Dengue Virus Net is the web resource for anyone interested in dengue. The objectives of Dengue Virus Net are to be the public and professional information resource for dengue and to serve as a network in the exchange of information and news related to dengue.
Dengue is a mosquito-borne infection that causes a severe flu-like illness (dengue fever), and sometimes a potentially lethal complication called dengue haemorrhagic fever. Global incidence of dengue has grown dramatically in recent decades. About two fifths of the world's population are now at risk. Dengue is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas. Dengue is transmitted to humans by the Aedes aegypti or more rarely the Aedes albopictus mosquito, which feed during the day. Dengue haemorrhagic fever is a leading cause of serious illness and death among children in some Asian countries. There is currently no specific treatment for dengue.
- Dengue fever claims two more lives - The News International
Sat, 25 Oct 2014 05:28:
- Depts directed to control dengue - The News International
Sat, 25 Oct 2014 05:28:
- Dengue spreads in Lucknow - Peninsula On-line
Sat, 25 Oct 2014 01:41:
- 5 More Hit by Dengue Fever in city - The New Indian Express
Sat, 25 Oct 2014 00:35:
- Gut bacterium may make mosquitoes less vulnerable to malaria, dengue - Zee News
Fri, 24 Oct 2014 11:58:
- Suman al momento 1605 casos de dengue en Sonora - Radioplay.com.mx
Fri, 24 Oct 2014 05:37:
- No let-up in arrival of dengue patients to hospitals - DAWN.com
Fri, 24 Oct 2014 01:43:
- Dengue fever appears in San Luis Rio Colorado - Yuma Sun
Fri, 24 Oct 2014 01:04:
- Civic Bodies Initiate Anti-dengue Drive - The New Indian Express
Fri, 24 Oct 2014 00:41:
- Big jump in dengue cases in KL - New Straits Times Online
Fri, 24 Oct 2014 00:25:
- Chromobacterium Csp_P Reduces Malaria and Dengue Infection in Vector Mosquitoes and Has Entomopathogenic and In Vitro Anti-pathogen Activities.
Ramirez JL, Short SM, Bahia AC, et al. Chromobacterium Csp_P Reduces Malaria and Dengue Infection in Vector Mosquitoes and Has Entomopathogenic and In Vitro Anti-pathogen Activities. [JOURNAL ARTICLE]PLoS Pathog 2014 Oct; 10(10):e1004398.Plasmodium and dengue virus, the causative agents of the two most devastating vector-borne diseases, malaria and dengue, are transmitted by the two most important mosquito vectors, Anopheles gambiae and Aedes aegypti, respectively. Insect-bacteria associations have been shown to influence vector competence for human pathogens through multi-faceted actions that include the elicitation of the insect immune system, pathogen sequestration by microbes, and bacteria-produced anti-pathogenic factors. These influences make the mosquito microbiota highly interesting from a disease control perspective. Here we present a bacterium of the genus Chromobacterium (Csp_P), which was isolated from the midgut of field-caught Aedes aegypti. Csp_P can effectively colonize the mosquito midgut when introduced through an artificial nectar meal, and it also inhibits the growth of other members of the midgut microbiota. Csp_P colonization of the midgut tissue activates mosquito immune responses, and Csp_P exposure dramatically reduces the survival of both the larval and adult stages. Ingestion of Csp_P by the mosquito significantly reduces its susceptibility to Plasmodium falciparum and dengue virus infection, thereby compromising the mosquito's vector competence. This bacterium also exerts in vitro anti-Plasmodium and anti-dengue activities, which appear to be mediated through Csp_P -produced stable bioactive factors with transmission-blocking and therapeutic potential. The anti-pathogen and entomopathogenic properties of Csp_P render it a potential candidate for the development of malaria and dengue control strategies.
- Sensing of Immature Particles Produced by Dengue Virus Infected Cells Induces an Antiviral Response by Plasmacytoid Dendritic Cells.
Décembre E, Assil S, Hillaire ML, et al. Sensing of Immature Particles Produced by Dengue Virus Infected Cells Induces an Antiviral Response by Plasmacytoid Dendritic Cells. [JOURNAL ARTICLE]PLoS Pathog 2014 Oct; 10(10):e1004434.Dengue virus (DENV) is the leading cause of mosquito-borne viral illness and death in humans. Like many viruses, DENV has evolved potent mechanisms that abolish the antiviral response within infected cells. Nevertheless, several in vivo studies have demonstrated a key role of the innate immune response in controlling DENV infection and disease progression. Here, we report that sensing of DENV infected cells by plasmacytoid dendritic cells (pDCs) triggers a robust TLR7-dependent production of IFNα, concomitant with additional antiviral responses, including inflammatory cytokine secretion and pDC maturation. We demonstrate that unlike the efficient cell-free transmission of viral infectivity, pDC activation depends on cell-to-cell contact, a feature observed for various cell types and primary cells infected by DENV, as well as West Nile virus, another member of the Flavivirus genus. We show that the sensing of DENV infected cells by pDCs requires viral envelope protein-dependent secretion and transmission of viral RNA. Consistently with the cell-to-cell sensing-dependent pDC activation, we found that DENV structural components are clustered at the interface between pDCs and infected cells. The actin cytoskeleton is pivotal for both this clustering at the contacts and pDC activation, suggesting that this structural network likely contributes to the transmission of viral components to the pDCs. Due to an evolutionarily conserved suboptimal cleavage of the precursor membrane protein (prM), DENV infected cells release uncleaved prM containing-immature particles, which are deficient for membrane fusion function. We demonstrate that cells releasing immature particles trigger pDC IFN response more potently than cells producing fusion-competent mature virus. Altogether, our results imply that immature particles, as a carrier to endolysosome-localized TLR7 sensor, may contribute to regulate the progression of dengue disease by eliciting a strong innate response.
- P. vivax Malaria and Dengue Fever Co-infection: A Cross-Sectional Study in the Brazilian Amazon.
Magalhães BM, Siqueira AM, Alexandre MA, et al. P. vivax Malaria and Dengue Fever Co-infection: A Cross-Sectional Study in the Brazilian Amazon. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2014 Oct; 8(10):e3239.Malaria and dengue are the most prevalent vector-borne diseases worldwide and represent major public health problems. Both are endemic in tropical regions, propitiating co-infection. Only few co-infection cases have been reported around the world, with insufficient data so far to enhance the understanding of the effects of co-infection in the clinical presentation and severity.A cross-sectional study was conducted (2009 to 2011) in hospitalized patients with acute febrile syndrome in the Brazilian Amazon. All patients were submitted to thick blood smear and PCR for Plasmodium sp. detection, ELISA, PCR and NS1 tests for dengue, viral hepatitis, HIV and leptospirosis. In total, 1,578 patients were recruited. Among them, 176 (11.1%) presented P. vivax malaria mono-infection, 584 (37%) dengue fever mono-infection, and 44 (2.8%) were co-infected. Co-infected patients had a higher chance of presenting severe disease (vs. dengue mono-infected), deep bleeding (vs. P. vivax mono-infected), hepatomegaly, and jaundice (vs. dengue mono-infected).In endemic areas for dengue and malaria, jaundice (in dengue patients) and spontaneous bleeding (in malaria patients) should raise the suspicion of co-infection. Besides, whenever co-infection is confirmed, we recommend careful monitoring for bleeding and hepatic complications, which may result in a higher chance of severity, despite of the fact that no increased fatality rate was seen in this group.
- Dengue virus infection presenting with diffuse brain hemorrhage.
Daher RT, Marussi VH, Pedroso JL, et al. Dengue virus infection presenting with diffuse brain hemorrhage. [JOURNAL ARTICLE]Arq Neuropsiquiatr 2014 Oct; 72(10):815.
- Preexisting Neutralizing Antibody Responses Distinguish Clinically Inapparent and Apparent Dengue Virus Infections in a Sri Lankan Pediatric Cohort.
Corbett KS, Katzelnick L, Tissera H, et al. Preexisting Neutralizing Antibody Responses Distinguish Clinically Inapparent and Apparent Dengue Virus Infections in a Sri Lankan Pediatric Cohort. [JOURNAL ARTICLE]J Infect Dis 2014 Oct 21.Dengue viruses (DENVs) are mosquito-borne flaviviruses that infect humans. The clinical presentation of DENV infection ranges from inapparent infection to dengue hemorrhagic fever and dengue shock syndrome. We analyzed samples from a pediatric dengue cohort study in Sri Lanka to explore whether antibody responses differentiated clinically apparent infections from clinically inapparent infections. In DENV-naive individuals exposed to primary DENV infections, we observed no difference in the quantity or quality of acquired antibodies between inapparent and apparent infections. Children who experienced primary infections had broad, serotype-cross-neutralizing antibody responses that narrowed in breadth to a single serotype over a 12-month period after infection. In DENV immune children who were experiencing a repeat infection, we observed a strong association between preexisting neutralizing antibodies and clinical outcome. Notably, children with preexisting monospecific neutralizing antibody responses were more likely to develop fever than children with cross-neutralizing responses. Preexisting DENV neutralizing antibodies are correlated with protection from dengue disease.
- The Causes and Consequences of Childhood Encephalitis in Asia.
Britton PN, Khandaker G, Booy R, et al. The Causes and Consequences of Childhood Encephalitis in Asia. [JOURNAL ARTICLE]Infect Disord Drug Targets 2014 Oct 21.Encephalitis is caused by inflammation and/or infection of the brain. It is a common condition in Asian children in whom it is most frequently caused by Japanese encephalitis virus, associated with a considerable burden of disease. Other common causes in Asia include: enteroviruses (especially enterovirus 71), dengue, influenza, the herpesviruses, measles, mumps and rubella viruses. Rabies continues to result in high mortality mostly in Asian children, which represents missed opportunities for prevention. Asia has also seen a number of emerging viral encephalitides including: Nipah, chikungunya, Chandipura and Me Tri viruses. We review the aetiology, epidemiology and outcome of encephalitis in Asian children and identify priorities for public health practice and research.
- Hemophagocytic syndrome in severe dengue Fever: a rare presentation.
Mitra S, Bhattacharyya R Hemophagocytic syndrome in severe dengue Fever: a rare presentation. [Journal Article]Indian J Hematol Blood Transfus 2014 Sep; 30(Suppl 1):97-100.We describe a 2-year old boy developing virus-associated hemophagocytic syndrome in severe dengue fever. The condition was diagnosed according to the established criteria of the International Histiocyte Society. There was uneventful recovery with corticosteroid therapy. Secondary hemophagocytosis in children can mimic severe sepsis, systemic inflammatory response syndrome, or multi organ dysfunction syndrome and lead to diagnostic difficulties. This report adds to the limited pediatric cases of dengue related hemophagocytic syndrome reported in literature; and underlines the importance of prompt diagnosis and appropriate treatment of this rare but serious complication.
- Evaluation of AaDOP2 receptor antagonists reveals antidepressants and antipsychotics as novel lead molecules for control of the yellow fever mosquito, Aedes aegypti.
Conley JM, Meyer JM, Nuss AB, et al. Evaluation of AaDOP2 receptor antagonists reveals antidepressants and antipsychotics as novel lead molecules for control of the yellow fever mosquito, Aedes aegypti. [JOURNAL ARTICLE]J Pharmacol Exp Ther 2014 Oct 20.The yellow fever mosquito, Aedes aegypti, vectors disease causing agents that adversely affect human health, most notably the viruses causing dengue and yellow fever. The efficacy of current mosquito control programs are challenged by the emergence of insecticide-resistant mosquito populations, suggesting an urgent need for the development of chemical insecticides with new mechanisms of action. One recently identified potential insecticide target is the A. aegypti D1-like dopamine receptor, AaDOP2. The focus of the present study was to evaluate AaDOP2 antagonism both in vitro and in vivo using assay technologies with increased throughput. The in vitro assays revealed AaDOP2 antagonism by four distinct chemical scaffolds from tricyclic antidepressant or antipsychotic chemical classes and elucidated several structure-activity-relationship (SAR) trends that contributed to enhanced antagonist potency including lipophilicity, halide substitution on the tricyclic core, and conformational rigidity. Six compounds displayed previously unparalleled potency for in vitro AaDOP2 antagonism, and among these, asenapine, methiothepin, and cis-(Z)-flupenthixol displayed sub-nanomolar IC50 values and caused rapid toxicity to A. aegypti larvae and/or adults in vivo. Our study revealed a significant correlation between in vitro potency for AaDOP2 antagonism and in vivo toxicity, suggesting viability of AaDOP2 as an insecticidal target. Taken together, this study expanded the repertoire of known AaDOP2 antagonists, enhanced our understanding of AaDOP2 pharmacology, provided further support for rational targeting of AaDOP2, and demonstrated the utility of efficiency-enhancing in vitro and in vivo assay technologies within our genome-to-lead pipeline for the discovery of next-generation insecticides.
- miR-281, an abundant midgut-specific miRNA of the vector mosquito Aedes albopictus enhances dengue virus replication.
Zhou Y, Liu Y, Yan H, et al. miR-281, an abundant midgut-specific miRNA of the vector mosquito Aedes albopictus enhances dengue virus replication. [JOURNAL ARTICLE]Parasit Vectors 2014 Oct 22; 7(1):488.BackgroundEmerging evidence indicates that microRNAs (miRNAs) are involved in host-virus interaction. We previously reported that some miRNAs were differentially expressed in sugar-fed and blood-fed females of Aedes albopictus (Ae. albopictus). Here, we analysis the role in the host-virus system of an abundant midgut-specific miRNA in the mosquito Ae. albopictus.MethodsThe expression profiles of miR-281 in different body parts of Ae. albopictus and following dengue virus infection were determined using RT-qPCR and Northern blot. miR-281 mimics, antagomiRs and corresponding negative controls were designed and their overexpression and knock-down efficiency were analyzed by qRT-PCR after transfecting the mosquito cell lines C6/36, and also by injecting female mosquitoes. Dengue virus serotype-2 (DENV-2) viral genomic RNA abundance was determined by RT-qPCR. The levels of DENV-2 E protein were detected using Western blot. Virus titers were tested using TCID50. RNAhybrid was used to predict targets of miR-281 in the DENV-2 genome. The EGFP plasmid-based reporter system was used to investigate the interaction between miR-281 and the predicted binding site in the C6/36 cell line.ResultsmiR-281 is specifically expressed in the female midgut where dengue virus first invades. After DENV-2 infection, this miRNA is up-regulated in response to viral infection. Functional intervention analyses in vitro with specifically designed miR-281 mimics and corresponding antagomiRs indicated that miR-281 enhances DENV-2 viral replication. Further depletion of miR-281 in female mosquitoes by injection of its specific antagomiRs led to a significant reduction in DENV-2 abundance. The interaction between miR-281 and its predicted target sequence, the DENV-2 genomic 5¿-untranslated region (UTR), is confirmed in the context of a plasmid-based reporter system.ConclusionThese findings confirm that miR-281, an abundant midgut-specific miRNA, facilitates DENV-2 replication.
- Prevalence of Patients with Acute Febrile Illnesses and Positive Dengue NS1 Tests in a Tertiary Hospital in Papua New Guinea.
Asigau V, Lavu EK, McBride WJ, et al. Prevalence of Patients with Acute Febrile Illnesses and Positive Dengue NS1 Tests in a Tertiary Hospital in Papua New Guinea. [JOURNAL ARTICLE]Am J Trop Med Hyg 2014 Oct 20.Because the prevalence of dengue fever in urban settings in Papua New Guinea is unknown, we investigated the presence of dengue using the NS1 antigen test in an outpatient-based prospective observational study at Port Moresby General Hospital. Of 140 patients with acute febrile illnesses, dengue fever was diagnosed in 14.9% (20 of 134; 95% confidence interval [95% CI] = 9.6-22.4). Malaria (2 of 137; 1.5%; 95% CI = 0.3-5.7), chikungunya (3 of 140; 2.1%; 95% CI = 0.6-6.6), and bacterial bloodstream infections (0 of 80; 0%; 95% CI = 0-5.7) were uncommon. Dengue fever should no longer be considered rare in Papua New Guinea.