农林科学最新文献

This study analysed the presence of Rickettsia (Rickettsiales: Rickettsiaceae) in fleas (Siphonaptera) associated with cricetid rodents in periurban localities of Gran La Plata, Argentina. Rodents were captured in three localities and fleas were collected directly from their fur. After DNA extraction, fleas were prepared for microscopic identification. PCR amplification of gltA and ompB genes was performed on each individual flea to detect and identify Rickettsia. The OmpB gene was sequenced and compared using nBLAST to initially identify its similarity with other sequences from GenBank. A phylogenetic tree was constructed to evaluate the relationships of the sequences obtained with others deposited in GenBank. Out of the 253 cricetids (seven species) captured, 87 fleas (four species) were collected. Of them, 10 fleas (11.5%) tested positive for Rickettsia. According to nBLAST and the phylogenetic tree results, sequences of this study were identified as R. felis Bouyer et al. Those sequences were obtained only from five of the seven cricetid species and from two of the three localities, as follows: from Street 143 and Diagonal 630, Arana neighbourhood, La Plata District: Polygenis (Polygenis) axius (Jordan and Rothschild) (n = 3) and Polygenis (Neopolygenis) atopus (Jordan and Rothschild) (n = 1); and from Balneario La Balandra, Berisso District: Polygenis (Polygenis) axius (n = 4), Polygenis (Neopolygenis) atopus (n = 1) and Craneopsylla minerva minerva (Rothschild) (n = 1). Our results confirm the presence of R. felis in fleas parasitizing cricetids in the periurban area of Gran La Plata, which could represent a risk to public health.

This study reports the first confirmed case of Myxobolus koi parasitic infection in koi (Cyprinus carpio koi) imported into Thailand. Infected fish exhibit clinical signs during the quarantine process, including lethargy, tachypnea, flared gill opercula and excessive mucus production in the gills. The gross pathological findings included swollen and pale gills interspersed with white nodules. Microscopic examination of gill biopsies revealed mucus clumps and numerous pyriform myxospores, with no evidence of other parasites. Molecular analysis confirmed the presence of Myxobolus spp. DNA through PCR amplification targeting the 18S SSU rRNA. Phylogenetic analysis of 776 bp sequences from our representative isolates (CU01, CU02 and CU03) revealed 100% nucleotide identity with M. koi sequences from goldfish in China (OM757920) and koi in the USA (FJ841887), which formed a distinct clade with strong bootstrap support. Haematological parameters were compared between infected and healthy fish from the same batch, revealing significantly elevated levels of creatine and ALT (p < 0.05) in the infected group. Histopathological examination revealed severe gill damage, with plasmodia infiltrating and disrupting the lamellar architecture. The well-delineated pink fibrous septa encapsulated mature myxospores and pansporoblasts. Scanning and transmission electron microscopy revealed that the M. koi spores, measuring 5.2 × 2.92 μm, were oval, elongated and pyriform, with coiled polar filaments enclosed within two polar capsules. These findings document the occurrence of M. koi in Thailand, underscore its transboundary transmission via international trade and highlight the need for enhanced biosecurity measures to mitigate the spread of aquatic pathogens.

This case report presents a recent case of scuticociliatosis in a whitetip reef shark (Triaenodon obesus), housed at a zoo (Haus des Meeres Aqua Terra Zoo, Vienna, Austria). Clinical signs such as uncoordinated swimming and body tilt were observed prior to death. Postmortem examination and magnetic resonance imaging (MRI) revealed significant brain lesions consistent with granulomatous or necrotising encephalitis. Histopathology and molecular diagnostics confirmed the presence of the scuticociliate Miamiensis avidus and/or Philasterides dicentrarchi in the brain, with extensive tissue invasion. This case underscores the pathogenicity of scuticociliates in elasmobranchs, highlighting the need for effective management practices in aquaria to prevent or mitigate such infections. In this study, we present the first documented infection with scuticociliates in the whitetip reef shark.

Poor gill health compromises the health and welfare of farmed Atlantic salmon (Salmo salar) by causing respiratory distress and increased ventilation frequency. Poor gill health is caused by numerous factors, including amoebic gill disease (AGD), jellyfish stings, and toxic algae, and is monitored by fish farmers by manual 'gill scoring'. Gill scoring involves visual inspection of gill surfaces for visible lesions, such as white mucoid patches. In commercial salmon farming, these patches are commonly associated with AGD, a major cause of poor gill health. Manual monitoring of gills is labour-intensive, costly, and stressful for fish. This study tested a non-invasive computer vision approach to detect the association between the gross gill score and fish ventilation rates in commercial farms. We hypothesised that increased ventilation rates of farmed Atlantic salmon were associated with a higher gross gill score. The computer vision model first detected fish heads and classified their mouth states (open or closed) using a convolutional neural network, followed by a tracking-by-detection method to estimate ventilation rates by calculating the frequency with which fish opened and closed their mouths. Ventilation rates were estimated from 240 videos recorded at Tasmanian salmon farms and analysed alongside gross gill score, water temperature, dissolved oxygen, and fish weight. Multiple linear regression analysis revealed a positive association between ventilation rates and gross gill score, although the observed change in ventilation rates was relatively small. As laboratory diagnostic methods did not confirm AGD in this study, the gross gill scores should be interpreted primarily as indicators of gill health, acknowledging that they may also reflect signs consistent with AGD. While the tested computer vision method cannot serve as a diagnostic tool, it may assist the industry in identifying health and welfare issues that require further examination. This approach provides a non-invasive way to oversee health and welfare, enhances management practices, and guides manual health assessments.

A retrospective analysis of medical records from a specialty dental practice was performed, and all cases of full-coverage titanium alloy crowns of canine teeth in dogs were reviewed. Only 5 cases of failure were noted in a total of 53 crowns in 25 dogs. No bond failures between the prepared tooth and the crown were noted; all cases of failure were due to fracture of the tooth apical to the crown margin. The success rate of retention was 100% whereas the overall tooth survival was 91%. Risk factors for tooth fracture, such as crown height-to-diameter ratio, were identified.

In this study, the changes caused by local and systemic inflammatory and immunological reactions and oxidative stress in the levels of some biomarkers and parameters in the gingival crevicular fluid (GCF) and blood in dogs with periodontal tissue inflammation were investigated. Fifty dogs were randomly assigned into five equal groups: 1. healthy control (NC); 2. local clinoptilolite applied during treatment (C); 3. amoxicillin-clavulanic acid, clinoptilolite and chlorhexidine used together during treatment (ACC); 4. amoxicillin-clavulanic acid and clinoptilolite applied together during treatment (AC); and 5. amoxicillin-clavulanic acid used during treatment (A). The results showed the increase in the total antioxidant capacity measurement level was significant between days 0 and 7 in all groups except NC. The decrease in the total antioxidant status (TOS) level between days 0 and 7 was found to be significant in all groups. The decrease in the malondialdehyde (MDA) level was significant between days 0 and 7 in all groups except NC. It was observed that the interleukin-1 β (IL-1B) level between days 0 and 7 showed a substantial decrease in the ACC and AC groups and that the matrix metalloproteinases-9 (MMP-9) and osteocalcin levels decreased significantly between days 0 and 7 in the C and AC groups. In evaluating the treatment used in this study, it was concluded that applying amoxicillin-clavulanic acid and clinoptilolite in dogs with periodontal tissue inflammation was more successful than other treatment protocols.

Lymph node (LN) metastasis has been associated with shorter survival times in dogs with mast cell tumour (MCT), and treatment of metastatic LN with lymphadenectomy or irradiation has been demonstrated to improve outcomes. Identification of metastatic LN in dogs with MCT is therefore of both prognostic and therapeutic significance. The aim of this prospective, exploratory study was to investigate whether fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) is a useful staging tool for the detection of metastatic LN in dogs with cutaneous or subcutaneous MCT, using histopathology as the gold standard. Sixteen client-owned dogs with cytologically or histologically confirmed cutaneous or subcutaneous MCTs underwent full-body ¹⁸F-FDG-PET/CT followed by surgical removal and histopathology of the primary tumour and regional LN(s). The maximum standard uptake value (SUV_max) of the tumour and LN(s) was measured. Primary tumours were graded using both the Patnaik and Kiupel grading systems, and mitotic count was tabulated. LNs were categorised based on Weishaar's histologic criteria for nodal metastasis. Eighteen primary tumours were excised: six subcutaneous and 12 cutaneous MCTs. Of 33 excised regional LNs, 18 (55%) were categorised as metastatic (≥ HN2). There was no difference between the median SUV_max of metastatic (3.88) and nonmetastatic LNs (3.16) (p = 0.41). SUV_max was positively correlated with the mitotic count of the primary tumour (p = 0.02). The results of this exploratory study suggest that ¹⁸F-FDG-PET/CT may not be useful for identifying metastatic LNs in canine MCT.

Mycobacterium genavense is a common cause of mycobacteriosis in passerine birds. In a research colony of zebra finches (Taeniopygia guttata), 8 birds were diagnosed with mycobacteriosis. The finches had granulomatous inflammation of the heart and heart-base, most with medial expansion of the great vessels containing foamy macrophages and acid-fast bacilli. Non-cardiac inflammatory lesions associated with acid-fast bacteria were found in 2 birds, and extracardiac bacteria were often in lower quantities. Pan-mycobacterial in situ hybridization detected periaortic bacteria in one bird with similar cardiac lesions that was negative for bacteria via acid-fast staining. Mycobacterium genus PCR and sequencing of pooled fecal samples confirmed the presence of M. genavense within the colony. Heart and great vessel lesions have not been previously recognized as a site of localized infection in passerines. To facilitate diagnosis of mycobacteriosis in zebra finches, routine necropsies should include microscopic examination of the heart base great vessels.

Porcine circovirus 3 (PCV-3) is associated with various pathological conditions, including systemic disease and reproductive disorders; however, its role in skeletal abnormalities has never been elucidated. This study included 36 cases displaying spinal malformations, rib swelling, head edema, gait abnormalities, and/or increased late-term abortions. Investigated animals consisted of 9 aborted fetuses, 9 piglets, 12 weaners, and 6 finishers. Histologically, PCV-3 associated lesions were identified in 23/36 cases (64%), including (peri-)arteritis and rib fractures with prominent callus formation. Central nervous system (CNS) lesions, in addition to vascular changes, comprised meningoencephalitis and gliosis. Thirteen animals (36%) did not display histological lesions. PCV-3 DNA was detected by real-time PCR (qPCR) in 25/36 animals (69%), with high viral loads in the bone and CNS. Three aborted fetuses tested positive for PCV-3 despite lacking macroscopic and histologic lesions. In situ hybridization (ISH) revealed the presence of PCV-3 RNA in multiple organs, including arteries, the heart, CNS, and bone. Signals were detected in periosteal arteries and osteoblasts, within calluses, and in arteries within the surrounding skeletal muscles. This study strengthens the association between PCV-3 and multisystemic inflammatory diseases, expanding its known pathogenicity to include skeletal lesions and spinal deformities. It is the first documentation of PCV-3 genome in histologically altered bone. This finding could suggest a possible etiological role in musculoskeletal abnormalities. In addition, this study is the first to report PCV-3-associated lesions in slaughter-ready finisher pigs. The integration of histological investigations, PCR, and ISH techniques is essential for the diagnosis of PCV-3-associated diseases and related lesions.