In Japan, avian nephritis virus (ANV) isolates associated with the 1989 outbreak of baby chick nephropathy (BCN) were previously reported as pathologically and serologically distinct from known ANV strains. However, genetic analysis conducted in this study revealed that these viruses were actually chicken astrovirus (CAstV), first described in 2004, and genetically distinct from ANV. Phylogenetic analysis based on the open reading frame 2 (ORF2) gene, which encodes the viral capsid protein, classified this virus within the subgroup Bi, along with isolates from Saga Prefecture in 2020 which were the only CAstV reported in Japan to date. These findings suggest that CAstV was already present in Japan in the 1980s, predating its first global report in 2004 and its first domestic report.

Escherichia albertii and Escherichia fergusonii have recently been recognized as emerging pathogens in humans and animals. E. albertii is a causative agent of foodborne infections in humans, but many aspects of its transmission routes and its prevalence in farm animals remain unclear. E. fergusonii has been isolated mainly from extraintestinal infections in humans and various animal species, but no large-scale surveys of its prevalence in farm animals have been reported. In this study, we isolated E. albertii and E. fergusonii from 3,975 fecal samples collected from farm animals throughout Japan. The prevalence of E. albertii was 3.1% (57/1,838) in swine, 2.2% (12/548) in poultry, and 0.4% (7/1,589) in cattle, while that of E. fergusonii was 37.4% (688/1,838) in swine, 46.2% (253/548) in poultry, and 17.1% (272/1,589) in cattle. We also isolated E. coli from fecal samples from which E. albertii or E. fergusonii was isolated and compared the antimicrobial resistance profiles of the E. albertii/E. fergusonii strains with those of the E. coli strains that were presumed to have experienced the same antimicrobial selection pressure in the farm animals. The antimicrobial resistance profiles of the E. fergusonii and E. coli strains isolated from the same swine fecal samples were similar, but those of the E. albertii and E. coli strains differed significantly (the former strains were highly susceptible). This suggests that E. albertii has not coexisted with E. coli for as long as E. fergusonii.

Canine melanoma is a malignant cancer affecting dogs, especially in the oral cavity, digits, and skin. This study investigated survival outcomes in 123 dogs diagnosed with melanoma at a veterinary teaching hospital in Japan between April 1, 2004, and March 31, 2023. Data were retrospectively obtained from electronic clinical records, with survival analysis performed using Kaplan-Meier curves, log-rank tests, and parametric survival models. The median survival time (MST) for all dogs was 244 days. Dogs that underwent surgical tumor removal had significantly longer survival (MST: 294 days) compared to those without surgery (MST: 93 days, P<0.001). The final parametric model with a log-logistic distribution identified tumor stage, location, and breed as key prognostic factors. Miniature Schnauzers and Toy Poodles had 3.36- and 4.80-fold longer survival times, respectively, compared to Golden Retrievers. Oral melanomas were associated with a 66% shorter survival time than non-oral melanomas (median survival times: 191 vs. 663 days; P=0.019). Advanced melanoma stages significantly decreased survival; time ratios for stage III and stage IV compared to stage I were 0.60 (95% confidence interval [CI]: 0.33–1.07; P-value: 0.084) and 0.42 (95% CI: 0.22–0.77; P-value: 0.006), respectively. These findings enhance understanding of canine melanoma in Japan and emphasize the need for multi-center studies to confirm these results.

Immunoglobulin E (IgE) is a key mediator of allergic reactions. Recent studies have suggested that chimeric IgE targeting cancer antigens exerts anti-cancer effects. However, whether IgE production is induced endogenously in cancer-bearing hosts remains unclear. We measured total IgE concentrations in healthy dogs (n=18) and dogs with hepatocellular carcinoma (HCC; n=10) before and after surgery. IgE concentrations did not differ between the healthy and HCC groups but decreased in nine of the ten dogs after HCC surgery. Statistical analysis indicated that HCC surgery was significantly associated with reduced IgE concentrations, suggesting endogenous IgE production in response to HCC. Further investigations with larger sample sizes and measurements of cancer-antigen–specific IgE are warranted to confirm these findings.

White Heifer Disease (WHD) is a congenital reproductive abnormality, especially in white female offspring in certain breeds of cattle like Belgian Blue. The roan locus was reported to affect coat color and fertility. It was suggested that a missense mutation (Ala218Asp) in the transmembrane domain of Kit ligand (KITL) gene was responsible for WHD. Here we generated two types of knock-in (KI) mice to reproduce the missense KITL mutation using pigmented agouti ICR mice. KI mice carrying compound mutations mimicking bovine transmembrane domain showed moderate coat color change, but single missense mutation KI did not. None of them exhibited uterine abnormalities, suggesting that localized gene modification may not fully affect murine KITL function.

In recent years, several cases of Mesocestoides vogae infection have been reported in domestic dogs in Japan. These cases typically involved the detection of tetrathyridia and segmented worms with immature proglottids, but not mature adults with gravid proglottids. In this study, mature and gravid proglottids of M. vogae were identified in a domestic dog from Niigata Prefecture. Morphological examination confirmed the parasite to be a Mesocestoides species based on the presence of a well-developed parauterine organ. Further molecular analysis identified the parasite as M. vogae. This is the first report of gravid proglottids of M. vogae in a domestic dog, suggesting the potential role of dogs as definitive hosts in the transmission cycle of this parasite.

Hemangioblastomas are rare intramedullary vascular tumors. Their biological nature is considered benign, but there is little information in dogs. This report describes histopathological and immunohistochemical features and postoperative clinical courses of three dogs to expand the current knowledge of this tumor. Histopathological examination revealed the proliferation of neoplastic stromal cells with irregularly arranged blood vessels and clusters of lymphocytes. Immunohistochemically, neoplastic stromal cells were immunolabeled for glial fibrillary acidic protein (GFAP), neuron specific antigen (NSE), and vimentin, and capillary endothelia and vessel walls were immunolabeled for CD31 and smooth muscle actin (SMA). Postoperative follow-up revealed improvements in neurological symptoms and no evidence of tumor recurrence for 3 months to 3 years, suggesting that surgical excision is a beneficial treatment method.

Malignant melanoma (MM) is difficult to diagnose because of its pleomorphic morphology and diverse protein profile. We describe a case of canine oral MM that exhibited rhabdoid cell differentiation. The tumor contained two cell types: typical MM cells and aggregated rhabdoid cells. Immunohistochemically, both types of neoplastic cells were positive for vimentin and desmin. Typical MM cells are positive for melanocytic markers; a subset of rhabdoid cells is negative for melanocytic markers and positive for myogenin. Consequently, the tumor was diagnosed as an MM with rhabdoid cell differentiation. This case highlights a potential diagnostic pitfall, as the morphological and immunohistochemical features may closely mimic those of collision tumors and myogenic tumors.

Understanding thermoregulation within the range of low body temperatures (Tb) in homeotherms is of special interest in various life science fields. Here, we report that mice exhibit long-lasting hypothermia induced by the administration of an A₁ adenosine receptor (A₁AR) agonist, N⁶-cyclohexyladenosine (CHA), in combination with pretreatment with bezafibrates (BZ), a peroxisome proliferator-activated receptor α (PPARα) agonist. Before the induction of hypothermia by CHA administration at a dose of 0.5 mg/kg, CBA/N mice were fed 0.5% BZ-supplemented food for 10 days at an ambient temperature of 23–24°C. Ten days after BZ treatment, intraperitoneal CHA administration induced low Tb (<33°C) lasting for 6 hr, while mice provided the control food without BZ supplementation experienced low Tb lasting for <1 hr after CHA administration. The combined administration of these drugs also marked decreased oxygen consumption, carbon dioxide output, and energy expenditure compared with those in control mice that received CHA injections alone. These findings demonstrate that BZ-induced PPARα activation enhanced the sensitivity of A₁AR, thereby prolonging low Tb. Both receptors are considered key factors in controlling torpor and/or hibernation; however, a synergistic relationship between these receptors has not been reported. Therefore, our findings suggest that metabolic activation of lipid catabolism via PPARα signaling may potentiate the hypothermic effects induced by A₁AR activation.

Anorexia in dairy cows arises from diverse causes, including metabolic disorders with and without hypocalcemia. We analyzed the serum metabolites of 21 clinical anorectic cows using two-dimensional gas chromatography coupled with mass spectrometry to determine if the serum metabolome varies across the continuum of total calcium (tCa) in anorectic cows. We tested associations between tCa and the 1,645 detected metabolites by using rank-based partial Spearman correlations, adjusting for age and days in milk. A composite fingerprint derived from the 24 metabolites traced tCa (ρ= −0.773, P=0.0004). A metabolomic fingerprint associated with serum calcium levels could provide new insights into the transition from threshold thinking to continuous exploratory physiology in dairy cows.

In Japan, sustainable national antimicrobial resistance (AMR) monitoring has been established in both human and veterinary fields. However, AMR monitoring in the environment, including wildlife, remains limited. This study aimed to assess the possibility of sustainable monitoring using wild deer transported to slaughterhouses and wild foxes surveyed for Echinococcus multilocularis. Escherichia coli, a common AMR indicator bacterium, was isolated from rectal swabs of deer and foxes using Chromagar ECC, with and without antimicrobials (cefotaxime (CTX) or nalidixic acid (NA). Antimicrobial susceptibility was determined, and β-lactamase genes were detected using polymerase chain reaction. Plasmids carrying β-lactamase genes were analyzed by whole-genome sequencing. A total of 104 E. coli strains were isolated from (103/120, 85.8%) deer and 61 strains from (56/99, 56.6%) foxes using medium without antimicrobials. Using a medium containing CTX and NA, two and three strains were isolated, respectively, exclusively from foxes. All deer strains were susceptible to the tested antimicrobials. However, 0–11.5% of fox strains from medium without antimicrobials (n=61) demonstrated resistance. Three strains from foxes had β-lactamase genes in plasmid. Finally, this study demonstrates the feasibility of sustainable AMR monitoring using wild deer transported to a slaughterhouse and wild foxes surveyed for E. multilocularis.

Phase 1 aimed to validate an ultrasound-guided approach for a lumbosacral trunk blockade proximal to the cranial gluteal nerve using cadavers. In Phase 2, sympathetic responses were evaluated for nociception detection through electrical stimulation of the deep gluteal muscles in living dogs. In Phase 1, 0.1% methylene blue (0.2 mL kg⁻¹) was injected alongside the lumbosacral trunk in the bilateral pelvic limbs of three adult cadavers. The median length of the stained lumbosacral trunk proximal to the cranial gluteal nerve was 16 mm. Cranial gluteal nerves were stained in all pelvic limbs. In Phase 2, under general anesthesia, ten healthy adult beagle dogs received injections of 0.5% bupivacaine (0.2 mL kg⁻¹) in one limb and saline (0.2 mL kg⁻¹) in the contralateral limb in a blinded, randomized fashion, following the Phase 1 methodology. Percutaneous electrical stimulation of the deep gluteal muscles was performed before, 15 min, and 60 min after administering 0.5% bupivacaine. Suppression of sympathetic response was defined as <10% increase in heart rate (HR) and mean arterial blood pressure (MAP) following electrical stimulation. Differences in relative changes of HR and MAP were analyzed using the Kruskal-Wallis and Dunn’s multiple comparison tests. After 0.5% bupivacaine injection, the sympathetic response to electrical stimulation of the deep gluteal muscles was suppressed. Ultrasound-guided, lumbosacral trunk blockade proximal to the cranial gluteal nerve inhibits the sympathetic response to deep gluteal muscle stimulation.

We retrospectively investigated the opioid-sparing effect of the oblique subcostal transversus abdominis plane (SCTAP) block with bupivacaine in dogs undergoing open hepatectomy via the Mercedes incision. Remifentanil was used for intraoperative analgesia. The SCTAP block was performed using 0.125% bupivacaine in the TAP group, and dogs that did not receive the nerve block were assigned to the control group. The remifentanil dose was significantly lower in the TAP group than in the control group. The number of dogs that received fentanyl as rescue analgesia was significantly lower in the TAP group than in the control group. The ultrasound-guided SCTAP block with bupivacaine may substantially reduce the intraoperative dose of opioid analgesics in dogs undergoing open hepatectomy via the Mercedes incision.

A female Holstein calf presented with clinical respiratory signs induced by a laryngeal mass, with an antemortem diagnosis of coronary artery fistula based on echocardiography and computed tomography. After surgical treatment, pathological examination of the mass revealed positive staining for Glut1 consistent with infantile hemangioma in humans. This was a rare case of an infantile hemangioma developing concurrently with a coronary artery fistula. To comprehensively investigate the genetic mutations involved in this concurrent occurrence, whole-genome DNA sequencing using next-generation sequencers was performed. Genetic analysis identified mutations in the VEGFA, NOTCH2, IHH, and PDGFβ genes, which might have contributed to the concurrent occurrence of infantile hemangioma and coronary artery fistula in this case.

A 6-year-old intact male French Bulldog presented with a 5-day history of vomiting. Radiographs revealed a round soft tissue mass in the right caudal thoracic cavity with tubular structures suggestive of small intestinal herniation through the diaphragm. Ultrasonography confirmed herniation of fluid-filled small intestinal loops and hepatic lobes positioned cranial to the diaphragm. Computed tomography (CT) revealed herniation of the involved organs through a dilated caval foramen and secondary caudal vena cava compression, consistent with Budd–Chiari-like syndrome resulting from venous outflow obstruction. Laparotomy confirmed strangulation of herniated organs, necessitating partial hepatectomy and segmental enterectomy. This case highlights the potential for small intestinal involvement in caval foramen hernia and underscores the diagnostic value of CT in assessing associated vascular compromise.

Neonicotinoids (NNs) are commonly used insecticides; however, their biotransformation in wild mammals remains poorly understood. Asian elephants, which are declining in numbers, may be vulnerable to these chemicals. In this study, we examined the liver metabolism of four major NNs: acetamiprid, imidacloprid, thiamethoxam, and clothianidin, using elephant liver microsomes. Metabolite profiling and targeted analysis were conducted with liquid chromatography quadrupole time-of-flight mass spectrometry and liquid chromatography tandem mass spectrometer, respectively. Results indicated that elephants mainly metabolize these NNs via reductive pathways, suggesting the involvement of nitroreductase-like enzymes. Conversely, cytochrome P450-mediated oxidation may be limited; however, the roles of other enzymatic or microbial systems cannot be ruled out. These findings provide insights into xenobiotic metabolism in elephants, helping evaluate their toxicological vulnerability and supporting conservation efforts and risk assessments.

Most members of the genus Gammacoronavirus infect avian hosts, but far fewer viruses have been characterized than in the other coronavirus genera, leaving their diversity largely unclear. Pigeon gammacoronaviruses were previously detected by consensus PCR, but only partial sequences were determined. In this study, we comprehensively analyzed public RNA-seq datasets and reconstructed two nearly complete genomes of pigeon gammacoronaviruses. Molecular evolutionary analyses showed pigeon gammacoronaviruses belong to the subgenus Igacovirus, and their pairwise distances to the members of this subgenus meet the International Committee on Taxonomy of Viruses (ICTV) species demarcation criteria, supporting their designation as a novel species in this subgenus. Notably, although nucleotide sequences are highly conserved among pigeon coronavirus variants, their 3’-genomic region exhibited differences in genome organization. These findings expand our knowledge of the diversity of gammacoronaviruses.

Influenza D virus (IDV) is an emerging pathogen associated with bovine respiratory disease complex. To update the epidemiological status of IDV in Hokkaido, Japan, we tested 73 serum samples collected in 2023 from cattle with respiratory disease or diarrhea. Hemagglutination inhibition (HI) assays were performed using three IDV strains representing distinct phylogenetic clades: D/swine/Oklahoma/1334/2011, D/bovine/Yamagata/10710/2016 (Y16), and D/bovine/Yamagata/1/2019 (Y19). Overall, 34 of the 73 samples (46.6%) were seropositive. Antibodies against Y16 were detected most frequently (42.5%), whereas the highest mean HI titers were observed against Y19 among the three strains. These results indicate that IDVs belonging to both the Y16- and Y19-lineages are circulating among cattle in Hokkaido, consistent with previous epidemiological findings.

We describe a case of scrotal hernia in an aging, vasectomized male doguera baboon with diabetes mellitus. The animal presented with anorexia and collapsed and was diagnosed with severe hyperglycemia. Despite the initiation of insulin therapy, its condition progressively deteriorated, finally culminating in death. Necropsy revealed a large scrotal hernia containing a necrotic and perforated segment of the small intestine. Histopathological examination demonstrated amyloid deposition within the pancreatic islets and glomerulosclerosis, consistent with chronic diabetes mellitus. This case highlights the occurrence of a scrotal hernia associated with diabetes in a non-human primate, and suggests that, as in humans, diabetes may serve as a risk factor for hernia development.

A two-year-old female leopard gecko presented with a mass in the oral cavity with apparent exophthalmos. Despite medical management, the animal died. Grossly, the firm and tan to white mass extended from the oropharyngeal region to the external surface overlying the cornea of the left eye. Histologically, the mass was a poorly-demarcated, densely cellular, invasive neoplasm. The neoplasm was composed of solid sheets and interlacing bundles of round, polygonal, and short spindle-shaped cells. Immunohistochemically, the neoplastic cells were positive for Iba-1 and CD204. These findings were consistent with a localized histiocytic sarcoma. This is the first documentation of the gross, histopathological, and immunohistochemical features of localized histiocytic sarcoma in a leopard gecko.