Thyroid tumors occur in many domestic species, but are most common in the dog, in which they are classified as follicular or medullary. During 2012-2016, we received tissue specimens or whole carcasses of 4 dogs with variable enlargement of the thyroid glands. The 2 males and 2 females were of mixed (mongrel) inbreeding, 3-4.5-y-old. All tumors had lobulated architecture forming follicular structures variably containing colloid. On immunohistochemistry of the tumors from 3 of the dogs, 2 were thyroglobulin positive, and all 3 were negative for calcitonin, confirming follicular thyroid carcinoma in 2 of the dogs. Thyroid carcinomas have not been reported previously in related mongrel dogs, to our knowledge.

A 15-y-old captive-born female bottlenose dolphin () had slowly progressive lethargy, inappetence, and pallor of the oral mucosa. Serial hemograms and serum biochemistry analysis revealed hemolyzed plasma, gradually severe anemia with reticulocytosis, spherocytosis, pronounced neutrophilia with left shift and toxic change, and indirect hyperbilirubinemia. Urinalysis identified both hemoglobinuria and bilirubinuria. Hyperglobulinemia with polyclonal gammopathy was evident by protein electrophoresis, and the saline agglutination test was positive. Splenomegaly and hyperechogenic liver were also observed on ultrasound. These findings meet the diagnostic criteria established for immune-mediated hemolytic anemia (IMHA) in small animals, which is extremely rare in cetacean species, and, to our knowledge, has not been fully documented. Several potential triggers of a secondary IMHA were ruled out, including the most common cetacean virus, exposure to new drugs, and recent vaccination events. Following recommendations from companion animal medicine, immunosuppressive therapy was implemented and proved effective in this bottlenose dolphin; the CBC returned to normal after 3 mo of treatment.

Piglet lethality is one of the major concerns in pig breeding programs. Deletion of a 212-kb region within the Bardet-Biedl syndrome 9 () gene has been linked to a reduction in the number of piglets born alive per litter. The mutant gene carrier-by-carrier mating scheme could result in mummification of piglets carrying 2 copies of the mutant allele, which ultimately affects the reproductive performance of the sow. Our aim was to develop a simple, rapid, and cost-efficient method that could be applied in a mutant gene carrier screening program in low- and middle-income countries within basic laboratory settings. Here, we report an optimized multiplex PCR assay that we have established successfully for detection of a 212-kb deletion within the genomic sequence. We genotyped 420 animals from Yorkshire, Duroc, and Landrace purebred populations in Vietnam. We found that while the mutant allele was not identified in Duroc pigs, the frequency of carriers was 10% in both Yorkshire and Landrace populations. We subsequently validated our results using Sanger sequencing. Our multiplex PCR method could be utilized as a screening test in pig breeding programs.

A mass was removed surgically from the right orbit of a 1-d-old Holstein calf. Grossly, the mass filled the rostral part of an enlarged orbit and compressed the globe toward the caudal pole of the orbit. The brown, 6-cm tumor had central yellow and brown areas, and a smooth, glistening cut surface. Microscopically, the neoplasm was highly cellular and composed of spindle cells arranged in irregular, broad, interlacing streams and bundles, forming a herringbone pattern and supported by a sparse collagenous matrix. Neoplastic cells infiltrated surrounding soft tissues and compressed the globe. The neoplastic cells had positive immunolabeling for α-smooth muscle actin, desmin, and vimentin, and negative immunolabeling for factor VIII, myoglobin, cytokeratin, and skeletal muscle actin. Histopathology and immunohistochemistry results confirmed a diagnosis of leiomyosarcoma. To our knowledge, congenital periocular leiomyosarcoma has not been reported in cattle previously. This rare tumor could be included as a differential diagnosis in newborn calves with periocular masses.

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.

We describe here a case of the sinus roundworm, , found incidentally in a rabies-positive striped skunk () 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 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 via PCR, but no parasite DNA was detected. Concurrent infection by and rabies virus may contribute to neurologic signs in skunks.

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.

The rapid geographic spread of chronic wasting disease (CWD) in white-tailed deer (WTD; ) 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.

A 2-y-old, intact female, mixed-breed dog was presented to the veterinary hospital with abdominal distension, anemia, and lethargy following a chronic history of nonspecific gastrointestinal signs. CBC and serum biochemistry revealed moderate nonregenerative anemia with neutrophilia, hypoalbuminemia, hyperglobulinemia, hypoglycemia, decreased urea and creatinine, and hypercholesterolemia. Abdominal radiographs and ultrasound revealed a large heterogeneous mesenteric mass and ascites. Abdominocentesis confirmed septic peritonitis with filamentous bacteria. Fine-needle aspiration of the mass yielded pyogranulomatous inflammation and hyphae. An exploratory laparotomy revealed a large cranial abdominal mass with granulomas present throughout the abdominal cavity. Due to the poor prognosis and disseminated disease, the owner elected euthanasia. Postmortem and histologic examinations detected intralesional mycetomas and bacterial colonies within the mesenteric masses. 16S ribosomal RNA gene PCR and sequencing using formalin-fixed, paraffin-embedded sections identified , , and . Fungal culture, PCR, and sequencing confirmed . Our report highlights the importance of molecular methods in conjunction with culture and histologic findings for diagnosing coinfections caused by infrequent etiologic agents. Additionally, we provide a comprehensive literature review of infections in dogs.

To prevent significant economic losses, some countries have successfully eradicated enzootic bovine leukosis (EBL), which is caused by bovine leukemia virus (BLV) infection. In Serbia, efforts to eliminate EBL commenced in the late 1990s. Recognizing the disparities in test selection among laboratories and variations in quality, we evaluated the diagnostic sensitivity and specificity of commercial ELISAs using field samples in Serbia. Using 5 commercial ELISA kits, we tested 138 cattle serum samples, submitted for confirmatory testing between 2020 and 2023, along with 100 serum samples from BLV-negative herds. We found 100% agreement of the ID Screen BLV Competition (IDvet), Svanovir BLV gp51-Ab (Svanova), and INgezim BLV Compac 2.0 (Ingenasa) ELISAs. We observed 93% agreement comparing these 3 kits to the Bovine Leukemia Virus Antibody test kit (VMRD). Agreements of 92% and 88.4% were determined between Idexx and IDvet, Svanova, and Ingenasa kits, and between Idexx and VMRD kits, respectively.

Natural oak toxicity, a phenomenon sporadically reported in the United States, is due to consumption of any part of most oak trees ( spp.). Ruminants, mainly cattle, are disproportionately susceptible to oak toxicity. Toxicity is attributed to degradation of the oak plant hydrolysable tannins by rumen microbes and enzymes into absorbable low-molecular-weight metabolites, which are postulated to bind and damage endothelial cells by unknown mechanisms. The clinical manifestations of acute toxicosis are nonspecific or broadly suggestive of renal disease due to acute tubular injury. Here we document the clinical, gross, histopathologic, and novel ultrastructural features of natural acute oak nephrotoxicity in 3 beef calves on 2 farms in Colorado, USA. Gross postmortem findings included perirenal edema with renomegaly and hemorrhagic gastroenteritis. Histologically, renal tubular epithelial necrosis was severe, with hemorrhage and intratubular hyaline casts. Transmission electron microscopy revealed extensive involvement of proximal and distal convoluted tubules, with predominantly intact basement membranes, and glomerular and interstitial endothelial injury and necrosis. The ultrastructural details of toxic nephropathy and vasculopathy induced by oak metabolites in natural cases of bovine oak toxicosis have not been described previously, to our knowledge.

To expand surveillance testing capacity through sample pooling, a thorough understanding is needed of how sample dilution through pooling affects the sensitivity of candidate assays. We validated a robust and representative framework for assessing the dilution effect of sample pooling using duplex rtPCR surveillance of and , both of which are causative agents of severe anemia in cattle and a serious threat to the cattle industry in Virginia and many other states. We used 200 known-positive samples with Ct values representative of typical surveillance results in a series of pools in which we re-tested each sample individually, followed by each sample diluted in equal volumes with negative samples to make pools of 2, 4, 6, 8, and 10 total samples. We compared the Ct values of the individual positives with the Ct values of each pool size to determine if Ct values increase past the limit of detection in the 45-cycle assay. We observed a maximum of 2% sensitivity loss (no more than 2 of 100 samples returned a false-negative result) for both and during the pooling series, with lower-than-expected average Ct increase and sensitivity loss. We conclude that pooling up to 10 samples would be acceptable for regional surveillance of and using our rtPCR assay. The described strategy is applicable to validate pooling for a wide range of single and duplex rtPCR assays, which could expand efficient disease surveillance.

The incidence of enzootic bovine leukosis (EBL), a type of B-cell lymphoma, is increasing in Japan. EBL is caused by bovine leukemia virus (BLV; , ) infection and is diagnosed by detecting antibodies against BLV in milk and blood or BLV DNA in blood. We assessed the feasibility of using stable flies () as a sampling tool to assess BLV infection status in cattle herds. First, we collected blood from 3 cattle herds and, based on the measurement of BLV-proviral load (PVL) by quantitative real-time PCR (qPCR), identified 1) a BLV-free herd, 2) a herd with a low prevalence of BLV-infected cattle and low PVL, and 3) a herd wherein half of the cattle were BLV-infected with low-to-high PVLs. Next, we collected stable flies from the 3 herds, extracted DNA from their blood meals, analyzed it for BLV DNA, and measured the BLV PVL. Cattle DNA and BLV DNA, but not other mammalian DNA, were successfully detected by digestion of the flies. Based on fly blood meal qPCR, we identified one herd as BLV-free and the other 2 herds as having <50% prevalence of BLV-infected cattle with low PVLs. Our fly results were not consistent with preliminary BLV-PVL measurements on cattle blood. Our pilot study indicated that, to assess the feasibility of a stable fly blood meal test as an alternative technique for evaluating BLV infection status in dairy and beef cattle, additional investigations involving more cattle herds and stable flies are needed.

A free-ranging, adult female two-toed sloth () was brought to a wildlife rescue center in Costa Rica with ocular and auricular myiasis and numerous skin lesions. After one month of unsuccessful systemic and topical antimicrobial treatment, the patient died. A postmortem examination was performed, and tissues were examined histologically, confirming disseminated amebic infection with intralesional trophozoites and cysts in the lungs, liver, eye, heart, spleen, and stomach. Immunohistochemistry identified the ameba as sp. A multiplex real-time PCR assay, 18S ribosomal DNA PCR, and sequencing performed on formalin-fixed, paraffin-embedded lung tissue confirmed the T17 genotype. The genus is in the group of free-living amebas that cause infection in humans and animals, and it is ubiquitous in the environment. T17 has been isolated from water and soil, but to our knowledge, this genotype has not been implicated in infections of animals previously and has not been reported from Costa Rica. Systemic infection has not been described in sloths previously. We provide a comprehensive literature review describing infections by free-living amebas of the genus spp., spp., and spp. in domestic, zoo, and wild mammals.

Congenital structural anomalies of the lower airways of the respiratory tract are uncommon in cats. We describe here a case of cystic pulmonary lesions in a 6-wk-old domestic shorthair cat consistent with congenital pulmonary airway malformation (CPAM; formerly referred to as cystic adenomatoid malformation of the lung, or congenital pulmonary adenomatoid malformation; Stocker type II). CPAM is rarely reported in veterinary species and, to our knowledge, has not been reported in cats. In humans and veterinary species, individuals with CPAM (Stocker types I-IV) can be asymptomatic at birth but are predisposed to developing respiratory abnormalities that typically manifest clinically in the early years of life. We review the pathologic features of CPAM.

Neoplasia is a common disease in guinea pigs (); 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.

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.

A 2-y-old, intact male roan antelope () 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 spp. Genomic DNA was extracted from abomasal and intestinal contents and subjected to PCR using primers specific for the 18S rRNA gene of spp., followed by Sanger sequencing. The sequence was >99% homologous to -associated proliferative abomasitis has not been reported previously in a captive hippotraginid, to our knowledge.

Rabbit hemorrhagic disease virus 2/genotype GI.2 (RHDV2/GI.2; , ) causes a highly contagious disease with hepatic necrosis and disseminated intravascular coagulation in several species. RHDV2 was first detected in European rabbits () in France in 2010 and has since spread widely. We gather here data on viral detections reported in various countries and affected species, and discuss pathology, genetic differences, and novel diagnostic aspects. RHDV2 has been detected almost globally, with cases reported in Europe, Africa, Oceania, Asia, and North America as of 2023. Since 2020, large scale outbreaks have occurred in the United States and Mexico and, at the same time, cases have been reported for the first time in previously unaffected countries, such as China, Japan, Singapore, and South Africa, among others. Detections have been notified in domestic and wild European rabbits, hares and jackrabbits ( spp.), several species of cottontail and brush rabbits ( spp.), pygmy rabbits (), and red rock rabbits ( spp.). RHDV2 has also been detected in a few non-lagomorph species. Detection of RHDV2 causing RHD in spp. and species other than those in the genera and is very novel. The global spread of this fast-evolving RNA virus into previously unexploited geographic areas increases the likelihood of host range expansion as new species are exposed; animals may also be infected by nonpathogenic caliciviruses that are disseminated by almost all species, and with which genetic recombination may occur.

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.