Tephrosia toxicaria (Sw.) Pers. extracts: Screening by examining aedicidal action under laboratory and field conditions along with its antioxidant, antileishmanial, and antimicrobial activities.

An increase in the incidence of arboviral, microbial and parasitic infections, and to disorders related to oxidative stress has encouraged the development of adjuvant therapies based on natural formulations, such as those involving plant extracts. Thus, to expand the repertoire of the available therapeutic options, this study aimed to describe the versatility of Tephrosia toxicaria (Sw.) (Pers., 1807) extracts for the control of arbovirus vectors, as well as their antioxidant, antileishmanial, and antimicrobial potential. Among the aqueous and hydroethanolic extracts obtained, the hydroethanolic extract from roots (RHA) was identified as the most active larvicide extract demonstrating, respectively, the lowest lethal concentration (mg/mL) for 50%, 90% and 99% of Aedes aegypti (L., 1762) and Aedes albopictus (S., 1894) larvae, observed at 24 h (0.33, 0.84 and 1.80; 0.32, 0.70 and 1.32) and 48 h (0.17, 0.51 and 1.22; 0.26, 0.47 and 0.78) post-exposure. Field assays revealed that RHA (0.84 mg/mL) is a potential oviposition deterrent, reducing egg-laying by approximately 90%. RHA (0.1 mg/mL) also exhibited antioxidant activity for the following tests: total antioxidant capacity (286.86 mg AAE/g), iron (87.16%) and copper (25.64%) chelation, and superoxide scavenging (10%). In the cell culture assays, RHA (0.1 mg/mL) promoted regeneration of metabolic activity (92% cell viability) in cells exposed to oxidative stress. Furthermore, RHA displayed weak antileishmanial activity (IC50 = 3.53 mg/mL) against Leishmania amazonensis and not exhibit antimicrobial activity. The extraction favored the concentration of carbohydrates in RHA, in addition to lectins and protease inhibitors, with molecular masses estimated between 10 and 24 kDa. Cytotoxicity and phytotoxicity analyses of RHA suggested its biosecurity. Thus, RHA is a multivalent extract with insecticide and antioxidant properties at low and safe concentrations. However, others studies on its indirect toxic effects are ongoing to ensure the complete safety of RHA.

pH-responsive phthalate cashew gum nanoparticles for improving drugs delivery and anti-Trypanosoma cruzi efficacy.

Nanotechnology is a crucial technology in recent years has resulted in new and creative applications of nanomedicine. Polymeric nanoparticles have increasing demands in pharmaceutical applications and require high reproducibility, homogeneity, and control over their properties. Work explores the use of cashew phthalate gum (PCG) as a particle-forming polymer. PCG exhibited a pH-sensitive behavior due to the of acid groups on its chains, and control drug release. We report the development of nanoparticles carrying benznidazole. Formulations were characterized by DLS, encapsulation efficiency, drug loading, FTIR, pH-responsive behavior, release, and in vitro kinetics. Interaction between polymer and drug was an evaluated by molecular dynamics. Morphology was observed by SEM, and in vitro cytotoxicity by MTT assay. Trypanocidal effect for epimastigote and trypomastigote forms was also evaluated. NPs responded to the slightly basic pH, triggering the release of BNZ. In acidic medium, they presented small size, spherical shape, and good stability. It was indicated NP with enhanced biological activity, reduced cytotoxicity, high anti T. cruzi performance, and pH-sensitive release. This work investigated properties related to the development and enhancement of nanoparticles. PCG has specific physicochemical properties that make it a promising alternative to drug delivery, however, there are still challenges to be overcome.

Quantum Biochemistry Screening and In Vitro Evaluation of Leishmania Metalloproteinase Inhibitors.

Leishmanolysin, also known as major promastigote protease (PSP) or gp63, is the most abundant surface glycoprotein of Leishmania spp., and has been extensively studied and recognized as the main parasite virulence factor. Characterized as a metalloprotease, gp63 can be powerfully inactivated in the presence of a metal chelator. In this study, we first used the structural parameters of a 7-hydroxycoumarin derivative, L1 compound, to evaluate the theoretical-computational experiments against gp63, comparing it with an available metal chelator already described. The methodology followed was (i) analysis of the three-dimensional structure of gp63 as well as its active site, and searching the literature and molecular databases for possible inhibitors; (ii) molecular docking simulations and investigation of the interactions in the generated protein-ligand complexes; and (iii) the individual energy of the gp63 amino acids that interacted most with the ligands of interest was quantified by ab initio calculations using Molecular Fraction with Conjugated Caps (MFCC). MFCC still allowed the final quantum balance calculations of the protein interaction to be obtained with each inhibitor candidate binder. L1 obtained the best energy quantum balance result with -2 eV, followed by DETC (-1.4 eV), doxycycline (-1.3 eV), and 4-terpineol (-0.6 eV), and showed evidence of covalent binding in the enzyme active site. In vitro experiments confirmed L1 as highly effective against L. amazonensis parasites. The compound also exhibited a low cytotoxicity profile against mammalian RAW and 3T3 cells lines, presenting a selective index of 149.19 and 380.64 µM, respectively. L1 induced promastigote forms' death by necrosis and the ultrastructural analysis revealed disruption in membrane integrity. Furthermore, leakage of the contents and destruction of the parasite were confirmed by Spectroscopy Dispersion analysis. These results together suggested L1 has a potential effect against L. amazonensis, the etiologic agent of diffuse leishmaniasis, and the only one that currently does not have a satisfactory treatment.

Silver Nanoparticles Containing Fucoidan Synthesized by Green Method Have Anti-Trypanosoma cruzi Activity.

The brown seaweed Spatoglossum schröederi synthesizes three bioactive fucoidans, the most abundant of which is fucan A. This fucoidan was extracted and its identity was confirmed by chemical analysis, Fourier-transform infrared spectroscopy (FTIR), and agarose gel electrophoresis. Thereafter, silver nanoparticles containing fucan A (AgFuc) were produced using an environmentally friendly synthesis method. AgFuc synthesis was analyzed via UV-vis spectroscopy and FTIR, which confirmed the presence of both silver and fucan A in the AgFuc product. Dynamic light scattering (DLS), X-ray diffraction, scanning electron microscopy, and atomic force microscopy revealed that the AgFuc particles were ~180.0 nm in size and spherical in shape. DLS further demonstrated that AgFuc was stable for five months. Coupled plasma optical emission spectrometry showed that the AgFuc particles contained 5% silver and 95% sugar. AgFuc was shown to be more effective in inhibiting the ability of parasites to reduce MTT than fucan A or silver, regardless of treatment time. In addition, AgFuc induced the death of ~60% of parasites by necrosis and ~17% by apoptosis. Therefore, AgFuc induces damage to the parasites' mitochondria, which suggests that it is an anti-Trypanosoma cruzi agent. This is the first study to analyze silver nanoparticles containing fucan as an anti-Trypanosoma cruzi agent. Our data indicate that AgFuc nanoparticles have potential therapeutic applications, which should be determined via preclinical in vitro and in vivo studies.

In Vitro Validation of Antiparasitic Activity of PLA-Nanoparticles of Sodium Diethyldithiocarbamate against Trypanosoma cruzi.

Trypanosoma cruzi is a protozoan parasite responsible for Chagas disease, which affects millions around the world and is not treatable in its chronic stage. Sodium diethyldithiocarbamate is a compound belonging to the carbamate class and, in a previous study, demonstrated high efficacy against T. cruzi, showing itself to be a promising compound for the treatment of Chagas disease. This study investigates the encapsulation of sodium diethyldithiocarbamate by poly-lactic acid in nanoparticles, a system of biodegradable nanoparticles that is capable of reducing the toxicity caused by free DETC against cells and maintaining the antiparasitic activity. The nanosystem PLA-DETC was fabricated using nanoprecipitation, and its physical characterization was measured via DLS, SEM, and AFM, demonstrating a small size around 168 nm and a zeta potential of around -19 mv. Furthermore, the toxicity was determined by MTT reduction against three cell lines (VERO, 3T3, and RAW), and when compared to free DETC, we observed a reduction in cell mortality, demonstrating the importance of DETC nanoencapsulation. In addition, the nanoparticles were stained with FITC and put in contact with cells for 24 h, followed by confirmation of whether the nanosystem was inside the cells. Lastly, the antiparasitic activity against different strains of T. cruzi in trypomastigote forms was determined by resazurin reduction and ROS production, which demonstrated high efficacy towards T. cruzi equal to that of free DETC.

Insights of antiparasitic activity of sodium diethyldithiocarbamate against different strains of Trypanosoma cruzi.

Chagas disease is caused by Trypanosoma cruzi and affects thousands of people. Drugs currently used in therapy are toxic and have therapeutic limitations. In addition, the genetic diversity of T. cruzi represents an important variable and challenge in treatment. Sodium diethyldithiocarbamate (DETC) is a compound with pharmacological versatility acting as metal chelators and ROS generation. Thus, the objective was to characterize the antiparasitic action of DETC against different strains and forms of T. cruzi and their mechanism. The different strains of T. cruzi were grown in LIT medium. To evaluate the antiparasitic activity of DETC, epimastigote and trypomastigote forms of T. cruzi were used by resazurin reduction methods and by counting. Different response patterns were obtained between the strains and an IC50 of DETC ranging from 9.44 ± 3,181 to 60.49 ± 7.62 µM. Cell cytotoxicity against 3T3 and RAW cell lines and evaluated by MTT, demonstrated that DETC in high concentration (2222.00 µM) presents low toxicity. Yet, DETC causes mitochondrial damage in T. cruzi, as well as disruption in parasite membrane. DETC has antiparasitic activity against different genotypes and forms of T. cruzi, therefore, representing a promising molecule as a drug for the treatment of Chagas disease.

VLP-Based Vaccines as a Suitable Technology to Target Trypanosomatid Diseases.

Research on vaccines against trypanosomatids, a family of protozoa that cause neglected tropical diseases, such as Chagas disease, leishmaniasis, and sleeping sickness, is a current need. Today, according to modern vaccinology, virus-like particle (VLP) technology is involved in many vaccines, including those undergoing studies related to COVID-19. The potential use of VLPs as vaccine adjuvants opens an opportunity for the use of protozoan antigens for the development of vaccines against diseases caused by Trypanosoma cruzi, Leishmania spp., and Trypanosoma brucei. In this context, it is important to consider the evasion mechanisms of these protozoa in the host and the antigens involved in the mechanisms of the parasite-host interaction. Thus, the immunostimulatory properties of VLPs can be part of an important strategy for the development and evaluation of new vaccines. This work aims to highlight the potential of VLPs as vaccine adjuvants for the development of immunity in complex diseases, specifically in the context of tropical diseases caused by trypanosomatids.

Antimicrobial Activity of Chitosan Oligosaccharides with Special Attention to Antiparasitic Potential.

The global rise of infectious disease outbreaks and the progression of microbial resistance reinforce the importance of researching new biomolecules. Obtained from the hydrolysis of chitosan, chitooligosaccharides (COSs) have demonstrated several biological properties, including antimicrobial, and greater advantage over chitosan due to their higher solubility and lower viscosity. Despite the evidence of the biotechnological potential of COSs, their effects on trypanosomatids are still scarce. The objectives of this study were the enzymatic production, characterization, and in vitro evaluation of the cytotoxic, antibacterial, antifungal, and antiparasitic effects of COSs. NMR and mass spectrometry analyses indicated the presence of a mixture with 81% deacetylated COS and acetylated hexamers. COSs demonstrated no evidence of cytotoxicity upon 2 mg/mL. In addition, COSs showed interesting activity against bacteria and yeasts and a time-dependent parasitic inhibition. Scanning electron microscopy images indicated a parasite aggregation ability of COSs. Thus, the broad biological effect of COSs makes them a promising molecule for the biomedical industry.

Adequacy of Severe Malaria Markers and Prognostic Scores in an Intensive Care Unit in Luanda, Angola: A Clinical Study.

Severe Plasmodium falciparum malaria remains the primary cause of mortality in several African countries, including Angola, where severe malaria patient admission into intensive care units (ICU) is mandatory. The present observational and prospective study enrolled 101 consecutive severe malaria patients admitted at the ICU of Américo Boavida University Hospital (Luanda, Angola). Malaria was confirmed by microscopy and RDT, and WHO criteria were used to define severe malaria. The Sequential Organ Failure Assessment (SOFA) score was used to monitor organ dysfunctions. Surviving and nonsurviving patients were compared using bivariate statistical methods. Two-step cluster analysis was used to find discriminant organ dysfunctions that may correlate better with the observed mortality (16.8%), which was much lower than the one generated by the SOFA score. The study population was young, and 87% of the patients were local native residents. There was no statistically significant correlation between the parasitemia and the outcome. Hematological and cerebral dysfunctions were prevalent but were not discriminant when cluster analyses were performed to detect homogeneous subgroups of patients. In conclusion, the SOFA score was readily applicable and efficient in monitoring daily organ dysfunction but was not effective enough in predicting the outcome of severe malaria patients.

Variable Surface Glycoprotein from Trypanosoma brucei Undergoes Cleavage by Matrix Metalloproteinases: An in silico Approach.

In order to survive as extracellular parasites in the mammalian host environment, Trypanosoma brucei has developed efficient mechanisms of immune system evasion, which include the abundant expression of a variable surface glycoprotein (VSG) coat. VSGs are anchored in the parasite membrane by covalent C-terminal binding to glycosylphosphatidylinositol and may be periodically removed by a phospholipase C (PLC) and a major surface protein (TbMSP). VSG molecules show extraordinary antigenic diversity and a comparative analysis of protein sequences suggests that conserved elements may be a suitable target against African trypanosomiasis. However, the cleavage mechanisms of these molecules remain unclear. Moreover, in protozoan infections, including those caused by Trypanosoma brucei, it is possible to observe an increased expression of the matrix metalloproteinases (MMPs). To address the cleavage mechanism of VSGs, the PROSPER server was used for the identification of VSG sequence cleavage sites. After data compilation, it was observed that 64 VSG consensus sequences showed a high conservation of hydrophobic residues, such as valine (V), methionine (M), leucine (L) and isoleucine (I) in the fifth position-the exact location of the cleavage site. In addition, the PROSPER server identified conserved cleavage site portions of VSG proteins recognized by three matrix metalloproteases (gelatinases: MMP-2, MMP-3 and MMP-9). However, further biological studies are needed in order to analyze and confirm this prediction.

Application of Dithiocarbamates as Potential New Antitrypanosomatids-Drugs: Approach Chemistry, Functional and Biological.

Dithiocarbamates represent a class of compounds that were evaluated in different biomedical applications because of their chemical versatility. For this reason, several pharmacological activities have already been attributed to these compounds, such as antiparasitic, antiviral, antifungal activities, among others. Therefore, compounds that are based on dithiocarbamates have been evaluated in different in vivo and in vitro models as potential new antimicrobials. Thus, the purpose of this review is to present the possibilities of using dithiocarbamate compounds as potential new antitrypanosomatids-drugs, which could be used for the pharmacological control of Chagas disease, leishmaniasis, and African trypanosomiasis.

Cross-Reactivity Using Chimeric Trypanosoma cruzi Antigens: Diagnostic Performance in Settings Where Chagas Disease and American Cutaneous or Visceral Leishmaniasis Are Coendemic.

Chimeric T. cruzi antigens have been proposed as a diagnostic tool for chronic Chagas disease (CD) in both settings where Chagas disease is endemic and those where it is not endemic. Antibody response varies in accordance to each T. cruzi strain, presenting challenges to the use of antigens lacking demonstrated cross-reactivity with Leishmania spp. Our group expressed four chimeric proteins (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) and previously assessed their diagnostic performance to determine cross-reactivity with Leishmania spp. Here, we validated our findings using serum samples from different Brazilian geographic areas reporting endemic Chagas disease, endemic visceral or American cutaneous leishmaniasis (ACL), or both. Overall, 829 serum samples were evaluated using commercial and IBMP enzyme-linked immunosorbent assays. Due to the absence of a reference assay to diagnosis CD, latent class analysis (LCA) was performed through the use of a statistical model. The incidence of cross-reactivity for ACL-positive samples varied from 0.35% (IBMP-8.3) to 0.70% (IBMP-8.1 and IBMP-8.2). Regarding visceral leishmaniasis (VL)-positive samples, the IBMP-8.2 and IBMP-8.3 antigens cross-reacted with six (3.49%) and with only one sample (0.58%), respectively. No cross-reactivity with either ACL or VL was observed for the IBMP-8.4 antigen. Similarly, no cross-reactions were found when VL-positive samples were assayed with IBMP-8.1. The agreement among the results obtained using IBMP antigens ranged from 97.3% for IBMP-8.2 and 99% for IBMP-8.1 and IBMP-8.3 to 100% for IBMP-8.4, demonstrating almost perfect agreement with LCA. Accordingly, in light of the negligible cross-reactivity with both ACL and VL, we suggest the use of IBMP antigens in regions where T. cruzi and Leishmania spp. are coendemic.

Trans-sialidase Protein as a Potential Serological Marker for African Trypanosomiasis.

Trypanosoma brucei is the etiological agent of African trypanosomiasis responsible for human and animal infections. T. brucei is transmitted by infected tsetse flies. There is no vaccine for the disease and drugs available for treatment are inefficient and high toxicity. In this context, it is a priority to find antigenic targets suitable for the development of new diagnostic tools, drugs and vaccines. In this work, we report that mice infected with T. b. brucei produce antibodies against trans-sialidase recombinant protein (TS). In addition, we also demonstrate that bloodstream T. b. brucei express messenger RNA related to the TS gene. Collectively, our data strongly suggest that bloodstream forms of T. b. brucei also express the TS gene, that to date was described only in the procyclic forms of the T. b. brucei. In conclusion, these results highlight the importance of TS protein as a possible antigen target during infection caused by T. b. brucei.

Clinical, laboratorial and immunological aspects of severe malaria in children from Guinea-Bissau.

Malaria is a parasitic disease of which Plasmodium falciparum causes the most severe form of the disease. The immune response against Plasmodium spp. is complex and remains unclear. The present report aimed to better understand the humoral immune response in severe malaria and analyse new immunodominant antigen candidates as possible serological marker in severe malaria in children. This study included children aged 0-16 years from Guinea-Bissau with clinical signs of severe malaria. Serological and immunochemical characterisation of different anti-P. falciparum antibodies were made by ELISA and immunoblotting using a crude protein extract of P. falciparum. Sera from 12 children with severe malaria were analysed. Nine samples were positive for total anti-P. falciparum antibodies, seven for IgM and eight for total IgG anti-P. falciparum. There was a predominance of IgG1 response, suggesting a cytophilic action in severe malaria and a major role of IgG1 over other immunoglobulins. The antigenic profile of P. falciparum showed a consistent immunoblotting pattern of approximately 180 kDa, 100 kDa and around 50-40 kDa. The serological reactivity found in protein bands makes them as immunodominant antigens and promising candidates for serological markers in the context of severe malaria.

Biological and Molecular Characterization of Trypanosoma cruzi Strains from Four States of Brazil.

Chagas disease affects between six and seven million people. Its etiological agent, Trypanosoma cruzi, is classified into six discrete typing units (DTUs). The biological study of 11 T. cruzi strains presented here included four parameters: growth kinetics, parasitemia curves, rate of macrophage infection, and serology to evaluate IgM, total IgG, IgG1, IgG2a, and IgG3. Sequencing of small subunit of ribosomal RNA (SSU rRNA)was performed and the T. cruzi strains were classified into three DTUs. When their growth in liver infusion tryptose medium was represented in curves, differences among the strains could be noted. The parasitemia profile varied among the strains from the TcI, TcII, and TcIII groups, and the 11 T. cruzi strains produced distinct parasitemia levels in infected BALB/c. The TcI group presented the highest rate of macrophage infection by amastigotes, followed by TcII and TcIII. Reactivity to immunoglobulins was observed in the TcI, TcII, and TcIII; all the animals infected with the different strains of T. cruzi showed anti-T. cruzi antibodies. The molecular study presented here resulted in the classification of the T. cruzi strains into the TcI (Bolivia, T lenti, Tm, SC90); TcII (Famema, SC96, SI8, Y); and TcIII (QMM3, QMM5, SI5) groups. These biological and molecular results from 11 T. cruzi strains clarified the factors involved in the biology of the parasite and its hosts. The collection of triatomine (vector) species, and the study of geographic distribution, as well as biological and molecular characterization of the parasite, will contribute to the reporting and surveillance measures in Brazilian states.

Use of Zymography in Trypanosomiasis Studies.

Zymography assay is a semiquantitative technique, very sensitive, and commonly used to determine metalloproteinase levels in different types of biological samples, including tissues, cells, and extracts of protein. Samples containing metalloproteinases are loaded onto a polyacrylamide gel containing sodium dodecyl sulphate (SDS) and a specific substrate (gelatin, casein, collagen, etc.). Then proteins are allowed to migrate under an electric current and the distance of migration is inversely correlated with the molecular weight. After migration, the gel is placed in a renaturing buffer to allow proteins to regain their tertiary structure, necessary for enzymatic activity (metalloproteinase activity). In the context of infections caused by trypanosomatids (Leishmania spp., Trypanosoma cruzi, and Trypanosoma brucei), the characterization of metalloproteinase by zymography can contribute to the comprehension of the pathogenesis mechanisms and host-parasite interaction.

Post-exposure serological responses to malaria parasites in potential blood donors.

BACKGROUND: Cases of transfusion-transmitted malaria have been described around the world and highlighted in some studies. Semi-immune individuals are more likely to transmit malaria as they may be asymptomatic. Some countries allow blood donations only based on epidemiological criteria while others reinforce their criteria with serological tests. However, little is known about the longevity of anti-Plasmodium spp. antibodies and its meaning in blood donation. Therefore, this study aims to assess the longevity of different subclasses of anti-Plasmodium spp. antibodies in individuals with previous stays in endemic areas, as well as to assess how those antibodies are related to personal features and travel characteristics. Based on those results, the suitability of the Portuguese blood donors screening method was addressed, i.e. the method to search for an eventual risk of transfusion-transmitted malaria among the population studied. RESULTS: Statistical associations were found between the presence of total anti-Plasmodium spp. antibodies and some travel characteristics, namely to be born in endemic area versus non endemic and previous episodes of malaria. The intersection between seropositive results and the last year of stay in endemic areas showed a longer longevity of anti-Plasmodium spp. antibodies than previously reported. Those results represented a considerable portion of the individuals having returned from their last stay in endemic areas more than 10 years before enrolment in this study. Considering the study population as potential blood donors, serological results also indicated that if epidemiological criteria alone were applied to screen blood donors, an important percentage of seropositive individuals would be approved for blood donation. Because the nature and meaning of those antibodies in the blood donation context is still not understood, those approved individuals could represent a risk for blood transfusion safety. CONCLUSIONS: The place of birth and past episodes of malaria seem to be related to the serological outcome. Epidemiological criteria to screen potential blood donors are insufficient to guarantee the safety of the blood, if applied alone.

Seroprevalence of Triatoma virus (Dicistroviridae: Cripaviridae) antibodies in Chagas disease patients.

BACKGROUND: Chagas disease is caused by Trypanosoma cruzi, and humans acquire the parasite by exposure to contaminated feces from hematophagous insect vectors known as triatomines. Triatoma virus (TrV) is the sole viral pathogen of triatomines, and is transmitted among insects through the fecal-oral route and, as it happens with T. cruzi, the infected insects release the virus when defecating during or after blood uptake. METHODS: In this work, we analysed the occurrence of anti-TrV antibodies in human sera from Chagas disease endemic and non-endemic countries, and developed a mathematical model to estimate the transmission probability of TrV from insects to man, which ranged between 0.00053 and 0.0015. RESULTS: Our results confirm that people with Chagas disease living in Bolivia, Argentina and Mexico have been exposed to TrV, and that TrV is unable to replicate in human hosts. CONCLUSIONS: We presented the first experimental evidence of antibodies against TrV structural proteins in human sera.

Triatoma virus structural polyprotein expression, processing and assembly into virus-like particles.

In contrast to the current wealth of structural information concerning dicistrovirus particle structure, very little is known about their morphogenetic pathways. Here, we describe the expression of the two ORFs encoded by the Triatoma virus (TrV) genome. TrV, a member of the Cripavirus genus of the Dicistroviridae family, infects blood-sucking insects belonging to the Triatominae subfamily that act as vectors for the transmission of Trypanosoma cruzi, the aetiological agent of the Chagas disease. We have established a baculovirus-based model for the expression of the NS (non-structural) and P1 (structural) polyproteins. A preliminary characterization of the proteolytic processing of both polyprotein precursors has been performed using this system. We show that the proteolytic processing of the P1 polyprotein is strictly dependent upon the coexpression of the NS polyprotein, and that NS/P1 coexpression leads to the assembly of virus-like particles (VLPs) exhibiting a morphology and a protein composition akin to natural TrV empty capsids. Remarkably, the unprocessed P1 polypeptide assembles into quasi-spherical structures conspicuously larger than VLPs produced in NS/P1-coexpressing cells, likely representing a previously undescribed morphogenetic intermediate. This intermediate has not been found in members of the related Picornaviridae family currently used as a model for dicistrovirus studies, thus suggesting the existence of major differences in the assembly pathways of these two virus groups.

Prevalence and Level of Antibodies Anti-Plasmodium spp. in Travellers with Clinical History of Imported Malaria.

In this study, we show that 40.29% of travellers with a possible history of malaria exposure were positive for anti-Plasmodium spp. antibodies, while these individuals were negative by microscopy. The antibody test described here is useful to elucidate malaria exposure in microscopy-negative travellers from endemic countries.