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.
- 35-year-old man dies of dengue - Times of India
Wed, 22 Oct 2014 21:40:
- 30 dengue cases detected, 1 dead - Times of India
Wed, 22 Oct 2014 21:07:
- Civic body to intensify drive against malaria, dengue - Times of India
Wed, 22 Oct 2014 19:43:
- 51 people test dengue positive in three weeks - Times of India
Wed, 22 Oct 2014 19:14:
- NMC's undertakes drive to search mosquito eggs to eliminate Dengue - Nagpur Today
Wed, 22 Oct 2014 14:48:
- Physicians witness sudden change in dengue symptoms in Mumbai - Times of India
Wed, 22 Oct 2014 17:12:
- More than 300 dengue cases tested positive - I am in dna of India
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- Dengue cases on the rise: Mumbai's blood banks struggle to meet demand - Hindustan Times
Wed, 22 Oct 2014 13:51:
- 19 new dengue cases reported in Indore; total number reaches 65 - Hindustan Times
Wed, 22 Oct 2014 10:45:
- Kaohsiung reports over 6000 dengue fever cases this year - Focus Taiwan News Channel
Wed, 22 Oct 2014 10:44:
- Mycoplasma Pneumonia as Cause of Acute Respiratory Distress Syndrome (ARDS) and Diffuse Alveolar Hemorrhage (DAH) Requiring Veno-Venous Extra Corporeal Membrane Oxygenation (VV-ECMO).
Patel K, Ali N, Nazir H, et al. Mycoplasma Pneumonia as Cause of Acute Respiratory Distress Syndrome (ARDS) and Diffuse Alveolar Hemorrhage (DAH) Requiring Veno-Venous Extra Corporeal Membrane Oxygenation (VV-ECMO). [JOURNAL ARTICLE]Chest 2014 Oct 1; 146(4_MeetingAbstracts):163A.Infectious Disease Student/Resident Case Report Posters ISESSION TYPE: Medical Student/Resident Case ReportPRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PMINTRODUCTION: DAH is an acute life threatening condition often associated with systemic disorders such as vasculitis, infections, toxins or patients on immunosuppression. Mycoplasma pneumonia is a common cause of community acquired pneumonia and rarely causes fulminant disease and respiratory failure. We report here a case of mycoplasma pneumonia in an immuno-competent female causing DAH and ARDS requiring mechanical ventilation and VV-ECMO.CASE PRESENTATION: Our patient is a 20 year old female with no significant past medical history presenting with cough, shortness of breath and subjective fevers for 4 days. She was seen twice in the emergency department and was treated with levofloxacin and prednisone for presumed community acquired pneumonia. She was subsequently admitted for worsening shortness of breath and hypoxia with O2 saturation of 89% on room air. Notable physical exam findings included scattered wheezing on auscultation. Labs revealed a WBC count of 15,300 with 91% neutrophils, 5% lymphocytes. Hemoglobin was 8.6 g/dl with 194,000 platelets. Metabolic panel was normal with a normal Brain Natriuretic Peptide. Arterial blood gas on 60% FiO2 via nasal cannula revealed a pH of 7.43, pCO2 35, pO2 of 69 and HCO3 of 22. Chest x-ray revealed left lower lobe, right lung base and right perihilar infiltrates. She was started on emperic antibiotics, steroids and nebulizer treatments. Sputum cultures as well as influenza A & B screening was negative. Further hypoxia developed requiring mechanical ventilation on day 2 of hospital course. CTA of the chest was done which showed extensive peripheral infiltrates in the mid and lower lung zones and within the lung apices with no evidence of pulmonary embolism. Bronchoscopy demonstrated DAH and she was started on high dose steroids. Rheumatological workup done was negative. Infectious etiology was remarkable only for mycoplasma IgM which was elevated at 777 U/mL. The patient clinical status worsened, requiring transfer to our institution on day 11 of admission for nitric oxide and possible VV-ECMO. Repeat bronchoscopy demonstrated DAH. Her rheumatological work-up was repeated and was negative. After nine days on nitric oxide, VV-ECMO and high dose steroids; the patient was able to be successfully weaned off mechanical ventilation. She recovered well and was discharged to rehab facility 51 days after originally being admitted.DISCUSSION: In immunocompetent people the most frequent infectious causes of DAH are influenza A, dengue, malaria and staphylococcus aureus infections. ARDS secondary to mycoplasma pneumonia is very rare and it leading to DAH is unheard of. We present the first reported case of mycoplasma induced DAH requiring VV-ECMO in an immunocompetent patient.CONCLUSIONS: Mycoplasma pneumonia should be one of the differentials for diffuse alveolar hemorrhage.Reference #1: Von Ranke FM, Lung. 2013 Feb;191(1):9-18. Infectious diseases causing diffuse alveolar hemorrhage in immunocompetent patients.DISCLOSURE: The following authors have nothing to disclose: Killol Patel, Nadeem Ali, Habib Nazir, Rashid Mamoona, Muneera Naeem, Christina MiglioreNo Product/Research Disclosure Information.
- 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.
- Limonoids from the Seeds of Swietenia macrophylla with Inhibitory Activity against Dengue Virus 2.
Cheng YB, Chien YT, Lee JC, et al. Limonoids from the Seeds of Swietenia macrophylla with Inhibitory Activity against Dengue Virus 2. [JOURNAL ARTICLE]J Nat Prod 2014 Oct 20.Fractionation of an ethanol-soluble extract of the seeds of Swietenia macrophylla yielded six new limonoids, swielimonoids A-F (1-6), along with 20 known compounds. Compounds 1 and 2, mexicanolide-type limonoids, were assigned with an α,β-unsaturated δ-lactone moiety (ring D) and a C═C bond between C-8 and C-30. Compounds 3-6 could be categorized as highly oxygenated phragmalin-type limonoids. The structures of these new compounds were elucidated through the interpretation of spectroscopic data. The antidengue virus 2 activities of the isolated components from S. macrophylla were investigated, and of 12 compounds subjected to bioassay, compounds 2 and 7-10 were found to show inhibitory activity in the range 3.5 to 12.5 μM. Among these, the new limonoid 2 exhibited significant antiviral activity (EC50 = 7.2 ± 1.33 μM) with a selectivity index (CC50/EC50) value of >27.7.
- QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti.
Reyes-Solis GD, Saavedra-Rodriguez K, Suarez AF, et al. QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2014 Oct; 8(10):e3177.The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations.Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México.Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome.
- Evaluation of Commercially Available Diagnostic Tests for the Detection of Dengue Virus NS1 Antigen and Anti-Dengue Virus IgM Antibody.
Hunsperger EA, Yoksan S, Buchy P, et al. Evaluation of Commercially Available Diagnostic Tests for the Detection of Dengue Virus NS1 Antigen and Anti-Dengue Virus IgM Antibody. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2014 Oct; 8(10):e3171.Commercially available diagnostic test kits for detection of dengue virus (DENV) non-structural protein 1 (NS1) and anti-DENV IgM were evaluated for their sensitivity and specificity and other performance characteristics by a diagnostic laboratory network developed by World Health Organization (WHO), the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) and the Pediatric Dengue Vaccine Initiative (PDVI). Each network laboratory contributed characterized serum specimens for the panels used in the evaluation. Microplate enzyme-linked immunosorbent assay (ELISA) and rapid diagnostic test (RDT formats) were represented by the kits. Each ELISA was evaluated by 2 laboratories and RDTs were evaluated by at least 3 laboratories. The reference tests for IgM anti-DENV were laboratory developed assays produced by the Armed Forces Research Institute for Medical Science (AFRIMS) and the Centers for Disease Control and Prevention (CDC), and the NS1 reference test was reverse transcriptase polymerase chain reaction (RT-PCR). Results were analyzed to determine sensitivity, specificity, inter-laboratory and inter-reader agreement, lot-to-lot variation and ease-of-use. NS1 ELISA sensitivity was 60-75% and specificity 71-80%; NS1 RDT sensitivity was 38-71% and specificity 76-80%; the IgM anti-DENV RDTs sensitivity was 30-96%, with a specificity of 86-92%, and IgM anti-DENV ELISA sensitivity was 96-98% and specificity 78-91%. NS1 tests were generally more sensitive in specimens from the acute phase of dengue and in primary DENV infection, whereas IgM anti-DENV tests were less sensitive in secondary DENV infections. The reproducibility of the NS1 RDTs ranged from 92-99% and the IgM anti-DENV RDTs from 88-94%.
- Autophagy Facilitates Antibody-Enhanced Dengue Virus Infection in Human Pre-Basophil/Mast Cells.
Fang YT, Wan SW, Lu YT, et al. Autophagy Facilitates Antibody-Enhanced Dengue Virus Infection in Human Pre-Basophil/Mast Cells. [JOURNAL ARTICLE]PLoS One 2014; 9(10):e110655.Dengue virus (DENV) infection can cause severe hemorrhagic disease in humans. Although the pathogenic mechanisms underlying severe DENV disease remain unclear, one of the possible contributing factors is antibody-dependent enhancement (ADE) which occurs when sub-neutralizing antibodies derived from a previous DENV infection enhance viral infection through interaction between virus-antibody complexes and FcR-bearing cells, such as macrophages and basophil/mast cells. Although recent reports showed that DENV induces autophagy, the relationship between antibody-enhanced DENV infection and autophagy is not clear.We showed that sub-neutralizing antibodies derived from dengue patient sera enhanced DENV infection and autophagy in the KU812 pre-basophil-like cell line as well as the HMC-1 immature mast cell line. Antibody-enhanced DENV infection of KU812 cells increased the number of autophagosome vesicles, LC3 punctation, LC3-II accumulation, and p62 degradation over that seen in cells infected with DENV alone. The percentages of DENV envelope (E) protein-positive cells and LC3 puncta following antibody-enhanced DENV infection of KU812 cells were reduced by the autophagy inhibitor 3-MA. Antibody-enhanced DENV infection of HMC-1 cells showed co-localization of DENV E protein and dsRNA with autophagosomes, which was inhibited by 3-MA treatment. Furthermore, DENV infection and replication were reduced when KU812 cells were transfected with the autophagy-inhibiting Atg4BC74A mutant.Our results demonstrate a significant induction of autophagy in antibody-enhanced DENV infection of pre-basophil-like KU812 and immature mast cell-like HMC-1 cells. Also, autophagy plays an important role in DENV infection and replication in these cells. Given the importance of ADE and FcR-bearing cells such as monocytes, macrophages and basophil/mast cells in dengue disease, the results provide insights into dengue pathogenesis and therapeutic means of control.
- Area-Wide Ground Applications of Bacillus thuringiensis var. israelensis for the Control of Aedes albopictus in Residential Neighborhoods: From Optimization to Operation.
Williams GM, Faraji A, Unlu I, et al. Area-Wide Ground Applications of Bacillus thuringiensis var. israelensis for the Control of Aedes albopictus in Residential Neighborhoods: From Optimization to Operation. [JOURNAL ARTICLE]PLoS One 2014; 9(10):e110035.The increasing range of Aedes albopictus, the Asian tiger mosquito, in the USA and the threat of chikungunya and dengue outbreaks vectored by this species have necessitated novel approaches to control this peridomestic mosquito. Conventional methods such as adulticiding provide temporary relief, but fail to manage this pest on a sustained basis. We explored the use of cold aerosol foggers and misting machines for area-wide applications of Bacillus thuringiensis var. israelensis (VectoBac WDG) as a larvicide targeting Aedes albopictus. During 2010-2013 we performed initially open field trials and then 19 operational area-wide applications in urban and suburban residential areas in northeastern USA to test three truck-mounted sprayers at two application rates. Area-wide applications of WDG in open field conditions at 400 and 800 g/ha killed on average 87% of tested larvae. Once techniques were optimized in residential areas, applications with a Buffalo Turbine Mist Sprayer at a rate of 800 g/ha, the best combination, consistently provided over 90% mortality. Importantly, there was no significant decrease in efficacy with distance from the spray line even in blocks of row homes with trees and bushes in the backyards. Under laboratory conditions Bti deposition in bioassay cups during the operational trials resulted in over 6 weeks of residual control. Our results demonstrate that area-wide truck mounted applications of WDG can effectively suppress Ae. albopictus larvae and should be used in integrated mosquito management approaches to control this nuisance pest and disease vector.