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.
- Yoyogi Park reopens fully after 2 month dengue virus closure - The Japan News
Fri, 31 Oct 2014 19:26:
- Kaohsiung to reward mosquito catchers as dengue spreads - China Post
Fri, 31 Oct 2014 17:15:
- Taiwan: Dengue fever mosquito competition offers prizes - BBC News
Fri, 31 Oct 2014 15:39:
- Rishi Kapoor hospitalised with dengue; Pali Hill home breeding ground for ... - Firstpost
Fri, 31 Oct 2014 13:42:
- Lisa Haydon suffering from dengue - Sahara Samay
Fri, 31 Oct 2014 13:38:
- Bacteria Lowers Mosquito-Transmission of Malaria, Dengue - Scientific American
Fri, 31 Oct 2014 13:13:
- Lisa Haydon suffering from dengue, skips film promotion - Zee News
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- Is NMC's special drive to curb Dengue spread a farce? Are preventive steps just ... - Nagpur Today
Fri, 31 Oct 2014 12:49:
- Madurai Corporation launches dengue preventive measures - Times of India
Fri, 31 Oct 2014 12:11:
- Lisa Haydon down with dengue - ABP News
Fri, 31 Oct 2014 11:53:
- Dengue Virus Infections among Haitian and Expatriate Non-governmental Organization Workers - Léogane and Port-au-Prince, Haiti, 2012.
Salyer SJ, Ellis EM, Salomon C, et al. Dengue Virus Infections among Haitian and Expatriate Non-governmental Organization Workers - Léogane and Port-au-Prince, Haiti, 2012. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2014 Oct; 8(10):e3269.In October 2012, the Haitian Ministry of Health and the US CDC were notified of 25 recent dengue cases, confirmed by rapid diagnostic tests (RDTs), among non-governmental organization (NGO) workers. We conducted a serosurvey among NGO workers in Léogane and Port-au-Prince to determine the extent of and risk factors for dengue virus infection. Of the total 776 staff from targeted NGOs in Léogane and Port-au-Prince, 173 (22%; 52 expatriates and 121 Haitians) participated. Anti-dengue virus (DENV) IgM antibody was detected in 8 (15%) expatriates and 9 (7%) Haitians, and DENV non-structural protein 1 in one expatriate. Anti-DENV IgG antibody was detected in 162 (94%) participants (79% of expatriates; 100% of Haitians), and confirmed by microneutralization testing as DENV-specific in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 pupae collected from 68 containers, 65% were Aedes aegypti; 27% were Ae. albopictus. Few NGO workers reported undertaking mosquito-avoidance action. Our findings underscore the risk of dengue in expatriate workers in Haiti and Haitians themselves.
- Evaluation of the immature platelet fraction as an indicator of platelet recovery in dengue patients.
Dadu T, Sehgal K, Joshi M, et al. Evaluation of the immature platelet fraction as an indicator of platelet recovery in dengue patients. [Journal Article]Int J Lab Hematol 2014 Oct; 36(5):499-504.Thrombocytopenia is a common complication in many disorders (such as aplastic anemia, ITP, dengue fever,), the etiology being multifactorial. Immature platelet fraction (IPF) is a new parameter which is a measure of reticulated platelets that reflects the rate of thrombopoiesis. We tried to evaluate IPF as an indicator to predict the recovery of platelets in patients with dengue.A total of 32 patients suffering from dengue fever (as confirmed by NS1 antigen or IgM antibody positivity for dengue) were taken for the study. The platelet count and IPF value of all these patients were evaluated on a daily basis.It was found out that IPF has a strong correlation with the recovery of platelet counts in patients with dengue. 84.3% patients showed recovery within 24 h after attaining the peak IPF, 93.75% of the patients showed recovery within 24-48 h of the rise of the IPF compared with the previous day's value, and 100% patients showed a recovery within 24 h of the fall of the IPF compared with the previous days. It was also observed that 93.75% of the patients show platelet recovery within 24-48 h if the IPF was more than 10%.Based on our study, we concluded that IPF can be used to evaluate the recovery of platelets in patients with dengue. It holds a great promise of becoming a reliable future guide for decisions concerning platelet transfusions.
- Structure of Acidic pH Dengue Virus Showing the Fusogenic Glycoprotein Trimers.
Zhang X, Sheng J, Austin SK, et al. Structure of Acidic pH Dengue Virus Showing the Fusogenic Glycoprotein Trimers. [JOURNAL ARTICLE]J Virol 2014 Oct 29.Flaviviruses undergo large conformational changes during their life cycle. Under acidic pH conditions the mature virus forms transient fusogenic trimers of E glycoproteins that engage the lipid membrane in host cells to initiate the viral fusion and nucleocapsid penetration into the cytoplasm. However, the dynamic nature of the fusogenic trimer has made the determination of its structure a challenge. Here we have used Fab fragments of the neutralizing antibody DV2-E104 to stop the conformational change of Dengue virus at an intermediate stage of the fusion process. Using cryo-electron microscopy, we show that in this intermediate stage the E glycoproteins form 60 trimers that are similar to the predicted "open" fusogenic trimer.The structure of a Dengue virus has been captured during the formation of fusogenic trimers. This was accomplished by binding Fab fragments of the neutralizing antibody DV2-E104 to the virus at neutral pH and then decreasing the pH to 5.5. These trimers had an "open" conformation, which is distinct from the "closed" conformation of post-fusion trimers. Only two of the three E proteins within each spike are bound by a Fab molecule at domain III. Steric hindrance around the icosahedral 3-fold axes prevents binding of a Fab to the third domain III of each E protein spike. Binding of the DV2-E104 Fab fragments prevents domain III from rotating by about 130° to the post-fusion orientation and thus precludes the stem region from "zipping" together the three E proteins along the domain II boundaries into the "closed" post-fusion conformation, thus inhibiting fusion.
- Ferritin levels predict severe dengue.
Soundravally R, Agieshkumar B, Daisy M, et al. Ferritin levels predict severe dengue. [JOURNAL ARTICLE]Infection 2014 Oct 30.Currently, no tests are available to monitor and predict severity and outcome of dengue. To find potential markers that predict dengue severity, the present study validated the serum level of three acute-phase proteins α-1 antitrypsin, ceruloplasmin and ferritin in a pool of severe dengue cases compared to non-severe forms and other febrile illness controls.A total of 96 patients were divided into two equal groups with group 'A' comprising dengue-infected cases and group 'B' with other febrile illness cases negative for dengue. Out of 48 dengue-infected cases, 13 had severe dengue and the remaining 35 were classified as non-severe dengue. Immunoassays were performed to evaluate the serum levels of acute-phase proteins both on the day of admission and on the day of defervescence. The efficiency of individual proteins in predicting the disease severity was assessed using receiver operating characteristic curve.The study did not find any significant difference in the levels of α-1 antitrypsin between the clinical groups. A significant increase in the levels of ceruloplasmin around defervescence in severe cases compared to non-severe and other febrile controls was observed and this is the first report describing the potential association of ceruloplasmin and dengue severity. Interestingly, a steady increase in the level of serum ferritin was recorded throughout the course of illness. Among all the three proteins, the elevated ferritin level could predict the disease severity with highest sensitivity and specificity of 76.9 and 83.3 %, respectively, on the day of admission and the same was found to be 90 and 91.6 % around defervescence.On the basis of this diagnostic efficiency, we propose that ferritin may serve as a potential biomarker for an early prediction of disease severity.
- Refolding of a fully functional flavivirus methyltransferase revealed that S-adenosyl methionine but not S-adenosyl homocysteine is co-purified with flavivirus methyltransferase.
Brecher MB, Li Z, Zhang J, et al. Refolding of a fully functional flavivirus methyltransferase revealed that S-adenosyl methionine but not S-adenosyl homocysteine is co-purified with flavivirus methyltransferase. [JOURNAL ARTICLE]Protein Sci 2014 Oct 29.Methylation of flavivirus RNA is vital for its stability and translation in the infected host cell. This methylation is mediated by the flavivirus methyltransferase (MTase), which methylates the N7 and 2'-O positions of the viral RNA cap by utilizing S-adenosyl-L-methionine (SAM) as a methyl donor. In this report, we demonstrate that SAM, in contrast to the reaction by-product S-adenosyl-L-homocysteine (SAH) which was assumed previously, is co-purified with the Dengue (DNV) and West Nile virus (WNV) MTases produced in Escherichia coli (E. coli). This endogenous SAM can be removed by denaturation and refolding of the MTase protein. The refolded MTase of DNV serotype 3 (DNV3) displays methylation activity comparable to native enzyme, and its crystal structure at 2.1 Å is almost identical to that of native MTase. We characterized the binding of Sinefungin (SIN), a previously described SAM-analog inhibitor of MTase function, to the native and refolded DNV3 MTase by isothermal titration calorimetry, and found that SIN binds to refolded MTase with more than sixteen times the affinity of SIN binding to the MTase purified natively. Moreover, we show that SAM is also co-purified with other flavivirus MTases, indicating that purification by refolding may be a generally applicable tool for studying flavivirus MTase inhibition.
- Functional Analysis of DENV-2 Envelope Protein Domain 3 Type-Specific and DENV Complex-Reactive Critical Epitope Residues.
Pitcher TJ, Sarathy VV, Matsui K, et al. Functional Analysis of DENV-2 Envelope Protein Domain 3 Type-Specific and DENV Complex-Reactive Critical Epitope Residues. [JOURNAL ARTICLE]J Gen Virol 2014 Oct 22.The dengue virus (DENV) envelope protein domain 3 (ED3) is the target of potent virus neutralizing antibodies. The DENV-2 ED3 contains adjacent type-specific and DENV complex-reactive antigenic sites that are composed of a small number of residues that were previously demonstrated to be critical for antibody binding. Site-directed mutagenesis of a DENV-2 16681 infectious clone was used to mutate critical residues in the DENV-2 type-specific (K305A and P384A) and DENV complex-reactive (K310A) antigenic sites. The K305A mutant virus multiplied like the parent virus in mosquito and mammalian cells, as did the P384A mutant virus, which required a compensatory mutation (G330D) for viability. However, the K310A mutant virus could not be recovered. The DENV-2 type-specific critical residue mutations K305A and P384A+G330D reduced the ability of DENV-2 type-specific, but not DENV complex-reactive, monoclonal antibodies (mAbs) to neutralize virus infectivity and this was directly correlated with mAb binding affinity to the rED3 mutants.
- Mosquito odorant receptor for DEET and methyl jasmonate.
Xu P, Choo YM, De La Rosa A, et al. Mosquito odorant receptor for DEET and methyl jasmonate. [JOURNAL ARTICLE]Proc Natl Acad Sci U S A 2014 Oct 27.Insect repellents are important prophylactic tools for travelers and populations living in endemic areas of malaria, dengue, encephalitis, and other vector-borne diseases. DEET (N,N-diethyl-3-methylbenzamide) is a 6-decade-old synthetic repellent, which is still considered the gold standard of mosquito repellents. Mosquitoes use their sense of smell to detect DEET, but there are currently two hypotheses regarding its mode of action: activation of ionotropic receptor IR40a vs. odorant receptor(s). Here, we demonstrate that DEET, picaridin, insect repellent 3535, and p-menthan-3,8-diol activate the odorant receptor CquiOR136 of the southern house mosquito, Culex quinquefasciatus. Electrophysiological and behavioral assays showed that CquiIR40a knockdown had no significant effect on DEET detection and repellency. By contrast, reduction of CquiOR136 transcript levels led to a significant decrease in electroantennographic responses to DEET and a complete lack of repellency. Thus, direct activation of an odorant receptor, not an ionotropic receptor, is necessary for DEET reception and repellency in Culex mosquitoes. Interestingly, methyl jasmonate, a repellent derived from the nonvolatile jasmonic acid in the signaling pathway of plant defenses, elicited robust responses in CquiOR136•CquiOrco-expressing Xenopus oocytes, thus suggesting a possible link between natural products with long insect-plant evolutionary history and synthetic repellents.
- Discovery and Characterization of Potential Prognostic Biomarkers for Dengue Hemorrhagic Fever.
Poole-Smith BK, Gilbert A, Gonzalez AL, et al. Discovery and Characterization of Potential Prognostic Biomarkers for Dengue Hemorrhagic Fever. [JOURNAL ARTICLE]Am J Trop Med Hyg 2014 Oct 27.Half a million patients are hospitalized with severe dengue every year, many of whom would die without timely, appropriate clinical intervention. The majority of dengue cases are uncomplicated; however, 2-5% progress to severe dengue. Severe dengue cases have been reported with increasing frequency over the last 30 years. To discover biomarkers for severe dengue, we used surface-enhanced laser desorption/ionization time-of-flight mass spectrometry to analyze dengue virus positive serum samples from the acute phase of infection. Using this method, 16 proteins were identified as candidate biomarkers for severe dengue. From these 16 biomarkers, three candidates were selected for confirmation by enzyme-linked immunosorbent assay and Western blot: vitronectin (Vtn, 55.1 kDa), hemopexin (Hx, 52.4 kDa), and serotransferrin (Tf, 79.2 kDa). Vitronectin, Hx, and Tf best differentiated between dengue and severe dengue.
- Clinical Features of and Risk Factors for Rhabdomyolysis Among Adult Patients with Dengue Virus Infection.
Huang SY, Lee IK, Liu JW, et al. Clinical Features of and Risk Factors for Rhabdomyolysis Among Adult Patients with Dengue Virus Infection. [JOURNAL ARTICLE]Am J Trop Med Hyg 2014 Oct 27.Among 1,076 dengue patients, 9 patients with rhabdomyolysis and 1,067 patients without rhabdomyolysis (controls) were retrospectively analyzed. Of nine patients with rhabdomyolysis, the most commonly reported symptom other than fever was myalgia; dengue hemorrhagic fever (DHF) was found in seven cases, and acute kidney injury was found in six cases. Furthermore, one (11.1%) patient died. The median duration from hospital admission to rhabdomyolysis diagnosis was 3 days. Patients with rhabdomyolysis had higher age, proportion of men, prevalence of hypertension, frequency of myalgia, and incidences of DHF, pleural effusion, and acute kidney injury than controls. Multivariate analysis showed that hypertension (odds ratio [OR] = 14.270), myalgia (OR = 20.377), and acute kidney injury (OR = 65.547) were independent risk factors for rhabdomyolysis. Comparison of cytokine/chemokine concentrations in 101 DHF patients, including those with (N = 4) and without (N = 97) rhabdomyolysis, showed that interleukin-6 and tumor necrosis factor-α levels were significantly increased in the former.
- MOLECULAR CHARACTERIZATION OF DENGUE AND CHIKUNGUNYA VIRUS STRAINS CIRCULATING IN NEW DELHI, INDIA.
Afreen N, Deeba F, Khan WH, et al. MOLECULAR CHARACTERIZATION OF DENGUE AND CHIKUNGUNYA VIRUS STRAINS CIRCULATING IN NEW DELHI, INDIA. [JOURNAL ARTICLE]Microbiol Immunol 2014 Oct 25.Dengue and chikungunya are acute viral infections with overlapping clinical symptoms. The two diseases are transmitted by common mosquito vectors resulting in their co-circulation in a region. Molecular and serological tests specific for both dengue and chikungunya infections were carried out on 87 acute phase blood samples collected from suspected dengue/chikungunya patients in Delhi from September to December, 2011. RT-PCR and IgM ELISA were done for detection of dengue virus (DENV) and chikungunya virus (CHIKV). NS1 ELISA and IgG ELISA were also conducted for detection of DENV specific antigen and secondary DENV infection. DENV infection was detected in 49% and CHIKV infection in 29% samples by RT-PCR. Co-infection by DENV and CHIKV were detected in 10% of the samples. DENV serotypes 1, 2 and 3 were detected in the study. Nine DENV-1 strains, 6 DENV-2 strains and 20 CHIKV strains were characterized by DNA sequencing and phylogenetic analysis of respective envelope protein genes. DENV-1 strains grouped in American African genotype, DENV- 2 strains in Cosmopolitan genotype and CHIKV strains in East Central South African (ECSA) genotype by phylogenetic analysis. This is one of the few studies that describe phylogeny of two dengue virus serotypes (DENV-1 and DENV-2) and chikungunya virus. The surveillance and monitoring of DENV and CHIKV strains are important for design of strategies for control of impending epidemic.