Plasma circulating nucleic acids levels increase according to the morbidity of Plasmodium vivax malaria

Standardization of DNA extraction from paraffinized spleen samples: molecular diagnosis of human malaria

BACKGROUND

Plasmodium vivax is the main species responsible for human malaria in Brazil, and one of its manifestations is splenic malaria, though there are still challenges in its diagnosis. The present study aimed to standardize Plasmodium sp. DNA extraction from histological slices of spleen and diagnosis using real-time qPCR.

METHODS

This study performed a microtomy of a paraffin-embedded spleen as a positive control for P. vivax from a patient who had been previously diagnosed with the parasite. The sample was deparaffinized with xylol and ethanol, then DNA extraction was performed with two commercial kits. qPCR was carried out with the Taqman system for detection of Plasmodium sp. and was made species-specific using PvmtCOX1 gene. From 2015 to 2019, 200 spleen samples were obtained from trauma patients subjected to splenectomy in Manaus, Amazonas. All the samples were tested for cell-free human DNA (cfDNA).

RESULTS

The deparaffinization and the Plasmodium vivax DNA extraction method was successfully standardized, and the control sample was positive for P. vivax. Of the 200 samples, all qPCRs were negative, but they were positive for human PCR.

CONCLUSION

Paraffinization is practical and efficient for the preservation of samples, but the formation of bonds between proteins and DNA makes extraction difficult. Despite this, in this study, it was possible to standardize a method of DNA extraction for detecting P. vivax.

Trends in clinical features and severity of Plasmodium vivax malaria among children at tertiary care center in North India

BACKGROUND

Malaria is a significant cause of morbidity and mortality in adults and children. Plasmodium falciparum is the primary cause of severe malaria, but recently Plasmodium vivax is also recognized to cause severe malaria-associated morbidity and mortality. The study focuses on determining the mortality related to severity parameters in individuals under 12 years and their critical presentation in P.vivax malaria-infected children.

METHODS

A prospective cross-sectional hospital-based study was conducted at Safdarjung Hospital, New Delhi, and ICMR-NIMR, New Delhi. All clinically suspected cases were admitted for screening. Exclusion criteria (rapid malaria antigen test, microscopy and medication history) were applied to all the admitted patients (n = 221) to obtain P.vivax patients only. Patients aged ≤ 12 years were included in the study. DNA was extracted from dried blood spots and amplified by nested PCR, followed by visualization on gel electrophoresis.

RESULT

A total of 221 clinically suspected cases of malaria were screened for P.vivax. After implementing various exclusion criteria, 45/221 cases were enrolled for the study, among which 44.4% (20/45) of children had the symptoms of severe malaria in terms of cerebral malaria, thrombocytopenia, anemia, pancytopenia, acute respiratory distress syndrome and hemophagocytic lymphohistiocytosis.

CONCLUSION

Plasmodium vivax mono-infection can cause severe manifestation and must be treated as P.falciparum without any delay because it may lead to increased morbidity and mortality. A changing trend in clinical symptoms has shown in P.vivax which was an earlier phenomenon of P.falciparum.

Ultralow-Fouling Zwitterionic Polyurethane-Modified Membranes for Rapid Separation of Plasma from Whole Blood

The separation of plasma from blood cells in whole blood is an essential step for many diagnostic and therapeutic applications. However, the current point-of-care plasma separation approaches have not yet satisfied the need for a rapid, high-flux, and low-cost process. Here, we report a portable, low-cost, disposable membrane-based plasma separation device that enables rapid plasma extraction from whole blood. Rapid separation of plasma can be obtained with a simple three-step operation: blood injection, separation, and plasma collection. Our device benefits from the zwitterionic polyurethane-modified cellulose acetate (PCBU-CA) membrane, which can greatly inhibit the surface fouling of blood cells and membrane flux decline. The zwitterionic coating is stable on the membrane surface during blood filtration and leads to a 60% decrease in surface fibrinogen adsorption than a nonmodified membrane surface. The ultralow-blood-fouling properties of the PCBU-CA membrane enable rapid, continuous separation of plasma: within 10 min, the device can yield 0.5-0.7 mL of plasma from 10 mL of whole blood. The extracted plasma is verified as cell-free, exhibits a low hemoglobin level, and has a high protein recovery. Our PCBU-CA membrane provides a pathway for developing a high-efficiency portable plasma separation device that can reduce the time to diagnosis, allow effective patient care, and eventually reduce hospital costs.

Epidemiology and clinical outcomes of severe Plasmodium vivax malaria in India

OBJECTIVES

A systematic review and meta-analysis (SR-MA) of the available Indian literature on severe vivax malaria (SVM) was undertaken.

METHODS

Relevant studies in eight electronic databases were retrieved and reviewed. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. The methodological quality of the studies included in the MA was assessed.

RESULTS

Overall, 162 studies were included in the work. The pooled proportion of SVM was 29.3%. The main severity signs/symptoms seen in SVM were jaundice, severe thrombocytopenia (ST), multi-organ dysfunction, and severe anaemia with pooled proportion of 37.4%, 37.2%, 24.2% and 20.4%, respectively. P. falciparum was inducing 6% less ST (RR = 0.94, 95% CI 0.5-1.5, I² = 77.87%), 10% less thrombocytopenia (RR = 0.9, 95% CI 0.7-1.1, I² = 91.68%) and 20% less DIC (RR = 0.8, 95% CI 0.3-1.9, I² = 0%) than P. vivax. An atypical condition like myocarditis, was most commonly observed among the studied SVM cases. The mortality rate in SVM cases ranged from 0 to 12.9% among hospital patients with P. vivax mono-infections.

CONCLUSIONS

The present SR-MA provides evidence for P. vivax as the etiologic agent of severe malaria leading to deaths in few cases as seen recently in India. However, research gaps outlined here emphasise the need for further studies on SVM in pregnancy, SVM in drug resistance and correlations with cytoadherence in disease severity due to P. vivax.

The Interface Between Inflammatory Mediators and MicroRNAs in Plasmodium vivax Severe Thrombocytopenia

Severe thrombocytopenia can be a determinant factor in the morbidity of Plasmodium vivax, the most widespread human malaria parasite. Although immune mechanisms may drive P. vivax-induced severe thrombocytopenia (PvST), the current data on the cytokine landscape in PvST is scarce and often conflicting. Here, we hypothesized that the analysis of the bidirectional circuit of inflammatory mediators and their regulatory miRNAs would lead to a better understanding of the mechanisms underlying PvST. For that, we combined Luminex proteomics, NanoString miRNA quantification, and machine learning to evaluate an extensive array of plasma mediators in uncomplicated P. vivax patients with different degrees of thrombocytopenia. Unsupervised clustering analysis identified a set of PvST-linked inflammatory (CXCL10, CCL4, and IL-18) and regulatory (IL-10, IL-1Ra, HGF) mediators. Among the mediators associated with PvST, IL-6 and IL-8 were critical to discriminate P. vivax subgroups, while CCL2 and IFN-γ from healthy controls. Supervised machine learning spotlighted IL-10 in P. vivax-mediated thrombocytopenia and provided evidence for a potential signaling route involving IL-8 and HGF. Finally, we identified a set of miRNAs capable of modulating these signaling pathways. In conclusion, the results place IL-10 and IL-8/HGF in the center of PvST and propose investigating these signaling pathways across the spectrum of malaria infections.

Association of cfDNA levels and bothrops envenomation

In the Amazon, around 90% of snakebites are caused by the Bothrops genus. Complications arising from Bothrops envenomations result from the inflammatory and coagulotoxic activities of the venom. The aim of this study was to investigate the potential of cell-free DNA (cfDNA) as a biomarker of severity in Bothrops snakebites. Patients were treated at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, in the Brazilian Amazon. cfDNA plasma levels were measured by amplifying the human telomerase reverse transcriptase (hTERT) sequence using quantitative RT-PCR. Median levels of cfDNA were compared between envenomed and healthy volunteers and among patients presenting different complications, such as renal failure, bleeding and infection. Of the 76 patients included, 82.9% were male, with a mean age of 32.8 years, and envenomations were mainly classified as severe (39.5%). ROC curve analysis showed a good accuracy of cfDNA levels (AUROC of 0.745) in envenomation diagnosis. A correlation analysis using laboratory variables showed positive correlation with lactate dehydrogenase (p = 0.033) and platelet count (p = 0.003). When cfDNA levels were compared with clinical complications, significant statistical differences were only found among individuals with mild and severe pain (p < 0.05). In summary, our results demonstrated that cfDNA levels are sufficiently accurate for discriminating between envenomed and non-envenomed patients, but are not able to distinguish different complications and the level of severity among envenomed patients. Thus, the role of cfDNA in the pathogenesis of the snakebite envenomations needs to be further investigated.

Plasma cell-free DNA predicts pediatric cerebral malaria severity

BACKGROUNDPrediction of adverse outcomes in cerebral malaria (CM) is difficult. We hypothesized that cell-free DNA (cfDNA) levels would facilitate identification of severe and potentially fatal CM cases.METHODSIn this retrospective study, plasma from Malawian children with CM (n = 134), uncomplicated malaria (UM, n = 77), and healthy controls (HC, n = 60) was assayed for cfDNA using a fluorescence assay. Host and parasite cfDNA was measured by quantitative PCR. Immune markers were determined by ELISA, Luminex, or cytometric bead array.RESULTSTotal cfDNA increased with malaria severity (HC versus UM, P < 0.001; HC versus CM, P < 0.0001; UM versus CM, P < 0.0001), was elevated in retinopathy-positive (Ret+) CM relative to Ret- CM (7.66 versus 5.47 ng/μL, P = 0.027), and differentiated Ret+ fatal cases from survivors (AUC 0.779; P < 0.001). cfDNA levels in patients with non-malarial febrile illness (NMF, P = 0.25) and non-malarial coma (NMC, P = 0.99) were comparable with UM. Host DNA, rather than parasite DNA, was the major cfDNA contributor (UM, 268 versus 67 pg/μL; CM, 2824 versus 463 pg/μL). Host and parasite cfDNA distinguished CM by retinopathy (host, AUC 0.715, P = 0.0001; parasite, AUC 0.745, P = 0.0001), but only host cfDNA distinguished fatal cases (AUC 0.715, P = 0.0001). Total cfDNA correlated with neutrophil markers IL-8 (rs = 0.433, P < 0.0001) and myeloperoxidase (rs = 0.683, P < 0.0001).CONCLUSIONQuantifying plasma cfDNA is a simple assay useful in identifying children at risk for fatal outcome and has promise as a point-of-care assay. Elevated cfDNA suggests a link with host inflammatory pathways in fatal CM.FUNDINGNIH NCATS (AK), Burroughs-Wellcome (AK), and National Health and Medical Research Council of Australia (SJR).

The immunology of Plasmodium vivax malaria

Plasmodium vivax infection, the predominant cause of malaria in Asia and Latin America, affects ~14 million individuals annually, with considerable adverse effects on wellbeing and socioeconomic development. A clinical hallmark of Plasmodium infection, the paroxysm, is driven by pyrogenic cytokines produced during the immune response. Here, we review studies on the role of specific immune cell types, cognate innate immune receptors, and inflammatory cytokines on parasite control and disease symptoms. This review also summarizes studies on recurrent infections in individuals living in endemic regions as well as asymptomatic infections, a serious barrier to eliminating this disease. We propose potential mechanisms behind these repeated and subclinical infections, such as poor induction of immunological memory cells and inefficient T effector cells. We address the role of antibody-mediated resistance to P. vivax infection and discuss current progress in vaccine development. Finally, we review immunoregulatory mechanisms, such as inhibitory receptors, T regulatory cells, and the anti-inflammatory cytokine, IL-10, that antagonizes both innate and acquired immune responses, interfering with the development of protective immunity and parasite clearance. These studies provide new insights for the clinical management of symptomatic as well as asymptomatic individuals and the development of an efficacious vaccine for vivax malaria.

Severe thrombocytopaenia in patients with vivax malaria compared to falciparum malaria: a systematic review and meta-analysis

Background

Plasmodium vivax is the most geographically widespread species among human malaria parasites. Immunopathological studies have shown that platelets are an important component of the host innate immune response against malaria infections. The objectives of this study were to quantify thrombocytopaenia in P. vivax malaria patients and to determine the associated risks of severe thrombocytopaenia in patients with vivax malaria compared to patients with P. falciparum malaria.

Main body

A systematic review and meta-analysis of the available literature on thrombocytopaenia in P. vivax malaria patients was undertaken. Relevant studies in health-related electronic databases were identified and reviewed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Fifty-eight observational studies (n = 29 664) were included in the current review. Severe thrombocytopaenia (< 50 000/mm³) to very severe thrombocytopaenia (< 20 000/mm³) was observed in 10.1% of patients with P. vivax infection. A meta-analysis of 11 observational studies showed an equal risk of developing severe/very severe thrombocytopaenia between the patients with P. vivax malaria and those with P. falciparum malaria (OR: 1.98, 95% CI: 0.92–4.25). This indicates that thrombocytopaenia is as equally a common manifestation in P. vivax and P. falciparum malaria patients. One study showed a higher risk of developing very severe thrombocytopaenia in children with severe P. vivax malaria than with severe P. falciparum malaria (OR: 2.80, 95% CI: 1.48–5.29). However, a pooled analysis of two studies showed an equal risk among adult severe cases (OR: 1.19, 95% CI: 0.51–2.77). This indicates that the risk of developing thrombocytopaenia in P. vivax malaria can vary with immune status in both children and adults. One study reported higher levels of urea and serum bilirubin in patients with P. vivax malaria and severe thrombocytopaenia compared with patients mild thrombocytopaenia or no thrombocytopaenia, (P < 0.001 in all comparisons). A pooled analysis of two other studies showed a similar proportion of bleeding episodes with thrombocytopaenia in severe P. vivax patients and severe P. falciparum patients (P = 0.09). This implied that both P. vivax and P. falciparum infections could present with bleeding episodes, if there had been a change in platelet counts in the infected patients. A pooled analysis of another two studies showed an equal risk of mortality with severe thrombocytopaenia in both P. vivax and P. falciparum malaria patients (OR: 1.16, 95% CI: 0.30–4.60). However, due to the low number of studies with small sample sizes within the subset of studies that provided clinically relevant information, our confidence in the estimates is limited.

Conclusion

The current review has provided some evidence of the clinical relevance of severe thrombocytopaenia in P. vivax malaria. To substantiate these findings, there is a need for well designed, large-scale, prospective studies among patients infected with P. vivax. These should include patients from different countries and epidemiological settings with various age and gender groups represented.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0392-9) contains supplementary material, which is available to authorized users.

Plasma metabolomics reveals membrane lipids, aspartate/asparagine and nucleotide metabolism pathway differences associated with chloroquine resistance in Plasmodium vivax malaria

Background

Chloroquine (CQ) is the main anti-schizontocidal drug used in the treatment of uncomplicated malaria caused by Plasmodium vivax. Chloroquine resistant P. vivax (PvCR) malaria in the Western Pacific region, Asia and in the Americas indicates a need for biomarkers of resistance to improve therapy and enhance understanding of the mechanisms associated with PvCR. In this study, we compared plasma metabolic profiles of P. vivax malaria patients with PvCR and chloroquine sensitive parasites before treatment to identify potential molecular markers of chloroquine resistance.

Methods

An untargeted high-resolution metabolomics analysis was performed on plasma samples collected in a malaria clinic in Manaus, Brazil. Male and female patients with Plasmodium vivax were included (n = 46); samples were collected before CQ treatment and followed for 28 days to determine PvCR, defined as the recurrence of parasitemia with detectable plasma concentrations of CQ ≥100 ng/dL. Differentially expressed metabolic features between CQ-Resistant (CQ-R) and CQ-Sensitive (CQ-S) patients were identified using partial least squares discriminant analysis and linear regression after adjusting for covariates and multiple testing correction. Pathway enrichment analysis was performed using Mummichog.

Results

Linear regression and PLS-DA methods yielded 69 discriminatory features between CQ-R and CQ-S groups, with 10-fold cross-validation classification accuracy of 89.6% using a SVM classifier. Pathway enrichment analysis showed significant enrichment (p<0.05) of glycerophospholipid metabolism, glycosphingolipid metabolism, aspartate and asparagine metabolism, purine and pyrimidine metabolism, and xenobiotics metabolism. Glycerophosphocholines levels were significantly lower in the CQ-R group as compared to CQ-S patients and also to independent control samples.

Conclusions

The results show differences in lipid, amino acids, and nucleotide metabolism pathways in the plasma of CQ-R versus CQ-S patients prior to antimalarial treatment. Metabolomics phenotyping of P. vivax samples from patients with well-defined clinical CQ-resistance is promising for the development of new tools to understand the biological process and to identify potential biomarkers of PvCR.

Self-driven filter-based blood plasma separator microfluidic chip for point-of-care testing

There is currently a growing need for lab-on-a-chip devices for use in clinical analysis and diagnostics, especially in the area of patient care. The first step in most blood assays is plasma extraction from whole blood. This paper presents a novel, self-driven blood plasma separation microfluidic chip, which can extract more than 0.1 μl plasma from a single droplet of undiluted fresh human blood (~5 μl). This volume of blood plasma is extracted from whole blood with high purity (more than 98%) in a reasonable time frame (3 to 5 min), and without the need for any external force. This would be the first step towards the realization of a single-use, self-blood test that does not require any external force or power source to deliver and analyze a fresh whole-blood sample, in contrast to the existing time-consuming conventional blood analysis. The prototypes are manufactured in polydimethylsiloxane that has been modified with a strong nonionic surfactant (Silwet L-77) to achieve hydrophilic behavior. The main advantage of this microfluidic chip design is the clogging delay in the filtration area, which results in an increased amount of extracted plasma (0.1 μl). Moreover, the plasma can be collected in one or more 10 μm-deep channels to facilitate the detection and readout of multiple blood assays. This high volume of extracted plasma is achieved thanks to a novel design that combines maximum pumping efficiency without disturbing the red blood cells' trajectory through the use of different hydrodynamic principles, such as a constriction effect and a symmetrical filtration mode. To demonstrate the microfluidic chip's functionality, we designed and fabricated a novel hybrid microdevice that exhibits the benefits of both microfluidics and lateral flow immunochromatographic tests. The performance of the presented hybrid microdevice is validated using rapid detection of thyroid stimulating hormone within a single droplet of whole blood.

Antithrombotic therapy: new areas to understand efficacy and bleeding

INTRODUCTION

Therapeutic options for antithrombotic therapy are limited due to associated adverse bleeding events. Traditionally, the antithrombotic effects of these agents have been closely linked with concomitant risks in bleeding complications.

AREAS COVERED

This article will review recent developments in the understanding of the mechanisms underlying physiological hemostasis and pathological thrombosis as well as key findings that may serve to 'uncouple' these two processes. In addition, we highlight the recent work identifying novel therapeutic agents targeting these novel mechanisms of pathological thrombus formation.

EXPERT OPINION

Recent research has identified several novel mediators of thrombus formation, including cell-free nucleic acids, histones, histone-DNA complexes and neutrophil extracellular traps that may serve to link inflammation and thrombosis as well as separate physiological hemostasis from pathological thrombosis. Researchers are developing ligands to target these mediators with an achievable goal to identify novel therapies that inhibit thrombus formation without increased bleeding risk.

Innate sensing of malaria parasites

Innate immune receptors have a key role in immune surveillance by sensing microorganisms and initiating protective immune responses. However, the innate immune system is a classic 'double-edged sword' that can overreact to pathogens, which can have deleterious effects and lead to clinical manifestations. Recent studies have unveiled the complexity of innate immune receptors that function as sensors of Plasmodium spp. in the vertebrate host. This Review highlights the cellular and molecular mechanisms by which Plasmodium infection is sensed by different families of innate immune receptors. We also discuss how these events mediate both host resistance to infection and the pathogenesis of malaria.

Altered platelet indices as potential markers of severe and complicated malaria caused by Plasmodium vivax: a cross-sectional descriptive study

Background

This study described altered platelet indices in patients with acute malaria caused by Plasmodium vivax and determined whether these alterations are associated with warning signs of severe and complicated malaria.

Methods

A total of 186 patients attending the Malaria Clinic at the University Hospital from the Federal University of Mato Grosso, Brazil, between 2008 and 2013 were included in this study. After parasitological confirmation of exclusive infection by P. vivax, blood cell counts and platelet indices were determined. Disease gravity was evaluated on the basis of classic signs of Plasmodium falciparum severe malaria, including severe anemia, or by changes in serum levels of glucose, bilirubin, aminotransferases and creatinine at the time of the patient’s admission. Patients with a longer duration of symptoms or those identified as primo infected were considered potential candidates for evolution into the severe form of malaria.

Results

The mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT) values exhibited significant variability. A significant inverse relationship was observed between parasitaemia and PCT. Patients with warning signs for evolution into severe disease, with primo infection, or presenting with symptoms for over three days had the highest MPV and PDW. The adjusted analyses showed the presence of warning signs for the development of severe and complicated malaria remained independently linked to elevated MPV and PDW.

Conclusion

Altered platelet indices should be analysed as potential markers for the severity of malaria caused by P. vivax. Future studies with appropriate methodology for prognostic evaluation could confirm the potential use of these indices in clinical practice.

Micro-scale blood plasma separation: from acoustophoresis to egg-beaters

Plasma is a rich mine of various biomarkers including proteins, metabolites and circulating nucleic acids. The diagnostic and therapeutic potential of these analytes has been quite recently uncovered, and the number of plasma biomarkers will still be growing in the coming years. A significant part of the blood plasma preparation is still handled manually, off-chip, via centrifugation or filtration. These batch methods have variable waiting times, and are often performed under non-reproducible conditions that may impair the collection of analytes of interest, with variable degradation. The development of miniaturised modules capable of automated and reproducible blood plasma separation would aid in the translation of lab-on-a-chip devices to the clinical market. Here we propose a systematic review of major plasma analytes and target applications, alongside existing solutions for micro-scale blood plasma extraction, focusing on the approaches that have been biologically validated for specific applications.

Current challenges in travelers' malaria

Travel health providers are often confronted with complex scenarios when advising travelers on malaria prevention. Current challenges in prevention include malaria risk assessment, where a detailed itinerary and knowledge of malaria epidemiology are needed. Up-to-date information on the correct use, limitations, and drug interactions of current priority chemoprophylaxis agents (atovaquone/proguanil, mefloquine, doxycycline) is key. Another challenge is to identify and reach travelers who are most at risk of malaria, such as the traveler visiting friends and relatives. Posttravel, delays in presentation, diagnosis, and inappropriate treatment of malaria are key risk factors leading to death. Treatment of malaria is an emergency requiring expert in-patient management and referral to a center with adequate expertise. Artemisinin combination therapies are the drugs of choice for uncomplicated malaria. Complicated malaria is treated preferably with intravenous artesunate, and the supply and quality of this life-saving antimalarial in some settings can pose one of the most urgent challenges in travelers' malaria.

Genetic variability in platelet integrin α2β1 density: possible contributor to Plasmodium vivax-induced severe thrombocytopenia

Understanding the pathogenesis of Plasmodium vivax malaria is challenging. We hypothesized that susceptibility to P. vivax-induced thrombocytopenia could be associated with polymorphisms on relevant platelet membrane integrins: integrin α2 (C807T), and integrin β3 (T1565C). Although β3 polymorphism was not related with P. vivax malaria, α2 807T carriers, which show high levels of integrin α2β1, had a higher probability for severe thrombocytopenia than wild-type carriers. This evidence of the association of integrin polymorphism and P. vivax morbidity was further demonstrated by a moderate but significant correlation between clinical disease and surface levels of the integrin α2β1.

Management of imported malaria in Europe

In this position paper, the European Society for Clinical Microbiology and Infectious Diseases, Study Group on Clinical Parasitology, summarizes main issues regarding the management of imported malaria cases. Malaria is a rare diagnosis in Europe, but it is a medical emergency. A travel history is the key to suspecting malaria and is mandatory in patients with fever. There are no specific clinical signs or symptoms of malaria although fever is seen in almost all non-immune patients. Migrants from malaria endemic areas may have few symptoms.Malaria diagnostics should be performed immediately on suspicion of malaria and the gold- standard is microscopy of Giemsa-stained thick and thin blood films. A Rapid Diagnostic Test (RDT) may be used as an initial screening tool, but does not replace urgent microscopy which should be done in parallel. Delays in microscopy, however, should not lead to delayed initiation of appropriate treatment. Patients diagnosed with malaria should usually be hospitalized. If outpatient management is preferred, as is the practice in some European centres, patients must usually be followed closely (at least daily) until clinical and parasitological cure. Treatment of uncomplicated Plasmodium falciparum malaria is either with oral artemisinin combination therapy (ACT) or with the combination atovaquone/proguanil. Two forms of ACT are available in Europe: artemether/lumefantrine and dihydroartemisinin/piperaquine. ACT is also effective against Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi, but these species can be treated with chloroquine. Treatment of persistent liver forms in P. vivax and P. ovale with primaquine is indicated after excluding glucose 6 phosphate dehydrogenase deficiency. There are modified schedules and drug options for the treatment of malaria in special patient groups, such as children and pregnant women. The potential for drug interactions and the role of food in the absorption of anti-malarials are important considerations in the choice of treatment.Complicated malaria is treated with intravenous artesunate resulting in a much more rapid decrease in parasite density compared to quinine. Patients treated with intravenous artesunate should be closely monitored for haemolysis for four weeks after treatment. There is a concern in some countries about the lack of artesunate produced according to Good Manufacturing Practice (GMP).

Vesicles as carriers of virulence factors in parasitic protozoan diseases

Different types of shed vesicles as, for example, exosomes, plasma-membrane-derived vesicles or microparticles, are the focus of intense research in view of their potential role in cell-cell communication and under the perspective that they might be good tools for immunotherapy, vaccination or diagnostic purposes. This review discusses ways employed by pathogenic trypanosomatids to interact with the host by shedding vesicles that contain molecules important for the establishment of infection, as opposed to previous beliefs considering them as a waste of cellular metabolism. Trypanosomatids are compared with Apicomplexa, which circulate parasite antigens bound to vesicles shed by host cells. The knowledge of the origin and chemical composition of these different vesicles might lead to the understanding of the mechanisms that determine their biological function.