Characterization of early host responses in adults with dengue disease

BACKGROUND: While dengue-elicited early and transient host responses preceding defervescence could shape the disease outcome and reveal mechanisms of the disease pathogenesis, assessment of these responses are difficult as patients rarely seek healthcare during the first days of benign fever and thus data are lacking. METHODS: In this study, focusing on early recruitment, we performed whole-blood transcriptional profiling on dengue virus PCR positive patients sampled within 72 h of self-reported fever presentation (average 43 h, SD 18.6 h) and compared the signatures with autologous samples drawn at defervescence and convalescence and to control patients with fever of other etiology. RESULTS: In the early dengue fever phase, a strong activation of the innate immune response related genes were seen that was absent at defervescence (4-7 days after fever debut), while at this second sampling genes related to biosynthesis and metabolism dominated. Transcripts relating to the adaptive immune response were over-expressed in the second sampling point with sustained activation at the third sampling. On an individual gene level, significant enrichment of transcripts early in dengue disease were chemokines CCL2 (MCP-1), CCL8 (MCP-2), CXCL10 (IP-10) and CCL3 (MIP-1α), antimicrobial peptide β-defensin 1 (DEFB1), desmosome/intermediate junction component plakoglobin (JUP) and a microRNA which may negatively regulate pro-inflammatory cytokines in dengue infected peripheral blood cells, mIR-147 (NMES1). CONCLUSIONS: These data show that the early response in patients mimics those previously described in vitro, where early assessment of transcriptional responses has been easily obtained. Several of the early transcripts identified may be affected by or mediate the pathogenesis and deserve further assessment at this timepoint in correlation to severe disease

Chikungunya as a cause of acute febrile illness in southern Sri Lanka

10.1371/journal.pone.0082259PLoS ONE812-POLN

A human PrM antibody that recognizes a novel cryptic epitope on dengue E glycoprotein

10.1371/journal.pone.0033451PLoS ONE74

The Early Clinical Features of Dengue in Adults: Challenges for Early Clinical Diagnosis

Dengue infection in adults has become increasingly common throughout the world. As most of the clinical features of dengue have been described in children, we undertook a prospective study to determine the early symptoms and signs of dengue in adults. We show here that, overall, dengue cases presented with high rates of symptoms listed in the WHO 1997 or 2009 classification schemes for probable dengue fever thus resulting in high sensitivities of these schemes when applied for early diagnosis. However, symptoms such as myalgia, arthralgia, retro-orbital pain and mucosal bleeding were less frequently reported in older adults. This trend resulted in reduced sensitivity of the WHO classification schemes in older adults even though they showed increased risks of hospitalization and severe dengue. Instead, we suggest that older adults who present with fever and leukopenia should be tested for dengue, even in the absence of other symptoms. This could be useful for early clinical diagnosis in older adults so that they can be monitored and treated for severe dengue, which is especially important when an antiviral drug becomes available

Adaptive confidence and adaptive curiosity

SIGLEAvailable from TIB Hannover: RO 9403(149) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Analysis of Dengue Virus Genetic Diversity during Human and Mosquito Infection Reveals Genetic Constraints

<div><p>Dengue viruses (DENV) cause debilitating and potentially life-threatening acute disease throughout the tropical world. While drug development efforts are underway, there are concerns that resistant strains will emerge rapidly. Indeed, antiviral drugs that target even conserved regions in other RNA viruses lose efficacy over time as the virus mutates. Here, we sought to determine if there are regions in the DENV genome that are not only evolutionarily conserved but genetically constrained in their ability to mutate and could hence serve as better antiviral targets. High-throughput sequencing of DENV-1 genome directly from twelve, paired dengue patients’ sera and then passaging these sera into the two primary mosquito vectors showed consistent and distinct sequence changes during infection. In particular, two residues in the NS5 protein coding sequence appear to be specifically acquired during infection in <i>Ae</i>. <i>aegypti</i> but not <i>Ae</i>. <i>albopictus</i>. Importantly, we identified a region within the NS3 protein coding sequence that is refractory to mutation during human and mosquito infection. Collectively, these findings provide fresh insights into antiviral targets and could serve as an approach to defining evolutionarily constrained regions for therapeutic targeting in other RNA viruses.</p></div

<i>Ae</i>. <i>aegypti</i> specific mutations in NS5.

<p>(<b>A</b>) DENV1 genomic RNA was <i>in vitro</i> transcribed from an infectious clone and inoculated into mosquitoes. Viral RNA was collected from duplicate pools of ten whole mosquitoes at 5, 10 and 21 days post inoculation and viral populations were analyzed. The time course of the experiment is demarcated on the circular timeline. The number of times we detected significant change at each position in the virus from human sera (wild type) or the virus derived from infectious clone (infectious clone) after incubation in mosquitoes is recorded in the table within the timeline. (<b>B</b>) The consensus change observed at position 8541 corresponding to amino acid 324 and the <i>Ae</i>. <i>aegypti</i> specific mutations in NS5 at position 9986 and 9998 which, correspond to amino acids 541 and 545 are highlighted on the crystal structure of the NS5 protein from Yap et al. 2007 [<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004044#pntd.0004044.ref030" target="_blank">30</a>]. (<b>C</b>) The secondary structure of region surrounding nucleotides 9986 and 9998 was modeled using mFold [<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004044#pntd.0004044.ref031" target="_blank">31</a>]. (<b>D</b>) The nucleotide changes observed in <i>Ae</i>. <i>aegypti</i> were added into the structure prediction.</p

Consensus shifts over time by position.

<p>(<b>A</b>) Serum samples were taken from patients on fever day 1–3 (Early Human) and again four days later (Late Human). These sera were inoculated into <i>Ae</i>. <i>aegypti</i> and <i>Ae</i>. <i>albopictus</i> and sampled 10 days later. (<b>B</b>) Positions evidencing a change in consensus sequence in at least a quarter of our samples were recorded and interrogated for each DENV-1 strain. Nucleotide sequences are color-coded and consensus is defined as >50% of reads mapping to the indicated position. Each of the circles depicted represents an experimental condition and are in the order of the experimental design figure depicted above.</p