Characterisation of avian pathogenic Escherichia coli (APEC) associated with colisepticaemia compared to faecal isolates from healthy birds     

McPeake SJ  Smyth JA  Ball HJ 《Veterinary microbiology》2005,110(3-4):245-253

A total of 114 avian pathogenic Escherichia coli (APEC) isolates were collected from cases of colisepticaemia occurring in broilers (77) and layers (37) within Ireland. In addition 45 strains isolated from faeces of healthy birds were included for comparison. All isolates were serogrouped, and examined for known virulence factors, mostly by PCR. The O78 serogroup represented 55 and 27% of broiler and layer colisepticaemic isolates respectively. All isolates were positive for curli fimbriae (crl, csg) and negative for afimbrial adhesin (afa). S-fimbrial (sfa) sequences were present in 8.8% of septicaemic isolates and 8.9% of healthy bird isolates. The majority of E. coli from cases of colisepticaemia (97.4%) and healthy bird (95.6%) isolates were positive for aerobactin (aer), and temperature sensitive haemagglutinin (tsh) was similarly detected in high numbers in 93.9 and 93.3%, respectively. In comparison to E. coli isolates from the faeces of healthy birds, a significantly higher percentage of isolates from septicaemic cases possessed Type 1 fimbriae (fimC) and increased serum survival (iss) gene sequences. Forty-seven (41.2%) isolates from septicaemic birds possessed P-fimbriae (pap) gene sequences, compared with only 15.6% from E. coli isolated from healthy birds. Haemolysin (hlyE) sequences were detected in 46.7% of isolates from healthy birds in comparison with 6.1% of septicaemic isolates. Sequences encoding colicin V (cvaC) were detected in 99.1% of septicaemic isolates and 82.2% of isolates from healthy birds. The K1 capsule was only present in two septicaemic isolates, both taken from layers. Motility was detected in 36.8% of E. coli isolated from cases of septicaemia, compared with 93.3% of isolates from healthy birds. These results demonstrate the presence of 11 virulence genes in E. coli isolated from cases of colisepticaemia within Ireland, and indicate the prevalence of iss and fimC.  相似文献   

Sandwich ELISA detection of Clostridium perfringens cells and alpha-toxin from field cases of necrotic enteritis of poultry     

McCourt MT  Finlay DA  Laird C  Smyth JA  Bell C  Ball HJ 《Veterinary microbiology》2005,106(3-4):259-264

Sandwich ELISAs (sELISAs) for the detection of Clostridium perfringens cells and alpha-toxin were developed and used to screen intestinal samples from normal broiler chickens and from clinical cases of necrotic enteritis. The assays clearly distinguished between the two sets of samples. The sELISA absorbance values from samples obtained from the majority of healthy birds were low and those from the majority of necrotic enteritis cases were high. Together, the assays provide a suitable test for the rapid screening for the diagnosis of necrotic enteritis in poultry.  相似文献   

Preliminary Trial: Motility Comparisons of a Unique Freezing Technology (UFT) to Liquid Nitrogen Mist Methodology for Cryopreservation of Porcine Spermatozoa     

HA Goolsby  JR Blanton  PZ Cotter  SD Prien 《Reproduction in domestic animals》2004,39(5):328-332

The motility outcomes of boar semen frozen with newly developed freezing techniques using a new unique freezing technology (UFT) compared with traditional liquid nitrogen methodology were investigated with the intent of improving current fertility outcomes using semen. The UFT is an electronically controlled cooling chamber that houses an organic fluid bath that can be maintained at temperatures below 0 degrees C without solidifying to freeze samples. Four ejaculates from four different boars were collected for this trial. Samples were handled consistently during the pre- and post-freeze processing. From each ejaculate, samples were separated into eight cryopreservation treatment groups, six UFT variations and two control liquid nitrogen groups, immediately before freezing, in replicates of two. After the initial cryopreservation was complete, all samples were stored in liquid nitrogen for at least 48 h. Post-thaw motilities and original motility return percentages were assessed on a random, individual-sample basis. After the initial evaluations, samples from two boars were recollected and frozen using the UFT for breeding purposes. Four sows were bred with the UFT frozen semen to confirm fertility capability. When assessing the individual UFT techniques, all of six UFT techniques had improved post-thaw motilities. However, treatments F (micro = 29%, return micro = 37%) and J (micro = 27%, return micro = 34%) showed the highest statistical improvement for post-thaw (p < 0.05) and original motility percent returns (p < 0.05) when compared with either the control cryo-tube (micro = 15%, return micro = 19%) or straw groups (micro = 12%, return micro = 16%). The UFT semen had a 50% conception rate, with an average of seven piglets from the sows that farrowed. Our preliminary data suggest a higher motility return with a slower pre-freeze phase below the freezing point before the acceleration to liquid nitrogen temperatures. The preliminary data suggest that the UFT could be utilized as a potential cryopreservation option for boar semen.  相似文献   

Ethics and evidence-based medicine     

JR Gilkerson  CR Wilks 《Australian veterinary journal》2005,83(12):730-731

  相似文献   

Attempts to immunize rats against infection with Fasciola hepatica using in vitro culture antigens from newly excysted metacercariae.     

C Davies  M D Rickard  J D Smyth  D L Hughes 《Research in veterinary science》1979,26(2):259-260

Attempts were made to immunise rats against Fasciola hepatica using the culture products obtained from the in vitro cultivation of newly excysted metacercariae. Three culture regimes were chosen: (1) medium NCTC 135 for 48 h (2) NCTC 135 + 20 per cent fetal calf serum (FCS) for 48 h (3) NCTC 135 + 20 per cent FCS for 14 days. The used culture medium from each of these regimes was concentrated, mixed with adjuvant and injected subcutaneously into rats. Similarly treated unused culture media was used in control rats. The rats were challenged with an oral dose of 20 F hepatica metacercariae 35 days later and autopsied 96 days after the start of the experiment. The fluke burdens in those rats which had received the culture antigens did not differ significantly from those in the control groups.  相似文献   

Serological responses to two serovar‐independent ELISA antigens of Actinobacillus pleuropneumoniae in Australian commercial pig herds     

GJ Eamens  JR Gonsalves  A‐M Whittington  B Turner 《Australian veterinary journal》2008,86(12):465-472

Objective To compare serological responses in pig herds classified as low or high risk for disease caused by Actinobacillus pleuropneumoniae, using two ELISA tests based on serovar‐independent antigens. Procedure Cross‐sectional sampling was undertaken in 13 commercial herds, the clinical and slaughter histories of which indicated either freedom from (n = 5) or prior confirmed cases of A. pleuropneumoniae (n = 8). In nine herds, approximately 40 pigs each were sampled at 4, 8, 12, 16 and 20 weeks. Three of the remaining four herds were sampled between 6 and 30 weeks of age, and the last was sampled only prior to slaughter, at approximately 24 weeks. Sera were tested in ELISA based on two antigens common among A. pleuropneumoniae serovars: a 39‐kDa outer membrane protein and a recombinant ApxIVA‐N terminus protein. Results Sampling of 1 and 5 to 6‐month‐old pigs provided the most useful information on herd status. The 39‐kDa ELISA was sensitive in detecting infected herds, but had evidence of cross‐reactivity with high seroreactivity rates in older pigs in some low‐risk herds. The ApxIVA‐N ELISA was less seroreactive in high‐risk herds and had higher specificity in low‐risk herds. Conclusion ELISA based on the 39‐kDa subunit are of limited use, because of possible cross‐reactivity, but a high negative predictive value may be useful for risk assessment in suspect herds. Maternal antibody to ApxIVA‐N may be of value in detecting high‐risk herds, but 5% of 4‐week‐old pigs in low‐risk herds were also seropositive in this assay.  相似文献   

Sequence comparison of pigeon circoviruses     

Todd D  Fringuelli E  Scott AN  Borghmans BJ  Duchatel JP  Shivaprasad HL  Raidal SR  Abadie JX  Franciosini MP  Smyth JA 《Research in veterinary science》2008,84(2):311-319

The genome sequences of eight pigeon circoviruses (PiCV) were determined and compared with four previously published sequences. The viruses compared were from the USA, five European countries, China and Australia and included PiCVs from racing, feral, ornamental and meat pigeons and a Senegal dove (Streptopelia senegalensis). The 12 PiCV genomes, ranging from 2032 to 2040 nucleotides in length, displayed similar organizations. Pairwise comparisons showed that the genome nucleotide sequence identities ranged from 85.1% to 97.8% and that the amino acid identities of the putative replication associated (Rep) and putative capsid (Cap) proteins displayed ranges of 91.5-99.1% and 73.0-99.3%, respectively. Comparative analyses identified conserved nucleotide sequences within the Rep gene and 3' intergenic regions, which would be suitable for diagnostic PCR primers, and variable amino acid sequences within the capsid proteins, which should be considered when selecting virus isolates for vaccine development.  相似文献   

Bile duct carcinoma in a gelding     

Habershon-Butcher JL  Smyth JB  Hallowell GD 《The Veterinary record》2008,162(9):281-282

  相似文献   

Recent advances in allelopathy for weed control: from knowledge to applications     

Francisco A Macías  Francisco JR Mejías  Jos MG Molinillo 《Pest management science》2019,75(9):2413-2436

Allelopathy is the biological phenomenon of chemical interactions between living organisms in the ecosystem, and must be taken into account in addressing pest and weed problems in future sustainable agriculture. Allelopathy is a multidisciplinary science, but in some cases, aspects of its chemistry are overlooked, despite the need for a deep knowledge of the chemical structural characteristics of allelochemicals to facilitate the design of new herbicides. This review is focused on the most important advances in allelopathy, paying particular attention to the design and development of phenolic compounds, terpenoids and alkaloids as herbicides. The isolation of allelochemicals is mainly addressed, but other aspects such as the analysis and activities of derivatives or analogs are also covered. Furthermore, the use of allelopathy in the fight against parasitic plants is included. The past 12 years have been a prolific period for publications on allelopathy. This critical review discusses future research areas in this field and the state of the art is analyzed from the chemist's perspective. © 2019 Society of Chemical Industry  相似文献   

Costing soil erosion: a state-wide approach     

R. E. Smyth  M. D. Young 《Land Degradation \u0026amp; Development》1998,9(6):513-527

Natural resources management is a multi-faceted discipline. It requires knowledge of the type, quantity and location of our existing natural resources, and information about how these resources are being utilized and impacted upon by human and other natural processes, whether these impacts are beneficial or detrimental and, finally, whether the impacts are reversible or have a permanent effect. Decision-makers need not only the snapshot view, but also a means to assess impact over time as land use and land-use practice change. This paper examines a methodology established to examine natural resource usage and the impacts of such usage in an integrated and repeatable fashion. Its heart is in ecological economics—a discipline which, among other things, seeks to combine economic and ecological models. The methodology was trialled initially by using it to estimate the rates of sheet and rill erosion in New South Wales, using the State-wide Resource Information and Accounting System (SRIAS), and loss hazard is estimated in physical and economic terms. The system facilitates the examination of costs to society and individuals of changes in land use and land-use practice. New estimates for the parameters of the universal soil loss equation (USLE) are derived and then mapped for the state of New South Wales. The approach is at a much finer scale than has previously been attempted. When the map of hazard of soil loss is compared with earlier maps, the physical hazard is significantly higher in the north of the state. Translation of the physical data into an economic perspective adds a new dimension to the information available to decision makers. Organization of data in this manner offers a significant opportunity to improve the cost-effectiveness of resource management. The paper reveals that failure to account for economic as well as physical rates of land degradation is likely to result in inappropriate decisions. © 1998 John Wiley & Sons, Ltd.  相似文献