Éditeur(s) : HAL CCSD American Society of Hematology
Résumé : International audience
ISSN: 0006-4971

inserm-00919490
http://www.hal.inserm.fr/inserm-00919490
http://www.hal.inserm.fr/inserm-00919490/document
http://www.hal.inserm.fr/inserm-00919490/file/2013_Lemonne_-_Does_increased_red_blood_cell_deformability_raise_the_risk_for_osteonecrosis_in_sickle_cell_anemia.pdf
http://www.hal.inserm.fr/inserm-00919490/file/inserm-00919490_edited.pdf

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
ABSTRACT: Eclipsed by the debates about malaria incidence and severity in individual patients, malaria transmission in helminth-infected persons has so far received very little attention. Studies in humans have shown increased malaria incidence and prevalence, and a trend for a reduction of symptoms in patients with malaria. This suggests that such patients could possibly be less likely to seek treatment thus carrying malaria parasites and their gametocytes for longer durations, therefore, being a greater potential source of transmission. In addition, in humans, a study showed increased gametocyte carriage, and in an animal model of helminth-malaria co-infection, there was increased malaria transmission. These elements converge towards the hypothesis that patients co-infected with worms and malaria may represent a hub of malaria transmission. The test of this hypothesis requires verifying, in different epidemiological settings, that helminth-infected patients have more gametocytes, that they have less symptomatic malaria and longer-lasting infections, and that they are more attractive for the vectors. The negative outcome in one setting of one of the above aspects does not necessarily mean that the other two aspects may suffice to increase transmission. If it is verified that patients co-infected by worms and malaria could be a transmission hub, this would be an interesting piece of strategic information in the context of the spread of anti-malarial resistance and the malaria eradication attempts.
ISSN: 1475-2875

inserm-00758017
http://www.hal.inserm.fr/inserm-00758017
http://www.hal.inserm.fr/inserm-00758017/document
http://www.hal.inserm.fr/inserm-00758017/file/1475-2875-11-376.pdf
DOI : 10.1186/1475-2875-11-376

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Sickle cell anemia (SS) is characterized by a reduced cerebral microvascular oxygen saturation (cerebral TOI), which is not associated with hemoglobin concentration. Cerebral TOI has never been studied in sickle cell-hemoglobin C disease (SC). We focused on the relationships between hemorheological alterations and cerebral TOI in sickle cell patients with no cerebral vasculopathy and on the usefulness of TOI variability to assess the cerebral vasomotion activity. The blood rheological profile, the level of cerebral TOI (spatial resolved spectroscopy) and the cerebral TOI variability, which reflects vasomotion activity, were compared between 20 healthy subjects (AA), 21 SC patients, and 21 SS patients. Cerebral TOI exhibited the following order: AA > SC > SS. The low cerebral TOI in SS patients was related to red blood cell aggregation and deformability properties. The cerebral TOI variability of SS and SC patients was increased above healthy values and vasomotion activity was negatively associated with the reduced cerebral TOI in SS patients. We demonstrated that (1) blood rheology could be involved in the reduced cerebral TOI in SS patients but not in SC patients; (2) vasomotion activity is increased in SS and SC patients to compensate for the reduced cerebral TOI.
ISSN: 0361-8609

inserm-00838966
http://www.hal.inserm.fr/inserm-00838966
http://www.hal.inserm.fr/inserm-00838966/document
http://www.hal.inserm.fr/inserm-00838966/file/2013_Waltz_American_Journalsur Hematology.pdf
DOI : 10.1002/ajh.23318

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Vascular function has been found to be impaired in patients with sickle cell disease (SCD). The present study investigated the determinants of systemic vascular resistance in two main SCD syndromes in children: sickle cell anemia (SCA) and sickle cell-hemoglobin C disease (SCC). Nitric oxide metabolites (NOx), hematological, hemorheological, and hemodynamical parameters were investigated in 61 children with SCA and 49 children with SCC. While mean arterial pressure was not different between SCA and SCC children, systemic vascular resistance (SVR) was greater in SCC children. Although SVR and blood viscosity (ηb) were not correlated in SCC children, the increase of ηb (+18%) in SCC children compared to SCA children results in a greater mean SVR in this former group. SVR was positively correlated with ηb, hemoglobin (Hb) level and RBC deformability, and negatively with NOx level in SCA children. Multivariate linear regression model showed that both NOx and Hb levels were independently associated with SVR in SCA children. In SCC children, only NOx level was associated with SVR. In conclusion, vascular function of SCC children seems to better cope with higher ηb compared to SCA children. Since the occurrence of vaso-occlusive like complications are less frequent in SCC than in SCA children, this finding suggests a pathophysiological link between the vascular function alteration and these clinical manifestations. In addition, our results suggested that nitric oxide metabolism plays a key role in the regulation of SVR, both in SCA and SCC.
ISSN: 1386-0291

inserm-00849031
http://www.hal.inserm.fr/inserm-00849031
http://www.hal.inserm.fr/inserm-00849031/document
http://www.hal.inserm.fr/inserm-00849031/file/2013_Lamarre_-_Relationships_between_SVR_BR_and_NO_in_children_with_sickle_cell_anemia_or_sickle_cell-hemoglobin_C_disease.pdf
DOI : 10.3233/CH-121661

Éditeur(s) : HAL CCSD Ferrata Storti Foundation
Résumé : International audience
BACKGROUND: Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease. DESIGN AND METHODS: To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematologic parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old) followed since birth. Clinical charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated. RESULTS: Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. CONCLUSIONS: Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease.
ISSN: 0390-6078

inserm-00849038
http://www.hal.inserm.fr/inserm-00849038
http://www.hal.inserm.fr/inserm-00849038/document
http://www.hal.inserm.fr/inserm-00849038/file/inserm-00849038.pdf
DOI : 10.3324/haematol.2012.066670

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
UNLABELLED: ABSTRACT: BACKGROUND: Malaria remains a major health problem in French Guiana, with a mean of 3800 cases each year. A previous study in Camopi, an Amerindian village on the Oyapock River, highlighted the major contribution of environmental features to the incidence of malaria attacks. We propose a method for the objective selection of the best multivariate peridomestic landscape characterisation that maximises the chances of identifying relationships between environmental features and malaria incidence, statistically significant and meaningful from an epidemiological point of view. METHODS: A land-cover map, the hydrological network and the geolocalised inhabited houses were used to characterise the peridomestic landscape in eleven discoid buffers with radii of 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 metres. Buffer-based landscape characterisations were first compared in terms of their capacity to discriminate between sites within the geographic space and of their effective multidimensionality in variable space. The Akaike information criterion (AIC) was then used to select the landscape model best explaining the incidences of P. vivax and P. falciparum malaria. Finally, we calculated Pearson correlation coefficients for the relationships between environmental variables and malaria incidence, by species, for the more relevant buffers. RESULTS: The optimal buffers for environmental characterisation had radii of 100 m around houses for P. vivax and 400 m around houses for P. falciparum. The incidence of P. falciparum malaria seemed to be more strongly linked to environmental features than that of P. vivax malaria, within these buffers. The incidence of P. falciparum malaria in children was strongly correlated with proportions of bare soil (r = -0.69), land under high vegetation (r = 0.68) and primary forest (r = 0.54), landscape division (r = 0.48) and the number of inhabited houses (r = -0.60). The incidence of P. vivax malaria was associated only with landscape division (r = 0.49). CONCLUSIONS: The proposed methodology provides a simple and general framework for objective characterisation of the landscape to account for field observations. The use of this method enabled us to identify different optimal observation horizons around houses, depending on the Plasmodium species considered, and to demonstrate significant correlations between environmental features and the incidence of malaria.
ISSN: 1476-072X

inserm-00674075
http://www.hal.inserm.fr/inserm-00674075
http://www.hal.inserm.fr/inserm-00674075/document
http://www.hal.inserm.fr/inserm-00674075/file/1476-072X-10-65.pdf
DOI : 10.1186/1476-072X-10-65

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
UNLABELLED: ABSTRACT: BACKGROUND: High circulating parasite load is one of the WHO criteria for severe falciparum malaria. During a period of 11 years (2000-2010), the frequency of hyperparasitaemia (HP) (≥4% infected erythrocytes) during bouts of malaria due to Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae in patients referred to Cayenne General Hospital (CGH) in French Guiana and the frequency of their admission to the Intensive Care Unit (ICU) were evaluated. METHODS: A mean of 1,150 malaria cases were referred to the Parasitology Laboratory of CGH each year over the last decade. During this period, malaria diagnostic (microscopy) and parasitaemia evaluation have remained unchanged: determination of the parasitized erythrocytes percentage with asexual forms on thin blood smears for all cases of parasitaemia exceeding 0.1%. Patients admitted to the ICU can be counted by origin of the request for malaria testing. All the data collected retrospectively were anonymized in a standardized case report form and in database. RESULTS: Between 2000 and 2010, 12,254 bouts of malaria were confirmed at the Parasitology Laboratory of CHG: P. vivax: 56.2%, P. falciparum: 39.5%, co-infection with both species: 3.4%, P. malariae: 0.9%. HP was observed in 262 cases, at a frequency of 4.9% for P. falciparum and only 0.041% for P. vivax, with no recorded cases for P. malariae. The need for intensive care was correlated with P. falciparum parasite load: 12.3% of cases for parasitaemia of 4-9%, 21.2% for parasitaemia 10-19%, 50% for parasitaemia 20-29% and 77.8% for parasitaemia ≥30% (n=9). The patient with the highest parasitaemia (75% infected erythrocytes with asexual form) presented a major concomitant lupus flare-up treated with corticoids. He survived without obvious sequelae. CONCLUSIONS: In French Guiana during bouts of malaria, HP was observed at a frequency of ~ 5% for P. falciparum and two orders of magnitude less frequent for P. vivax. HP is a severity criterion for falciparum malaria in this endemic area. However, two of the patients with HP ≥30% were not admitted to the ICU and sequel-free cure in malaria patients with 75% parasitaemia is, therefore, possible.
ISSN: 1475-2875

inserm-00780740
http://www.hal.inserm.fr/inserm-00780740
http://www.hal.inserm.fr/inserm-00780740/document
http://www.hal.inserm.fr/inserm-00780740/file/1475-2875-12-20.pdf
DOI : 10.1186/1475-2875-12-20

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Malaria is a major public health problem in French Guiana, where Plasmodium vivax has become the dominant malaria species since 2000. As in others endemic areas, it is important to specify the pattern of vivax malaria relapses and to try to discriminate efficiently re-infections from relapses. METHODS: This study was conducted in children born between January 1, 2001 and December 31, 2008 in Camopi, an Amerindian village located in the Amazon forest (n = 325), using an open cohort design. Primary and secondary attack rates of P. vivax were calculated using survival analysis. With the difference between the primary and secondary rates, this study aimed to estimate indirectly P. vivax relapse rate and evaluate its time evolution. RESULTS: Of the 1042 malaria attacks recorded, 689 (66%) were due to P. vivax (without mixed infection). One hundred and fifty one children had their primary attack with P. vivax and 106 had their two first attacks with P. vivax. In the absence of primaquine treatment, it was shown that P. vivax relapses mainly occurred during the first three months after the first attack. Thirty percent of children never had a relapse, 42% had a relapse before the first month after primary attack, 59% before the second month and 63% before the third month. CONCLUSION: This study confirmed that the relapse pattern in Camopi was compatible with the pattern described for the P. vivax Chesson (tropical) strain. In addition, due to the relapse rate time evolution, a simple arbitrary classification rule could be constructed: before 90 days after the primary attack, the secondary attack is a relapse; after 90 days, it is a re-infection. Adapted management of malaria cases based on these results could be devised.
ISSN: 1475-2875

inserm-00663913
http://www.hal.inserm.fr/inserm-00663913
http://www.hal.inserm.fr/inserm-00663913/document
http://www.hal.inserm.fr/inserm-00663913/file/1475-2875-8-278.pdf
DOI : 10.1186/1475-2875-8-278

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
The hematocrit-to-viscosity ratio (HVR) has been widely used has an estimate of red blood cell (RBC) oxygen transport effectiveness into the microvasculature or as an oxygen delivery index. However, no study investigated the possibility of HVR to truly reflect RBC oxygen transport effectiveness or to be an oxygen delivery index. We measured blood viscosity at high shear rate (225 s −1), hematocrit, HVR, as well as the microvascular oxyhemoglobin saturation (TOI; tissue oxygen index) by spatial resolved near-infrared spectroscopy (NIRS) at cerebral and muscle levels in three population known to have various degrees of hemorheological abnormalities: healthy subjects (AA), patients with sickle cell SC disease (SC) characterized by moderate anemia and patients with sickle cell anemia (SS) marked by severe anemia. At both the cerebral and muscle level, HVR was positively correlated with TOI (r = 0.28; p = 0.03 and r = 0.38; p = 0.003, at the cerebral and muscle level, respectively). These findings suggest that HVR probably play a key role in blood flow and hemodynamic regulation in the microvasculature, hence modulating the amount of oxygen available for tissues. Nevertheless, the strengths of the associations are weak (R 2 < 0.50), suggesting that other determinants modulate microvascular blood flow and oxygenation, such as vascular geometry and vasomotor reserve.
ISSN: 1386-0291

hal-01163460
https://hal.univ-antilles.fr/hal-01163460
DOI : 10.3233/CH-131742

Éditeur(s) : HAL CCSD Lamb T. Wiley Blackwell.
Résumé : Le numéro ISSN inscrit dans ce dépôt est en fait le numéro ISBN, nous n'avons pas le numéro ISSN ISBN: 978-0-470-97247-2
Immunity to parasitic infection.

inserm-00838983
http://www.hal.inserm.fr/inserm-00838983
http://www.hal.inserm.fr/inserm-00838983/document
http://www.hal.inserm.fr/inserm-00838983/file/2013_Nacher_-_The_interaction_between_gastrointestinal_nematodes_and_malaria.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: Dengue and malaria are two major public health concerns in tropical settings. Although the pathogeneses of these two arthropod-borne diseases differ, their clinical and biological presentations are unspecific. During dengue epidemics, several hundred patients with fever and diffuse pain are weekly admitted at the emergency room. It is difficult to discriminate them from patients presenting malaria attacks. Furthermore, it may be impossible to provide a parasitological microscopic examination for all patients. This study aimed to establish a diagnostic algorithm for communities where dengue fever and malaria occur at some frequency in adults. METHODOLOGY/PRINCIPAL FINDINGS: A sub-study using the control groups of a case-control study in French Guiana - originally designed to compare dengue and malaria co-infected cases to single infected cases - was performed between 2004 and 2010. In brief, 208 patients with malaria matched to 208 patients with dengue fever were compared in the present study. A predictive score of malaria versus dengue was established using .632 bootstrap procedures. Multivariate analysis showed that male gender, age, tachycardia, anemia, thrombocytopenia, and CRP>5 mg/l were independently associated with malaria. The predictive score using those variables had an AUC of 0.86 (95%CI: 0.82-0.89), and the CRP was the preponderant predictive factor. The sensitivity and specificity of CRP>5 mg/L to discriminate malaria from dengue were of 0.995 (95%CI: 0.991-1) and 0.35 (95%CI 0.32-0.39), respectively. CONCLUSIONS/SIGNIFICANCE: The clinical and biological score performed relatively well for discriminating cases of dengue versus malaria. Moreover, using only the CRP level turned to be a useful biomarker to discriminate feverish patients at low risk of malaria in an area where both infections exist. It would avoid more than 33% of unnecessary parasitological examinations with a very low risk of missing a malaria attack.
ISSN: 1935-2727

inserm-00872353
http://www.hal.inserm.fr/inserm-00872353
http://www.hal.inserm.fr/inserm-00872353/document
http://www.hal.inserm.fr/inserm-00872353/file/journal.pntd.0002420.pdf
DOI : 10.1371/journal.pntd.0002420

Éditeur(s) : HAL CCSD
Résumé : Anopheles darlingi, one of the main malaria vectors in the Neotropics, is widely distributed in French Guiana, where malaria remains a major public-health problem. Elucidation of the relationships between the population dynamics of An. darlingi and local environmental factors would appear to be an essential factor in the epidemiology of human malaria in French Guiana and the design of effective vector-control strategies. In a recent investigation, longitudinal entomological surveys were carried out for 2-4 years in one village in each of three distinct endemic areas of French Guiana. Anopheles darlingi was always the anopheline mosquito that was most frequently caught on human bait, although its relative abundance (as a proportion of all the anophelines collected) and human biting rate (in bites/person-year) differed with the study site. Seasonality in the abundance of human-landing An. darlingi (with peaks at the end of the rainy season) was observed in only two of the three study sites. Just three An. darlingi were found positive for Plasmodium (either P. falciparum or P. vivax) circumsporozoite protein, giving entomological inoculation rates of 0*0-8*7 infectious bites/person-year. Curiously, no infected An. darlingi were collected in the village with the highest incidence of human malaria. Relationships between malaria incidence, An. darlingi densities, rainfall and water levels in the nearest rivers were found to be variable and apparently dependent on land-cover specificities that reflected the diversity and availability of habitats suitable for the development and reproduction of An. darlingi.
Annals of Tropical Medicine and Parasitology / Annals of Tropical Medicine & Parasitology

pasteur-00583507
https://hal-riip.archives-ouvertes.fr/pasteur-00583507
DOI : 10.1179/136485911X12899838683322
PUBMED : 21396247