Delayed-Onset Hemolytic Anemia in Patients with Travel-Associated Severe Malaria Treated with Artesunate, France, 2011–2013

French Artesunate Working GroupInternational audienceArtesunate is the most effective treatment for severe malaria. However, delayed-onset hemolytic anemia has been observed in ≈20% of travelers who receive artesunate, ≈60% of whom require transfusion. This finding could discourage physicians from using artesunate. We prospectively evaluated a cohort of 123 patients in France who had severe imported malaria that was treated with artesunate; our evaluation focused on outcome, adverse events, and postartesunate delayed-onset hemolysis (PADH). Of the 123 patients, 6 (5%) died. Overall, 97 adverse events occurred. Among the 78 patients who received follow-up for >8 days after treatment initiation, 76 (97%) had anemia, and 21 (27%) of the 78 cases were recorded as PADH. The median drop in hemoglobin levels was 1.3 g/dL; 15% of patients with PADH had hemoglobin levels of <7 g/dL, and 1 required transfusion. Despite the high incidence of PADH, the resulting anemia remained mild in 85% of cases. This reassuring result confirms the safety and therapeutic benefit of artesunate

A micro-bead device to explore Plasmodium falciparum-infected, spherocytic or aged red blood cells prone to mechanical retention by spleen endothelial slits

Présentation oraleInternational audiencen.

Plasmodium falciparum Clearance Is Rapid and Pitting Independent in Immune Malian Children Treated With Artesunate for Malaria

Background. In Plasmodium falciparum-infected patients treated with artemisinins, parasitemia declines through so-called pitting, an innate splenic process that transforms infected red blood cells (iRBCs) into onceinfected RBCs (O-iRBCs). Methods. We measured pitting in 83 French travelers and 42 Malian children treated for malaria with artesunate. Results. In travelers, O-iRBCs peaked at 107.7% initial parasitemia. In Malian children aged 1.5-4 years, OiRBCs peaked at higher concentrations than in children aged 9-13 years (91.60% vs 31.95%; P = .0097). The parasite clearance time in older children was shorter than in younger children (P = .0001), and the decline in parasitemia in children aged 1.5-4 years often started 6 hours after treatment initiation, a lag phase generally absent in infants and older children. A 6-hour lag phase in artificial pitting of artesunate-exposed iRBCs was also observed in vitro. The proportion of iRBCs recognized by autologous immunoglobulin G (IgG) correlated with the parasite clearance time (r = −0.501; P = .0006) and peak O-iRBC concentration (r = −0.420; P = .0033). Conclusions. Antimalarial immunity correlates with fast artemisinin-induced parasite clearance and low pitting rates. In nonimmune populations, artemisinin-induced P. falciparum clearance is related to pitting and starts after a 6-hour lag phase. In immune populations, passively and naturally acquired immune mechanisms operating faster than pitting may exist. This mechanism may mitigate the emergence of artemisinin-resistant P. falciparum in Africa

Les Microsporidioses intestinales humaines (Evaluation d'outils immunologiques et moléculaires pour le diagnostic d'espèces et d'analyse des variations génétiques des isolats)

Deux espèces de microsporidies sont responsables de parasitisme intestinal chez l'homme, Encephalitozoon intestinalis et Enterocytozoon bieneusi. Le diagnostic d'espèce est indispensable pour débuter un traitement curatif spécifique et mieux préciser l'épidémiologie propre à chacune des espèces. Ce diagnostic reposait jusqu'à présent sur la microscopie électronique ou sur la PCR. Deux anticorps monoclonaux (AcMx) de type IgG, dirigés contre les parois des spores matures de ces deux espèces sont testés sur 78 échantillons de selles positives à microsporidies, collectées de septembre 1994 à février 2000 et conservées à +4C (67 dans le formol). Les résultats obtenus montrent que ces AcMx réagissent fortement et spécifiquement avec les spores en immunofluorescence indirecte (IFI-AcM). On retrouve 69 E. bieneusi, 6 E. intestinalis et 8 co-infections. Cette technique présente de nombreux avantages, facilité de mise en oeuvre, rapidité et réalisation et coût modéré en comparaison à la PCR et à la microscopie électronique comme technique de références. Elle peut être utilisé pour le diagnostic d'espèce de manière rétrospective sur des échantillons de selles conservées dans du formol. Concernant l'épidémiologie de l'espèce E. Bieneusi, les données sont encore très fragmentaires. Si la présence de spores de cette espèce à bien été retrouvée chez l'homme et de nombreux animaux proches de l'homme, aucune identité génétique n'a pu jusqu'à présent être établie entre les isolats humains et ceux des animaux. L'analyse de la séquence ITS (Internal Transcribed Spacer) du gène codant pour l'ARN ribosomal de E. bieneusi permet d'étudier les variations génétiques intra spécifiques...PARIS7-Villemin (751102101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Analyse d'une cohorte de patients suspects de paludisme d'importation au Groupe hospitalier Pitié-Salpêtrière en 2001 (intérêt de la PCR nichée pour le diagnostic d'espèce à plasmodium)

PARIS-BIUP (751062107) / SudocSudocFranceF

SIMS study of the calcium-deprivation step related to epidermal meristem production induced in flax by cold shock or radiation from a GSM telephone

Exposing seedlings of the flax, Linum usitatissimum L., to a variety of weak environmental stresses plus a 2-day calcium deprivation triggers the common response of production of epidermal meristems in the hypocotyl. Here, we show that the same response was induced by a 1 min cold shock. Epidermal meristem production was also induced by a single 2-h exposure to radiation emitted at 0.9 GHz at non-thermal levels by a GSM telephone. This flax-based system is therefore well suited to studying the effects of low intensity stimuli, including those of electromagnetic radiation. To begin to determine the underlying mechanisms, in which calcium is implicated, it is desirable to analyse the changes in ions in the tissues affected. We therefore performed a Secondary Ion Mass Spectrometry (SIMS) study of the distribution of the main inorganic cations in the hypocotyl of control and calcium-deprived seedlings. This showed decreases in calcium, sodium and potassium and an increase in magnesium that did not alter substantially the overall ratio of divalent to monovalent cations

[Epidemiology of importedmalaria to France].

International audienc

[Epidemiology of importedmalaria to France].

International audienc