Dengue virus seroprevalence study in Bangphae district, Ratchaburi, Thailand: A cohort study in 2012-2015

Background To determine the seroprevalence and transmission dynamics of dengue virus (DENV), age-stratified longitudinal serological surveys were conducted in Bangphae district, Ratchaburi province, Thailand, for 3 years between April 2012 and April 2015. Methodology The surveys enrolled 2012 healthy children and adults between 1 and 55 years-of-age, and a longitudinal serosurvey of six repeated bleeds of the same cohort of individuals was conducted every 8 months for the first 2 years (M0, M8, M16) and every half a year (M24, M30, M36) for the rest of the study period. All samples were tested using in-house indirect sandwich dengue IgG ELISA to determine DENV antibody titer, and 640 paired samples which showed rising of DENV IgG titers in paired serum were further tested using in-house neutralization assay, Plaque Reduction Neutralization Test (PRNT50). Principal findings When compared against the gold standard based on the results of PRNT50, sensitivity and specificity of indirect ELISA were found to be both about 85%. The overall DENV IgG positivity determined by ELISA was 74.3% in 2012 and increased to 79.4% by the final sample collection in 2015. In our study sample, more than 98% of subjects older than 25 years were found to be seropositive. Among 518 IgG negative subjects at enrollment, the seroconversion rates were measured in paired bleeds; the rates (between successive visits, approximately 6 months) ranged between 4.8% (between M16 and M24) and 14.7% (between M0 and M8). The dominant serotype of primary DENV infection cases based on seroconversion was identified from the PRNT results and it was DENV-2. Conclusions Our study documented high levels of seroprevalence and rate of transmission. Given the importance of the serostatus and disease burden in consideration for dengue vaccine introduction, our data could be used in decision-making on implementation of various dengue control and preventive measures.

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Boosting can explain patterns of fluctuations of ratios of inapparent to symptomatic dengue virus infections

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2013941118 ◽

2021 ◽

Vol 118 (14) ◽

pp. e2013941118

Author(s):

Laura W. Alexander ◽

Rotem Ben-Shachar ◽

Leah C. Katzelnick ◽

Guillermina Kuan ◽

Angel Balmaseda ◽

...

Keyword(s):

Dengue Virus ◽

Denv Infection ◽

Protective Effects ◽

Virus Infections ◽

Denv Serotypes ◽

Symptomatic Disease ◽

Large Fluctuations ◽

Antibody Titers ◽

Dengue Control ◽

Arboviral Disease

Dengue is the most prevalent arboviral disease worldwide, and the four dengue virus (DENV) serotypes circulate endemically in many tropical and subtropical regions. Numerous studies have shown that the majority of DENV infections are inapparent, and that the ratio of inapparent to symptomatic infections (I/S) fluctuates substantially year-to-year. For example, in the ongoing Pediatric Dengue Cohort Study (PDCS) in Nicaragua, which was established in 2004, the I/S ratio has varied from 16.5:1 in 2006–2007 to 1.2:1 in 2009–2010. However, the mechanisms explaining these large fluctuations are not well understood. We hypothesized that in dengue-endemic areas, frequent boosting (i.e., exposures to DENV that do not lead to extensive viremia and result in a less than fourfold rise in antibody titers) of the immune response can be protective against symptomatic disease, and this can explain fluctuating I/S ratios. We formulate mechanistic epidemiologic models to examine the epidemiologic effects of protective homologous and heterologous boosting of the antibody response in preventing subsequent symptomatic DENV infection. We show that models that include frequent boosts that protect against symptomatic disease can recover the fluctuations in the I/S ratio that we observe, whereas a classic model without boosting cannot. Furthermore, we show that a boosting model can recover the inverse relationship between the number of symptomatic cases and the I/S ratio observed in the PDCS. These results highlight the importance of robust dengue control efforts, as intermediate dengue control may have the potential to decrease the protective effects of boosting.

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Natural infection of cynomolgus monkeys with dengue virus occurs in epidemic cycles in the Philippines

Journal of General Virology ◽

10.1099/vir.0.055343-0 ◽

2013 ◽

Vol 94 (10) ◽

pp. 2202-2207 ◽

Cited By ~ 10

Author(s):

Fumihiro Kato ◽

Yuki Ishida ◽

Takahiro Kawagishi ◽

Takeshi Kobayashi ◽

Takayuki Hishiki ◽

...

Keyword(s):

Dengue Virus ◽

Phylogenetic Analyses ◽

Natural Infection ◽

Denv Infection ◽

Neutralization Assay ◽

The Philippines ◽

Cynomolgus Monkeys ◽

Genomic Studies ◽

Ns1 Gene

To investigate the potential role of non-human primates (NHPs) in a dengue virus (DENV) epidemic, we conducted serological and genomic studies using plasma samples collected from 100 cynomolgus monkeys (Macaca fascicularis) in an animal breeding facility in the Philippines. An ELISA revealed 21 monkeys with a positive IgM reaction and 19 positive for IgG. Five of the monkeys were positive for both IgM and IgG. Of the 21 IgM-positive samples, a neutralization assay identified seven containing DENV-specific antibodies. We amplified the viral non-structural 1 (NS1) gene in two and the envelope (E) gene in one of these seven samples by RT-PCR. Phylogenetic analyses revealed that these DENV genes belonged to the epidemic DENV-2 family, not the sylvatic DENV family. These results suggest that NHPs may serve as a reservoir of epidemic DENV; therefore, the ecology of the urban DENV infection cycle should be investigated in these animals in detail.

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An experimental and theoretical approach to understand Fever, DENF & its cure

Infectious Disorders - Drug Targets ◽

10.2174/1871526520999200905122052 ◽

2020 ◽

Vol 20 ◽

Author(s):

Vijay Kumar Vishvakarma ◽

Ramesh Chandra ◽

Prashant Singh

Keyword(s):

Catalytic Activity ◽

Dengue Virus ◽

Theoretical Approach ◽

Major Part ◽

Genomic Structure ◽

Denv Infection ◽

Structural Proteins ◽

Experimental Approaches ◽

Ns3 Protease ◽

Prime Target

: Fever is a response of human body due to an increase the temperature against the certain stimuli. It may be associated with several reasons and one of the major causes of fever is mosquito bite. Fever due to dengue virus (DENV) infection is being paid most attention out of several other fevers because of a large number of deaths reported worldwide. Dengue virus is transmitted by biting of the mosquitoes, Aedes aegypti and Aedes albopictus. DENV1, DENV2, DENV3 and DENV4 are the four serotypes of dengue virus and these serotypes have 65% similarities in their genomic structure. Genome of DENV is composed of single stranded RNA and it encodes for the polyprotein. Structural and non-structural proteins (nsP) are the two major part of protese. Researchers have paid high attention on the non-structural protease (nsP) of DENV like nsP1, nsP2A, nsP2B, nsP3, nsP4A, nsP4B and nsP5. The NS2B-NS3 protease of DENV is the prime target of the researchers as it is responsible for the catalytic activity. In the present time, Dengvaxia (vaccine) is being recommended to the patients suffering severely due to DENV infection in few countries only. Till date, neither a vaccine nor an effective medicine is available to combat with all four serotypes. This review describes the fever, its causes and studies to cure the infection due to DENV using theoretical and experimental approaches.

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Potential Phosphorylation of Viral Nonstructural Protein 1 in Dengue Virus Infection

Viruses ◽

10.3390/v13071393 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1393

Author(s):

Thanyaporn Dechtawewat ◽

Sittiruk Roytrakul ◽

Yodying Yingchutrakul ◽

Sawanya Charoenlappanit ◽

Bunpote Siridechadilok ◽

...

Keyword(s):

Dengue Virus ◽

Nonstructural Protein ◽

Antiviral Drug ◽

Denv Infection ◽

Site Directed Mutagenesis ◽

Phosphorylation Sites ◽

Post Translational Modification ◽

Multifunctional Protein ◽

Nonstructural Protein 1 ◽

Underlying Mechanisms

Dengue virus (DENV) infection causes a spectrum of dengue diseases that have unclear underlying mechanisms. Nonstructural protein 1 (NS1) is a multifunctional protein of DENV that is involved in DENV infection and dengue pathogenesis. This study investigated the potential post-translational modification of DENV NS1 by phosphorylation following DENV infection. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), 24 potential phosphorylation sites were identified in both cell-associated and extracellular NS1 proteins from three different cell lines infected with DENV. Cell-free kinase assays also demonstrated kinase activity in purified preparations of DENV NS1 proteins. Further studies were conducted to determine the roles of specific phosphorylation sites on NS1 proteins by site-directed mutagenesis with alanine substitution. The T27A and Y32A mutations had a deleterious effect on DENV infectivity. The T29A, T230A, and S233A mutations significantly decreased the production of infectious DENV but did not affect relative levels of intracellular DENV NS1 expression or NS1 secretion. Only the T230A mutation led to a significant reduction of detectable DENV NS1 dimers in virus-infected cells; however, none of the mutations interfered with DENV NS1 oligomeric formation. These findings highlight the importance of DENV NS1 phosphorylation that may pave the way for future target-specific antiviral drug design.

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Phage display demonstrates durable differences in serological profile by route of inoculation in primary infections of non-human primates with Dengue Virus 1

Scientific Reports ◽

10.1038/s41598-021-90318-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jayant V. Rajan ◽

Michael McCracken ◽

Caleigh Mandel-Brehm ◽

Greg Gromowski ◽

Simon Pollett ◽

...

Keyword(s):

Dengue Virus ◽

Phage Display ◽

Denv Infection ◽

Phage Library ◽

Humoral Immune ◽

Linear Peptide ◽

Humoral Immune Responses ◽

High Resolution Map ◽

Domain Iii ◽

Inoculation Route

AbstractNatural dengue virus (DENV) infections occur by mosquito bite but how the inoculation route affects the humoral immune response is unknown. We serologically profiled 20 non-human primates (NHP) from a prior study of DENV1 infection where animals were inoculated by mosquito (N = 10) or subcutaneous injection (N = 10). Using a comprehensive, densely tiled and highly redundant pan-flavivirus programmable phage library containing 91,562 overlapping 62 amino acid peptides, we produced a high-resolution map of linear peptide sequences enriched during DENV seroconversion. Profiles in mosquito-inoculated and subcutaneously-inoculated animals were similar up to 90 days after primary infection, but diverged at 1 year with differences in sero-reactivity in the Envelope (E; residues 215–406; p < 0.08), and Nonstructural-3 (NS3; residues 549–615; p < 0.05) proteins in mosquito-inoculated versus subcutaneously-inoculated animals. Within the E protein, residues 339–384 in domain III accounted for > 99% of the observed sero-reactivity difference. Antibody breadth did not vary by mode of inoculation. The differential reactivity to E domain III seen by phage display validated orthogonally by ELISA, but did not correlate with late neutralization titers. Serological profiling of humoral immune responses to DENV infection in NHP by programmable phage display demonstrated durable differences in sero-reactivity by route of inoculation.

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Micafungin Inhibits Dengue Virus Infection through the Disruption of Virus Binding, Entry, and Stability

Pharmaceuticals ◽

10.3390/ph14040338 ◽

2021 ◽

Vol 14 (4) ◽

pp. 338

Author(s):

Yen-Chen Chen ◽

Jeng-Wei Lu ◽

Chia-Tsui Yeh ◽

Te-Yu Lin ◽

Feng-Cheng Liu ◽

...

Keyword(s):

Dengue Virus ◽

Dengue Fever ◽

Early Stage ◽

Quantitative Polymerase Chain Reaction ◽

Enterovirus 71 ◽

Denv Infection ◽

Immunofluorescence Assay ◽

Dependent Manner ◽

Virus Binding ◽

Virus Serotype

Dengue fever is an arbovirus disease caused by infection with the dengue virus (DENV). Half of the world’s population lives under the threat of dengue fever, however, researchers have yet to develop any drugs that are clinically applicable to this infection. Micafungin is a member of the echinocandins family of anti-fungal drugs, capable of blocking the synthesis of β-1,3-D-glucan in the walls of fungal cells. Previous studies have demonstrated the effectiveness of Micafungin against infections of enterovirus 71 (EV71) and chikungunya virus (CHIKV). This is the first study demonstrating the effectiveness of micafungin in inhibiting the cytopathic effects of dengue virus serotype 2 (DENV-2) in a dose-dependent manner. Time-of-addition assays verified the inhibitory effects of micafungin in pre-treated, co-treated, and full-treatment groups. Binding and entry assays also demonstrated the effectiveness of micafungin in the early stage of DENV-2 infection. The virucidal efficacy of micafungin appears to lie in its ability to destroy the virion. Molecular docking assays revealed the binding of micafungin to the envelope protein of DENV-2, thereby revealing the mechanism by which micafungin affects the early stage of DENV infection and the stability of DENV. Two other micafungin analogs, caspofungin and anidulafungin, were also shown to have the antiviral effects on DENV-2. Finally, immunofluorescence assay (IFA) and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) confirmed the broad anti-DENV ability of micafungin against dengue virus serotypes 1, 3, and 4 (DENV-1, DENV-3, and DENV-4). Taken together, these results demonstrate the potential of micafungin and its analogs as candidates for the development of broad-spectrum treatments for DENV infection.

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Development of a Robust Cytopathic Effect-Based High-Throughput Screening Assay To Identify Novel Inhibitors of Dengue Virus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06425-11 ◽

2012 ◽

Vol 56 (6) ◽

pp. 3399-3401 ◽

Cited By ~ 11

Author(s):

Kevin D. McCormick ◽

Shufeng Liu ◽

Jana L. Jacobs ◽

Ernesto T. A. Marques ◽

Nicolas Sluis-Cremer ◽

...

Keyword(s):

Dengue Virus ◽

Natural Product ◽

High Throughput ◽

High Throughput Screening ◽

Cytopathic Effect ◽

Complex Molecule ◽

Denv Infection ◽

Screening Assay ◽

High Throughput Screening Assay ◽

Natural Product Library

ABSTRACTWe have developed a robust cytopathic effect-based high-throughput screening assay to identify inhibitors of dengue virus (DENV) infection. Screening of a small natural product library yielded 11 hits. Four of these were found to be potent inhibitors of DENV, although serotype differences were noted. Taken together, these data suggest that screening of larger and more complex molecule libraries may result in the identification of more potent and specific DENV inhibitors.

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Vitamin D regulates the expression of immune and stress response genes in dengue virus-infected macrophages by inducing specific microRNAs

MicroRNA ◽

10.2174/2211536610666211221151949 ◽

2021 ◽

Vol 11 ◽

Author(s):

Geysson Javier Fernandez ◽

Jorge Andrés Castillo ◽

Diana Marcela Giraldo ◽

Silvio Urcuqui-Inchima

Keyword(s):

Vitamin D ◽

Immune Response ◽

Stress Response ◽

Dengue Virus ◽

Mirna Expression ◽

Expression Profiles ◽

Denv Infection ◽

High Dose ◽

Regulatory Pathways ◽

Stress Response Genes

Background: The pathogenesis associated with Dengue virus (DENV) infection is marked by the impairment of host immune response. Consequently, the modulation of immune response has emerged as an important therapeutic target for the control of DENV infection. Vitamin D has been shown to regulate the immune response in DENV infection, although the molecular mechanism remains poorly understood. Post-transcriptional regulation of mRNA by miRNAs offers an opportunity to gain insight into the immunomodulation mediated by vitamin D Objective: Previously, it has been observed that a high dose of vitamin D (4000 IU) decreased DENV-2 infection and inflammatory response in monocyte-derived macrophages (MDMs). Here, we examine whether high or low doses of vitamin D supplements exert differential effect on miRNA expression in DENV-infected macrophages Methods: We analyzed miRNA expression profiles in MDMs isolated from healthy individuals who were given either 1000 or 4000 IU/day of vitamin D for 10 days. MDMs before or after vitamin D supplementation were challenged with DENV-2, and miRNAs profiles were analyzed by qPCR arrays. Results: DENV-2 infected MDMs supplemented with 4000 IU, showed up-regulation of miR-374a-5p, miR-363-3p, miR-101-3p, miR-9-5p, miR-34a-5p, miR-200a-3p, and the family of miRNAs miR-21-5p, and miR-590-p. The miRNA profile and predicted target mRNAs suggested regulatory pathways in MDMs obtained from healthy donors who received higher doses of vitamin D. These DENV-2 infected MDMs expressed a unique set of miRNAs that target immune and cellular stress response genes. Conclusion: The results suggest vitamin D dose-dependent differential expression of miRNAs target key signaling pathways of the pathogenesis of dengue disease.

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Dengue Virus Activates the AMP Kinase-mTOR Axis To Stimulate a Proviral Lipophagy

Journal of Virology ◽

10.1128/jvi.02020-16 ◽

2017 ◽

Vol 91 (11) ◽

Cited By ~ 47

Author(s):

Tristan X. Jordan ◽

Glenn Randall

Keyword(s):

Dengue Virus ◽

Viral Replication ◽

Lipid Droplets ◽

Adenosine Monophosphate ◽

Denv Infection ◽

Ampk Signaling ◽

Selective Autophagy ◽

Dependent Inactivation ◽

Mtorc1 Signaling ◽

Infected Cells

ABSTRACT Robust dengue virus (DENV) replication requires lipophagy, a selective autophagy that targets lipid droplets. The autophagic mobilization of lipids leads to increased β-oxidation in DENV-infected cells. The mechanism by which DENV induces lipophagy is unknown. Here, we show that infection with DENV activates the metabolic regulator 5′ adenosine-monophosphate activated kinase (AMPK), and that the silencing or pharmacological inhibition of AMPK activity decreases DENV replication and the induction of lipophagy. The activity of the mechanistic target of rapamycin complex 1 (mTORC1) decreases in DENV-infected cells and is inversely correlated with lipophagy induction. Constitutive activation of mTORC1 by depletion of tuberous sclerosis complex 2 (TSC2) inhibits lipophagy induction in DENV-infected cells and decreases viral replication. While AMPK normally stimulates TSC2-dependent inactivation of mTORC1 signaling, mTORC1 inactivation is independent of AMPK activation during DENV infection. Thus, DENV stimulates and requires AMPK signaling as well as AMPK-independent suppression of mTORC1 activity for proviral lipophagy. IMPORTANCE Dengue virus alters host cell lipid metabolism to promote its infection. One mechanism for altered metabolism is the induction of a selective autophagy that targets lipid droplets, termed lipophagy. Lipophagy mobilizes lipid stores, resulting in enhanced β-oxidation and viral replication. We show here that DENV infection activates and requires the central metabolic regulator AMPK for its replication and the induction of lipophagy. This is required for the induction of lipophagy, but not basal autophagy, in DENV-infected cells.

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