 y, respectively. No sex or breed predisposition was evident in dogs, but 13 of 18 cats were spayed females and 14 of 18 were domestic shorthair cats. The main clinical signs were seizures (10 cases) and epistaxis (5 cases) in dogs, and red-to-brown nasal discharge (5 cases) and seizures (4 cases) in cats. In dogs, the 22 sinonasal neoplasms included adenocarcinoma (14 cases), transitional carcinoma (4), squamous cell carcinoma (2), lymphoma (1), and histiocytic sarcoma (1); the 10 intracranial neoplasms consisted of high-grade gliomas (3 cases), psammomatous meningiomas (2), histiocytic sarcomas (2), olfactory neuroblastomas (2), and a meningeal granular cell tumor (1). In cats, the 14 sinonasal neoplasms included lymphoma (8 cases), adenocarcinoma (4), adenosquamous carcinoma (1), and squamous cell carcinoma (1); the 3 intracranial neoplasms consisted of oligodendroglioma (1), transitional meningioma (1), and olfactory neuroblastoma (1).

A geriatric captive bobcat (Lynx rufus) was euthanized due to progressive anorexia and lethargy. Meningoencephalitis with intralesional apicomplexan organisms was identified histologically. With immunohistochemistry, the organisms were immunolabeled by anti-Sarcocystis neurona antibodies. PCR targeting the ITS region of the parasite yielded an amplicon with >99.6% identity to several Sarcocystis dasypi, S. neurona, and S. speeri sequences. Amplification of the 18S region yielded a sequence that was 99.9% similar to sequences of both S. neurona (MN169125) and S. speeri (KX470746). Inflammatory disease of the CNS due to Sarcocystis sp. infection is uncommonly reported in felids and has not been reported previously in bobcats, to our knowledge. Here, we briefly review Sarcocystis-associated CNS disease in other felids, confirm that it can affect bobcats, and highlight the challenges of species-level identification of Sarcocystis sp. in routine diagnostic work.

Synovial myxoma, a rare joint tumor in dogs, has traditionally been considered benign, acknowledging that local invasion into regional tissues including bone may be present. Given the diagnostic challenges in distinguishing synovial myxoma from other joint lesions through clinical features and diagnostic imaging, definitive diagnosis relies on characteristic gross and histologic features. Within the inner surface of the joint capsule, synovial myxomas form nodules of stellate-to-spindle cells within abundant myxomatous matrix. We present here 2 cases of synovial myxoma with metastasis to regional lymph nodes and compare these 2 cases to 3 cases without evidence of lymph node metastasis. Aside from lymphovascular invasion in one case with metastasis, there were no overt histologic features of the primary tumor to suggest aggressive biologic behavior. The finding of lymph node metastasis warrants reconsideration of the term "synovial myxoma" for this neoplasm. We suggest the term "synovial myxosarcoma," considering that histologic features of the primary tumor do not predict biologic behavior. Our case series highlights the importance of lymph node sampling in suspected synovial myxosarcoma cases as well as thorough histologic examination, emphasizing careful evaluation for lymphovascular invasion.

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. FMD poses an economic threat to the livestock industry in the United States. Due to the potential use of vaccines composed of partially purified structural proteins of the FMD virus (FMDV), it is important to test samples from infected and vaccinated animals with a competitive ELISA that detects antibodies against nonstructural proteins (NSPs) of FMDV. Our study extends the diagnostic validation of the Prionics ELISA (Thermo Fisher) and the VMRD ELISA. We used diverse serum sample sets from bovine, porcine, and other cloven-hoofed animals to evaluate the analytical specificity and sensitivity, diagnostic specificity and sensitivity, and differentiation of infected from vaccinated animals (DIVA) per validation guidelines outlined by the World Organisation for Animal Health (WOAH). The 2 tests were analytically 100% accurate. The VMRD test was diagnostically more sensitive than Prionics, but Prionics was diagnostically more specific than the VMRD test. Both tests could tell if animals were infected or vaccinated. Considering these data, both VMRD and Prionics ELISAs can be used for serodetection of FMDV antibodies at the Foreign Animal Disease Diagnostic Laboratory and within the National Animal Health Laboratory Network laboratories.

Per- and polyfluoroalkyl substances (PFASs) have attracted increasing attention due to their persistence in the environment and potential adverse effects on human and animal health. The detection and quantification of PFASs in livestock could substantially contribute to monitoring their presence within the food chain. We developed a targeted quantification method for 34 PFASs in livestock serum by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). We used protein precipitation for serum sample extraction and accurate mass measurement of targeted PFAS compounds for quantification. We validated the method with various analytical parameters, achieving accuracy of 70-120% and precision of <20%. The method also demonstrated good analytical sensitivity, with a limit of detection of <0.051 ng/mL and a limit of quantification of <0.175 ng/mL. When applying the developed method to actual serum samples from a variety of livestock, we successfully identified and quantified various PFASs in different livestock species. Our method has the potential to be a valuable tool for veterinary laboratory analysis of PFAS contamination in livestock.