Triangular test applied to the clinical trial of azithromycin against relapses in Plasmodium vivax infections

BACKGROUND: Sequential analysis enables repeated statistical analyses to be performed throughout a trial recruitment period, while maintaining a pre-specified power and type I error. Thus the trial can be stopped as soon as the information accumulated is considered sufficient to reach a conclusion. Sequential tests are easy to use and their statistical properties are especially suitable to trials with very straightforward objectives such as non-comparative phase II trials. We report on a phase II study based on the triangular test (TT) aiming at assessing the effectiveness of azithromycin in preventing Plasmodium vivax relapses. METHODS: To test whether the P. vivax relapse rate was either <12% or ≥ 45% in patients treated with azithromycin, a sequential analysis based on the TT was as used. Patients infected with P. vivax were treated with azithromycin, 1.2 g daily, for 7 days. The onset of a relapse infection was monitored. RESULTS: Five patients presenting with an acute P. vivax infection were included in the study. All the patients were initially cured. Three patients reported mild gastrointestinal adverse effects. When the third patient relapsed, the sample path crossed the upper boundary of the TT, and the trial was stopped. CONCLUSIONS: Using the triangular test, with only a small number of patients, we concluded that azithromycin was not effective enough in preventing P. vivax relapses to warrant further evaluation in phase III. It is suggested that a wider use of sequential analysis in phase II anti-infective drugs trials may have financial and ethical benefits

Relatively Low Prevalence of Peripheral and Placental Plasmodium Infection at Delivery in Bangui, Central African Republic

Introduction. The aim of this study was to estimate the prevalence of malaria among women giving birth in Bangui. Association between sociodemographic characteristics of those women and malaria, as well as prevention compliance (use of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTsp) and insecticide-treated bed nets (ITNs)), was analyzed. Methods. During September 2009, a survey was conducted on 328 women who gave birth at two main maternities of Bangui. Information was obtained by standardized questionnaire about sociodemographic criteria, IPTsp, other antimalarial treatment, and use of bet nets. Smears prepared from peripheral and placental blood were analysed for malaria parasites. Findings and Discussion. Positive results were found in 2.8% of thick peripheral blood smears and in 4.0% of placental slides. A proportion of 30.5% of the women had received at least two doses of IPTsp during the current pregnancy. Only a proportion of 42.4% of this study population had ITNs. Multigravid women were less likely to use IPTsp and ITNs. However, use of IPTsp was associated with personal income and secondary or university educational status. Hence, although this relatively prevalence was observed, more efforts are needed to implement IPTsp and ITNs, taking into account sociodemographic criteria

Pattern of the Antimalarials Prescription during Pregnancy in Bangui, Central African Republic

Introduction. The aim of this study was to identify the antimalarials prescribed during the pregnancy and to document their timing. Method. From June to September 2009, a survey was conducted on 565 women who gave birth in the Castors maternity in Bangui. The antenatal clinics cards were checked in order to record the types of antimalarials prescribed during pregnancy according to gestational age. Results. A proportion of 28.8% ANC cards contained at least one antimalarial prescription. The commonest categories of antimalarials prescribed were: quinine (56.7%), artemisinin-based combinations (26.8%) and artemisinin monotherapy (14.4%). Among the prescriptions that occurred in the first trimester of pregnancy, artemisinin-based combinations and artemisinin monotherapies represented the proportions of (10.9%) and (13.3%). respectively. Conclusion. This study showed a relatively high rate (>80%) of the recommended antimalarials prescription regarding categories of indicated antimalarials from national guidelines. But, there is a concern about the prescription of the artemisinin derivatives in the first trimester of pregnancy, and the prescription of artemisinin monotherapy. Thus, the reinforcement of awareness activities of health care providers on the national malaria treatment during pregnancy is suggested

Influence of oxygen on asexual blood cycle and susceptibility of Plasmodium falciparum to chloroquine: requirement of a standardized in vitro assay

OBJECTIVE: The main objective of this study was to assess the influence of gas mixtures on in vitro Plasmodium falciparum growth and 50% inhibitory concentration (IC(50)) for chloroquine. METHODS: The study was performed between February 2004 and December 2005. 136 Plasmodium falciparum isolates were used to evaluate gas mixtures effect on IC(50 )for chloroquine by isotopic microtest. The oxygen effect on asexual blood cycle of 3D7 and W2 clones was determined by thin blood smears examination and tritiated hypoxanthine uptake. RESULTS: From 5% O(2 )to 21% O(2 )conditions, no parasiticide effect of O(2 )concentration was observed in vitro on the clones 3D7 and W2. A parasitostatic effect was observed during the exposure of mature trophozoïtes and schizonts at 21% O(2 )with an increase in the length of schizogony. The chloroquine IC(50 )at 10% O(2 )were significantly higher than those at 21% O(2), means of 173.5 nM and 121.5 nM respectively (p < 0.0001). In particular of interest, among the 63 isolates that were in vitro resistant to chloroquine (IC(50 )> 100 nM) at 10% O(2), 17 were sensitive to chloroquine (IC(50 )< 100 nM) at 21% O(2). CONCLUSION: Based on these results, laboratories should use the same gas mixture to realize isotopic microtest. Further studies on comparison of isotopic and non-isotopic assays are needed to establish a standardized in vitro assay protocol to survey malaria drug resistance

Rabies Postexposure Prophylaxis, Marseille, France, 1994–2005

The administration of human rabies postexposure prophylaxis near Marseille (southern France) has changed since the eradication of terrestrial mammal rabies in 2001. Most injuries were associated with indigenous dogs; rabies vaccine was overprescribed. We suggest that the World Health Organization guidelines be adapted for countries free of terrestrial mammal rabies

Outdoor Augmented Reality: State of the Art and Issues

International audienceThe goal of an outdoor augmented reality system is to allow the human operator to move freely without restraint in its environment, to view and interact in real time with geo-referenced data via mobile wireless devices. This requires proposing new techniques for 3D localization, visualization and 3D interaction, adapted to working conditions in outdoor environment (brightness variation, features of displays used, etc.). This paper surveys recent advances in outdoor augmented reality. It resumes a large retrospective of the work carried out in this field, especially on methodological aspects (localization methods, generation of 3D models, visualization and interaction approaches), technological aspects (sensors, visualization devices and architecture software) and industrial aspects

Genetic Structure of Plasmodium falciparum and Elimination of Malaria, Comoros Archipelago

Elimination interventions should be implemented simultaneously throughout the entire archipelago