Overview of latest articles and publications on ebola in PubMed. PubMed is a service of the US National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals.
- Dengue Fever-associated catatonia.
Aggarwal A, Nimber JS Dengue Fever-associated catatonia. [Journal Article]J Neuropsychiatry Clin Neurosci 2015; 27(1):e66-7.
- Identification, Molecular Cloning, and Analysis of Full-Length Hepatitis C Virus Transmitted/Founder Genotypes 1, 3, and 4.
Stoddard MB, Li H, Wang S, et al. Identification, Molecular Cloning, and Analysis of Full-Length Hepatitis C Virus Transmitted/Founder Genotypes 1, 3, and 4. [JOURNAL ARTICLE]MBio 2015; 6(2)Hepatitis C virus (HCV) infection is characterized by persistent replication of a complex mixture of viruses termed a "quasispecies." Transmission is generally associated with a stringent population bottleneck characterized by infection by limited numbers of "transmitted/founder" (T/F) viruses. Characterization of T/F genomes of human immunodeficiency virus type 1 (HIV-1) has been integral to studies of transmission, immunopathogenesis, and vaccine development. Here, we describe the identification of complete T/F genomes of HCV by single-genome sequencing of plasma viral RNA from acutely infected subjects. A total of 2,739 single-genome-derived amplicons comprising 10,966,507 bp from 18 acute-phase and 11 chronically infected subjects were analyzed. Acute-phase sequences diversified essentially randomly, except for the poly(U/UC) tract, which was subject to polymerase slippage. Fourteen acute-phase subjects were productively infected by more than one genetically distinct virus, permitting assessment of recombination between replicating genomes. No evidence of recombination was found among 1,589 sequences analyzed. Envelope sequences of T/F genomes lacked transmission signatures that could distinguish them from chronic infection viruses. Among chronically infected subjects, higher nucleotide substitution rates were observed in the poly(U/UC) tract than in envelope hypervariable region 1. Fourteen full-length molecular clones with variable poly(U/UC) sequences corresponding to seven genotype 1a, 1b, 3a, and 4a T/F viruses were generated. Like most unadapted HCV clones, T/F genomes did not replicate efficiently in Huh 7.5 cells, indicating that additional cellular factors or viral adaptations are necessary for in vitro replication. Full-length T/F HCV genomes and their progeny provide unique insights into virus transmission, virus evolution, and virus-host interactions associated with immunopathogenesis.Hepatitis C virus (HCV) infects 2% to 3% of the world's population and exhibits extraordinary genetic diversity. This diversity is mirrored by HIV-1, where characterization of transmitted/founder (T/F) genomes has been instrumental in studies of virus transmission, immunopathogenesis, and vaccine development. Here, we show that despite major differences in genome organization, replication strategy, and natural history, HCV (like HIV-1) diversifies essentially randomly early in infection, and as a consequence, sequences of actual T/F viruses can be identified. This allowed us to capture by molecular cloning the full-length HCV genomes that are responsible for infecting the first hepatocytes and eliciting the initial immune responses, weeks before these events could be directly analyzed in human subjects. These findings represent an enabling experimental strategy, not only for HCV and HIV-1 research, but also for other RNA viruses of medical importance, including West Nile, chikungunya, dengue, Venezuelan encephalitis, and Ebola viruses.
- Rapid selection against arbovirus-induced apoptosis during infection of a mosquito vector.
O'Neill K, Olson BJ, Huang N, et al. Rapid selection against arbovirus-induced apoptosis during infection of a mosquito vector. [JOURNAL ARTICLE]Proc Natl Acad Sci U S A 2015 Feb 23.Millions of people are infected each year by arboviruses (arthropod-borne viruses) such as chikungunya, dengue, and West Nile viruses, yet for reasons that are largely unknown, only a relatively small number of mosquito species are able to transmit arboviruses. Understanding the complex factors that determine vector competence could facilitate strategies for controlling arbovirus infections. Apoptosis is a potential antiviral defense response that has been shown to be important in other virus-host systems. However, apoptosis is rarely seen in arbovirus-infected mosquito cells, raising questions about its importance as an antiviral defense in mosquitoes. We tested the effect of stimulating apoptosis during arbovirus infection by infecting Aedes aegypti mosquitoes with a Sindbis virus (SINV) clone called MRE/Rpr, in which the MRE-16 strain of SINV was engineered to express the proapoptotic gene reaper from Drosophila. MRE/Rpr exhibited an impaired infection phenotype that included delayed midgut infection, delayed virus replication, and reduced virus accumulation in saliva. Nucleotide sequencing of the reaper insert in virus populations isolated from individual mosquitoes revealed evidence of rapid and strong selection against maintenance of Reaper expression in MRE/Rpr-infected mosquitoes. The impaired phenotype of MRE/Rpr, coupled with the observed negative selection against Reaper expression, indicates that apoptosis is a powerful defense against arbovirus infection in mosquitoes and suggests that arboviruses have evolved mechanisms to avoid stimulating apoptosis in mosquitoes that serve as vectors.
- A new moment for facing dengue?
Guzman MG A new moment for facing dengue? [JOURNAL ARTICLE]Pathog Glob Health 2015 Feb; 109(1):2-3.
- Rapid Diagnostic Tests for Dengue Virus Infection in Febrile Cambodian Children: Diagnostic Accuracy and Incorporation into Diagnostic Algorithms.
Carter MJ, Emary KR, Moore CE, et al. Rapid Diagnostic Tests for Dengue Virus Infection in Febrile Cambodian Children: Diagnostic Accuracy and Incorporation into Diagnostic Algorithms. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2015 Feb; 9(2):e0003424.Dengue virus (DENV) infection is prevalent across tropical regions and may cause severe disease. Early diagnosis may improve supportive care. We prospectively assessed the Standard Diagnostics (Korea) BIOLINE Dengue Duo DENV rapid diagnostic test (RDT) to NS1 antigen and anti-DENV IgM (NS1 and IgM) in children in Cambodia, with the aim of improving the diagnosis of DENV infection.We enrolled children admitted to hospital with non-localised febrile illnesses during the 5-month DENV transmission season. Clinical and laboratory variables, and DENV RDT results were recorded at admission. Children had blood culture and serological and molecular tests for common local pathogens, including reference laboratory DENV NS1 antigen and IgM assays. 337 children were admitted with non-localised febrile illness over 5 months. 71 (21%) had DENV infection (reference assay positive). Sensitivity was 58%, and specificity 85% for RDT NS1 and IgM combined. Conditional inference framework analysis showed the additional value of platelet and white cell counts for diagnosis of DENV infection. Variables associated with diagnosis of DENV infection were not associated with critical care admission (70 children, 21%) or mortality (19 children, 6%). Known causes of mortality were melioidosis (4), other sepsis (5), and malignancy (1). 22 (27%) children with a positive DENV RDT had a treatable other infection.The DENV RDT had low sensitivity for the diagnosis of DENV infection. The high co-prevalence of infections in our cohort indicates the need for a broad microbiological assessment of non-localised febrile illness in these children.
- Correlation of serological markers and platelet count in the diagnosis of Dengue virus infection.
Jyothi P, Metri BC Correlation of serological markers and platelet count in the diagnosis of Dengue virus infection. [Journal Article]Adv Biomed Res 2015.:26.The dengue virus causes one of the most important mosquito-borne viral diseases. Annually, it affects up to 100 million people. Detection of the secreted NS1 protein represents a new approach to the diagnosis of acute dengue infection. Platelet count is the only non-dengue parameter that can support the diagnosis of the dengue shock syndrome (DSS) and dengue hemorrhagic fever (DHF). This study was done to correlate the platelet count and dengue parameters detected by the immunochromatographic test (ICT).Serum samples collected from patients presenting with dengue-like illness and for whom an anti-dengue antibody test was requested between August 2010 and August 2012, were included in this study. A total of 520 serum samples were collected from the suspected dengue fever patients. The samples were tested for NS1 antigen, IgM, and IgG antibodies, using the ICT kit. The platelet count was recorded in dengue parameter-positive and -negative cases.A total of 520 serum samples were collected from the suspected dengue fever patients. Sixty-two samples tested positive for one or more dengue-specific parameters. Out of the 62 samples, 39 (62.9%) were positive for the NS1 antigen, only seven (11.3%) were positive for IgM, and only three (4.9%) were positive for IgG. A platelet count < 1,00,000/ml was observed in 32 cases (51.6%). When the platelet count was done in 100 dengue parameter-negative fever patients (controls), thrombocytopenia was observed in 30% of the cases.Association of thrombocytopenia in dengue parameter-positive cases was highly significant (Z = 2.76, P = 0.006) when compared to thrombocytopenia in dengue parameter-negative patients.
- Acute hemorrhagic encephalitis: An unusual presentation of dengue viral infection.
Nadarajah J, Madhusudhan KS, Yadav AK, et al. Acute hemorrhagic encephalitis: An unusual presentation of dengue viral infection. [Journal Article]Indian J Radiol Imaging 2015 Jan-Mar; 25(1):52-5.Dengue is a common viral infection worldwide with presentation varying from clinically silent infection to dengue fever, dengue hemorrhagic fever, and severe fulminant dengue shock syndrome. Neurological manifestation usually results from multisystem dysfunction secondary to vascular leak. Presentation as hemorrhagic encephalitis is very rare. Here we present the case of a 13-year-old female admitted with generalized tonic clonic seizures. Plain computed tomography (CT) scan of head revealed hypodensities in bilateral deep gray matter nuclei and right posterior parietal lobe without any hemorrhage. Cerebrospinal fluid (CSF) and serology were positive for IgM and IgG antibodies to dengue viral antigen. Contrast-enhanced magnetic resonance imaging (MRI) revealed multifocal T2 and fluid attenuated inversion recovery (FLAIR) hyperintensities in bilateral cerebral parenchyma including basal ganglia. No hemorrhage was seen. She was managed with steroids. As her clinical condition deteriorated, after being stable for 2 days, repeat MRI was done which revealed development of hemorrhage within the lesions, and diagnosis of acute hemorrhagic encephalitis of dengue viral etiology was made.
- Community Effectiveness of Copepods for Dengue Vector Control: Systematic Review*
Lazaro A A, Han WW, Manrique-Saide P, et al. Community Effectiveness of Copepods for Dengue Vector Control: Systematic Review* [JOURNAL ARTICLE]Trop Med Int Health 2015 Feb 23.Vector control remains the only available method for primary prevention of dengue. Several interventions exist for dengue vector control, with limited evidence of their efficacy and community effectiveness. This systematic review compiles and analyses the existing global evidence for community effectiveness of Copepods for dengue vector control.The systematic review follows the PRISMA statement, searching six relevant databases. Applying all inclusion and exclusion criteria, 11 articles were included.There is evidence that Cyclopoid Copepods (Mesocyclops spp.) could potentially be an effective vector control option, as shown in five community effectiveness studies in Vietnam. This includes long-term effectiveness for larval and adult control of Ae. aegypti, as well as dengue incidence. However, this success has so far not been replicated elsewhere (six studies, three community effectiveness studies- - Costa Rica, Mexico and USA, and three studies analysing both efficacy and community effectiveness - Honduras, Laos and USA), probably due to community participation, environmental and/or biological factors. Judging by the quality of existing studies, there is a lack of good study design, data quality, and appropriate statistics.There is limited evidence for the use of Cyclopoid Copepods as a single intervention. There are very few studies, and more are needed in other communities and environments. Clear best practice guidelines for the methodology of entomological studies should be developed. This article is protected by copyright. All rights reserved.
- The role of antibody in enhancing Dengue Virus Infection.
Nikin-Beers R, Ciupe SM The role of antibody in enhancing Dengue Virus Infection. [JOURNAL ARTICLE]Math Biosci 2015 Feb 20.Dengue virus has four distinct serotypes whose cross-reactive immune responses contribute to increased disease severity following heterologous infections. It was proposed that non-protective cross-reactive antibodies may play a role in disease enhancement. In this study we develop a mathematical model of host-virus interaction and predict the mechanisms responsible for virus expansion and loss during primary and secondary dengue infections. We use the model to determine the role of cross-reactive antibodies during dengue fever and dengue hemorrhagic fever-inducing secondary infections, and then compare the model to published patient data. We predict that the cross-reactive antibodies interfere with the non-neutralizing antibody effects by reducing the phagocyte-mediated removal of antibody-virus immune complexes.
- Evolution of Dengue Disease and Entomological Monitoring in Santa Cruz, Bolivia 2002 - 2008.
Brémond P, Roca Y, Brenière SF, et al. Evolution of Dengue Disease and Entomological Monitoring in Santa Cruz, Bolivia 2002 - 2008. [JOURNAL ARTICLE]PLoS One 2015; 10(2):e0118337.In the context of a rapid increase of dengue cases in the Americas, a monitoring system based on systematic serological control (IgM) of patients consulting for suspected dengue was developed in Bolivia at the end of the 1990s. In the most affected city of Santa Cruz, this system was complemented by an entomological surveillance program based on periodical search for immature stages of Aedes aegypti in dwelling water-holding containers. Here, we analyze these data and describe dengue patterns over 6 years (2002-2008), highlighting the spatial distribution of patients and vectors.Data mining concerned six annual epidemic cycles (2002-2008), with continuous serological and clinical results and entomological data from 16 surveys, examined at the scales of 36 urban areas and four concentric areas covering the entire city. Annual incidence varied from 0.28‰ to 0.95‰; overall incidence was higher in women and adults, and dengue dynamics followed successive periods of high (January-June) and low (July-December) transmission. Lower numbers of cases from the city center to the periphery were observed, poorly related to the more homogeneous and permanent distribution of A. aegypti. "Plant pots" were a major vector source in the city center, and "Tires" and "Odds and ends" beyond the second ring of the city.Over the years, the increasing trend of dengue cases has been highlighted as well as its widespread distribution over the entire city, but an underestimation of the number of cases is strongly suspected. Contrary to popular belief, the city center appears more affected than the periphery, and dengue is not particularly related to waste. Interestingly, the clinical diagnosis of dengue by physicians improved over the years, whatever the gender, age and residential area of suspected cases.