Journal of Veterinary Science最新文献

Importance: Canine distemper virus (CDV) has a broad host range, spanning mammals of the order Carnivora and other orders, often proving fatal. The detection of CDV in a Malayan tiger (Panthera tigris jacksoni) in Malaysia in 2019 marks the first such case diagnosed in Malayan tigers, suggesting possible exposure from domestic animals or wildlife reservoirs.

Objective: This study aims to describe histological manifestations and characterise the CDV strain in the tiger to determine its molecular epidemiology and postulate viral pathogenicity.

Methods: Histopathology characterisation of the infected tissues were performed through haematoxylin and eosin and immunohistochemistry staining, respectively. We conducted virus isolation and titration in Chinese hamster ovarian expressing the dog signalling lymphocytic activation molecule (CHO-SLAM) cells. Reverse transcription polymerase chain reaction was performed to confirm the presence of CDV RNA, nucleotide and amino acid sequence analyses for comprehensive characterisation of the CDV strain.

Results: Notable histopathological changes were observed primarily in the brain, lung, liver, kidney, spleen, and stomach, with viral antigens localised in the lung, liver, kidney, and stomach tissues. CDV-induced cell cytopathic effects yielding 4.27 × 10⁶ TCID₅₀/mL were observed at 48 h post-inoculation in CHO-SLAM cells. Phylogenetic analysis suggested that the virus originated from the Asia-1 clade. Notably, 549H and 519I mutations in the hemagglutinin protein were observed, indicating adaptation to a non-canid wildlife species.

Conclusions and relevance: Overall, this study enhances our understanding of the molecular characterisation and evolutionary dynamics of the CDV strain present in the Malayan tiger and serves as a benchmark for developing effective preventative measures to protect Malayan tigers and mitigate their risk of extinction.

Importance: With a growing companion animal population and their extended lifespans in South Korea, the need for health examinations tailored to specific life stages is increasing. However, an objective standard for defining these life stages is currently lacking.

Objective: To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs.

Methods: We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages. The 10 most highest-proportion diagnoses diseases were determined for each cluster.

Results: Canine life stages were classified as ≤ 1 year, 2-5 years, 6-10 years, and 11-15+ years. Feline life stages were 1-2 years, 3-8 years, 9-12 years, and 13-15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age.

Conclusions and relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.

Importance: Fulvic acid can protect liver tissue against amoxicillin-clavulanate-induced hepatotoxicity through antioxidant and antiapoptotic effects.

Objective: To evaluate the protective effects of fulvic acid against amoxicillin-clavulanate-induced hepatotoxicity using biochemical, histopathological, immunohistochemical, functional, and bioinformatic analyses.

Methods: Twenty-eight male Wistar rats were randomly assigned to 4 groups (n = 7/group): sham (saline), amoxicillin-clavulanate (10 mg/kg/day), fulvic acid (100 mg/kg/day), and combined treatment. Treatments were administered orally for 21 days. Liver injury and oxidative stress were assessed by serum alanine aminotransferase, aspartate aminotransferase, malondialdehyde, total antioxidant status, and total oxidant status; tissue injury was assessed histologically. Apoptosis was evaluated by immunohistochemistry for BAX and BCL2. Hepatic detoxification capacity was assessed by a caffeine clearance test. In silico analyses predicted molecular targets of fulvic acid and enriched pathways.

Results: Amoxicillin-clavulanate increased transaminases, oxidative stress markers, and proapoptotic signaling and induced vascular congestion and sinusoidal dilatation. Co-treatment with fulvic acid improved serum biomarkers, reduced histological injury, downregulated BAX, and restored BCL2 staining intensity. In silico analysis identified predicted fulvic-acid targets enriched in metabolic and proliferation-related pathways.

Conclusions and relevance: Fulvic acid attenuated amoxicillin-clavulanate-induced hepatotoxicity, consistent with antioxidant and antiapoptotic mechanisms. Further studies are warranted to define dose-response relationships and translational potential.

Importance: Lower peak kilovoltage (kVp) can reduce radiation dose and increase iodine conspicuity, but veterinary CT protocols integrating kVp reduction with iodine-dose reduction are not well defined.

Objective: To evaluate the effects of reduced kVp and reduced iodinated contrast volume on radiation dose and image quality in canine abdominal CT.

Methods: A phantom study (0%-10% iodine dilutions) at 120, 100, and 80 kVp quantified the relationship between iodine concentration and CT attenuation. Eight healthy Beagle dogs underwent multiphase abdominal CT at 120, 100, and 80 kVp (1-week intervals) with weight-based contrast volumes adjusted using phantom-derived slope ratios. Radiation output (CTDI_vol, dose-length product) and quantitative image quality (attenuation, background noise, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) were assessed, along with blinded qualitative scoring by 2 readers.

Results: Compared with 120 kVp, CTDI_vol decreased by 41% at 100 kVp and 74% at 80 kVp, with similar proportional decreases in dose-length product. Lower kVp increased iodine-related attenuation, permitting iodine-dose reductions (17% at 100 kVp; 34% at 80 kVp). Quantitative noise increased and SNR decreased at 80 kVp, particularly in delayed-phase images; qualitative noise scores were significantly worse at 80 kVp, whereas overall qualitative image quality did not differ across protocols.

Conclusions and relevance: In dogs, a 100 kVp protocol reduced radiation output and iodine dose while maintaining diagnostic image quality, supporting 100 kVp as a practical optimization strategy for clinical abdominal CT.

Importance: The vomeronasal organ (VNO), a component of the accessory olfactory system, plays a critical role in pheromone detection in mammals and contributes to a wide range of behaviors, including reproduction and social communication. Pigs have emerged as an important species both in industry and research. To elucidate the VNO in domestic animals, this review summarizes the anatomical, histological, developmental, and pathological characteristics of the porcine vomeronasal system, with particular attention to its role during development and under inflammatory conditions.

Observations: The literature indicates that the porcine VNO, encased by vomeronasal cartilages, is located at the base of the nasal septum in the form of blind-ended tubes. Olfactory marker protein is clearly detected in receptor cells at the fetal stage, indicating that the VNO is functional. The morphological features of the pig VNO are like those of other ungulates, such as goats. Notably, molecular findings imply that the pheromone receptor repertoire is less extensive in pigs than in rodents. In addition, under certain environmental conditions and with aging, inflammatory responses may occur in the porcine VNO, potentially leading to pheromone perception dysfunction.

Conclusions and relevance: Collectively, these observations underscore the importance of the VNO, not merely as an accessory olfactory system but as a central organ that links environmental conditions, endocrine regulation, and reproductive performance. This highlights its relevance in clinical diagnostics and welfare-oriented livestock management.

Importance: Platelet-rich plasma (PRP) is widely used in clinical and research applications due to its abundant growth factors and cytokines. However, the lack of a standardized method for PRP preparation results in variability in platelet yield, leukocyte carryover, and function.

Objective: To identify centrifugation parameters that maximize platelet recovery while preserving function in canine PRP.

Methods: Whole blood from 10 healthy dogs was processed by single-spin (10 min at 800, 1,200, 1,500, or 2,000 rpm) or dual-spin (two-time immediate sequential repetition of the same centrifugation speed for 5 min) using a fixed-angle rotor (radius = 15 cm; 1,500 rpm = 364 × g equivalent). Platelet recovery and white blood cell (WBC) contamination were quantified, and platelet aggregation and dense-granule secretion (2-MeSADP, thrombin), thromboxane (Tx) A₂ generation (TxB₂ enzyme-linked immunosorbent assay [ELISA]), protein kinase B (AKT)/extracellular signal-regulated kinase (ERK) phosphorylation (immunoblot), and platelet-derived growth factor (PDGF)-BB release (ELISA) were measured.

Results: Among single-spin conditions, PRP obtained at 1,500 rpm/10 min yielded the highest platelet recovery (≈25.1%) with < 1% WBC carryover. This PRP exhibited maximum 2-MeSADP- and thrombin-induced platelet aggregation and secretion, TxA₂ generation, AKT/ERK phosphorylation, and PDGF-BB release, suggesting that optimizing the centrifugal speed is crucial for achieving the optimal PRP collection with the utmost platelet function. Compared with the optimal single-spin condition, dual-spin at 1,500 rpm/5+5 min further increased platelet recovery (≈48.7%) and enhanced functional readouts.

Conclusions and relevance: A dual-spin at 1,500 rpm/5+5 min protocol produces leukocyte-poor PRP with superior platelet recovery and function in dogs, supporting more effective and reproducible clinical and research applications.

Importance: The quadratus lumborum block (QLB) may provide locoregional analgesia of the trunk.

Objective: To investigate the feasibility of 2 ultrasound-guided QLB approaches - lateral (QLB-L) and transmuscular (QLB-T) - in calf cadavers.

Methods: Ten calf cadavers underwent bilateral QLB at L1 using QLB-L (n = 5) or QLB-T (n = 5). Each cadaver received 0.4 mL/kg on one side and 0.6 mL/kg on the other. A 1:2 iohexol:methylene blue mixture was injected under ultrasound guidance. Computed tomography and gross dissection assessed craniocaudal spread and staining of ventral rami and sympathetic trunk segments.

Results: The number of stained nerves was similar for both approaches. L1 and L2 were stained in all injections; T13 was stained in all but 1 QLB-L small-volume injection; T12 staining occurred most often with QLB-T small-volume injections (4/5) and in 2/5 injections in the remaining groups; T11 staining was limited (1/5 QLB-L and 2/5 QLB-T; both volumes); T10 to T4 staining occurred once (QLB-T large volume).

Conclusions and relevance: Both approaches were anatomically feasible in calf cadavers and produced injectate spread consistent with potential abdominal wall target coverage. Clinical trials are needed to determine analgesic efficacy and safety.

Importance: Foot diseases are common causes of lameness in horses. Computed tomography (CT) is a valuable tool for diagnosing musculoskeletal lesions in horses and providing a detailed evaluation of foot diseases.

Objective: The objective of this study was to establish reference ranges related to the feet of normal Jeju horses by measuring the angles and length of the hoof, and the Hounsfield Unit (HU) value of soft tissues in the foot.

Methods: Sixteen normal Jeju horses (mean age: 4.25 years; mean body weight: 282.06 kg) without lameness were examined using CT. After CT scanning, the angles and lengths of the hoof, such as hoof width and dorsal hoof wall angle, and the HU values of the soft tissues, such as the deep digital flexor tendon, were measured.

Results: We identified significant differences in the HU values of overall soft tissues between the forelimbs and hindlimbs, and between the medial and lateral parts (p < 0.05). Length measurements showed no differences between left and right limbs or between medial and lateral parts, but significant fore-hind differences were found in most parameters (p < 0.05). Angle measurements revealed significant differences between left and right limbs and between fore- and hindlimbs, with an additional medial-lateral difference in the left hindlimb (p < 0.05).

Conclusions and relevance: The CT-based reference values established in this study provide valuable breed-specific data that may support assessment of hoof conformation and interpretation of CT findings in Jeju horses.

Importance: Pasteurella multocida is a Gram-negative bacterium commonly present in the oropharyngeal microbiota of many animals. In pigs, it contributes to progressive atrophic rhinitis and the porcine respiratory disease complex, both associated with major economic losses.

Objective: This study performed a longitudinal molecular characterization of P. multocida isolates from pigs with respiratory lesions in South Korea (2016-2023), including subspecies identification, capsular serogrouping, virulence gene profiling, and multilocus sequence typing (MLST).

Methods: A total of 1,358 pneumonic lung samples were collected from 960 pig farms between 2016 and 2023, yielding 169 P. multocida isolates. Subspecies were assigned by 16S rRNA gene sequencing. Capsular serogroups were determined using multiplex Virulence genes (pfhA, hgbB, tbpA, and toxA) were detected by PCR assays. MLST was conducted using the RIRDC scheme, and phylogenetic analysis of concatenated loci assessed clonal relationships.

Results: Serogroup A predominated (109/169, 64.5%), followed by D (47/169, 27.8%) and B (3/169, 1.8%). Serogroups F and A/D were each detected once (0.6%), and 8 isolates were untypable (4.7%). Co-detection of hgbB and pfhA occurred in multiple isolates. Notably, two serogroup B isolates carried both genes, representing the first such finding in Korea and suggesting enhanced virulence potential. MLST identified 5 clonal complexes and 15 sequence types, including ST9 linked to serogroup B.

Conclusions and relevance: The emergence of serogroup B/ST9 isolates co-harboring hgbB and pfhA highlights evolving virulence patterns in Korean swine and supports continued molecular and genomic surveillance to guide control strategies and reduce health risks.

Importance: Airborne bacteria contribute to environmental hygiene challenges and may increase infection risk in veterinary hospitals.

Objective: To evaluate the efficacy of a high-pressure spray disinfection system using neutral electrolyzed water to reduce airborne bacterial concentrations in veterinary hospitals and to characterize clinically relevant airborne pathogens and antimicrobial resistance.

Methods: Active air sampling was performed before and after disinfection in multiple room types across five small animal hospitals in South Korea. Total airborne bacterial concentrations were quantified as colony-forming units per cubic meter. Representative colonies were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, with confirmatory sequencing for selected isolates. Susceptibility testing was performed for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species using disk diffusion.

Results: Mean airborne bacterial concentrations decreased from 358.2 to 150.6 colony-forming units per cubic meter (58% reduction; p < 0.05). Waiting rooms showed the highest pre-disinfection concentrations, and operating rooms the lowest. Among 848 isolates, Micrococcus luteus, staphylococci, and Bacillus species were most frequent. Eight isolates were clinically important pathogens; two met multidrug resistance criteria. No targeted pathogens were detected after disinfection.

Conclusions and relevance: High-pressure neutral electrolyzed water spraying significantly reduced airborne bacterial loads in veterinary clinical environments, supporting routine air disinfection and microbial surveillance as components of infection prevention programs.