4 results on '"Jean-Yves Le Hesran"'
Search Results
2. Role of environment and behaviour in familial resemblances of Plasmodium falciparum infection in a population of Senegalese children
- Author
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Jean Yves Le Hesran, André Garcia, Florence Rouget, Florence Migot-Nabias, Oumar Gaye, and Allé Baba Dieng
- Subjects
Male ,Rural Population ,EPIDEMIOLOGIE ,medicine.medical_specialty ,Adolescent ,Plasmodium falciparum ,Immunology ,Population ,Disease ,Environment ,Biology ,ENVIRONNEMENT ,Microbiology ,Risk Factors ,Immunity ,INFECTION ,Epidemiology ,medicine ,Animals ,Humans ,Family ,Malaria, Falciparum ,PARASITE ,Child ,education ,Genetics ,education.field_of_study ,Infant ,Family aggregation ,PALUDISME ,GENETIQUE ,medicine.disease ,biology.organism_classification ,Senegal ,DENSITE DE POPULATION ,ENFANT ,Infectious Diseases ,El Niño ,FAMILLE ,SENSIBILITE RESISTANCE ,RESSEMBLANCE FAMILIALE ,Child, Preschool ,Population Surveillance ,Female ,Stereotyped Behavior ,COMMUNAUTE VILLAGEOISE ,Malaria - Abstract
Despite the importance of both environment and behaviour in vector-borne disease epidemiology, these factors are unable to explain alone the distribution of cases in a community and the diversity of clinical presentations, suggesting the involvement of more individual factors such as age, sex, immunity or genetic background. The existence of a genetic factor involved in the susceptibility/resistance to a disease can be suspected by the demonstration of a familial aggregation of cases or by the stability over time of infectious status (infected vs. uninfected; mean level of parasite density (PD), etc.). These familial resemblances can be explained by shared environment, family habits and behaviours (use of bed nets, field activities, etc.). In this preliminary study, we essentially investigated the influence of environment and behaviour on Plasmodium falciparum infection levels and reported the effects of these factors on the existence of familial resemblances. Our results are consistent with the existence of familial resemblances for both the level of P. falciparum infection and the qualitative infection status (QIS) (infected vs. uninfected) that seem to be more related to shared behaviour and environment than to a genetic factor. However, although familial resemblances decreased significantly when adjusted for shared behaviour and environment, this decrease is around 12% for the variability between families, against only 4.5% of that within families. Furthermore, we also demonstrated that the QIS is remarkably stable over time. Both these results are consistent with the hypothesis of the existence of a strong and complex individual factor involved in the control of infection status. more...
- Published
- 2004
- Full Text
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3. Hidden Plasmodium falciparum parasites in human infections: different genotype distribution in the peripheral circulation and in the placenta
- Author
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Odile Mercereau-Puijalon, Dietlind Schleiermacher, Jean-Yves Le Hesran, Jean Louis Ndiaye, Ronald Perraut, and Alioune Gaye
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Microbiology (medical) ,Placenta ,Plasmodium falciparum ,INFECTION MULTIPLE ,Biology ,Microbiology ,Multiplicity of infection ,Gene Frequency ,GROSSESSE ,INFECTION ,parasitic diseases ,Genotype ,ETUDE COMPARATIVE ,Genetics ,medicine ,Animals ,Humans ,Distribution (pharmacology) ,PLACENTA ,Malaria, Falciparum ,Allele ,PARASITE ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics ,SANG PERIPHERIQUE ,PALUDISME ,medicine.disease ,biology.organism_classification ,Virology ,GENOTYPE ,Peripheral ,ALLELE ,Infectious Diseases ,medicine.anatomical_structure ,FEMME ,DISTRIBUTION ,Immunology ,Female ,ANALYSE GENETIQUE ,Malaria - Abstract
Sequestration of the mature Plasmodium falciparum forms complicates detection, quantification and molecular analysis of human infections. Whether the circulating parasites represent all or only a subset of co-infecting genotypes is unclear. We have investigated this issue and compared placenta and peripheral blood msp1 and msp2 genotypes in 58 women delivering with an ICT-positive placenta in Guediawaye, Senegal. Most placenta (91%) and blood samples (98%) were multiply infected. Multiplicity of infection was positively correlated in both tissues. However, the placental and circulating genotype profiles differed markedly. Only 10% of matched peripheral blood/placenta samples had identical genotypes, whereas 74% had only partially concordant genotypes, with some alleles detected in both tissues, together with additional allele(s) detected in one tissue only. Eight women (14%) had totally discordant placental and peripheral blood genotypes. Thus, in the vast majority of cases, some sequestered genotypes remain hidden, undetected in the peripheral circulation, indicating that analysis of peripheral parasites generates a partial picture of a P. falciparum infection. more...
- Published
- 2002
- Full Text
- View/download PDF
4. Humoral and Cellular Immune Responses to Synthetic Peptides from the Plasmodium falciparum Blood-Stage Antigen, Pf155/RESA, in Cameroonian Women
- Author
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Yveline Frobert, Nadine Fievet, Florence Migot, B. Dubois, C. Chougnet, Jean Bickij, Bertrand Maubert, Michel Cot, Philippe Deloron, and Jean-Yves Le Hesran
- Subjects
Adult ,Cellular immunity ,medicine.medical_treatment ,Molecular Sequence Data ,Plasmodium falciparum ,Immunology ,Protozoan Proteins ,Antigens, Protozoan ,Epitope ,Pathology and Forensic Medicine ,Antigen ,parasitic diseases ,medicine ,Animals ,Humans ,Immunology and Allergy ,Amino Acid Sequence ,Cameroon ,Immunity, Cellular ,biology ,Lymphokine ,biology.organism_classification ,Cytokine ,Antibody Formation ,Humoral immunity ,biology.protein ,Female ,Antibody - Abstract
T- and B-cell responses to the Plasmodium falciparum blood-stage antigen Pf155/RESA were investigated in 104 Cameroonian women, half of whom were pregnant. We used purified protein and six synthetic peptides representing T- and B-cell epitopes. In vitro T-cell responses were measured by proliferation and IL2, IFN-gamma, and IL4 release. B-cell responses were assessed by plasma antibodies. All peptides induced a cellular response in some individuals. A proliferative response was induced in 25% of the donors by Pf155/RESA, and in 7 to 11% by any peptide. Cytokine release occurred in 23 to 30% of the Pf155/RESA-stimulated cultures, and in 8 to 25% of the peptide-stimulated cultures. Overall, each peptide induced a cellular response (proliferation and/or cytokine release) in 44% of the donors. T-cells from 23% of the donors failed to respond to any peptide. Responding cells did not usually respond in all readouts, and proliferation and release of any of the three cytokines were not correlated. Similarly, antibody and T-cell responses were not related. Selected epitopes of Pf155/RESA, an important vaccine candidate, are well recognized in naturally exposed individuals and are able to activate T-cells to proliferate and to produce various lymphokines in numerous individuals from a malaria endemic area. more...
- Published
- 1995
- Full Text
- View/download PDF
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