Veterinary Laboratories Agency VLA

Addlestone, United Kingdom

Veterinary Laboratories Agency VLA

Addlestone, United Kingdom

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Searle L.E.J.,Veterinary Laboratories Agency VLA | Cooley W.A.,Veterinary Laboratories Agency VLA | Jones G.,Veterinary Laboratories Agency VLA | Nunez A.,Veterinary Laboratories Agency VLA | And 8 more authors.
Journal of Medical Microbiology | Year: 2010

The prebiotic Bimuno® is a mixture containing galactooligosaccharides (GOSs), produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41171 using lactose as the substrate. Previous in vivo and in vitro studies demonstrating the efficacy of Bimuno® in reducing Salmonella enterica serovar Typhimurium (S. Typhimurium) colonization did not ascertain whether or not the protective effects could be attributed to the prebiotic component GOS. Here we wished to test the hypothesis that GOS, derived from Bimuno®, may confer the direct anti-invasive and protective effects of Bimuno®. In this study the efficacy of Bimuno®, a basal solution of Bimuno® without GOS [which contained glucose, galactose, lactose, maltodextrin and gum arabic in the same relative proportions (w/w) as they are found in Bimuno®] and purified GOS to reduce S. Typhimurium adhesion and invasion was assessed using a series of in vitro and in vivo models. The novel use of three dimensionally cultured HT-29-16E cells to study prebiotics in vitro demonstrated that the presence of ∼5 mg Bimuno® ml-1 or ∼2.5 mg GOS ml-1 significantly reduced the invasion of S. Typhimurium (SL1344nalr) (P<0.0001). Furthermore, ∼2.5 mgGOS ml-1 significantly reduced the adherence of S. Typhimurium (SL1344nalr) (P<0.0001). It was demonstrated that cells produced using this system formed multi-layered aggregates of cells that displayed excellent formation of brush borders and tight junctions. In the murine ligated ileal gut loops, the presence of Bimuno® or GOS prevented the adherence or invasion of S. Typhimurium to enterocytes, and thus reduced its associated pathology. This protection appeared to correlate with significant reductions in the neutral and acidic mucins detected in goblet cells, possibly as a consequence of stimulating the cells to secrete the mucin into the lumen. In all assays, Bimuno® without GOS conferred no such protection, indicating that the basal solution confers no protective effects against S. Typhimurium. Collectively, the studies presented here clearly indicate that the protective effects conferred by Bimuno® can be attributed to GOS. © 2010 Crown copyright.

Bentley S.D.,Wellcome Trust Sanger Institute | Comas I.,Genomics and Health Unit | Comas I.,UK National Institute for Medical Research | Bryant J.M.,Wellcome Trust Sanger Institute | And 17 more authors.
PLoS Neglected Tropical Diseases | Year: 2012

Background: M. africanum West African 2 constitutes an ancient lineage of the M. tuberculosis complex that commonly causes human tuberculosis in West Africa and has an attenuated phenotype relative to M. tuberculosis. Methodology/Principal Findings: In search of candidate genes underlying these differences, the genome of M. africanum West African 2 was sequenced using classical capillary sequencing techniques. Our findings reveal a unique sequence, RD900, that was independently lost during the evolution of two important lineages within the complex: the "modern" M. tuberculosis group and the lineage leading to M. bovis. Closely related to M. bovis and other animal strains within the M. tuberculosis complex, M. africanum West African 2 shares an abundance of pseudogenes with M. bovis but also with M. africanum West African clade 1. Comparison with other strains of the M. tuberculosis complex revealed pseudogenes events in all the known lineages pointing toward ongoing genome erosion likely due to increased genetic drift and relaxed selection linked to serial transmission-bottlenecks and an intracellular lifestyle. Conclusions/Significance: The genomic differences identified between M. africanum West African 2 and the other strains of the Mycobacterium tuberculosis complex may explain its attenuated phenotype, and pave the way for targeted experiments to elucidate the phenotypic characteristic of M. africanum. Moreover, availability of the whole genome data allows for verification of conservation of targets used for the next generation of diagnostics and vaccines, in order to ensure similar efficacy in West Africa. © 2012 Bentley et al.

Alban L.,Danish Agriculture and Food Council DAFC | Pozio E.,Instituto Superiore Of Sanita Iss | Boes J.,Danish Agriculture and Food Council DAFC | Boireau P.,Agence Francaise de Securite Sanitaire des Aliments AFSSA | And 18 more authors.
Preventive Veterinary Medicine | Year: 2011

Each year, more than 167 million pigs in the European Union (EU) are tested for Trichinella spp. under the current meat hygiene regulations. This imposes large economic costs on countries, yet the vast majority of these pigs test negative and the public health risk in many countries is therefore considered very low. This work reviewed the current Trichinella status across the EU as well as the national level of monitoring and reporting. It also reviewed which animal species were affected by Trichinella and in which species it should be surveyed. This information was used to design a cost-effective surveillance programme that enables a standardised monitoring approach within the EU. The proposed surveillance programme relies on identifying sub-populations of animals with a distinct risk. Low-risk pigs are finisher pigs that originate from so-called controlled housing. All other pigs are considered high-risk pigs. Controlled housing is identified by the application of a specific list of management and husbandry practices. We suggest that member states (MS) be categorised into three classes based on the confidence that Trichinella can be considered absent, in the specified sub-population of pigs above a specified design prevalence which we set to 1 per million pigs. A simple and transparent method is proposed to estimate this confidence, based on the sensitivity of the surveillance system, taking into account the sensitivity of testing and the design prevalence. The probability of detecting a positive case, if present, must be high (>95 or >99%) to ensure that there is a low or negligible risk of transmission to humans through the food chain. In MS where the probability of a positive pig is demonstrated to be negligible, testing of fattening pigs from a sub-population consisting of pigs from controlled housing can be considered unnecessary. Furthermore, reduced testing of finishers from the sub-population consisting of pigs from non-controlled housing might even be considered, if conducted in conjunction with a proportionate sampling scheme and a risk-based wildlife surveillance programme where applicable. The proposed surveillance programme specifies the required number of samples to be taken and found negative, in a MS. A MS with no data or positive findings will initially be allocated to class 1, in which all pigs should be tested. When a MS is able to demonstrate a 95% or 99% confidence that Trichinella is absent, the MS will be allocated to class 2 or 3, in which the testing requirement is lower than in class 1. © 2011 Elsevier B.V.

Kauko T.,Finnish National Institute for Health and Welfare | Haukka K.,Finnish National Institute for Health and Welfare | AbuOun M.,Veterinary Laboratories Agency VLA | Anjum M.F.,Veterinary Laboratories Agency VLA | And 2 more authors.
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2010

The Phenotype MicroArray™ (PM) technology was used to study the metabolic characteristics of 29 Salmonella strains belonging to seven serotypes of S. enterica spp. enterica. Strains of serotypes Typhimurium (six strains among definite phage types DTs 1, 40 and 104) and Agona (two strains) were tested for 949 substrates, Enteritidis (six strains of phage type PT1), Give, Hvittingfoss, Infantis and Newport strains (two of each) were tested for 190 substrates and seven other Agona strains for 95 substrates. The strains represented 18 genotypes in pulsed-field gel electrophoresis (PFGE). Among 949 substrates, 18 were identified that could be used to differentiate between the strains of those seven serotypes or within a single serotype. Unique metabolic differences between the Finnish endemic Typhimurium DT1 and Agona strains were detected, for example, in the metabolism of D-tagatose, D-galactonic acid ?-lactone and L-proline as a carbon source. Thus, the PM technique is a useful tool for identifying potential differential markers on a metabolic basis that could be used for epidemiological surveillance. © Springer-Verlag 2010.

Gonzalez L.,Veterinary Laboratories Agency VLA | Siso S.,Veterinary Laboratories Agency VLA | Monleon E.,University of Zaragoza | Casalone C.,Instituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle dAosta IZS | And 9 more authors.
Journal of General Virology | Year: 2010

Variability of pathological phenotypes within classical sheep scrapie cases has been reported for some time, but in many instances it has been attributed to differences in the PRNP genotype of the host. To address this issue we have examined by immunohistochemistry (IHC) and Western blotting (WB) for the disease-associated form of the prion protein (PrPd), the brains of 23 sheep from five European countries, all of which were of the same ARQ/ARQ genotype. As a result of IHC examinations, sheep were distributed into five groups with different phenotypes and the groups were the same regardless of the scoring method used, 'long' or 'short' PrPd profiling. The groups made did not respond to the geographical origin of the cases and did not correlate with the vacuolar lesion profiles, which showed a high individual variability. Discriminatory IHC and WB methods coincided to detect a 'CH1641-like' case but otherwise correlated poorly in the classification of disease phenotypes. No other polymorphisms of the PRNP gene were found that could account for the pathological differences, except perhaps for a sheep from Spain with a mutation at codon 103 and a unique pathological phenotype. Preliminary evidence indicates that those different IHC phenotypes correlate with distinct biological properties on bioassay, suggesting that they are indicative of strain diversity. We therefore conclude that natural scrapie strains exist and that they can be revealed by detailed pathological examinations, which can be harmonized between laboratories to produce comparable results. © 2010 Crown copyright.

Santos A.C.,London School of Hygiene and Tropical Medicine | Roberts J.A.,London School of Hygiene and Tropical Medicine | Cook A.J.C.,Veterinary Laboratories Agency VLA | Simons R.,Veterinary Laboratories Agency VLA | And 5 more authors.
Epidemiology and Infection | Year: 2011

This is the first study comparing societal costs of acute illness with Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE) in the UK. It included the cost and severity of the illness and explored the impact of each Salmonella serovar on the patients, their families, the NHS, and the wider economy. The study ascertained confirmed cases of ST and SE between July and November 2008. The mean costs per case were £1282 (ST) and £993 (SE). The indirect costs associated with the work-time lost by the case, parents, or carers were £409 (ST) and £228 (SE); this difference was statistically significant. The aggregate cost of ST and SE identified using laboratory test results for the UK as a whole was estimated as £6.5 million. Work-time lost and caring activities are cost categories that are not frequently investigated within the infectious intestinal disease literature, although they represent an important societal cost. © Copyright Cambridge University Press 2010.

Bublot M.,Merial S.A.S. | Manvell R.J.,Veterinary Laboratories Agency VLA | Shell W.,Veterinary Laboratories Agency VLA | Brown I.H.,Veterinary Laboratories Agency VLA
Avian Diseases | Year: 2010

The objective of the study was to compare efficacy of two fowlpox (FP) vector vaccines (FP-AI) against H5N1 highly pathogenic avian influenza (HPAI): one (vFP89) expressing the native hemagglutinin (HA) gene from H5N8 A/turkey/ Ireland/1378/83 and the other (vFP2211) expressing a modified synthetic HA gene from H5N1 A/chicken/Indonesia/7/2003. Four groups of 20 1-day-old specific-pathogen-free chickens were made: Groups 1 and 2 were immunized with 3 log10 tissueculture infectious dose 50% (TCID50) of vFP89 and vFP2211, respectively, whereas group 3 was immunized with vFP89, but received a booster immunization at 2 wk of age with an inactivated vaccine containing A/turkey/Wisconsin/68 H5N9 virus (inH5N9); group 4 was left unvaccinated. Ten birds from each group were challenged on day 21 with A/turkey/Turkey/1/2005 clade 2.2 H5N1 HPAI virus. The 10 other chickens from each group were put in contact with their groupmates on day 22. FP-AI induced low hemagglutination inhibition (HI) titers before challenge (GMT <4 log 2) and an HI titer boost was observed 1 wk after the inH5N9 boost. All directly challenged and 9/10 nonvaccinated contact chickens died after challenge (mean death time of 2.3 and 6.1 days, respectively) and most of them shed virus before death via cloacal and buccal routes. All vaccinated birds were clinically protected from HPAI challenge. One (vFP2211), 2 (vFP89+inact.), or 3 (vFP89) out of the 10 directly challenged vaccinated chickens shed virus via the buccal route 2-5 days postinfection. No shedding was detected in the contact-challenged vaccinated birds. Altogether, these data show excellent levels of protection in all three vaccinated groups, and therefore no detectable effect of the origin of the inserted H5 gene on protection under these tested conditions. © 2010 American Association of Avian Pathologists.

Hamza E.,University of Bern | Gerber V.,University of Bern | Steinbach F.,Veterinary Laboratories Agency VLA | Marti E.,University of Bern
Immunology | Year: 2011

Horses are particularly prone to allergic and autoimmune diseases, but little information about equine regulatory T cells (Treg) is currently available. The aim of this study therefore was to investigate the existence of CD4 + Treg cells in horses, determine their suppressive function as well as their mechanism of action. Freshly isolated peripheral blood mononuclear cells (PBMC) from healthy horses were examined for CD4, CD25 and forkhead box P3 (FoxP3) expression. We show that equine FoxP3 is expressed constitutively by a population of CD4 +CD25 + T cells, mainly in the CD4 +CD25 high subpopulation. Proliferation of CD4 +CD25 - sorted cells stimulated with irradiated allogenic PBMC was significantly suppressed in co-culture with CD4 +CD25 high sorted cells in a dose-dependent manner. The mechanism of suppression by the CD4 +CD25 high cell population is mediated by close contact as well as interleukin (IL)-10 and transforming growth factor-β1 (TGF-β1) and probably other factors. In addition, we studied the in vitro induction of CD4 + Treg and their characteristics compared to those of freshly isolated CD4 + Treg cells. Upon stimulation with a combination of concanavalin A, TGF-β1 and IL-2, CD4 +CD25 + T cells which express FoxP3 and have suppressive capability were induced from CD4 +CD25 - cells. The induced CD4 +CD25 high express higher levels of IL-10 and TGF-β1 mRNA compared to the freshly isolated ones. Thus, in horses as in man, the circulating CD4 +CD25 high subpopulation contains natural Treg cells and functional Treg can be induced in vitro upon appropriate stimulation. Our study provides the first evidence of the regulatory function of CD4 +CD25 + cells in horses and offers insights into ex vivo manipulation of Treg cells. © 2011 The Authors. Immunology © 2011 Blackwell Publishing Ltd.

Smith R.P.,Veterinary Laboratories Agency VLA | Chalmers R.M.,Singleton Hospital | Mueller-Doblies D.,Veterinary Laboratories Agency VLA | Clifton-Hadley F.A.,Veterinary Laboratories Agency VLA | And 5 more authors.
Preventive Veterinary Medicine | Year: 2010

The study investigates farms suspected of being sources of zoonotic human cryptosporidiosis. A variety of implicated farm animal species were sampled and tested to detect Cryptosporidium oocysts and investigate genetic linkage with human patients. Risk factor information was collected from each farm and analysed by multivariable logistic regression to detect significant associations between factors and Cryptosporidium in animals. The results showed that average sample prevalence of Cryptosporidium infection was highest in cattle, sheep and pigs (∼40-50%), in the mid-range in goats and horses (20-25%) and lowest in rabbits/guinea pigs, chickens and other birds (∼4-7%). A single sample from a farm dog was also positive. Cryptosporidium parvum, which has zoonotic potential, was the commonest species and was most likely to be present in cattle and, to a lesser extent, in sheep. In particular, young calves and lambs shed C. parvum and this finding was corroborated in a statistical model which demonstrated that samples from groups of preweaned animals were 11 times, and immature animal groups six times, more likely to be positive than groups of adult animals, and that samples from a farm with a cattle enterprise were twice as likely to be positive than farms without a cattle enterprise. On seven out of eight farms, at least one C. parvum isolate from an animal sample was indistinguishable at the gp60 locus from those found in the human patients, indicating that farm animals are a likely source of infection for humans. Crown Copyright © 2010.

PubMed | Veterinary Laboratories Agency VLA
Type: Journal Article | Journal: Research in veterinary science | Year: 2010

Individual animal samples were collected from ten VTEC O157 positive farms approximately monthly over 11months to investigate the shedding of VTEC O157 by youngstock. VTEC O157 was isolated from 7.7% of the 6266 samples and 28.9% of the 1383 animals. On six of the farms VTEC O157 was isolated at multiple visits from several animals, whereas the remaining four farms had one or two positive animals at any one visit, with VTEC isolated from a maximum of four visits. A total of 92 animals were positive more than once (up to four sampling occasions) with a maximum of four negative samples between positive isolations. The results reveal a large variation in individual animal shedding patterns; the proportion of shedding animals on positive farms; and over time within the same farm. The lack of consistent shedding restricts the ability to target potential interventions to specific positive animals/groups or herds.

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