Presence of bacterial glycocalyx and fimbriae on Pasteurella haemolytica in feedlot cattle with pneumonic pasteurellosis.   总被引：2，自引：1，他引：1       下载免费PDF全文

D W Morck  M E Olson  S D Acres  P Y Daoust    J W Costerton 《Canadian journal of veterinary research》1989,53(2):167-171

This investigation was conducted to determine if Pasteurella haemolytica within feedlot cattle affected by pneumonic pasteurellosis express fimbriae (pili) and bacterial glycocalyx. Bacteriological culture of pulmonary tissue from three calves with fibrinous pneumonia resulted in heavy growth of P. haemolytica. Transmission electron microscopy of the lungs showed numerous microcolonies of gram-negative bacteria with morphology typical of Pasteurella haemolytica. The cells within these microcolonies possessed bacterial glycocalyces which stained with ruthenium red. Glycocalyx-encased microcolonies were also present in specimens examined by scanning electron microscopy. Typical P. haemolytica cells were evident in a tracheal specimen and these bacteria had radial glycocalyces consistent with polysaccharide and proteinaceous material condensed on linear structures suggestive of fimbriae. The pathogenetic importance of the bacterial glycocalyx and fimbriae in shipping fever pneumonia has yet to be established but their presence in clinical cases of Pasteurella pneumonia in feedlot cattle further supports a possible role in the initiation and progression of this disease as well as bacterial resistance to antimicrobial agents.  相似文献   

Surgical implantation of temperature‐sensitive transmitters and data‐loggers to record body temperature in koalas (Phascolarctos cinereus)          下载免费PDF全文

D Adam  SD Johnston  L Beard  V Nicholson  A Lisle  J Gaughan  R Larkin  P Theilemann  A Mckinnon  W Ellis 《Australian veterinary journal》2016,94(1-2):42-47

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Plasma lipopolysaccharide elevations in cattle associated with early-stage infection by Fasciola hepatica     

D Marendy  L Gabor  SD George  A Parker  E Doyle 《Australian veterinary journal》2023,101(9):334-338

Fasciolosis is an endemic zoonotic parasitic disease with significant impacts on human health and both animal health and production. Early post-infection impacts on the host remain unclear. The objective of this study was to determine the changes, if any, to levels of endotoxin in cattle plasma in response to early-stage infection with Fasciola hepatica. Thirty-six (36) commercial bred cattle were experimentally infected with approximately 400 viable metacercariae. Plasma lipopolysaccharide (endotoxin) levels were examined on 24 occasions from 0 h before infection to 336 h after infection using the Limulus Amoebocyte Lysate chromogenic end point assay and compared with that of six (6) uninfected control animals. Peak lipopolysaccharide levels in infected animals were reached at 52 h after infection and returned to pre-infection levels at time 144 h after infection. Infected animals had significantly elevated lipopolysaccharide levels between 24 and 120 h after infection when compared to uninfected animals. The mean change in endotoxin units (EU)/mL over time after infection was statistically significant in infected animals. Elevations of lipopolysaccharide occurred in all infected animals suggesting a possible repeatable and titratable endotoxemia conducive to therapeutic agent model development.  相似文献   

The Prevention and Control of Epidemics of Acute Undifferentiated Diarrhea of Beef Calves in Western Canada   总被引：1，自引：0，他引：1       下载免费PDF全文

O. M. Radostits  S. D. Acres 《The Canadian veterinary journal. La revue veterinaire canadienne》1980,21(9):243-249

It is frequently evident that outbreaks of diarrhea occur in spite of apparent “good management” and “good calving conditions”. This observation underlies the fact that we still do not understand many of the epidemiological factors which contribute to calf diarrhea outbreaks. For example, we still lack biological criteria by which to judge the degree of crowding and the degree of stress. Nevertheless, application of the principles described above will prevent or decrease the severity of many annual epidemics. To be successful, a program of prevention and control should be discussed with producers long before the calving season, preferably during the preceding summer or fall. Implementation of a complete program may take several calving seasons and producers should be made aware that prevention by improved management is an on-going, evolutionary process. More and improved vaccines are becoming available; however, as is the case with most biologicals, their impact cannot be determined until after they have been used for several years. They should be recognized as only one of several managent tools at the disposal of the veterinarian and livestock producer.  相似文献   

Bluetongue virus serotypes 1 and 3 infection in Poll Dorset sheep   总被引：1，自引：0，他引：1  

C. HAMBLIN  JS SALT  SD GRAHAM  K. HOPWOOD  AM WADE-EVANS 《Australian veterinary journal》1998,76(9):622-629

Objective To study the clinical signs following bluetongue virus serotypes 1 and 3 infection in Poll Dorset sheep.
Design A clinical and pathological study.
Procedure Twenty Poll Dorset sheep were inoculated with bluetongue virus serotypes 1 or 3, each inoculum having a different passage history. The sheep were examined daily and their clinical appearance and rectal temperatures recorded. Heparinised and non-heparinised blood samples were taken at intervals for virological and serological study. Gross pathological findings were recorded for several sheep at necropsy and tissue samples were collected from three sheep for virological studies.
Results All inoculated sheep developed clinical disease. The clinical signs and gross pathological changes varied considerably but were consistent with damage to the vascular endothelial system. There was a decline in the titres of infectious bluetongue virus and of antigen in tissues collected between 7 and 12 days after infection.
Conclusions The severity of disease was related to the speed of onset and duration of pyrexia and not the development or titre of viraemia. Generally, those animals with sensitive mouths, depression, coronitis, recumbency and reluctance to move were the most debilitated. Whole blood was the most reliable source of infectious virus from acutely and chronically infected and convalescent animals. However, tissue samples particularly spleen, collected from dead or killed animals suffering from either peracute or acute forms of disease were most appropriate for the rapid confirmation of a clinical diagnosis.  相似文献   

Effect of Oil Overlay on Inhibition Potential of Roscovitine in Sheep Cumulus‐Oocyte Complexes          下载免费PDF全文

LF Crocomo  WC Marques Filho  CMV Ulian  NS Branchini  DT Silva  CL Ackermann  FC Landim‐Alvarenga  SD Bicudo 《Reproduction in domestic animals》2015,50(3):410-416

Inhibitors of cyclin‐dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus‐oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor‐free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (?) at 38.5°C and 5% CO₂. At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/?) exhibited total expansion while in both Rosco groups (+/?) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/?). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression.  相似文献   

The efficacy of a modified live reo-like virus vaccine and an E. coli bacterin for prevention of acute undifferentiated neonatal diarrhea of beef calves.          下载免费PDF全文

S D Acres  O M Radostits 《The Canadian veterinary journal. La revue veterinaire canadienne》1976,17(8):197-212

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Fungal disease in reptiles     

CJ Harvey  KD McSporran  RM Jakob-Hoff  JS Potter  SD Shaw 《New Zealand veterinary journal》2013,61(2)

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Aural plaques in two imported horses in New Zealand     

RA Fairley  CM Morley  SD Williams  DA Senior  MA Neill 《New Zealand veterinary journal》2013,61(4):232-233

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Segmental axonopathy of Merino sheep in New Zealand     

RD Jolly  AC Johnstone  SD Williams  K Zhang  TW Jordan 《New Zealand veterinary journal》2013,61(5):210-217

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.  相似文献