Assessment of the impact of resistant and susceptible canola on Plasmodiophora brassicae inoculum potential

The impact on clubroot severity of growing susceptible canola or mixtures of resistant and susceptible canola genotypes was examined. Bioassays revealed greater clubroot severity and incidence, and reduced plant height, where 100% of a susceptible cultivar had been grown. A higher proportion of susceptible plants within a resistant canola crop increased root hair and secondary infections. Regression analysis of root hair infection and the amount of Plasmodiophora brassicae DNA (as determined by quantitative PCR) revealed strong linear relationships between the two parameters. The linear relationships between root hair infection and P. brassicae DNA were stronger for the resistant cultivar than for the susceptible cultivar when regression analysis was conducted by cultivar over the sampling dates. In conclusion, the cropping of a resistant cultivar reduced clubroot severity, while the presence of susceptible volunteer canola increased inoculum potential. Quantitative PCR was a reliable tool for the quantification of root hair infection.     

Accidental fatal aflatoxicosis due to contaminated commercial diet in 50 dogs

Aflatoxins, produced by Aspergillus spp., are toxic contaminants of stored grain. This study describes 50 dogs presented with foodborne aflatoxicosis. Common clinical signs included lethargy (78%), vomiting (76%), anorexia (74%), icterus (66%), depression (66%), melena (60%), haematuria (36%) and diarrhoea (36%). Common laboratory abnormalities included increased activities of aspartate aminotransferase (86%), alkaline phosphatase (84%) and alanine aminotransferase (79%), hypoantithrombinaemia (86%), prolonged prothrombin (PT, 82%) and activated partial thromboplastin times (aPTT, 80%), hyperbilirubinaemia (73%), hypocholesterolaemia (60%) hypoalbuminemia (47%) and thrombocytopenia (42%). Non-survivors had longer PT and aPTT and lower antithrombin (P<0.001) at presentation compared to survivors (23.8s vs.10.5; 37.9 vs.17.6s and 5% vs. 54%, respectively). Hyperbilirubinaemia (>56.6 μmol/L) and albumin concentration <32.5 g/L at presentation were risk factors for mortality (P<0.0001). Common complications included disseminated intravascular coagulation (58%), hepatic encephalopathy (35%) and acute kidney injury (4%). The mortality rate was 68%, suggesting that dogs with aflatoxicosis have poor prognosis.     

Population diversity of Staphylococcus aureus isolated from bovine mastitis in Brazilian dairy herds

Population diversity was evaluated in strains of Staphylococcus aureus isolated from bovine mastitis in Brazilian dairy herds by PCR-RFLP and sequencing of the 3'-terminal portion of the coagulase gene, and the susceptibility of strains to antimicrobials. The results showed great diversity in S. aureus population studied and the existence of predominant clones that account for most infections. No associations between the predominant types observed in the PCR-RFLP and the forms of presentation of the mastitis or to any of the different patterns of antimicrobial resistance were observed.     

Ultrasonography of the urinary tract in 29 female Saanen goats

The left and right kidneys, ureters, urinary bladder and urethra of 29 female clinically healthy Saanen goats were examined via transcutaneous and transrectal ultrasonography. In order to establish reference values the examinations were performed using a 5.0 MHz linear transducer to scan the right caudal costal part of the abdominal wall, right and left dorsal flanks and right and left inguinal regions of standing goats. A 5.0 MHz intracavity probe was used for transrectal ultrasonographic examination of the urinary bladder and urethra. The kidneys were examined in longitudinal and cross section and assessed subjectively. They could usually be seen from the 12th intercostal space on the right side and dorsal right flank. The right kidney was 8.0 ± 0.67 cm long and the left was 8.4 ± 0.64 cm long. The ureters could not be visualized in any of the goats. The length of the urinary bladder was 5.1 ± 1.38 cm, and its largest cross-sectional diameter was 2.6 ± 1.01 cm. The urethra was seen in 23 goats and appeared as echogenic lines with no visible lumen. The transition from the neck of the bladder to the internal urethral orifice extended beyond the brim of the pelvis in only one goat.     

Escherichia coli O115 forms fewer attaching and effacing lesions in the ovine colon in the presence of E. coli O157:H7

Escherichia coli O115 has been isolated from healthy sheep and was shown to be associated with attaching-effacing (AE) lesions in the large intestine. Following previous observations of interactions between E. coli O157 and O26, the aim of the present study was to assess what influence an O115 AE E. coli (AEEC) would have on E. coli O157 colonisation in vitro and in vivo. We report that E. coli O115- and O157-associated AE lesions were observed on HEp-2 cells and on the mucosa of ligated ovine spiral colon. In single strain inoculum, E. coli O115 associated intimately with HEp-2 cells and the spiral colon in greater numbers than E. coli O157:H7. However, in mixed inoculum studies, the number of E. coli O115 AE lesions was significantly reduced suggesting negative interference by E. coli O157. Use of the ligated colon model in the present work has allowed in vitro observations to be extended and confirmed whilst using a minimum of experimental animals. The findings support a hypothesis that some AEEC can inhibit adhesion of other AEEC in vivo. The mechanisms involved may prove to be of utility in the control of AE pathovars.     

The influence of colostral antibodies on the postvaccinale humorale immune response in neonatal calves

The aim of this study was to evaluate the efficiency of vaccination of young calves and to see whether maternal antibodies may influence the immunological response in calves. For this project 20 matched-pairs of cows and their offspring were selected. Of each pair, one cow received a placebo 8 and 4 weeks before term (group A) and the other was vaccinated against Feline Leucose Virus, FeLV, with Leucogen? (group B). All calves received colostrum from their respective mother shortly after birth and all calves were vaccinated with Leucogen? 10 days after birth. Blood samples from the cows and calves were taken during the whole study period (till four weeks after calf vaccination). An ELISA test was done in the lab to define the FeLV antibody concentration. 30 % of the vaccinated cows showed a seroconversion, 13 out of 20 vaccinated cows passed the antibodies onto their calves. 11 calves of group B did not convert in comparation of only 4 of group A. All seroconverted calves had low antibody concentration before their vaccination. Calves of group B with a low passive antibody level at the beginning showed a higher seroconversion as compared to calves with higher antibody concentrations of the same group. Two thirds of the calves without maternal antibodies reacted adequately to the vaccination. Therefore, an early vaccination of calves can be recommended.     

Mastitis severity induced by two Streptococcus uberis strains is reflected by the mammary immune response in vitro

Streptococcus uberis is the most common environmental mastitis pathogen causing udder inflammations of different severities in dairy cows. The aim of the study was to investigate if the different clinical outcome of mastitis induced by different strains of S. uberis can be reflected in the mammary immune response. Mammary epithelial cells and somatic milk cells were treated with heat inactivated and living S. uberis of strain A and strain B in vitro. Strain A was repeatedly isolated from a chronically infected quarter during 8 months, and persisted in the quarter despite antibiotic treatment. Strain B caused an acute clinical mastitis and was not further isolated after a single antibiotic treatment. Treatment with Strain B induced a more pronounced increase of mRNA-expression of various immune factors (interleukin-8, interleukin-1beta, RANTES, and lactoferrin) in mammary epithelial cells than strain A. In contrast to mammary epithelial cells the response of removed somatic milk cells showed no differences between the stimulation with two S. uberis strains. Tumor necrosis factor-alpha mRNA expression was not differently induced by the two strains. In conclusion, the characteristics of different severities of mastitis that are induced by different S. uberis strains in vivo can also be reflected at the level of the immune response of the mammary gland in vitro.