农林科学最新文献

Canine phaeochromocytomas (PCCs) are neuroendocrine tumours with malignant potential. Metastatic disease remains the sole definitive evidence of malignancy. Histopathological criteria to predict long-term survival have not been established in dogs. This study evaluated the reproducibility and prognostic value of histopathological parameters derived from human scoring systems, along with the Ki67 proliferation index (PI), in dogs after adrenalectomy for PCC. Tumour samples from 41 dogs were assessed by a veterinary pathologist and pathology resident. Of 10 histopathological parameters examined, only necrosis, tumour cell spindling, and extension into adipose tissue achieved sufficient inter- and intra-observer agreement (≥ 0.40) for inclusion in survival analyses, while Ki67 PI demonstrated excellent reproducibility (≥ 0.95). A composite histopathological score was generated by summing these three parameters and a dichotomised Ki67 PI (optimal cutoff 18%), as determined by ROC analysis. Among the 41 dogs, eight died within 2 weeks postoperatively, leaving 33 long-term survivors with four tumour-related events. Kaplan-Meier analysis showed significantly poorer survival (p < 0.001) in dogs with a high Ki67 PI (≥ 18%), whereas the composite score showed a borderline significant association with outcome in Cox regression (p = 0.056; hazard ratio 2.80). Overall, dogs surviving the immediate postoperative period demonstrated a favourable prognosis (mean overall survival of 2456 days). These findings suggest that, in this cohort with few tumour-related events, the dichotomised Ki67 PI alone may serve as a clinically applicable prognosticator for canine PCC. However, further research in larger populations is needed to determine whether a composite score adds prognostic value and guides postoperative management.

Canine lymphoma is a common haematopoietic neoplasm. Immunophenotype is a major prognostic factor and may influence treatment recommendations. This study assessed the diagnostic performance of the Sysmex XN-1000V white blood cell differential (WDF) scattergram to differentiate canine nodal large B-cell and T-cell lymphoma, using the percentage of highly fluorescent cells (%HFC) and visual WDF scattergram evaluation. A retrospective study was conducted on data from cases of cytologically diagnosed canine large cell lymphoma. Cases had concurrent lymph node aspirate cell suspensions in saline that were analysed using the Sysmex XN-1000V and multiparametric flow cytometry (FC) for lymphoma classification as B or T-cell. Large B-cell lymphomas (n = 86) showed significantly higher %HFC compared to large T-cell lymphomas (n = 17), with a median (IQR) of 50% (36-84) and 9.7% (3.9-19), respectively. The ROC analysis showed an AUC of 0.93, with an optimal cutoff of < 24.15 %HFC for identifying T-cell lymphoma, achieving 88.24% sensitivity, 87.21% specificity, 57.69% PPV and 97.40% NPV. The following data is expressed as 'overall-percentage-agreement (kappa value)'. Using the previous cutoff, the agreement between the %HFC classification and FC was 88.24% (κ = 0.76). Regarding the WDF scattergram evaluation, the intra- and inter-observer agreement were 86.27% (κ = 0.71) and 67.65% (κ = 0.55), respectively. Agreement between the WDF scattergram evaluation and FC was 77.45% (κ = 0.55), and improved to 90.63% (κ = 0.74) when just the confident cases were used. In conclusion, a preliminary assessment of the phenotype of canine nodal large cell lymphoma can be made using either the visual inspection of the WDF scattergram or the %HFC. This could serve as a cost-effective, fast screening tool while awaiting definitive flow cytometry results.

Stereotactic body radiation therapy (SBRT) has become a non-invasive alternative option for canine adrenal tumours with high surgical risks; however, its clinical benefits and risks are still to be fully understood. The goal of this multi-institutional retrospective study was to describe the clinical outcome and safety of SBRT for the treatment of 21 dogs with adrenal tumours. Ten were suspected pheochromocytomas, two adenocarcinomas, and the diagnosis was unknown in nine dogs. Vascular invasion was present in 81% of cases (17/21). Thirteen dogs received 3 fractions of 6 to 11 Gy, 7 received 5 fractions of 6 to 9 Gy, and 1 received 4 fractions of 6 Gy. For the 20 patients with follow-up imaging, 9 (43%) had partial response, 10 (47%) stable disease, and 1 (5%) progressive disease. Progression-free survival was 16.8 months (95% CI: 3.4-23), and overall survival time was 16.8 months (95% CI: 3.7-23.7). Twelve patients (57%) experienced acute adverse events (AEs); of those, seven were gastrointestinal grade ≥ III, including one grade V. Late AEs were suspected in seven dogs (33%), including gastrointestinal grade V in four of them. A total of five dogs (24%) died from radiation-related toxicities. Although SBRT seems to be effective against adrenal tumours, it was associated with a high morbidity and mortality rate, suggesting that re-evaluation of radiation therapy protocols is necessary for maintaining patient safety.

Case history: In a 520-cow, spring-calving, pasture-based Waikato dairy farm, the bulk milk somatic cell count (SCC) increased by approximately 20% from 203,000 cells/mL in the 2020/21 season to 245,000 cells/mL in the 2021/22 season. Analysis of herd test SCC data found that the incidence of intramammary infection increased more than 10-fold from 1.8 to 19.2 cows/30 days at the March 2021 and March 2022 herd tests, respectively.

Laboratory findings: Milk sampling of all quarters of 43 cows with a SCC > 200,000 cells/mL following herd testing in March 2022, identified 12 quarters from 10 cows infected with Staphylococcus aureus. Antimicrobial sensitivity testing by disc diffusion testing found nine of these isolates (from seven cows) were methicillin resistant.

Diagnosis: Whole genome sequencing demonstrated the presence of mecA, a gene encoding an alternative penicillin-binding protein (PBP2a) associated with methicillin-resistant Staph. aureus (MRSA). These isolates were sequence type 5, spa type t002, and all were carrying one or more of the immune human immune evasion cluster genes, scn, chp, sak and sea.

Conclusions: Due to concerns for public safety, the Ministry for Primary Industries, the milk processor and the farm's staff were notified. A comprehensive management plan was implemented which focused on reducing the risk of human exposure by wearing gloves, discouraging consumption of raw milk, and smoking or eating in the milking parlour, alongside measures designed to minimise cow-to-cow transmission such as improving teat spray application, milking machine maintenance, additional sampling, and segregation of likely infected (that is, high SCC and confirmed presence of Staph. aureus) cows. Implementation of the plan resulted in a significantly lower bulk milk SCC and reduced incidence rate of new infections in the subsequent two lactations. However, MRSA was isolated from cows for at least a further 13 months, with some cows remaining infected this entire period despite having been treated with cloxacillin-based antimicrobials at the end of lactation. One staff member had a history of being hospitalised during 2021/22 for significant soft tissue infections.

Clinical relevance: Given the sequence type, spa type, and presence of the immune evasion cluster genes, it is probable that the MRSA was introduced into the herd from a human. Veterinarians need to be aware of the possibility of MRSA within dairy herds and the possible human origin for these infections.

Abbreviations: BMSCC: Bulk milk somatic cell count; MRSA: Methicillin-resistant Staphylococcus aureus; NAS: Non-aureus staphylococci; PBP: Penicillin-binding protein; SCC: Somatic cell count; spa: Staphylococcal protein A; ST: Sequence type.

This case describes the diagnosis and treatment of a bilateral caudoventral temporomandibular joint (TMJ) luxation in a 7-year-old intact male Persian cat following a fall from the fourth floor of a building. The patient sustained traumatic brain injury and dental fractures. Diagnostic imaging, including intraoral radiographs and computed tomography, confirmed a bilateral caudoventral TMJ luxation. Surgical intervention was delayed for 10 days due to the patient's neurological status, limiting the chances for a successful joint reduction. A modified surgical approach facilitated precise localization of the condylar process and minimized morbidity. Postoperative outcome was favorable, with the patient resuming voluntary eating within 5 days. Timely and accurate treatment is essential for the successful restoration of joint function in feline patients suffering from traumatic dislocation of the TMJ. This is particularly critical in brachycephalic breeds, which may have a predisposition to such injuries.

Human epidermal growth factor receptor 2 (HER2) gene mutations have been reported in 5% to 38% of canine pulmonary adenocarcinomas (cPACs), most commonly as V659E mutations in exon 20. However, their prognostic and predictive significance remains unclear. This retrospective, single-centre cohort study investigated the frequency of HER2 mutations in surgically resected cPACs and their association with clinical outcomes. Between 2005 and 2021, lung masses histologically diagnosed as cPACs were collected and subjected to direct sequencing of HER2 exons 20 and 21. A total of 72 dogs were enrolled, with successful HER2 gene analysis in 69 cases. HER2 exon 20 missense mutations were identified in 20 dogs (29.0%), including 18 harbouring the previously reported V659E hotspot mutation within the transmembrane domain. Homozygous mutations were detected in 13 dogs. Univariable analysis revealed associations between progression-free interval (PFI) and clinical signs, tumour size classification, lymph node metastasis, surgical margin status, and histologic grade. Overall survival time (OST) was associated with age, clinical signs, tumour size > 7 cm, histologic subtype, lymph node metastasis, and margin status. In multivariable analysis, tumour size classification and margin status remained significantly associated with PFI, while age, tumour size > 7 cm, and histologic subtype were independently associated with OST. Notably, the presence of HER2 mutations was significantly associated with prolonged PFI in both univariable and multivariable analyses, although no significant association with OST was observed. These findings suggest that HER2 mutation status may serve as a favourable prognostic marker for disease progression in surgically resected cPACs.

Sucking lice (Anoplura) are highly specific parasites that depend extensively on their mammal hosts for survival. However, the climate to which their hosts are exposed can cause changes in their populations, independent of the protection provided by their hosts. Despite its harsh climate, arid northern Chile is home to a wide variety of rodents, particularly cricetids. This area comprises four distinct ecoregions with different sub-climates. We aimed to evaluate the spatial and seasonal variability of sucking lice (Anoplura) parasitizing rodents in northern Chile. Specifically, we analysed the association of environmental variables and host density with the louse point prevalence (P%), mean abundance (_MA) and mean infestation intensity (_MI). Rodent samples were collected during autumn and spring of 2011 and summer and winter of 2012 in 13 sites representative of the Coastal Desert (CD), Continental (Interior) Desert (ID), Andean Tropical (AT) and Pre-Andean Tropical (PAT) ecoregions. A total of 992 rodents of eight species were captured and anaesthetized, and lice were collected and identified. The P%, _MA and _MI of lice were estimated. The association of climatic variables (temperature, precipitation and relative humidity) and host density (capture success as a proxy) with louse P% and _MA was assessed using Spearman correlation and Fisher's test. Four lice species were identified based on external morphology (Hoplopleuridae: Hoplopleura aitkeni Johnson, Hoplopleura reducta Ferris, Hoplopleura sp. travassosi group; Poliplacidae: Polyplax spinulosa (Burmeister)). Hoplopleura aitkeni and H. reducta showed significant seasonal differences in P%, _MA and _MI in the AT and PAT ecoregions. In contrast, the H. sp. travassosi group showed no significant seasonal variation. Polyplax spinulosa was found exclusively on introduced rodents in the ID ecoregion, with distinct seasonal variations observed in Rattus norvegicus Berkenhout and Rattus rattus Linnaeus (Muridae). We reported 17 new host-parasite associations, and one lice species not previously described in the country. This study demonstrates that seasonal environmental variation does not equally impact all lice species, emphasizing the need for further research into the ecological and biological drivers of these dynamics.

Oral mucosal melanomas (OMMs) are the most frequent oral malignancy in dogs, often characterized by aggressive local behavior and a high metastatic rate. The mechanisms that drive canine OMM metastasis are still largely unknown, providing for limited therapeutic approaches once the disease has spread to metastatic sites. The objective of this investigation was to evaluate the differences in gene expression between canine primary OMMs and their matched nodal metastases. Transcriptional profiling of formalin-fixed, paraffin-embedded biopsies of 4 canine OMMs and their respective lymph node biopsies was performed using exon microarrays. Confirmation of the differential expression of selected genes was subsequently sought by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) on 13 paired samples (primary tumor-metastatic lymph node). Results highlight the activation of pathways associated with actin cytoskeleton organization, and cellular motility and migration. In particular, transcriptional data indicated increased expression of genes associated with Rac1 signaling-regulated cell migration, including ELMO1, VAV3, and DOCK2, in nodal metastases. Overall, the results of this investigation point to a significant role for Rac1 signaling in the pathogenesis of OMM metastasis to regional lymph nodes. The Rac1 signaling-associated genes highlighted herein are indeed involved in the activation of cellular migration, and one, or more, may represent a future therapeutic target to prevent metastatic dissemination, or treat OMM with distant metastases.

Intracytoplasmic inclusions in atrial cardiomyocytes of guinea pigs were incidentally identified on routine postmortem evaluation. This study was conducted to assess their location, incidence, morphology, staining properties, ultrastructural appearance, epidemiological characteristics, and pathologic significance. Retrospective cases from 2014 to 2022 with right and/or left atria sampled for histologic examination were selected, and hearts of guinea pigs necropsied in 2023 were systematically formalin-fixed and included. Inclusions were identified in 27 of 28 animals (96%). They were significantly more numerous in the right atrium compared with the left atrium (P < .001, Wilcoxon signed-rank test) and preferentially located as clusters in the subendocardial region. None of these inclusions were detected in the ventricular myocardium. These inclusions were intracytoplasmic, ovoid to linear, frequently fragmented, slightly basophilic to amphophilic in hemalum, eosin, and saffron-stained sections and measured from 1 to 130 µm in length. They stained positively with periodic acid-Schiff, Gomori-Grocott's methenamine silver, and Alcian blue pH 2.5; negatively or unstained with Alcian blue pH 1, toluidine blue, von Kossa, Congo red, and Masson's trichrome; and were amylase resistant. Transmission electronic microscopy revealed slightly electron-dense, non-membrane-bound aggregates of filaments interspersed with granular material compatible with polyglucosan bodies. Animals under 1-year-old had significantly fewer inclusions than older animals (P = .002, Mann-Whitney U test). Inclusion density in the right atrium was not associated with sex, body weight, local heart lesions, or cardiac or systemic disease. Those features are similar to a human condition named basophilic degeneration, reported here for the first time in guinea pigs.

In the summer of 2023 in southern Brazil, there was a fatal outbreak of acute gastrointestinal disease in calves that ingested Titya abstersa caterpillars. The outbreak affected 6 of the 40 calves raised in an extensive system, with a mortality rate of 15%. The clinical signs included anorexia, hypersalivation, ruminal bloat, fever (39.8-40.5°C), polydipsia, and gastric reflux. Death occurred within 24 to 48 hours after the onset of the clinical signs. Macroscopic and microscopic findings revealed necrotic rumenitis, reticulitis, esophagitis, and longitudinal and transverse sections of golden structures with backward-facing barbs, consistent with intralesional caterpillar setae. This study aimed to characterize the clinical, epidemiological, and pathological aspects from the necropsies of 3 affected calves. To date, there have been no similar reports regarding the ingestion of T. abstersa caterpillars.