C Beaumont

Assistance Publique – Hôpitaux de Paris, Lutetia Parisorum, Île-de-France, France

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Publications (107)482.5 Total impact

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    P Zongo, A Ducrot, J-B Burie, C Beaumont
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    ABSTRACT: SUMMARY Salmonellosis is a foodborne disease of humans and animals caused by infection with Salmonella. The aim of this paper is to improve a deterministic model (DM) and an individual-based model (IBM) with reference to Salmonella propagation in flocks of laying hens taking into account variations in hens housed in the same cage and to compare both models. The spatio-temporal evolution, the basic reproduction number, R 0, and the speed of wave propagation were computed for both models. While in most cases the DM allows summary of all the features of the model in the formula for computation of R 0, slight differences between individuals or groups may be observed with the IBM that could not be expected from the DM, especially when initial environmental contamination is very low and some cages may get rid of bacteria. Both models suggest that the cage size plays a role on the risk and speed of propagation of the bacteria, which should be considered when designing new breeding systems.
    Epidemiology and Infection 08/2014; · 2.49 Impact Factor
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    ISAG 33rd Conference, Cairns, Australia; 07/2012
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    ABSTRACT: Iron deficiency is the most frequent cause of hypochromic microcytic anemia in children, but other causes, some of them requiring specific management, may be involved. Checking the iron-status is absolutely mandatory. When iron-status parameters are low, inadequate intake, malabsorption, blood loss, and abnormal iron utilization must be tested. In absence of iron deficiency, α- and β-globin and heme biosynthetic gene status must be checked. Assessing the iron stock level is difficult, because there is an overlap between the values observed in iron-replete and iron-deprived patients, so that at least 2 iron-status parameters must be below normal for diagnosing iron deficiency. Furthermore, inflammation may also mimic some characteristics of iron deficiency. Diagnosing iron deficiency leads to prescribing iron supplementation with follow-up at the end and 3 months after cessation of treatment. When iron stores are not replete at the end of treatment, compliance and dosage must be reevaluated and occult bleeding sought. The latter is also required when the iron store decreases 3 months after cessation of iron replacement.
    Archives de Pédiatrie 03/2012; 19(3):295-304. · 0.41 Impact Factor
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    ABSTRACT: Iron deficiency is the most frequent cause of hypochromic microcytic anemia in children, but other causes, some of them requiring specific management, may be involved. Checking the iron-status is absolutely mandatory. When iron-status parameters are low, inadequate intake, malabsorption, blood loss, and abnormal iron utilization must be tested. In absence of iron deficiency, α- and β-globin and heme biosynthetic gene status must be checked. Assessing the iron stock level is difficult, because there is an overlap between the values observed in iron-replete and iron-deprived patients, so that at least 2 iron-status parameters must be below normal for diagnosing iron deficiency. Furthermore, inflammation may also mimic some characteristics of iron deficiency. Diagnosing iron deficiency leads to prescribing iron supplementation with follow-up at the end and 3 months after cessation of treatment. When iron stores are not replete at the end of treatment, compliance and dosage must be reevaluated and occult bleeding sought. The latter is also required when the iron store decreases 3 months after cessation of iron replacement.
    Archives de Pédiatrie. 03/2012; 19(3):295–304.
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    C. BEAUMONT, J.-B. BURIE, A. DUCROT, P. ZONGO
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    ABSTRACT: We propose a mathematical spatial and age structured model to describe the spatial spread of Salmonella among laying hens in industrial hen houses. We provide a mathematical study of traveling pulses of infection and describe a minimal speed property for such a problem. The dependence with respect to some heterogeneities of the medium is also discussed. Finally, based on biological data, the parameters of the model are estimated to provide some information on the propagation speed of the bacteria.
    SIAM Journal on Applied Mathematics 01/2012; 72(4):1113-1148. · 1.41 Impact Factor
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    ABSTRACT: Salmonella propagation by apparently healthy chickens could be decreased by the selection and use of chicken lines that are more resistant to carrier state. Using a reduced set of markers, this study investigates, for the first time to the authors' knowledge, the feasibility of a genomic selection approach for resistance to carrier state in hen lines. In this study, commercial laying hen lines were divergently selected for resistance to Salmonella carrier state at 2 different ages: young chicks and adults at the peak of lay. A total of 600 birds were typed with 831 informative SNP markers and artificially infected with Salmonella Enteritidis. Phenotypes were collected 28 d (389 young animals) or 38 d (208 adults) after infection. Two types of variance component analyses, including SNP data or not, were performed and compared. The set of SNP used was efficient in capturing a large part of the genetic variation. Average accuracies from mixed model equations did not change between analyses, showing that using SNP data does not increase information in this data set. These results confirm that genomic selection for Salmonella carrier state resistance in laying hens is promising. Nevertheless, a denser SNP coverage of the genome on a greater number of animals is still needed to assess its feasibility and efficiency.
    Poultry Science 04/2011; 90(4):731-6. · 1.54 Impact Factor
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    P. Zongo, A. F. Viet, P. Magal, C. Beaumont
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    ABSTRACT: Salmonella is a major source of toxi-infection in humans. Prophylactic means have been de-veloped to reduce the prevalence of Salmonella carriers but none allows a total reduction of the risk. Evaluating synergy by modelling approach would be very useful to estimate such gain in food safety. Here, we used an individual-based model of the spatio-temporal spread of Salmonella within a laying flock taking into account the animal’s bacterial load and ability to reduce it thanks to the immune response. We illustrate the effects, on the Salmonella spatio-temporal spread, of a heterogeneity of excretion.
    European Poultry Conference, Tours, France; 08/2010
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    ABSTRACT: An F(2) population (695 individuals) was established from broiler chickens divergently selected for either high (HG) or low (LG) growth, and used to localize QTL for developmental changes in body weight (BW), shank length (SL9) and shank diameter (SD9) at 9 weeks. QTL mapping revealed three genome-wide QTL on chromosomes (GGA) 2, 4 and 26 and three suggestive QTL on GGA 1, 3 and 5. Most of the BW QTL individually explained 2-5% of the phenotypic variance. The BW QTL on GGA2 explained about 7% of BW from 3 to 7 weeks of age, while that on GGA4 explained 15% of BW from 5 to 9 weeks. The BW QTL on GGA2 and GGA4 could be associated with early and late growth respectively. The GGA4 QTL also had the largest effect on SL9 and SD9 and explained 7% and 10% of their phenotypic variances respectively. However, when SL9 and SD9 were corrected with BW9, a shank length percent QTL was identified on GGA2. We identified novel QTL and also confirmed previously identified loci in other chicken populations. As the foundation population was established from commercial broiler strains, it is possible that QTL identified in this study could still be segregating in commercial strains.
    Animal Genetics 08/2010; 41(4):400-5. · 2.21 Impact Factor
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    ABSTRACT: Egg quality has gained importance in genetic improvement of laying hens. Egg weight, eggshell thickness (either directly or indirectly recorded), yolk proportion and egg albumen quality (Haugh units) exhibit moderate to high heritability values (0.30 to 0.60) but egg weight is negatively correlated with egg number. Combining within-line selection with crossbreeding has resulted in an increase in the number of eggs with a constant and rather high egg weight (62 g on average). Moreover, experimental selection and exploration of genetic diversity, have given access to new genetic variability, in chickens and quails, of egg shell colour, yolk proportion and lipid composition of the yolk. Yet, the genes controlling egg laying traits and technological qualities of the egg are still poorly known. QTL controlling a significant part of genetic variability were identified in fowl and quail. Recently, major genes were identified, such as a mutation of the FMO3 enzyme responsible for the fishy taint of eggs when the hen is fed with rapeseed. Numerous studies are focussed on microbial quality of eggs, with a priority to the study of the salmonella carrier state, where the effects of several genes have been identified ( SLC11A1, TLR4).
    Productions Animales -Paris- Institut National de la Recherche Agronomique- 06/2010; 23(2):123-1432. · 0.69 Impact Factor
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    ABSTRACT: Improving the fowl's natural ability to clear Salmonella from their body is important in reducing disease prevalence in poultry flocks, as recommended by a recent regulation of the European Commission. It may be efficient, as expected from estimation of heritability coefficients : 0.16 in chicks and 0.18 for global contamination of hens. The animal's age has to be considered since the genetic correlation between resistances at the two ages is negative. Selecting two series of divergent lines for increased or decreased resistance, after inoculation at one week of age (chick resistance) or at the peak of lay (adult resistance) confirmed the efficiency at least of selection for the adult resistance. In parallel, genes controlling variations to Salmonella resistance were researched and several QTLs identified in crosses between experimental lines and, for some of them, confirmed in commercial lines. Thanks to the derivation of a model of Salmonella propagation within a flock, it has been shown that a combination of vaccination and genetic selection can result in very low percentage of contamination.
    World's Poultry Science Journal 05/2010; 66(02):251 - 260. · 1.25 Impact Factor
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    ABSTRACT: Farm animal welfare is a major issue in Europe, which resulted in regulations and development of research dedicated to animal welfare, especially on standard poultry production, which is often considered as resulting in very poor welfare. The effect of selection is also often questioned. Indeed, capacities of adaptation have been very little considered during the first years of commercial selection and thus have been reduced. Nowadays, a much greater importance is given to welfare-related traits and genomic selection should alleviate the need for their measurements in the short-term. However, the choice of the fittest selection criteria is still to be made. Because behavioral traits are highly dependent on environment, general reactivity may be more efficient. For example, selection against undesirable behavior such as feather pecking has been proven to be efficient, but selection for reduced mortality rates in collective cages proved to be preferable. Most often, selection should not exacerbate extreme values, which are most often detrimental, as in the case of social motivation, which, when increased to too large of an extent, results in increased aggressivity. Moreover, a general propensity will not result in overall improvement; for example, reducing fearfulness has positive effects but does not modify response to social stress. Detrimental effects on other traits may also be observed: although genetic resistance to diseases should increase animal welfare, it may also result in increased frequency of silent carriers and in turn to human transmission. Indeed, an optimum must be found. Studying lines selected for or against these traits will be of great help to choose the best strategy of selection. Another and longer term concern should be on links with other production traits but also on sustainability, which will probably be of greater importance in the coming years.
    Poultry Science 04/2010; 89(4):825-31. · 1.54 Impact Factor
  • C. Beaumont
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    ABSTRACT: About 60% of body iron is associated with hemoglobin in circulating red blood cells and daily erythropoiesis requires about 25 to 30 mg iron per day. This iron is provided by macrophages through recycling of heme iron following phagocytosis of senescent red blood cells and heme catabolism. Intestinal iron absorption (1 to 2 mg per day) only compensates for daily iron losses. Hepcidin, a 25 amino-acid peptide synthesized in hepatocytes, secreted in plasma and rapidly removed in urines, is a negative regulator of both intestinal iron absorption and heme iron recycling by macrophages. Hepcidin synthesis is stimulated by iron or by inflammation (mostly by IL-6) and is repressed by iron deficiency and by all conditions that stimulate bone marrow erythropoiesis such as anemia, bleeding, hemolysis, dyserythropoiesis or erythropoietin injections. A defect in the activation of hepcidin normally triggered by iron excess is the underlying mechanism for all juvenile or adult forms of hemochromatosis whereas a defect in hepcidin repression is responsible for an iron deficiency iron refractory anemia (IRIDA). Reduced hepcidin filtration in renal insufficiency contributes to the associated anemia and stimulation of hepcidin synthesis by inflammation is a major determinant of the anemia of chronic disorders. New therapeutic perspectives are currently underway such as the development of agonists or antagonists of hepcidin or siRNA approaches aiming at reducing hepcidin synthesis. The validation of hepcidin assays in a near future will allow identifying the patients most likely to benefit from intravenous iron therapy.
    La Revue de Médecine Interne 12/2009; 30. · 1.32 Impact Factor
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    ABSTRACT: Salmonella may colonize the gastrointestinal tract of most animals, including fowls (Beaumont et al , 2009a) and ducks. They often result in asymptomatic carrier-state, when animals carry the bacteria without showing any symptoms. These silent carriers may transmit the bacteria to other animals or humans beings; indeed poultry products are a main source of human toxi-infections and contamination of ducks by Salmonella may result in severe losses (Barrow et al., 1999). Since there is a partial genetic control of resistance of fowls to Salmonella and Salmonella carrier-state (Beaumont et al., 2003) which may contribute to the prevention of this disease in fowl, a first experiment was achieved in ducks to test the feasibility of such an approach in this species. A protocol of experimental inoculation resulting in carrier-state was derived by orally inoculating female ducks at one day of age with three different doses of the S. Enteritidis T51 strain resistant to nalidix acid and kanamycin. A persistent carrier-state was observed in the three cases and a dose of 5x 10 6 colonies forming units (c.f.u.) chosen for the second experiment.
    6th european Poultry Genetic Symposium, Poznan, Poland; 09/2009
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    ABSTRACT: The ability of chickens to carry Salmonella without displaying disease symptoms is responsible for Salmonella propagation in poultry stocks and for subsequent human contamination through the consumption of contaminated eggs or meat. The selection of animals more resistant to carrier state might be a way to decrease the propagation of Salmonella in poultry stocks and its transmission to humans. Five QTL controlling variation for resistance to carrier state in a chicken F(2) progeny derived from the White Leghorn inbred lines N and 6(1) had been previously identified using a selective genotyping approach. Here, a second analysis on the whole progeny was performed, which led to the confirmation of two QTL on chromosomes 2 and 16. To assess the utility of these genomic regions for selection in commercial lines, we tested them together with other QTL identified in an [Nx6(1)] x N backcross progeny and with the candidate genes SLC11A1 and TLR4. We used a commercial line divergently selected for either low or high carrier-state resistance both in young chicks and in adult hens. In divergent chick lines, one QTL on chromosome 1 and one in the SLC11A1 region were significantly associated with carrier-state resistance variations; in divergent adult lines, one QTL located in the major histocompatibility complex on chromosome 16 and one in the SLC11A1 region were involved in these variations. Genetic studies conducted on experimental lines can therefore be of potential interest for marker-assisted selection in commercial lines.
    Animal Genetics 05/2009; 40(5):590-7. · 2.21 Impact Factor
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    ABSTRACT: In neonatal rat liver, AFP is localized only in typical hepatocytes. Their lobular distribution changes throughout the neonatal period. Some AFP+ cells also contain albumin. Less than 5% of AFP+ cells incorporate 3H-thymidine (2-hour pulse). Injections of dexamethasone suppress AFP positivity but not albumin positivity nor 3H-thymidine incorporation. AFP is also localized in typical hepatocytes in newborn rat isolated liver cells or liver explants in culture. During the early phase of AFP induction in rats, by mDAB feeding, AFP is detected in cells smaller than the normal hepatocytes and preferentially situated in periportal areas of the liver.Electron microscope immunoperoxidase localizations in newborn rat liver show that AFP is present on bound ribosomes, in the lumina of rough and smooth endoplasmic reticulum, and in the Golgi apparatus. Direct AFP measurement on isolated organelles confirmed this distribution. It indicates a synthesis and secretion pattern similar to that of albumin.
    Scandinavian Journal of Immunology 02/2009; 8(s8):289 - 296. · 1.88 Impact Factor
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    ABSTRACT: Partial deficiency of the last enzyme of the heme biosynthetic pathway (namely ferrochelatase, FECH) in humans is responsible for erythropoietic protoporphyria (EPP). This disorder is characterised by painful photosensitivity, due to excessive production of protoporphyrin IX (PPIX) by erythrocytes. Controversial hypotheses have been proposed to explain the hematologic and iron status of EPP patients. In the present work, we explored these parameters in 55 patients with dominant EPP recruited at the French Center of Porphyrias (Colombes, France) and confirmed by molecular analysis. Our data show that erythrocyte accumulation of PPIX in EPP patients influences hematologic and iron status. Patients studied had a mild anemia and thrombocytopenia, as shown by the downward shift of hematologic parameters, which positively correlated with the amount of erythrocyte PPIX. Interestingly, erythropoiesis did not seem to be limited by iron supply in patients, since serum iron and soluble transferring (Tf) receptor (sTfR) were normal. However, iron and Tf saturation negatively correlated with erythrocyte PPIX. Moreover, and as previously described in a mouse model of EPP, we noted a positive correlation between erythrocyte PPIX and Tf levels. Altogether, these results suggest a positive effect of PPIX on the synthesis on Tf, which could facilitate the mobilization of tissue iron stores to meet erythropoiesis requirement. Based on these observations and previous results in EPP mouse model, we propose that the PPIX-liver transferrin pathway plays a role in the orchestration of iron distribution between peripheral iron stores, the spleen and the bone marrow.
    Cellular and molecular biology (Noisy-le-Grand, France) 02/2009; 55(1):45-52. · 1.46 Impact Factor
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    ABSTRACT: Résumé Une première étude de la résistance génétique au portage asymptomatique de salmonelles a été réalisée chez le canard mulard. Dans une première étape, nous avons déterminé notre modèle d'infection expérimentale, c'est-à-dire les conditions d'inoculation et la durée d'étude du portage. Les canetons sont inoculés à un jour par voie orale avec 5x10 6 UFC (unité formant colonie) de Salmonella Enteritidis et les salmonelles sont dénombrées dans les caeca 4 semaines plus tard. La seconde étape a consisté à appliquer ce modèle à 400 canetons mulards de généalogies connues, issus d'un dispositif de détection de QTL (Quantitative Tait Loci) en backcross, du programme GENECAN décrit par Marie-Etancelin et al. (2008). L'héritabilité de la résistance au portage de salmonelles chez le caneton a été évaluée à 0,24, avec une corrélation génétique nulle entre contamination et poids de caeca.
    8èmes Journées de la Recherche sur les Palmipèdes à Foie Gras, Arcachon, France; 10/2008
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    ABSTRACT: DMT1 deficiency causes microcytic hypochromic anemia due to decreased erythroid iron utilization. Anemia is present from birth. Transferrin saturation is high and serum ferritin is mildly elevated, despite liver iron overload. DMT1 deficiency must be considered in the differential diagnosis of microcytic hypochromic anemia observed in the newborn period.
    The Journal of pediatrics 02/2008; 152(1):136-9. · 4.02 Impact Factor
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    ABSTRACT: Increasing resistance to acute Salmonellosis (that is, contamination level shortly after infection) is not sufficient to reduce the risk for consumers to be contaminated by Salmonella. Indeed, animals may remain contaminated at a low level for weeks or months. Increased resistance to the Salmonella carrier state, i.e., animals' ability to clear bacteria, is needed; it involves measuring bacterial contamination several weeks after inoculation with a low dose. To study such resistance traits, three convergent approaches were used. A quantitative trait loci (QTL) study was performed, taking advantage of inbred lines differing in resistance. Several QTLs controlling resistance at a younger age were identified and are currently being confirmed in a new cross before finer mapping, using advanced intercross lines. These inbred lines are also presently being compared using functional genomics. In parallel, a selection experiment for increased or decreased resistance at a younger and a later age was undertaken. Besides providing genetic models differing in their levels of resistance, it underlined the importance of the choice of selection criterion, whether marker assisted or not. Indeed, genes controlling resistance are strongly dependant on age; selecting for resistance at a younger age might result in increased susceptibility at an older age. Finally, the results of this experiment were used in a model of the intra-flock propagation of Salmonella. It showed that introducing a proportion of resistant animals within a flock of susceptible hens could dramatically change the evolution of contamination. Moreover, it demonstrated the magnitude of synergy between selection and vaccination, which should enhance the interest of increased resistance. The results show that selection for increased resistance to the Salmonella carrier state may be efficient, providing that the appropriate criteria of selection are used.
    Developments in biologicals 02/2008; 132:353-7.
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    ABSTRACT: 1. The repeatability and heritability of growth inhibition by egg albumen of two major pathogenic bacteria, a Gram-negative (Salmonella Enteritidis) and a Gram-positive (Staphyloccocus aureus) and of two antimicrobial albumen proteins, lysozyme and ovotransferrin, were estimated in commercial pedigree hens. 2. Repeatability was evaluated in 100 egg-type hens at the beginning, middle and end of the laying cycle on eggs collected for 3 weeks. Heritabilities were estimated at 36 to 40 weeks of age on 400 pedigree hens (2 eggs/hen), which were the offspring of 25 sires each mated with 4 dams. Ovotransferrin and lysozyme were quantified by ELISA. Salmonella Enteritidis (S.E.) and Staphyloccocus aureus (S.A.) were inoculated into a sample of sterilised albumen and enumerated after incubation. 3. Total protein content in albumen decreased with age of laying hens, whereas there were increases in lysozyme or ovotransferrin concentrations and in the bacteriostatic effect of albumen. 4. Repeatability for bacterial growth in albumen ranged from 0.29 to 0.39 for the number of S.E. (log cfu/ml) one day post inoculation (p.i.) but was lower and more variable at 5 d p.i. or for S.A. number. It ranged from 0.27 to 0.38 for S.E. and S.A. number at the mid period of the laying cycle. Repeatabilities were low and variable for total egg albumen protein or lysozyme and ovotranferrin concentrations (0 to 0.22). 5. Negative phenotypic correlations were observed between lysozyme concentrations and S.E. number but that between lysozyme and S.A. number was not significant. 6. Heritabilities were low (0.01 to 0.09) for protein traits. They were 0.11 for S.A. number and 0.16 for S.E. number one day p.i. 7. It appears to be more efficient to select on global bacterial growth than on specific antimicrobial proteins. The most promising trait is the number of S.E. one day p.i.
    British Poultry Science 11/2007; 48(5):559-66. · 0.78 Impact Factor

Publication Stats

3k Citations
482.50 Total Impact Points

Institutions

  • 2012
    • Assistance Publique – Hôpitaux de Paris
      Lutetia Parisorum, Île-de-France, France
  • 2007–2012
    • Paris Diderot University
      • Centre de recherche biomédicale Bichat, Beaujon (CRB3) UMR-S 773
      Lutetia Parisorum, Île-de-France, France
    • French Institute of Health and Medical Research
      • Centre de Recherche Biomédicale Bichat-Beaujon U773
      Paris, Ile-de-France, France
  • 1997–2011
    • French National Institute for Agricultural Research
      • • Laboratoire de Génétique Cellulaire
      • • Département de Génétique Animale
      Lutetia Parisorum, Île-de-France, France
  • 2008
    • University of Naples Federico II
      Napoli, Campania, Italy
  • 2006
    • Université du Havre
      El Havre, Upper Normandy, France
  • 1983–1999
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 1985
    • St Louis University Hospital
      San Luis, Missouri, United States