Project description:Arthropod-borne viruses (arboviruses) represent a threat to global public health, especially in the tropical and subtropical regions of the world. More than 150 arboviruses can infect humans; they cause mainly febrile illness, although hemorrhagic complications and diseases affecting the central nervous system (SNC) can also be observed. Arboviruses represent a threat to Brazil and, therefore, a permanent surveillance of these viruses is required to timely reduce the risk of epidemic outbreaks. The Brazilian Amazon region is where the highest number of arboviruses has been detected in the world. Besides, malaria is also endemic in the Amazon region, with a significant predominance of Plasmodium vivax. It is often difficult to differentiate between malaria and arboviral diseases, as they share similar clinical features and laboratory findings, mainly undifferentiated fever. This study aimed to estimate possible viral etiology in patients with febrile syndrome negative for Plasmodium infection, in the Brazilian Amazon. We initially analyzed serum samples of 124 participants with a DNA microarray platform designed for the detection of arboviruses and viruses transmitted by small mammals, but no virus was detected. Then, the serum samples of 76 participants were analyzed with a deep New Generation Sequencing, which showed evidence of the presence of only one arbovirus, the Zika virus in only one pool of 9 serum samples. This result is in contrast with our hypothesis, showing that arboviruses are not frequent in suspected malaria cases in Manaus, Brazil. Other viruses instead of arboviruses were found in this study. Primate erythrovirus 1 was the virus most frequently found virus in the suspected malaria patients, followed by Enterobacteria phage lambda. Besides, we detected, in a lower frequency, the Pegivirus C. In addition to the exogenous viruses, we also detected human endogenous retrovirus in all pools. Due to the high number of viruses that are important in the differential diagnosis of malaria, cost-effective and simple high throughput methods are required, helping molecular surveillance of misdiagnosed viral infections. Further studies with more robust sample sizes in other areas in the Amazon are needed.
Project description:Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate maintenance of chronic symptomless infections that sustain malaria transmission. Here, we have determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children (<15 years). We compared children who were defined as uninfected, asymptomatic and those with febrile malaria. Children with asymptomatic infections had a parasite transcriptional profile characterized by a bias toward trophozoite stage (~12 hours-post invasion) parasites and low parasite levels, while earlier ring stage parasites were characteristic of febrile malaria. The host response of asymptomatic children was characterized by downregulated transcription of genes associated with inflammatory responses, compared with children with febrile malaria, which may lead to less cytoadherence of more mature parasite stages. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses. The priming effect of prior asymptomatic infection may explain the blunted acquisition of antibody responses seen to malaria antigens following natural exposure or vaccination in malaria endemic areas.
Project description:Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. However, there is limited information on how host-parasite interactions mediate maintenance of chronic symptomless infections that sustain malaria transmission. In this study, we identified uninfected and asymptomatic individuals and followed them until they manifested with symptoms of fever in the presence of malaria parasites and compared the gene expression profiles of peripheral blood mononuclear cells (PBMCs). The host response of asymptomatic children was characterized by downregulation of genes associated with inflammatory responses, compared to uninfected children and children with febrile malaria. They did show greater expression of some genes associated with the humoral response compared to uninfected children. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses.
Project description:Viral infections are among the most common causes for fever without an apparent source (FWS) in young children; however, many febrile children are treated with antibiotics despite the absence of bacterial infection. Adenovirus, human herpesvirus 6 (HHV-6) and enterovirus are detected in children with FWS more often than other viral species. Virus and bacteria interact with pattern recognition receptors in circulating blood leukocytes and trigger specific host transcriptional programs that mediate immune response, and unique transcriptional signatures may be ascertained to discriminate between viral and bacterial causes for children with FWS. Microarray analyses were conducted on peripheral blood samples obtained from 51 pediatric patients with confirmed adenovirus, human herpesvirus 6 (HHV-6), enterovirus or bacterial infection. Whole blood transcriptional profiles could clearly distinguish febrile children from healthy controls, and febrile children with viral infections from afebrile children carrying the same virus. Molecular pathways regulating host immune response were the most affected in febrile children with infection. Pattern recognition programs were prominently activated in all febrile children with infection, while differential activation of transcriptional programs was observed among viral species. Interferon signaling pathway was uniquely activated in children with febrile viral infection, while a different set of pathways was uniquely activated in children with bacterial infection. Transcriptional signatures were identified and classified febrile children with viral or bacterial infection with 87% overall accuracy, an improvement from the current clinical practice of deducing from white blood cell (WBC) count status. Similar degree of accuracy was observed when we validated the signature probes on data sets from an independent study with different microarray platforms. The current study confirms the clinical utility of blood transcriptional analysis, suggests the composition of transcriptional signatures which can be used to ascertain the infectious etiology of febrile young children without an apparent source, thus limit the overuse of antibiotics on febrile children presenting with this common clinical complaint.
Project description:Viral infections are among the most common causes for fever without an apparent source (FWS) in young children; however, many febrile children are treated with antibiotics despite the absence of bacterial infection. Adenovirus, human herpesvirus 6 (HHV-6) and enterovirus are detected in children with FWS more often than other viral species. Virus and bacteria interact with pattern recognition receptors in circulating blood leukocytes and trigger specific host transcriptional programs that mediate immune response, and unique transcriptional signatures may be ascertained to discriminate between viral and bacterial causes for children with FWS. Microarray analyses were conducted on peripheral blood samples obtained from 51 pediatric patients with confirmed adenovirus, human herpesvirus 6 (HHV-6), enterovirus or bacterial infection. Whole blood transcriptional profiles could clearly distinguish febrile children from healthy controls, and febrile children with viral infections from afebrile children carrying the same virus. Molecular pathways regulating host immune response were the most affected in febrile children with infection. Pattern recognition programs were prominently activated in all febrile children with infection, while differential activation of transcriptional programs was observed among viral species. Interferon signaling pathway was uniquely activated in children with febrile viral infection, while a different set of pathways was uniquely activated in children with bacterial infection. Transcriptional signatures were identified and classified febrile children with viral or bacterial infection with 87% overall accuracy, an improvement from the current clinical practice of deducing from white blood cell (WBC) count status. Similar degree of accuracy was observed when we validated the signature probes on data sets from an independent study with different microarray platforms. The current study confirms the clinical utility of blood transcriptional analysis, suggests the composition of transcriptional signatures which can be used to ascertain the infectious etiology of febrile young children without an apparent source, thus limit the overuse of antibiotics on febrile children presenting with this common clinical complaint. Total RNA samples extracted from whole blood of young children were processed for hybridization onto Illumina Human-HT12 version 4 beadchips, and differential expression of the transcripts was analyzed between sick children with either viral or bacterial infection and healthy children.
Project description:Malaria is by far the world’s most significant tropical infectious disease and over the last a few decades large-scale malaria epidemics have happened in almost all continents. Plasmodium falciparum and Plasmodium vivax account for over 90% of the total malaria cases worldwide. The estimated number of annual clinical cases of vivax malaria is even higher than that of falciparum malaria, but yet the morbidity associated with this infection and its spectrum of disease is largely neglected. Identification of serum/plasma proteins, which exhibit altered abundance at the onset and during the acute phase of any infection, could be informative to understand the pathobiology of different infectious diseases and host responses against the invading pathogens. To this end, in recent years, quite a few research groups including us have investigated alterations in serum/plasma proteome in severe and non-severe falciparum malaria (and also vivax malaria) to study malaria pathogenesis. In all these studies, serum/plasma proteome of the malaria patients have been analyzed during the febrile stages of the infection, either at the onset of the disease or at the fastigium stage. However, temporal profiling of serum/plasma proteome during acute and remission stages in malaria, which can provide snapshots of the transient and enduring alterations in serum proteome during the febrile, defervescence and convalescent stages has not been reported hitherto. Here, we report, for the first time, serum proteomic alterations in a longitudinal cohort of P. vivax infected patients to elucidate host responses when fever is established (temperature of the body reaches above higher normal level), during the stage when the temperature comes down to normal, and also during the gradual recovery of health after the illness. The three stages discussed in our study have been categorically chosen depending upon the clinical course of uncomplicated vivax malaria. Analysis of the early febrile stage represents host proteome profile immediately after onset of the infection, without any effect of anti-malarial drugs. The second, defervescence stage, reflects any immediate change in blood proteome at early recovery phase, while the convalescent stage indicates a phase after administration of 14 days radical cure treatment with primaquine and a complete recovery, when none of the patients displayed any apparent symptoms of malaria. We have also performed an extensive quantitative proteomics analysis to compare the serum proteome profiles of vivax malaria patients with low and moderately-high parasitemia with healthy community controls. Isobaric tags for relative and absolute quantitation (iTRAQ) and 2-D fluorescence difference gel electrophoresis (2D-DIGE)-based quantitative proteomics approaches were used in the discovery-phase of the study, and some selected differentially abundant serum proteins were validated further by using ELISA. Interestingly, some of the serum proteins like Serum amyloid A, Apolipoprotein A1, C-reactive protein, Titin and Haptoglobin, were found to be sequentially altered with respect to increased parasite counts, while many of the quantified candidates such as Hemopexin, Vitronectin, Clusterin and Apolipoprotein E exhibited nearly equal levels of differential serum abundance in different parasitemic malaria patients. Analysis of a longitudinal cohort of malaria patients indicated reversible alterations in serum levels of some proteins such as Haptoglobin, Apolipoprotein E, Apolipoprotein A1, Carbonic anhydrase 1, and Hemoglobin subunit alpha upon treatment; however, the levels of a few other proteins did not return to the baseline even during the convalescent phase of the infection. Identification of the differentially abundant serum proteins and associated physiological pathways in vivax malaria along with phase-specific protein profiles during the acute and convalescent phases of the infection can effectively enhance our understanding of P. vivax disease biology and host immune responses.
Project description:In order to determine the microRNAs profile in peripheral blood mononuclear cell (PBMC) from severe febrile with thrombocytopenia syndrome virus infection and investigate possible diagnostic value of these differential microRNAs.
Project description:By studying differently expressed immune genes with gene expression profiling in immune competent children researchers have been able to distinguish between children with asymptomatic viral infection and those with symptomatic viral infection as well as patients with bacterial infection. In this study we asked if gene expression profiling is feasible as a diagnostic tool in febrile neutropenia. We included children under treatment for a malignancy presenting with febrile neutropenia. Clinical data regarding the infectious episode was prospectively collected and children grouped based on microbiological agent detected into virus, bacteria, co-infection and unknown aetiology. Fourty three episodes had sufficient RNA for RNA-sequencing, 15 with respiratory tract virus, 22 with unknown etiology, 4 with co-infection and 2 with bacteria. No pathogen specific host-innate immune expression profile was seen in the group with virus, bacteria nor unknown aetiology probably due to the low white blood cell account (WBC). In the co-infection group with higher WBC but lower absolute neutrophil count (ANC) compared to the other groups, a downregulated innate response were detected. We conclude that gene expression profiling in children presenting with neutropenic fever is not a feasible diagnostic tool for febrile neutropenia in children with cancer due the low WBC.: