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São José do Rio Preto, Brazil

Ferraz F.O.,Federal University of Minas Gerais | Bomfim M.R.Q.,University do Ceuma | Totola A.H.,Federal University of Sao Joao del Rei | Avila T.V.,Federal University of Minas Gerais | And 8 more authors.
Journal of Clinical Virology | Year: 2013

Background: Dengue is a widely spread arboviral disease in tropical and subtropical regions of the world. Dengue fever presents clinical characteristics similar to other febrile illness. Thus laboratory diagnosis is important for adequate management of the disease. Objectives: The present study was designed to evaluate the diagnostic performance of real-time PCR and serological methods for dengue in a real epidemic context. Study design: Clinical data and blood samples were collected from consecutive patients with suspected dengue who attended a primary health care unit in Belo Horizonte, Brazil. Serologic methods and real-time PCR were performed in serum samples to confirm dengue diagnosis. Results: Among the 181 consecutive patients enrolled in this study with suspected dengue, 146 were considered positive by serological criteria (positive NS1 ELISA and/or anti-dengue IgM ELISA) and 138 were positive by real-time PCR. Clinical criteria were not sufficient for distinguishing between dengue and non-dengue febrile illness. The PCR reaction was pre-optimized using samples from patients with known viral infection. It had similar sensitivity compared to NS1 ELISA (88% and 89%, respectively). We also evaluated three commercial lateral flow immunochromatographic tests for NS1 detection (BIOEASY, BIORAD and PANBIO). All three tests showed high sensitivity (94%, 91% and 81%, respectively) for dengue diagnosis. Conclusion: According to our results it can be suggested that lateral flow tests for NS1 detection are the most feasible methods for early diagnosis of dengue. © 2013 Elsevier B.V. Source

Villabona-Arenas C.J.,University of Sao Paulo | Mondini A.,Sao Paulo State University | Bosch I.,Massachusetts Institute of Technology | Schimitt D.,Tufts University | And 2 more authors.
PLoS ONE | Year: 2013

Global dengue virus spread in tropical and sub-tropical regions has become a major international public health concern. It is evident that DENV genetic diversity plays a significant role in the immunopathology of the disease and that the identification of polymorphisms associated with adaptive responses is important for vaccine development. The investigation of naturally occurring genomic variants may play an important role in the comprehension of different adaptive strategies used by these mutants to evade the human immune system. In order to elucidate this role we sequenced the complete polyprotein-coding region of thirty-three DENV-3 isolates to characterize variants circulating under high endemicity in the city of São José de Rio Preto, Brazil, during the onset of the 2006-07 epidemic. By inferring the evolutionary history on a local-scale and estimating rates of synonymous (dS) and nonsynonimous (dN) substitutions, we have documented at least two different introductions of DENV-3 into the city and detected 10 polymorphic codon sites under significant positive selection (dN/dS > 1) and 8 under significant purifying selection (dN/dS < 1). We found several polymorphic amino acid coding sites in the envelope (15), NS1 (17), NS2A (11), and NS5 (24) genes, which suggests that these genes may be experiencing relatively recent adaptive changes. Furthermore, some polymorphisms correlated with changes in the immunogenicity of several epitopes. Our study highlights the existence of significant and informative DENV variability at the spatio-temporal scale of an urban outbreak. © 2013 Villabona-Arenas et al. Source

Schmidt D.J.,University of Massachusetts Medical School | Schmidt D.J.,Tuft University Veternary School | Pickett B.E.,University of Alabama at Birmingham | Pickett B.E.,University of Texas Southwestern Medical Center | And 22 more authors.
Infection, Genetics and Evolution | Year: 2011

Dengue virus currently causes 50-100. million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3 (DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008, respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of seven amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may give additional insight into the adaptive response of DENV-3 at the population level. © 2011. Source

Nogueira M.L.,Laboratorio Of Pesquisas Em Virologia | Nogueira M.C.L.,Laboratorio Of Pesquisas Em Virologia | Pacca C.,Laboratorio Of Pesquisas Em Virologia
Central Nervous System Agents in Medicinal Chemistry | Year: 2011

Encephalitis refers to an acute, usually diffuse, inflammatory process affecting the brain. The clinical hallmark of acute encephalitis is the triad of fever, headache, and altered mental status. The most common and important cause of encephalitis is the infection by a virus although other organisms can cause the disease. This article is a general overview of the most common viral encephalitides, divided into two families, Flavivirus and Alphavirus, and provides details about virus and RNA interference. More detailed descriptions of each viral family are provided bellow. © 2011 Bentham Science Publishers. Source

Morais A.T.S.,Laboratorio Of Pesquisas Em Virologia | Morais A.T.S.,Sao Paulo State University | Araujo G.C.,Sao Paulo State University | Vidotto A.,Laboratorio Of Pesquisas Em Virologia | And 4 more authors.
Protein and Peptide Letters | Year: 2014

The eukaryotic translation initiation factor 3, subunit L (eIF3L) is one of the subunits of the eIF3 complex, an accessory protein of the Polymerase I enzyme and may have an important role in the Flavivirus replication by interaction with a viral non-structural 5 protein. Considering the importance of eIF3L in a diversity of cellular functions, we have produced the recombinant full-length eIF3L protein in Escherichia coli and performed spectroscopic and in silico analyses to gain insights into its hydrodynamic behavior and structure. Dynamic light scattering showed that eIF3L behaves as monomer when it is not interacting with other molecular partners. Circular dichroism experiments showed a typical spectrum of α-helical protein for eIF3L, which is supported by sequence-based predictions of secondary structure and the 3D in silico model. The molecular docking with the K subunit of the eIF3 complex revealed a strong interaction. It was also predicted several potential interaction sites in eIF3L, indicating that the protein is likely capable of interacting with other molecules as experimentally shown in other functional studies. Moreover, bioinformatics analyses showed approximately 8 putative phosphorylation sites and one possible N-glycosylation site, suggesting its regulation by post-translational modifications. The production of the eIF3L protein in E. coli and structural information gained in this study can be instrumental for target-based drug design and inhibitors against Flavivirus replication and to shed light on the molecular mechanisms involved in the eukaryotic translation initiation. © 2014 Bentham Science Publishers. Source

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