农林科学最新文献

The biting midges, Culicoides peregrinus Kieffer and Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) are the most significant vector species of bluetongue virus (BTV) in the Oriental region, including India. Rearing of these vector species was cumbersome; previous researchers supplemented the rearing substrates primarily with cattle dung (the habitat), yeast and nutrient broth. Other investigations reiterated that an enriched milieu of live bacteria is required for the oviposition and developmental progression of the immatures as they failed to develop in sterile medium. Therefore, bacteria-based approaches provide novel opportunities for artificial rearing. This investigation tries to simplify and create a cleaner version of rearing based on different bacterial strains. The substrate bacterial strains were biochemically characterised, and their influence on oviposition, hatching and larval development was analysed and evaluated under laboratory conditions. We artificially reared two vector species by utilising three different strains of Bacillus cereus and one strain of Alcaligenes faecalis retrieved from the substrates. The results demonstrated that gravid females select their oviposition substrates based on stimuli derived from live microorganisms that indicate the suitability of the developmental substrate for immature development. Bacillus cereus 1B stimulated the greatest extent of egg hatching (>99%), larval survivability (>74%), pupae formation (>83%) and adult emergence (>98%) in both species. This present investigation proposes to utilise B. cereus 1B as an alternative approach to artificially rear and establish laboratory colonies of these vector species.

Vibrio infections cause enteritis in grouper fish, leading to high mortality and stunted growth, which is a major challenge for aquaculture. Oligochitosans, marine prebiotics with bioactive properties, have proven their potential for growth promotion and immune regulation. However, the impacts of Vibrio harveyi on the gut microbiome of grouper fish and the potential of oligochitosans to modulate these effects remain poorly understood. This study investigates the influence of oligochitosan on the gut morphology, microbiota and metabolic patterns of hybrid grouper following low-dose infection with V. harveyi. After 8 weeks of feeding, infected groupers exhibited histopathological changes in the intestine that were mitigated by oligochitosan, as evidenced by improved villus height and intestinal wall thickness. Microbiome sequencing revealed that oligochitosan enhanced α-diversity and shifted bacterial communities, particularly increasing the abundance of Fusobacteriota and Actinobacteriota. Furthermore, the prevalence of Shewanella and Vibrio, which were more abundant in infected groupers, was reduced upon oligochitosan treatment. Metabolomic analysis indicated that lipid metabolism pathways were significantly altered in response to infection and oligochitosan intervention. Overall, oligochitosan modulates the gut microbiome and metabolite profiles, potentially protecting against V. harveyi-induced intestinal dysbiosis and metabolic disorders in hybrid groupers.

Bluetongue virus (BTV) is an arthropod-borne virus that is transmitted between ruminants by Culicoides (Order Diptera, Family Ceratopogonidae) midges. In September 2023, BTV serotype 3 (BTV-3/NET2023) emerged in the Netherlands, causing a devastating epidemic in sheep and cattle. The aim of this study was to determine which midge species contributed to the spread of BTV-3 and to what extent the virus is present in local midge populations. Midges were collected using Onderstepoort UV-light suction traps on BTV-affected farms in the centre of the Netherlands, from October 2023 till March 2024. Species, sex and parity of the midges were morphologically determined. Pooled female parous and gravid midges were subjected to pan-BTV and BTV-3 real-time polymerase chain reaction (PCR) testing. Pool prevalence, minimum infection rate (MIR) and infection rate (IR) were calculated. In total, 33,093 midges were morphologically identified, all being indigenous Culicoides species. Of these, 10,835 parous or gravid female midges were selected and pooled in 383 pools (mean 28.3 midges per pool, range 1-115). A total of 155 pools (40.5%) tested BTV positive, with a mean MIR/100 of 1.4 and an IR of 2.2 (95% confidence interval: 1.9-2.6). All positive pools were from batches that were collected in October 2023 (week 40 and 41). BTV-RNA was detected in the Culicoides species C. obsoletus Meigen, C. scoticus Downes and Kettle, C. chiopterus Meigen, C. dewulfi Goetghebuer and C. punctatus Meigen. The high proportion of BTV-PCR positive midge pools is indicative of a high vector competence for BTV-3/NET2023 of Dutch indigenous midges present on farms; it could potentially partly explain the rapid spread of the virus throughout the Netherlands.

Melanocytic tumours (MT) occur in both humans and companion animals, presenting an opportunity for comparative oncology research. Thus, this study provides a comprehensive epidemiological analysis comparing MT in Portuguese dogs, cats and humans. Data were obtained from the Portuguese National Cancer Registry (RON) (2011-2021) and Vet-OncoNet (2020-2023), utilising standardised oncological classification systems (ICD-O-3.2 and Vet-ICD-O-canine-1). The results indicate that Melanoma was the most frequently diagnosed MT across all three species, while melanocytomas were common in dogs but rare in cats and humans. A higher incidence rate (IR) for MT was observed in dogs (IR = 16.1) compared to humans (IR = 8.1) and cats (IR = 6.3), and neutered dogs (10.8 years) were diagnosed at significantly older ages than intact ones (9.9 years). Shar-Peis (RR = 14.2, p < 0.001) had the highest RR compared to mixed-breed dogs, followed closely by Rhodesian Ridgebacks (RR = 12.2, p < 0.001) and Golden Retrievers (RR = 6.4, p < 0.001). Spatial analysis revealed significant clustering of MT cases in humans and dogs, with a strong geographical overlap (BLISA = 0.345, p < 0.001) in urban regions. This study provides the first epidemiological comparison of MT in these three species in Portugal, underscoring the sentinel role of companion animals in human oncology and the relevance of comparative oncology in translational cancer research.

Peripheral odontogenic fibromas (POFs) are benign masses of mesenchymal cells with features of periodontal ligament/gingival ligament fibroblasts and are among the most commonly diagnosed oral masses in dogs. Recently, a subset of hypercellular POFs (hPOFs) has garnered attention due to atypical histologic features giving concern for malignant potential. This retrospective study describes 54 hPOFs characterized by increased cellularity, increased pleomorphism, increased mitotic count, and/or bony remodeling in the absence of inflammation. Data collected from records included signalment, degree of excision, and location of the mass. Follow-up questionnaires were distributed to referring veterinarians to assess biologic behavior and patient outcomes. The hPOFs represented 76/6303 (1.2%) of all canine POF diagnoses in a 12.6-year time frame. Of 29 cases where follow-up data were available, 4/29 (14%) experienced local recurrence, similar to published recurrence rates of typical POFs. No evidence of malignant behavior nor metastasis was identified in any case. The median survival time (17 months) was greater than the median follow-up time for living patients (14 months), and the deaths of 14 patients were all attributed to unrelated illnesses. These results suggest that despite concerning histologic features, hPOFs are not associated with a shorter survival time, nor do they carry a greater risk of local recurrence or metastasis relative to histologically typical POFs. Our findings suggest that hPOFs can be clinically managed similar to typical POFs. Pathologists presented with POFs with hypercellularity, increased pleomorphism, increased mitotic count, and bone remodeling should be aware of hPOF as a potential diagnosis.

Formaldehyde-based fixation is the most used chemical system for histopathological examination worldwide. However, its toxicity is well known, and preservation of gross features, proteins, and nucleic acids is not optimal. Alternative fixatives resulting in similar morphological tissue quality and costs, but with reduced toxicity and with better preservation of gross features, proteins, and nucleic acids would increase operator safety and application possibilities in pathology. This multi-institutional study aimed to compare the morphological, histochemical, immunohistochemical (IHC), and molecular outcomes of fixation with a newly patented, non-toxic, acid-free glyoxal (GAF) fixative with neutral-buffered formalin (NBF). Fifty-nine tissue biopsies and 21 necropsies of different animal species were analyzed. Gross features were preserved after GAF fixation, with no tissue hardening or discoloration. Cellular ultrastructure was better preserved with GAF. Histology, histochemistry, and in situ hybridization results from GAF-fixed samples were mainly equal when compared to NBF-fixed samples, except for the loss of mast cell granules in GAF-fixed samples compared to NBF. IHC analyses showed comparable results with slight and rare protocol adjustment. DNA yields were higher and amplification of selected genes (ie, TP53 and COX1) was more efficient in GAF-fixed biopsies (P < .05). DNA and RNA yields were higher also in necropsy GAF-fixed tissues, but no difference was detected for selected gene amplification (ie, COX1, GAPDH, β-actin). Based on these data, despite not yet being economically competitive, GAF could represent a valuable alternative to NBF for standard laboratory applications, while also improving on-field sampling and teaching applications.

Case history: The medical records of a veterinary hospital in Italy were reviewed retrospectively for cases of dogs and cats diagnosed with vertebral instability (VI) and treated surgically using a bone plate, screws with bushings, and polymethylmethacrylate (PMMA) that had ≥ 4 weeks' follow-up data. Dogs were a median of 16.15 (min 2.7, max 32) kg and 90 (min 38, max 142) months old, and cats were a median of 4.05 (min 2.7, max 5) kg and 33 (min 5, max 61) months old. The aetiology of VI was primarily traumatic in eight cases (road traffic accidents, n = 6; fall from height, n = 1; bite injury, n = 1) and degenerative in two cases (C1-C2 luxation, n = 1; and lumbosacral instability, n = 1).

Clinical findings: Neurological examinations were performed pre- and post-operatively using the modified Frankel scale. Neurological grades prior to surgery were grade 0 (n = 1), grade 1 (n = 2), grade 3b (n = 6), and grade 5 (n = 1). Diagnostic imaging (CT and radiography) was conducted to classify fractures/luxations, plan surgical interventions and evaluate post-operative progress. VI was localised to the lumbar (n = 2), lumbosacral (n = 1), or thoracic (n = 1) spinal segments of cats and the cervical (n = 1), thoracolumbar junction (n = 1), lumbar (n = 2), or lumbosacral (n = 2) spinal segments of dogs.

Treatment and outcome: All animals were treated surgically with a bone plate, screws with bushings and PMMA for stabilisation, as unilateral constructs (three cats, two dogs) or bilateral constructs (one cat, four dogs). A minor complication (Kirschner wire breakage) occurred in one dog, and a major complication (cement rupture) occurred in one cat; both resolved without surgical intervention and did not compromise stability or cause neurological deterioration.Post-operative neurological assessment revealed improvement in 9/10 cases, with two cases improving by one neurological grade, and seven cases improving by two grades. At the 4-week follow-up assessment, seven cases maintained their discharge status, while three improved by one additional grade at the 16-week follow-up assessment.

Conclusions and clinical relevance: This case series suggests that VI stabilisation with a bone plate, screws with bushings, and PMMA is a viable method producing satisfactory outcomes. Increased exposure surface at the screw/bushing/PMMA interface may increase the strength of the fixation.

Abbreviations: K-wire: Kirschner wire; PMMA: Polymethylmethacrylate; VI: Vertebral instability.

Mycobacterium ulcerans pseudoshottsii is a mycolactone-producing bacterium previously isolated from Striped Bass (Morone saxatilis (Walbaum)) from Chesapeake Bay and adjacent waters of the Atlantic Coast of North America. We report the first molecular detection of this pathogen in the native Gulf strain of Morone saxatilis collected from the Pearl River, Mississippi (USA). Molecular identification was conducted using a novel PCR assay targeting the parA-625 intergenic spacer of the virulence-associated pMUM plasmid. The isolate was unambiguously assigned to M. u. pseudoshottsii based on diagnostic single nucleotide polymorphisms (SNPs) and phylogenetic analysis. This report expands the known range of M. u. pseudoshottsii to include Gulf Coast watersheds and highlights the need for enhanced surveillance in wild and aquacultured fish populations of the southern United States.