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Franz E.,National Institute for Public Health and the Environment RIVM | Van Hoek A.H.A.M.,National Institute for Public Health and the Environment RIVM | Van Der Wal F.J.,Wageningen University | De Boer A.,Wageningen University | And 5 more authors.
Journal of Clinical Microbiology | Year: 2012

The frequency of Escherichia coli O157 genotypes among bovine, food, and human clinical isolates from The Netherlands was studied. Genotyping included the lineage-specific polymorphism assay (LSPA6), the Shiga-toxin-encoding bacteriophage insertion site assay (SBI), and PCR detection and/or subtyping of virulence factors and markers [stx1, stx 2a/stx 2c, q21/Q933, tir(A255T), and rhsA(C3468G)]. LSPA6 lineage II dominated among bovine isolates (63%), followed by lineage I/II (35.6%) and lineage I (1.4%). In contrast, the majority of the human isolates were typed as lineage I/II (77.6%), followed by lineage I (14.1%) and lineage II (8.2%). Multivariate analysis revealed that the tir(A255T) SNP and the stx 2a/stx 2c gene variants were the genetic features most differentiating human from bovine isolates. Bovine and food isolates were dominated by stx 2c (86.4% and 65.5%, respectively). Among human isolates, the frequency of stx 2c was 36.5%, while the frequencies of stx 2a and stx 2a plus stx 2c were 41.2% and 22.4%, respectively. Bovine isolates showed equal distribution of tir(255A) (54.8%) and tir(255T) (45.2%), while human isolates were dominated by the tir(255T) genotype (92.9%). LSPA6 lineage I isolates were all genotype stx 2c and tir(255T), while LSPA6 lineage II was dominated by tir(255A) (86.4%) and stx 2c (90.9%). LSPA6 lineage I/II isolates were all genotype tir(255T) but showed more variation in stx 2 types. The results support the hypothesis that in The Netherlands, the genotypes primarily associated with human disease form a minor subpopulation in the bovine reservoir. Comparison with published data revealed that the distribution of LSPA6 lineages among bovine and human clinical isolates differs considerably between The Netherlands and North America. Copyright © 2012, American Society for Microbiology. All Rights Reserved.

Akineden O.,Justus Liebig University | Hassan A.A.,GD Animal Health Service | Schneider E.,Justus Liebig University | Usleber E.,Justus Liebig University
Journal of Dairy Research | Year: 2011

Bacteriological analysis of milk samples from quarters of a dairy cow suffering from subclinical mastitis yielded two isolates of Staphylococcus aureus which gave a negative reaction in the standard coagulase test. Both isolates were also clumping factor and thermonuclease negative, and gave a negative reaction in the Staphaurex® test. The isolates were identified by using commercial biochemical systems, and by PCR analysis of different staphylococcal cell surface protein and exoprotein genes. Further molecular identification of the isolates, which included sequencing of the 16S rRNA gene and RT-PCR of coagulase (coa), clumping-factor (clfA) and thermonuclease (nuc) genes, was consistent with the diagnosis phenotypically coagulase-negative variant of Staph. aureus. The fact that coagulase-negative Staph. aureus variants can occur in the context of intramammary infections in cattle may result in the incorrect diagnosis coagulase-negative staphylococci (CNS) in routine mastitis diagnostic, at least in rare cases. To fully ensure correct species diagnosis, sequencing of the 16S rRNA gene and amplification of specific genes such as coa is necessary in these cases. © 2010 Proprietors of Journal of Dairy Research.

Elbers A.R.W.,Central Veterinary Institute | Loeffen W.L.A.,Central Veterinary Institute | Quak S.,Central Veterinary Institute | de Boer-Luijtze E.,Central Veterinary Institute | And 7 more authors.
Emerging Infectious Diseases | Year: 2012

Infections with Schmallenberg virus (SBV) are associated with congenital malformations in ruminants. Because reporting of suspected cases only could underestimate the true rate of infection, we conducted a seroprevalence study in the Netherlands to detect past exposure to SBV among dairy cattle. A total of 1,123 serum samples collected from cattle during November 2011-January 2012 were tested for antibodies against SBV by using a virus neutralization test; seroprevalence was 72.5%. Seroprevalence was significantly higher in the central-eastern part of the Netherlands than in the northern and southern regions (p<0.001). In addition, high (70%-100%) within-herd seroprevalence was observed in 2 SBV-infected dairy herds and 2 SBV-infected sheep herds. No significant differences were found in age-specific prevalence of antibodies against SBV, which is an indication that SBV is newly arrived in the country.

Veldhuis A.M.B.,GD Animal Health Service | van Schaik G.,GD Animal Health Service | Vellema P.,GD Animal Health Service | Elbers A.R.W.,Central Veterinary Institute | And 3 more authors.
Preventive Veterinary Medicine | Year: 2013

This study aimed at estimating the Schmallenberg virus (SBV) seroprevalence in dairy heifers, non-dairy adult cattle, sheep and goats in the Netherlands after cessation of SBV transmission at the end of 2011. Archived serum samples from ruminants submitted to the GD Animal Health Service for monitoring purposes between November 2011 and March 2012 were selected and tested for presence of SBV-specific antibodies using an in-house ELISA. Animal seroprevalences were estimated at 63.4% in dairy heifers, 98.5% in adult non-dairy cattle, 89.0% in sheep and 50.8% in goats. Multivariable analyses were carried out to describe the relationship between potential risk factors and the ELISA outcome S/P%. The overall SBV seroprevalence in ruminants and ruminant herds in the Netherlands at the end of 2011 was high, with considerable differences between species and farm types. No gradient spatial pattern in final seroprevalence could be detected and therefore no suggestions about the site of introduction and spread of SBV in the Netherlands in 2011 could be made. In dairy heifers, it was shown that S/P% increased with age. In sheep, S/P% was lower in animals located in the coastal area. Whether herds were located near the German border did not affect the S/P% in sheep nor in dairy heifers. An attempt was made to gain insight in the spatiotemporal introduction of SBV in the Netherlands in 2011, by testing sheep serum samples from 2011. A seroprevalence of about 2% was found in samples from April, June and July 2011, but the ELISA positive samples could not be confirmed in a virus neutralization test. A clear increase in seroprevalence started at August 2011. From mid-August 2011 onwards, seropositive samples were confirmed positive by virus neutralization testing. This indicated the start of the epidemic, but without a clear spatial pattern. © 2013 Elsevier B.V.

Landman W.J.M.,GD Animal Health Service | Heuvelink A.,GD Animal Health Service | van Eck J.H.H.,University Utrecht
Avian Pathology | Year: 2013

In five experiments, each consisting of four or six groups with seven or 14 brown laying hens per group, birds were inoculated with an Escherichia coli strain, isolated from a layer with the E. coli peritonitis syndrome (EPS) by different routes between 23 and 33 weeks of age. Aerosol-exposed hens inhaled 105.1 to 106.2 colony-forming units per hen; hens inoculated by other routes received 107.6 to 109.1 colony-forming units per hen. In one experiment, one-half of the birds of each group were injected intraperitoneally with sterile egg yolk simultaneously with E. coli. Dead and surviving birds were necropsied and bacteriological examination of the bone marrow was performed. The percentage of birds with EPS that died was 89 (159/179). Nearly all dead birds showed septicaemia (155/159 = 97%), while most had septicaemia and peritonitis (126/159 = 79%). Surviving hens with EPS (20/179 = 11%) showed chronic peritonitis and inactive ovaries. Taking all experiments together, exposure of hens by the intravenous, intratracheal and intraperitoneal routes induced EPS in 84% (41/49), 80% (55/69) and 76% (16/21), respectively, while aerosol and intravaginal exposure resulted in EPS percentages of 57% (32/56) and 49% (28/57), respectively. Except for orally inoculated groups (7/56 = 13% EPS), in all other groups the EPS rates differed significantly (P <0.01) from those of the placebo-exposed groups (0/42). Neither the age of hens nor the presence of free yolk in the abdomen influenced the EPS rate. The results of the present study are suggestive of the respiratory and vaginal origin of EPS in the field. © 2013 Copyright Houghton Trust Ltd.

Kester E.,Qdossier eCTDconsultancy | Holzhauer M.,GD Animal Health Service | Frankena K.,Wageningen University
Veterinary Journal | Year: 2014

This article reviews the literature on hock lesions in dairy cattle, focusing in particular on their prevalence and associated clinical signs, as well as the scoring systems used to assess them and the data on risk factors. This analysis was limited to hock lesions where there was inflammation and damage of the skin and the subcutaneous tissue only without involvement of the joint. The presence of hock lesions, or tarsal peri-arthritis, is strongly related to time spent lying on abrasive surfaces, prolonged high local pressure or friction of the hock on hard surfaces, and collisions of the hock with cubicle fittings. Since hocks have almost no fatty tissue or muscles between the bones and skin, there is no protection against these types of trauma and skin damage occurs (resulting in hock lesions). The risk of these lesions becoming infected is strongly dependent on the hygiene of the lying area. The prevalence of hock lesions in dairy cows is generally reported as high (>50%). As hock lesions are often correlated with lameness, they are associated with economic losses and impaired welfare, as well as negative societal perception of the dairy sector. Alterations in cubicle characteristics, bedding material, pasture access and lameness prevention may all lower the prevalence of hock lesions; nevertheless, the actual relationship between housing design and other cow- and management-related risk factors on the occurrence of hock lesions appears to be complex and interrelated. © 2014 Elsevier Ltd.

de Wit J.J.,GD Animal Health Service | Swart W.A.J.M.,GD Animal Health Service | Fabri T.H.F.,GD Animal Health Service
Avian Pathology | Year: 2010

Infectious bronchitis virus (IBV) is, in spite of vaccination, still a major cause of respiratory problems in broilers and of poor egg production in breeders and layers in many parts of the world. A possible cause of the insufficient protection induced by vaccination is an inadequate application of the vaccine. This paper reports the results of two field studies. In the first, the results of the α-IBV IgM enzyme-linked immunosorbent assay (ELISA) on post-vaccination sera were compared with the efficacy of the IBV vaccination against homologous challenge of the same broilers. The results showed that groups with at least 50% positive sera in the IgM ELISA at 10 days post vaccination had a high level of protection against challenge. Most groups of broilers with a low level of IgM ELISA positives had a low or moderate level of protection against challenge. In a second field study, the IgM response to IBV vaccination was compared with detailed information of the vaccination process of 360 spray-vaccinated flocks of about 2-week-old broilers, layer pullets, broiler breeders and broiler grandparents. The information included parameters such as flock size, type of chicken, housing, age of the chicken, application route, vaccine, dose, water quantity and temperature, ventilation and light management, combination with other vaccines and temperature of the house. The aim was to identify factors that might be associated positively or negatively with the IgM response and thereby with the expected level of protection against homologous challenge under field conditions. Significant associations were detected between the level of IgM response and factors regarding type of bird, flock size, housing type, ventilation management, light management, age/interval of vaccination, interval between vaccination and blood sampling, and temperature of the water that was used to reconstitute the vaccine. This knowledge can be useful to improve the average efficacy of IBV vaccination in the field. © 2010 Houghton Trust Ltd.

de Wit J.J.S.,GD Animal Health Service | Cook J.K.A.,2138 Hartford Road | van der Heijden H.M.J.F.,GD Animal Health Service
Avian Pathology | Year: 2011

The history, current situation and control measures for infectious bronchitis virus (IBV) variants are reviewed. A large number of IBV variants exist worldwide; some being unique to a particular area, others having a more general distribution. The possible reasons why some strains spread readily over major parts of the world, whereas other strains stay more localized are discussed. The advantages and disadvantages of strain classification by protecto typing, sero typing and genotyping are discussed in relation to in vivo protection. The different vaccination strategies are also considered. © 2011 Houghton Trust Ltd.

Saini V.,University of Calgary | Olde Riekerink R.G.M.,University of Prince Edward Island | Olde Riekerink R.G.M.,GD Animal Health Service | McClure J.T.,University of Prince Edward Island | Barkema H.W.,University of Calgary
Journal of Clinical Microbiology | Year: 2011

Determining the accuracy and precision of a measuring instrument is pertinent in antimicrobial susceptibility testing. This study was conducted to predict the diagnostic accuracy of the Sensititre MIC mastitis panel (Sensititre) and agar disk diffusion (ADD) method with reference to the manual broth microdilution test method for antimicrobial resistance profiling of Escherichia coli (n = 156), Staphylococcus aureus (n = 154), streptococcal (n = 116), and enterococcal (n = 31) bovine clinical mastitis isolates. The activities of ampicillin, ceftiofur, cephalothin, erythromycin, oxacillin, penicillin, the penicillin-novobiocin combination, pirlimycin, and tetracycline were tested against the isolates. Diagnostic accuracy was determined by estimating the area under the receiver operating characteristic curve; intertest essential and categorical agreements were determined as well. Sensititre and the ADD method demonstrated moderate to highly accurate (71 to 99%) and moderate to perfect (71 to 100%) predictive accuracies for 74 and 76% of the isolate-antimicrobial MIC combinations, respectively. However, the diagnostic accuracy was low for S. aureus-ceftiofur/oxacillin combinations and other streptococcus-ampicillin combinations by either testing method. Essential agreement between Sensititre automatic MIC readings and MIC readings obtained by the broth microdilution test method was 87%. Essential agreement between Sensititre automatic and manual MIC reading methods was 97%. Furthermore, the ADD test method and Sensititre MIC method exhibited 92 and 91% categorical agreement (sensitive, intermediate, resistant) of results, respectively, compared with the reference method. However, both methods demonstrated lower agreement for E. coli-ampicillin/cephalothin combinations than for Gram-positive isolates. In conclusion, the Sensititre and ADD methods had moderate to high diagnostic accuracy and very good essential and categorical agreement for most udder pathogen-antimicrobial combinations and can be readily employed in veterinary diagnostic laboratories. Copyright © 2011, American Society for Microbiology.

Bartels C.J.M.,GD Animal Health Service | Holzhauer M.,GD Animal Health Service | Jorritsma R.,University Utrecht | Swart W.A.J.M.,GD Animal Health Service | Lam T.J.G.M.,GD Animal Health Service
Preventive Veterinary Medicine | Year: 2010

Between January and April 2007, 424 calves under 22 days of age from 108 Dutch dairy herds were sampled to estimate the prevalence of non-normal faeces ('custard-like'-yellowish-coloured with custard consistency or diarrhoea: watery-like faeces) and the shedding of enteropathogens Escherichia coli K99 (E. coli), Coronavirus, Cryptosporidium parvum (C. parvum), Rotavirus and Clostridium perfringens (Cl. perfringens). In addition, information was collected on animal characteristics and herd-management practices. The probability of detecting each one of five enteropathogens given a calf with 'custard-like' faeces or diarrhoea was estimated using Bayes' rule and was based on the predicted probabilities from a multinominal model including each of five enteropathogens as independent variables. In addition, putative risk factors for the presence of each of five enteropathogens were analysed using logistic regression models with random herd effects. Fifty-seven percent of calves had faeces of normal colour (brownish) and consistency (firm), 23.8% (95%CI: 19.8-28.2%) had 'custard-like' faeces and 19.1% (95%CI: 15.5-23.2%) had diarrhoea. E. coli was the least detected enteropathogen (2.6% (95%CI: 1.3-4.6%) of calves, 9% (95%CI: 5-16%) of herds) and Cl. perfringens was most detected (54.0% (95%CI: 49.1-58.8%) of calves, 85% (95%CI: 77-91%) of herds). E. coli and Coronavirus were detected incidentally in only one or two calves per herd, whereas C. parvum and Cl. perfringens were frequently detected in up to four calves per herd. For calves with 'custard-like' faeces, the probability of detecting Rotavirus from a calf in its first week of age was 0.31 whereas for a calf in its second week, there was a 0.66 probability of detecting C. parvum. The probabilities of detecting E. coli, Rotavirus and C. parvum in calves with diarrhoea in their first week of age were 0.10, 0.20 and 0.43, respectively. In calves with diarrhoea between 1 and 2 weeks of age, the probability of detecting enteropathogens was 0.43 for C. parvum. None of the tested enteropathogens were related to 'custard-like' faeces or diarrhoea in the third week of age. Putative risk factors for E. coli, Coronavirus and C. parvum included the presence of peer-calves shedding Coronavirus, C. parvum or Rotavirus, respectively. Additionally, managerial risk factors such as non-optimal hygienic housing (for Coronavirus) and the routine use of antibiotics for diarrhoeic calves (for C. parvum) were found. No animal or managerial factors were associated with shedding of Cl. perfringens. © 2009 Elsevier B.V. All rights reserved.

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