Journal of Veterinary Medical Science最新文献

Cutaneous plasmacytosis (CP) is a rare condition characterized by multiple cutaneous plasmacytomas without multiple myeloma. While no pruritus or spontaneous regression occurs in typical CP, the clinical behavior is limitedly understood due to its low incidence. This case report describes atypical cases of CP. Case 1 had skin nodules on the face and limbs and pruritus, whose pruritus kept progressing. After the diagnosis of CP, the dog died on Day 170 despite the treatment with prednisolone and melphalan since Day 157. Case 2 had multiple skin nodules on the back and abdomen. After the skin biopsy, the nodules regressed without treatment on Day 28. These cases suggest the variation of CP's clinical behavior, which helps further understand the disease.

Bovine adenovirus type 10 (BAdV-10) was isolated for the first time in Japan from a calf with severe hemorrhagic diarrhea at a farm in Gifu Prefecture. Histopathologically, lesions were mainly in the colon, with pseudomembrane formation accompanied by extensive fibrosis and viral inclusion bodies in the nuclei of vascular endothelial cells. The isolated virus showed cytopathic effect in bovine testicular cells and was genetically confirmed to be BAdV-10. Although the BAdV-10 gene was not detected in the rectal stools of cohabiting calves, an increase in antibody titers was observed. Involvement of BAdV-10 in lesion formation was suspected, but extensive fibrosis was not reported overseas. Further investigation is needed to clarify the prevalence and epidemiological significance of BAdV-10 in Japan.

Influenza D virus (IDV), a respiratory pathogen primarily affecting cattle, is known to have the potential to infect a wide range of animal species. In this study, a novel IDV strain, designated D/JLSL and belonging to the D/Yama2019 lineage, was isolated from a stillborn bovine fetus. Phylogenetic analysis revealed that all 7 genomic segments of the D/JLSL cluster within the D/Yama2019 lineage. Notably, the hemagglutinin-esterase-fusion (HEF) protein of D/JLSL exhibits 7 amino acid substitutions compared with the 3 previously characterized D/Yama2019 strains. These findings suggest that D/JLSL may represent a distinct variant within the D/Yama2019 lineage. This study marks the first identification and genetic characterization of IDV from the D/Yama2019 lineage in a stillborn bovine fetus, highlighting the need for further surveillance to elucidate its prevalence and biological properties.

A 6-month-old female toy poodle, weighing 2.15 kg, presented with acute vomiting and lethargy after ingesting ibuprofen. Hemoperfusion was performed using an extracorporeal blood purification cartridge, comprising polystyrene-divinylbenzene copolymer beads, connected to a hemodialysis platform as a pre-dialyzer. Serum ibuprofen concentration, measured using high-performance liquid chromatography, was 61.9 mg/L before therapy. The ibuprofen concentrations gradually decreased, reaching 20.5 mg/L after 2 hr (66.8% reduction; half-life of 1.4 hr). The dog showed significant improvement in vitality and recovered fully without further extracorporeal treatment. This case is the first documented instance of successfully treating ibuprofen intoxication in a small dog using hemoperfusion with a blood purification cartridge specifically designed for small animals.

Ticks are major public health vectors that rely on long-term extravascular feeding, a process critically dependent on establishing a subcutaneous blood pool. While tick salivary molecules suppress host hemostasis and immunity, the precise mechanism by which vascular integrity is compromised to sustain massive hemorrhage in the deep dermis, outside the tick hypostome's reach, remains a longstanding enigma. Using time-series pathological and multiplex immunohistochemical analyses in a mouse model infected with Haemaphysalis longicornis tick, we redefined the blood pool not as a cystic reservoir, but as a severe inflammatory lesion characterized by massive, diffuse extravasation of red blood cells. We observed that ticks induce pathological angiogenesis, forming fragile microvessels. Crucially, the formation of neutrophil extracellular traps (NETs), known as NETosis surged in clustering neutrophils on Day 3 of feeding, coinciding with the transition to massive hemorrhage. Furthermore, extravasated platelets co-localized with NETs in the hemorrhagic tissue. We propose a sophisticated parasitic strategy, whereby the tick hijacks host immunothrombosis to mediate massive hemorrhage. The dysregulated interaction between NETs and platelets drives a vicious inflammatory cycle, which destroys the fragile, newly formed vasculature and extracellular matrix. This process establishes a blood-soaked, sponge-like stroma, which the tick exploits for efficient blood intake. Our findings redefine the fundamental mechanism of tick feeding success.

Equine rhinitis B virus (ERBV), a member of the Picornaviridae family, is associated with mild to moderate respiratory illness in horses, yet its genomic diversity remains incompletely characterized. In this study, we performed metagenomic analysis on a rectal swab sample from a diarrheic foal confirmed to be positive for rotavirus A. Unexpectedly, we identified a highly divergent ERBV strain with a 9,448-nucleotide genome encoding a 2,721-amino-acid polyprotein. Sequence analysis revealed only 62.5-63.1% identity in the polyprotein and 47.1-49.8% in the VP1 region compared to known ERBV serotypes, suggesting a novel genotype. The genome exhibited typical picornavirus features, including a type II internal ribosome entry site (IRES), but also unique elements such as an 87-amino-acid insertion in the leader proteinase region and atypical cleavage motifs. A strain-specific RT-qPCR assay was developed alongside a broadly reactive assay targeting ERBV1-3. Screening of 37 rectal swab samples from horses revealed a 10.8% positivity rate using the new assay, with clustered cases from the same farm in 2022 and an additional case in 2024. No samples were positive using the broad-range primers, indicating potential gaps in surveillance. These findings highlight the importance of metagenomics in pathogen discovery and underscore the need for updated molecular tools to monitor genetically distinct ERBV strains and assess their clinical significance.

Surgical treatment options for feline ureteral obstruction are lacking. Based on its use in human medicine, tamsulosin may be a promising candidate. We have accumulated evidence of its extra-label use at our hospital in cases where surgery was declined by the owner. Accordingly, in this single-center, retrospective study, we investigated the responses to tamsulosin in patients with multi-causal feline ureteral obstruction by determining response rates and evaluating the demographic and clinicopathological characteristics of responders. Cats were classified as responders if they showed complete or partial hydronephrosis remission (renal pelvic diameter <50% of the presentation value). We evaluated 62 cats, of which 32 had ureteral calculi (51.6%) and 30 (48.4%) did not. All cats had received 50 μg oral tamsulosin once daily as initial treatment. A total of 30/62 (48.4%) cats were defined as responders, and the response rates were similar irrespective of the presence or absence of ureteral calculi. Body weight was significantly higher in responders than in non-responders. Adverse drug reactions were rare, mild, reversible, and did not include hypotension. The response rate we report for tamsulosin may be of interest to clinicians considering its use in combination therapy where surgery is declined or delayed and for future research on feline ureteral obstruction.

Bovine mastitis is an inflammatory disease of the udder caused by pathogen infection. In case of aerobic cultivation, 30% of milk samples have nonbacterial; this may relate to anaerobic bacteria, although this remains unclear. This study analyzed 173 mastitis milk samples collected via aerobic and anaerobic cultivation. The detection rate by anaerobic culture was significantly higher (P<0.01; 136 samples: 78.6%) than that by aerobic culture (125 samples: 72.3%). Furthermore, the detection rates of Streptococcus dysgalactiae, Streptococcus uberis, and Trueperella pyogenes were higher in anaerobic than aerobic culture. Clostridium perfringens was detected one sample (0.61%) and Fusobacterium necrophorum in two samples (1.22%) were detected. Overall, these findings indicated the value of anaerobic culture for detecting the causative bacteria of mastitis.

ELISA antibody titers against Rhodococcus equi strain ATCC 6939 were measured in serum samples collected from 644 horses aged 1-21 years at 13 provinces and the capital of Mongolia, of which 631 (98%) samples showed values of approximately zero. The mean antibody titers in the 14 areas ranged from -0.08 to -0.01. Nine samples (1.4%) exhibited titers of 0.1-0.2, and surprisingly, four horses (0.6%) each aged 2, 5, 8, and 9 years demonstrated positive values in the range of 0.3-0.8. Considering the age resistance characteristic of this disease, the positive horses were hypothesized to exhibit nonspecific reactions against R. equi antigens, potentially attributable to underlying infections, such as Corynebacterium pseudotuberculosis infection, or others as unidentified factors. Further investigation of these positive sera could potentially reveal previously unknown infectious diseases.

Aortic thrombotic disease occurs in both dogs and cats. In dogs, it typically presents as aortic thrombosis (ATh), whereas in cats, it most commonly manifests as aortic thromboembolism (ATE). Canine ATh is rare, with no standardized treatment. Rivaroxaban, a direct factor Xa inhibitor, is increasingly used in veterinary medicine. Recently, the efficacy of dual antithrombotic therapy with clopidogrel and rivaroxaban in feline ATE has been suggested. Here, we report two canine ATh cases. Clopidogrel monotherapy was insufficient, but adding rivaroxaban improved gait, relieved pain, and reduced thrombus size on ultrasonography. This combination therapy may be effective for canine ATh, as has been suggested for feline ATE. Further case studies are needed to evaluate the efficacy of rivaroxaban for canine ATh.