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Sy AK, Koo C, Privaldos KJR, Quinones MAT, Igoy MAU, Villanueva SYAM, Hibberd ML, Ng LC, Hapuarachchi HC. Genetic Diversity and Dispersal of DENGUE Virus among Three Main Island Groups of the Philippines during 2015-2017. Viruses 2023; 15:v15051079. [PMID: 37243165 DOI: 10.3390/v15051079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/22/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
Dengue has been one of the major public health concerns in the Philippines for more than a century. The annual dengue case burden has been increasing in recent years, exceeding 200,000 in 2015 and 2019. However, there is limited information on the molecular epidemiology of dengue in the Philippines. We, therefore, conducted a study to understand the genetic composition and dispersal of DENV in the Philippines from 2015 to 2017 under UNITEDengue. Our analyses included 377 envelope (E) gene sequences of all 4 serotypes obtained from infections in 3 main island groups (Luzon, Visayas, and Mindanao) of the Philippines. The findings showed that the overall diversity of DENV was generally low. DENV-1 was relatively more diverse than the other serotypes. Virus dispersal was evident among the three main island groups, but each island group demonstrated a distinct genotype composition. These observations suggested that the intensity of virus dispersal was not substantive enough to maintain a uniform heterogeneity among island groups so that each island group behaved as an independent epidemiological unit. The analyses suggested Luzon as one of the major sources of DENV emergence and CAR, Calabarzon, and CARAGA as important hubs of virus dispersal in the Philippines. Our findings highlight the importance of virus surveillance and molecular epidemiological analyses to gain deep insights into virus diversity, lineage dominance, and dispersal patterns that could assist in understanding the epidemiology and transmission risk of dengue in endemic regions.
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Affiliation(s)
- Ava Kristy Sy
- National Reference Laboratory for Dengue and Other Arbovirus, Virology Department, Research Institute for Tropical Medicine, Filinvest Corporate City Compound, Alabang, Muntinlupa City 1781, Philippines
| | - Carmen Koo
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore 138667, Singapore
| | - Kristine J R Privaldos
- National Reference Laboratory for Dengue and Other Arbovirus, Virology Department, Research Institute for Tropical Medicine, Filinvest Corporate City Compound, Alabang, Muntinlupa City 1781, Philippines
| | - Mary Ann T Quinones
- National Reference Laboratory for Dengue and Other Arbovirus, Virology Department, Research Institute for Tropical Medicine, Filinvest Corporate City Compound, Alabang, Muntinlupa City 1781, Philippines
| | - Mary A U Igoy
- National Reference Laboratory for Dengue and Other Arbovirus, Virology Department, Research Institute for Tropical Medicine, Filinvest Corporate City Compound, Alabang, Muntinlupa City 1781, Philippines
| | - Sharon Y A M Villanueva
- Department of Medical Microbiology, College of Public Health, University of the Philippines Manila, 625, Pedro Gil Street, Ermita, Manila 1000, Philippines
| | - Martin L Hibberd
- Department of Infection Biology, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
- Philippine Genome Centre, Dilliman Campus, University of the Philippines, Dilman, Ma. Regidor, U.P. Campus, Quezon City 1101, Philippines
- National Institutes of Health, University of the Philippines Manila, 623, Pedro Gil Street, Ermita, Manila 1000, Philippines
- Genome Institute of Singapore, 60, Biopolis Street, Genome, #02-01, Singapore 138672, Singapore
| | - Lee Ching Ng
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore 138667, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
| | - Hapuarachchige C Hapuarachchi
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore 138667, Singapore
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Hu TY, Chow JC, Chien TW, Chou W. Detecting dengue fever in children using online Rasch analysis to develop algorithms for parents: An APP development and usability study. Medicine (Baltimore) 2023; 102:e33296. [PMID: 37000053 PMCID: PMC10063317 DOI: 10.1097/md.0000000000033296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 04/01/2023] Open
Abstract
BACKGROUND Dengue fever (DF) is a significant public health concern in Asia. However, detecting the disease using traditional dichotomous criteria (i.e., absent vs present) can be extremely difficult. Convolutional neural networks (CNNs) and artificial neural networks (ANNs), due to their use of a large number of parameters for modeling, have shown the potential to improve prediction accuracy (ACC). To date, there has been no research conducted to understand item features and responses using online Rasch analysis. To verify the hypothesis that a combination of CNN, ANN, K-nearest-neighbor algorithm (KNN), and logistic regression (LR) can improve the ACC of DF prediction for children, further research is required. METHODS We extracted 19 feature variables related to DF symptoms from 177 pediatric patients, of whom 69 were diagnosed with DF. Using the RaschOnline technique for Rasch analysis, we examined 11 variables for their statistical significance in predicting the risk of DF. Based on 2 sets of data, 1 for training (80%) and the other for testing (20%), we calculated the prediction ACC by comparing the areas under the receiver operating characteristic curve (AUCs) between DF + and DF- in both sets. In the training set, we compared 2 scenarios: the combined scheme and individual algorithms. RESULTS Our findings indicate that visual displays of DF data are easily interpreted using Rasch analysis; the k-nearest neighbors algorithm has a lower AUC (<0.50); LR has a relatively higher AUC (0.70); all 3 algorithms have an almost equal AUC (=0.68), which is smaller than the individual algorithms of Naive Bayes, LR in raw data, and Naive Bayes in normalized data; and we developed an app to assist parents in detecting DF in children during the dengue season. CONCLUSION The development of an LR-based APP for the detection of DF in children has been completed. To help patients, family members, and clinicians differentiate DF from other febrile illnesses at an early stage, an 11-item model is proposed for developing the APP.
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Affiliation(s)
- Ting-Yun Hu
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Julie Chi Chow
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
- Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsair-Wei Chien
- Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan
| | - Willy Chou
- Department of Physical Medicine and Rehabilitation, Chi Mei Medical Center, Tainan, Taiwan
- Department of Physical Medicine and Rehabilitation, Chung San Medical University Hospital, Taichung, Taiwan
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Gaber M, Ahmad AA, El-Kady AM, Tolba M, Suzuki Y, Mohammed SM, Elossily NA. Dengue fever as a reemerging disease in upper Egypt: Diagnosis, vector surveillance and genetic diversity using RT-LAMP assay. PLoS One 2022; 17:e0265760. [PMID: 35499983 PMCID: PMC9060354 DOI: 10.1371/journal.pone.0265760] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 03/07/2022] [Indexed: 11/18/2022] Open
Abstract
Background
The recent increase in dengue virus (DENV) outbreaks and the absence of an effective vaccine have highlighted the importance of developing rapid and effective diagnostic surveillance tests and mosquito-based screening programs. To establish effective control measures for preventing future DENV transmission, the present study was established to identify the main mosquito vector involved in the dengue fever (DF) outbreak in Upper Egypt in 2016 and detect the diversity of dengue virus serotypes circulating in both humans and vectors.
Methods
We investigated the prevalence of DENV infection and circulating serotypes in the sera of 51 humans clinically suspected of DF and 1800 field-collected Aedes aegypti adult female mosquitoes grouped into 36 pooled samples. Both DENV non-structural protein (NS1) immunochromatographic strip assay and loop-mediated isothermal amplification (LAMP) were used for screening.
Results
Overall, the rate of DENV infection in both human sera and pooled mosquito homogenate was 33.3%, as revealed by rapid dipstick immunochromatographic analysis. However, higher detection rates were observed with RT-LAMP assay of 60.8% and 44.4% for humans and vector mosquitoes, respectively. DENV-1 was the most prevalent serotype in both populations. A combination of two, three, or even four circulating serotypes was found in 87.5% of total positive pooled mosquito samples and 83.87% of DENV-positive human sera.
Conclusion
The study reinforces the evidence of the reemergence of Aedes aegypti in Upper Egypt, inducing an outbreak of DENV. Mosquito-based surveillance of DENV infection is important to elucidate the viral activity rate and define serotype diversity to understand the virus dynamics in the reinfested area. Up to our knowledge, this is the first report of serotyping of DENV infection in an outbreak in Egypt using RT-LAMP assay.
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Affiliation(s)
- Mona Gaber
- Department of Parasitology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | | | - Asmaa M. El-Kady
- Department of Parasitology, Faculty of Medicine, South Valley University, Qena, Egypt
| | - Mohammed Tolba
- Department of Parasitology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
| | - Shereen M. Mohammed
- Department of Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Nahed Ahmed Elossily
- Department of Parasitology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Yu X, Cheng G. Adaptive Evolution as a Driving Force of the Emergence and Re-Emergence of Mosquito-Borne Viral Diseases. Viruses 2022; 14:v14020435. [PMID: 35216028 PMCID: PMC8878277 DOI: 10.3390/v14020435] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 02/06/2023] Open
Abstract
Emerging and re-emerging mosquito-borne viral diseases impose a significant burden on global public health. The most common mosquito-borne viruses causing recent epidemics include flaviviruses in the family Flaviviridae, including Dengue virus (DENV), Zika virus (ZIKV), Japanese encephalitis virus (JEV) and West Nile virus (WNV) and Togaviridae viruses, such as chikungunya virus (CHIKV). Several factors may have contributed to the recent re-emergence and spread of mosquito-borne viral diseases. Among these important causes are the evolution of mosquito-borne viruses and the genetic mutations that make them more adaptive and virulent, leading to widespread epidemics. RNA viruses tend to acquire genetic diversity due to error-prone RNA-dependent RNA polymerases, thus promoting high mutation rates that support adaptation to environmental changes or host immunity. In this review, we discuss recent findings on the adaptive evolution of mosquito-borne viruses and their impact on viral infectivity, pathogenicity, vector fitness, transmissibility, epidemic potential and disease emergence.
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Affiliation(s)
- Xi Yu
- Tsinghua-Peking Center for Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China;
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen 518000, China
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gong Cheng
- Tsinghua-Peking Center for Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China;
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen 518000, China
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
- Correspondence:
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A Cluster of Dengue Cases in Travelers: A Clinical Series from Thailand. Trop Med Infect Dis 2021; 6:tropicalmed6030152. [PMID: 34449752 PMCID: PMC8396219 DOI: 10.3390/tropicalmed6030152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 12/19/2022] Open
Abstract
Dengue is an overlooked tropical disease for which billions of people are at risk. The disease, caused by a Flavivirus with four distinct serotypes, is transmitted primarily by urban Aedes mosquito species. The infection leads to a spectrum of clinical manifestations, with the majority being asymptomatic. Primary dengue fever and, to a greater extent, a subsequent infection with a different serotype is associated with increased severity. Increased global travel and recreational tourism expose individuals naïve to the dengue viruses, the most common arboviral infections among travelers. We describe a cluster of possible primary acute dengue infections in a group of 12 individuals who presented to Bangkok Hospital for Tropical Diseases in 2017. Infection was confirmed by dengue NS1 antigen and multiplex real-time RT-PCR. Nine individuals required hospitalization, and four developed dengue warning signs. Leukocytes, neutrophils, and platelets declined towards defervescence and were negatively correlated with day of illness. Six clinical isolates were identified as dengue serotype-1, with 100% nucleotide identity suggesting that these patients were infected with the same virus.
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The Antiviral and Virucidal Activities of Voacangine and Structural Analogs Extracted from Tabernaemontana cymosa Depend on the Dengue Virus Strain. PLANTS 2021; 10:plants10071280. [PMID: 34201900 PMCID: PMC8309144 DOI: 10.3390/plants10071280] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 12/21/2022]
Abstract
Currently, no specific licensed antiviral exists for treating the illness caused by dengue virus (DENV). Therefore, the search for compounds of natural origin with antiviral activity is an important area of research. In the present study, three compounds were isolated and identified from seeds of Tabernaemontana cymosa plants. The in vitro antiviral effect of those compounds and voacangine against different DENV strains was assessed using different experimental approaches: compounds added before the infection (Pre), at the same time with the virus (Trans), after the infection (Post) or compounds present in all moments of the experiment (Pre-Trans-Post, Combined treatment). In silico studies (docking and molecular dynamics) were also performed to explain the possible antiviral mechanisms. The identified compounds were three structural analogs of voacangine (voacangine-7-hydroxyindolenine, rupicoline and 3-oxo-voacangine). In the Pre-treatment, only voacangine-7-hydroxyindolenine and rupicoline inhibited the infection caused by the DENV-2/NG strain (16.4% and 29.6% infection, respectively). In the Trans-treatment approach, voacangine, voacangine-7-hydroxyindolenine and rupicoline inhibited the infection in both DENV-2/NG (11.2%, 80.4% and 75.7% infection, respectively) and DENV-2/16681 infection models (73.7%, 74.0% and 75.3% infection, respectively). The latter strain was also inhibited by 3-oxo-voacangine (82.8% infection). Moreover, voacangine (most effective virucidal agent) was also effective against one strain of DENV-1 (DENV-1/WestPac/74) and against the third strain of DENV-2 (DENV-2/S16803) (48.5% and 32.4% infection, respectively). Conversely, no inhibition was observed in the post-treatment approach. The last approach (combined) showed that voacangine, voacangine-7-hydroxyindolenine and rupicoline inhibited over 90% of infections (3.5%, 6.9% and 3.5% infection, respectively) of both strains (DENV-2/NG and DENV-2/16681). The free energy of binding obtained with an in silico approach was favorable for the E protein and compounds, which ranged between −5.1 and −6.3 kcal/mol. Finally, the complex formed between DENV-2 E protein and the best virucidal compound was stable for 50 ns. Our results show that the antiviral effect of indole alkaloids derived from T. cymose depends on the serotype and the virus strain.
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A Bibliometric Analysis on Dengue Outbreaks in Tropical and Sub-Tropical Climates Worldwide Since 1950. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18063197. [PMID: 33808795 PMCID: PMC8003706 DOI: 10.3390/ijerph18063197] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/17/2021] [Accepted: 03/17/2021] [Indexed: 01/19/2023]
Abstract
Severe dengue outbreaks (DOs) affect the majority of Asian and Latin American countries. Whether all DOs always occurred in sub-tropical and tropical areas (STTA) has not been verified. We downloaded abstracts by searching keywords “dengue (MeSH Major Topic)” from Pubmed Central since 1950, including three collections: country names in abstracts (CNA), no abstracts (WA), and no country names in abstracts (Non-CNA). Visualizations were created to present the DOs across countries/areas in STTA. The percentages of mentioned country names and authors’ countries in STTA were computed on the CNA and Non-CNA bases. The social network analysis was applied to highlight the most cited articles and countries. We found that (1) three collections are 3427 (25.48%), 3137 (23.33%), and 6884 (51.19%) in CNA, WA, and Non-CNA, respectively; (2) the percentages of 94.3% and 79.9% were found in the CNA and Non-CNA groups; (3) the most mentioned country in abstracts were India, Thailand, and Brazil; (4) most authors in the Non-CNA collections were from the United States, Brazil, and China; (5) the most cited article (PMID = 23563266) authored by Bhatt et al. had 2604 citations since 2013. Our findings provide in-depth insights into the DO knowledge. The research approaches are recommended for authors in research on other infectious diseases in the future, not just limited to the DO topic.
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Murugesan A, Aridoss D, Senthilkumar S, Sivathanu L, Sekar R, Shankar EM, Manickan E. Molecular diversity of dengue virus serotypes 1-4 during an outbreak of acute dengue virus infection in Theni, India. Indian J Med Microbiol 2020; 38:401-408. [PMID: 33154254 DOI: 10.4103/ijmm.ijmm_20_89] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background Dengue fever (DF) is caused by an arthropod-borne dengue virus (DENV), has four serotypes and several genotypes. Although having clinical and epidemiological significance, the information on the circulating serotypes/genotypes is scarce in India. Materials and Methods Blood specimens were collected from the patients suspected of DF and they are tested for DENV NS1 antigen and DENV IgM by ELISA. Antigen-positive samples were further serotyped by reverse transcriptase polymerase chain reaction. Representative samples from each serotype were sequenced to identify the genotypes. Results All the four DENV serotypes were detected with the pre-dominance of DENV-1 (n = 49; 41.9%). Cases with multiple DENV serotype infections were also identified. Genotyping showed that DENV-1 belonging to genotype I, DENV-2 cosmopolitan (IV), DENV-3 genotype III and DENV-4 genotype I were active in the circulation during the outbreak in 2017. Conclusion Our study documents the molecular characteristics of DENV circulating in our geographical locality. The detection of heterologous DENV serotypes highlights the importance of regular molecular monitoring for the early recognition of any switch in pre-dominant serotype.
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Affiliation(s)
- Amudhan Murugesan
- Department of Microbiology, Government Theni Medical College, Theni; Department of Microbiology, Dr ALM PG IBMS, University of Madras, Chennai; Department of Microbiology, Virus Research and Diagnostic Laboratory, Government Theni Medical College, Theni, Tamil Nadu, India
| | - Dhanasezhian Aridoss
- Department of Microbiology, Government Theni Medical College, Theni; Department of Microbiology, Dr ALM PG IBMS, University of Madras, Chennai; Department of Microbiology, Virus Research and Diagnostic Laboratory, Government Theni Medical College, Theni, Tamil Nadu, India
| | - Swarna Senthilkumar
- Department of Microbiology; Department of Microbiology, Virus Research and Diagnostic Laboratory, Government Theni Medical College, Theni, Tamil Nadu, India
| | - Lallitha Sivathanu
- Department of Microbiology; Department of Microbiology, Virus Research and Diagnostic Laboratory, Government Theni Medical College, Theni, Tamil Nadu, India
| | - Ramalingam Sekar
- Department of Microbiology; Department of Microbiology, Virus Research and Diagnostic Laboratory, Government Theni Medical College, Theni, Tamil Nadu, India
| | - Esaki M Shankar
- Infection Biology, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India
| | - Elanchezhiyan Manickan
- Department of Microbiology, Dr ALM PG IBMS, University of Madras, Chennai, Tamil Nadu, India
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Cross-serotype interactions and disease outcome prediction of dengue infections in Vietnam. Sci Rep 2019; 9:9395. [PMID: 31253823 PMCID: PMC6598999 DOI: 10.1038/s41598-019-45816-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/04/2019] [Indexed: 11/30/2022] Open
Abstract
Dengue pathogenesis is extremely complex. Dengue infections are thought to induce life-long immunity from homologous challenges as well as a multi-factorial heterologous risk enhancement. Here, we use the data collected from a prospective cohort study of dengue infections in schoolchildren in Vietnam to disentangle how serotype interactions modulate clinical disease risk in the year following serum collection. We use multinomial logistic regression to correlate the yearly neutralizing antibody measurements obtained with each infecting serotype in all dengue clinical cases collected over the course of 6 years (2004–2009). This allowed us to extrapolate a fully discretised matrix of serotype interactions, revealing clear signals of increased risk of clinical illness in individuals primed with a previous dengue infection. The sequences of infections which produced a higher risk of dengue fever upon secondary infection are: DEN1 followed by DEN2; DEN1 followed by DEN4; DEN2 followed by DEN3; and DEN4 followed by DEN3. We also used this longitudinal data to train a machine learning algorithm on antibody titre differences between consecutive years to unveil asymptomatic dengue infections and estimate asymptomatic infection to clinical case ratios over time, allowing for a better characterisation of the population’s past exposure to different serotypes.
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Valero N, Mosquera J, Torres M, Duran A, Velastegui M, Reyes J, Fernandez M, Fernandez G, Veliz T. Increased serum ferritin and interleukin-18 levels in children with dengue. Braz J Microbiol 2019; 50:649-656. [PMID: 31243722 DOI: 10.1007/s42770-019-00105-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/12/2019] [Indexed: 12/12/2022] Open
Abstract
Activated monocytes/macrophages that produce a cytokine storm play an important role in the pathogenesis of dengue. Interleukin-18 (IL-18) is a proinflammatory cytokine produced by monocyte/macrophages that is increased during dengue. Ferritin is an acute-phase reactant and expressed by cells of the reticulo-endothelial system in response to infection by dengue virus. The aims of this study were to analyze the simultaneous expression of both IL-18 and ferritins in children infected by diverse serotypes of dengue virus (DENV) and determine their association with dengue severity. In this regard, children with dengue (n = 25) and healthy controls with similar age and sex (n = 20) were analyzed for circulating ferritin and cytokines. Monocytes were isolated by Hystopaque gradient and co-cultured with DENV-2. IL-18 and ferritin contents in blood, and IL-18 in culture supernatants were determined by ELISA. Increased levels of ferritin and IL-18 (p < 0.0001) were observed in dengue patients, not associated to NS1expression or type of infection (primary or secondary). Highest values of both molecules (p < 0.001) were observed in dengue with warning signs and severe dengue. Differential effect on IL-18/ferritin production was observed associated to viral serotype infection. There were no correlations between ferritin vs. IL-18 production, ferritin vs. NS1 status, and IL-18 vs. NS1 status. Viral-infected monocyte cultures showed increased production of IL-18 (p < 0.001). In conclusion, increased circulating ferritin and IL-18 are expressed in children infected by different serotypes of DENV associated with dengue severity.
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Affiliation(s)
- Nereida Valero
- Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, Zulia, 4001-A, Venezuela. .,Universidad Estatal del Sur de Manabi, Jipijapa, Ecuador.
| | - Jesus Mosquera
- Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, Zulia, 4001-A, Venezuela
| | - Mariana Torres
- Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, Zulia, 4001-A, Venezuela
| | - Anyelo Duran
- Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, Zulia, 4001-A, Venezuela
| | - Maria Velastegui
- Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, Zulia, 4001-A, Venezuela
| | - Javier Reyes
- Universidad Estatal del Sur de Manabi, Jipijapa, Ecuador
| | - Miriam Fernandez
- Facultad Ciencias de la Salud, Universidad Técnica de Ambato, Ambato, Ecuador
| | - Gerardo Fernandez
- Facultad Ciencias de la Salud, Universidad Técnica de Ambato, Ambato, Ecuador
| | - Teresa Veliz
- Universidad Estatal del Sur de Manabi, Jipijapa, Ecuador
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Malisheni M, Khaiboullina SF, Rizvanov AA, Takah N, Murewanhema G, Bates M. Clinical Efficacy, Safety, and Immunogenicity of a Live Attenuated Tetravalent Dengue Vaccine (CYD-TDV) in Children: A Systematic Review with Meta-analysis. Front Immunol 2017; 8:863. [PMID: 28824613 PMCID: PMC5543029 DOI: 10.3389/fimmu.2017.00863] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/07/2017] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Dengue hemorrhagic fever is the leading cause of hospitalization and death in children living in Asia and Latin America. There is an urgent need for an effective and safe dengue vaccine to reduce morbidity and mortality in this high-risk population given the lack of dengue specific treatment at present. This review aims to determine the efficacy, safety, and immunogenicity of CYD-TDV vaccine in children. METHODS This is a systematic review including meta-analysis of randomized controlled clinical trial data from Embase, Medline, the Cochrane Library, Web of Science, and ClinicalTrials.gov. Studies that assessed CYD-TDV vaccine efficacy [(1 - RR)*100], safety (RR), and immunogenicity (weighted mean difference) in children were included in this study. Random effects model was employed to analyze patient-level data extracted from primary studies. RESULTS The overall efficacy of CYD-TDV vaccine was 54% (40-64), while serotype-specific efficacy was 77% (66-85) for DENV4, 75% (65-82) for DENV3, 50% (36-61) for DENV1, and 34% (14-49) for DENV2. 15% (-174-74) vaccine efficacy was obtained for the unknown serotype. Meta-analysis of included studies with longer follow-up time (25 months) revealed that CYD-TDV vaccine significantly increased the risk of injection site reactions (RR = 1.1: 1.04-1.17; p-value = 0.001). Immunogenicity (expressed as geometric mean titers) in descending order was 439.7 (331.7-547.7), 323 (247 - 398.7), 144.1 (117.9-170.2), and 105 (88.7-122.8) for DENV3, DENV2, DENV1, and DENV4, respectively. CONCLUSION CYD-TDV vaccine is effective and immunogenic in children overall. Reduced efficacy of CYD-TDV vaccine against DENV2 notoriously known for causing severe dengue infection and dengue outbreaks cause for serious concern. Post hoc meta-analysis of long-term follow-up data (≥25 months) from children previously vaccinated with CYD-TDV vaccine is needed to make a conclusion regarding CYD-TDV vaccine safety in children. However, CYD-TDV vaccine should be considered for use in regions where DENV2 is not endemic as currently there is no specific treatment for dengue infection.
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Affiliation(s)
- Moffat Malisheni
- Ministry of Health, Lusaka, Zambia
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
| | - Svetlana F Khaiboullina
- Department of Microbiology and Immunology, University of Nevada Reno, Reno, NV, United States
- Kazan Federal University, Kazan, Russia
| | | | - Noah Takah
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom
- Ministry of Health, Yaounde, Cameroon
| | - Grant Murewanhema
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom
- College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Matthew Bates
- University College London Research & Training Programme, University of Zambia, University Teaching Hospital, Lusaka, Zambia
- HerpeZ, University Teaching Hospital, Lusaka, Zambia
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12
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Progress towards understanding the pathogenesis of dengue hemorrhagic fever. Virol Sin 2016; 32:16-22. [PMID: 27853992 PMCID: PMC6702245 DOI: 10.1007/s12250-016-3855-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/12/2016] [Indexed: 01/22/2023] Open
Abstract
Dengue virus (DENV) is a mosquito-borne virus belonging to the Flaviviridae family. There are 4 serotypes of DENV that cause human disease through transmission by mosquito vectors. DENV infection results in a broad spectrum of clinical symptoms, ranging from mild fever to dengue hemorrhagic fever (DHF), the latter of which can progress to dengue shock syndrome (DSS) and death. Researchers have made unremitting efforts over the last half-century to understand DHF pathogenesis. DHF is probably caused by multiple factors, such as virus-specific antibodies, viral antigens and host immune responses. This review summarizes the current progress of studies on DHF pathogenesis, which may provide important information for achieving effective control of dengue in the future.
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Leaungwutiwong P, Kelley JF, Sachair A, Jittmittraphap A, Luplertlop N. Relationship between MMP Expression and Virulence of Dengue Virus Type-2 in Infected Mosquito and Mammalian Cells. Jpn J Infect Dis 2016; 69:45-50. [DOI: 10.7883/yoken.jjid.2014.323] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - James F. Kelley
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, University of Hawaii John A. Burns School of Medicine
| | - Aucha Sachair
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University
| | - Akanitt Jittmittraphap
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University
| | - Natthanej Luplertlop
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University
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Chiow KH, Phoon MC, Putti T, Tan BKH, Chow VT. Evaluation of antiviral activities of Houttuynia cordata Thunb. extract, quercetin, quercetrin and cinanserin on murine coronavirus and dengue virus infection. ASIAN PAC J TROP MED 2015; 9:1-7. [PMID: 26851778 PMCID: PMC7104935 DOI: 10.1016/j.apjtm.2015.12.002] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/20/2015] [Accepted: 12/03/2015] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE To evaluate the in vitro activities of the ethyl acetate (EA) fraction of Houttuynia cordata (H. cordata) Thunb. (Saururaceae) and three of its constituent flavonoids (quercetin, quercitrin and rutin) against murine coronavirus and dengue virus (DENV). METHODS The antiviral activities of various concentrations of the EA fraction of H. cordata and flavonoids were assessed using virus neutralization tests against mouse hepatitis virus (MHV) and DENV type 2 (DENV-2). Cinanserin hydrochloride was also tested against MHV. The EA fraction of H. cordata was tested for acute oral toxicity in C57BL/6 mice. RESULTS The EA fraction of H. cordata inhibited viral infectivity up to 6 d. Cinanserin hydrochloride was able to inhibit MHV for only 2 d. The 50% inhibitory concentrations (IC50) of the EA fraction of H. cordata added before the viral adsorption stage were 0.98 μg/mL for MHV and 7.50 μg/mL for DENV-2 with absence of cytotoxicity. The mice fed with the EA fraction up to 2000 mg/kg did not induce any signs of acute toxicity, with normal histological features of major organs. Certain flavonoids exhibited comparatively weaker antiviral activity, notably quercetin which could inhibit both MHV and DENV-2. This was followed by quercitrin which could inhibit DENV-2 but not MHV, whereas rutin did not exert any inhibitory effect on either virus. When quercetin was combined with quercitrin, enhancement of anti-DENV-2 activity and reduced cytotoxicity were observed. However, the synergistic efficacy of the flavonoid combination was still less than that of the EA fraction. CONCLUSIONS The compounds in H. cordata contribute to the superior antiviral efficacy of the EA fraction which lacked cytotoxicity in vitro and acute toxicity in vivo. H. cordata has much potential for the development of antiviral agents against coronavirus and dengue infections.
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Affiliation(s)
- K H Chiow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore
| | - M C Phoon
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore
| | - Thomas Putti
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore
| | - Benny K H Tan
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore
| | - Vincent T Chow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, Singapore.
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Medina FA, Torres-Malavé G, Chase AJ, Santiago GA, Medina JF, Santiago LM, Muñoz-Jordán JL. Differences in type I interferon signaling antagonism by dengue viruses in human and non-human primate cell lines. PLoS Negl Trop Dis 2015; 9:e0003468. [PMID: 25768016 PMCID: PMC4359095 DOI: 10.1371/journal.pntd.0003468] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/10/2014] [Indexed: 12/22/2022] Open
Abstract
Background/Objectives In vitro studies have shown that dengue virus (DENV) can thwart the actions of interferon (IFN)-α/β and prevent the development of an antiviral state in infected cells. Clinical studies looking at gene expression in patients with severe dengue show a reduced expression of interferon stimulated genes compared to patients with dengue fever. Interestingly, there are conflicting reports as to the ability of DENV or other flaviviruses to inhibit IFN-α/β signaling. Methodology/Principal Findings In order to determine the relative inhibition of IFN-α/β signaling by DENVs, a method combining flow cytometry and a four-parameter logistic regression model was established. A representative isolate from DENV-1, -3 and -4 and seventeen representative isolates encompassing all DENV-2 genotypes were evaluated. All of the DENVs evaluated in this study were capable of inhibiting IFN-α/β signaling. Most of the strains were able to inhibit IFN-α/β to a degree similar to DENV strain 16681; however, DENV-2 sylvatic strains demonstrated an increased inhibition of phosphorylated signal transducer and activator of transcription (pSTAT1). Surprisingly, we were unable to observe inhibition of pSTAT1 by DENV-2 sylvatic strains or the Asian strain 16681 in non-human primate (NHP) cell lines. Analysis in primary Rhesus macaque dendritic cells suggests that DENVs are capable of inhibiting IFN signaling in these cells. However, contrary to human dendritic cells, production of IFN-α was detected in the supernatant of DENV-infected Rhesus macaque dendritic cells. Conclusions The ability of DENVs to inhibit IFN-α/β signaling is conserved. Although some variation in the inhibition was observed, the moderate differences may be difficult to correlate with clinical outcomes. DENVs were unable to inhibit pSTAT1 in NHP cell lines, but their ability to inhibit pSTAT1 in primary Rhesus macaque dendritic cells suggests that this may be a cell specific phenomena or due to the transformed nature of the cell lines. Dengue is a viral illness acquired through the bite of an infected mosquito. This flu-like illness, which in rare instances can be fatal, threatens more than half of the world’s population. Both in vitro and clinical studies looking at how the virus operates have consistently found that the interferon response is modulated by the virus during infection. We looked at the ability of dengue virus (DENV) strains to inhibit phosphorylated signal transducer and activator of transcription (pSTAT1) after IFN-β stimulation and observed that contrary to earlier published reports; all DENVs are capable of inhibiting IFN-α/β signaling. Strains from the DENV-2 sylvatic genotype, which mainly infect non-human primates (NHP), displayed an increased ability to inhibit pSTAT1 compared to the Asian strain 16681. To our surprise, DENVs were only capable of inhibiting pSTAT1 in human cell lines, but not in NHP cell lines. Inhibition of pSTAT1 is observed in both human and NHP primary dendritic cells. These results have important implications in the use of NHP cell lines for studies of IFN-α/β inhibition by DENV in vitro and may be a relevant consideration when using NHPs for DENV pre-clinical studies.
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Affiliation(s)
- Freddy A. Medina
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
| | - Giselle Torres-Malavé
- University of Puerto Rico Medical Science Campus, Department of Microbiology & Medical Zoology, San Juan, Puerto Rico, United States of America
| | - Amanda J. Chase
- Mercer University School of Medicine, Division of Basic Medical Sciences, Macon, Georgia, United States of America
| | - Gilberto A. Santiago
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
| | - Juan F. Medina
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
| | - Luis M. Santiago
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
| | - Jorge L. Muñoz-Jordán
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
- * E-mail:
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Increased production of interleukin-4, interleukin-10, and granulocyte-macrophage colony-stimulating factor by type 2 diabetes' mononuclear cells infected with dengue virus, but not increased intracellular viral multiplication. BIOMED RESEARCH INTERNATIONAL 2013; 2013:965853. [PMID: 24078930 PMCID: PMC3773921 DOI: 10.1155/2013/965853] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/03/2013] [Accepted: 07/05/2013] [Indexed: 12/20/2022]
Abstract
It has been reported that diabetes mellitus (DM) was an epidemiologically identified risk factor for development of dengue hemorrhagic fever (DHF)/severe dengue in dengue virus (DENV) affected patients, and T helper 2 (Th2) cytokines such as interleukin-4 (IL-4) and IL-10 each plays an important role in the immunopathogenesis of DHF in studies involving general population. To better understand the relationship between these epidemiological and immunological findings, we performed an in vitro study evaluating the sequential immunological reactions and viral load in the DENV infected mononuclear cells of adults with type 2 DM (T2DM group, n = 33) and normal adults (control group, n = 29). We found in the T2DM group significantly higher IL-4 level on the first (P = 0.049) and the third (P = 0.022) postinfection days, while higher IL-10 (P = 0.042) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (P = 0.009) were detected on the third postinfection day. No significant difference in DENV viral load between the cultured mononuclear cells from both groups was found on the first and third post-infection days. These data immunologically suggest that patients with T2DM are at higher risk for development of DHF/severe dengue and strengthen the previously epidemiologically identified role of DM being a predictive risk factor for progressing into DHF/severe dengue in DENV-affected patients.
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Gibbons RV, Nisalak A, Yoon IK, Tannitisupawong D, Rungsimunpaiboon K, Vaughn DW, Endy TP, Innis BL, Burke DS, Mammen MP, Scott RM, Thomas SJ, Hoke CH. A model international partnership for community-based research on vaccine-preventable diseases: the Kamphaeng Phet-AFRIMS Virology Research Unit (KAVRU). Vaccine 2013; 31:4487-500. [PMID: 23933334 DOI: 10.1016/j.vaccine.2013.07.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/12/2013] [Accepted: 07/30/2013] [Indexed: 11/19/2022]
Abstract
This paper describes an international collaboration to carry out studies that contributed to the understanding of pathogenesis, diagnosis, treatment, and prevention of several diseases of public health importance for Thailand and the United States. In Kamphaeng Phet Province, Thailand, febrile syndromes, including encephalitis, hepatitis, hemorrhagic fever, and influenza-like illnesses, occurred commonly and were clinically diagnosed, but the etiology was rarely confirmed. Since 1982, the Kamphaeng Phet Provincial Hospital, the Thai Ministry of Public Health, and the US Army Component of the Armed Forces Research Institute of Medical Sciences, along with vaccine manufacturers and universities, have collaborated on studies that evaluated and capitalized on improved diagnostic capabilities for infections caused by Japanese encephalitis, hepatitis A, dengue, and influenza viruses. The collaboration clarified clinical and epidemiological features of these infections and, in large clinical trials, demonstrated that vaccines against Japanese encephalitis and hepatitis A viruses were over 90% efficacious, supporting licensure of both vaccines. With the introduction of Japanese encephalitis vaccines in Thailand's Expanded Program on Immunization, reported encephalitis rates dropped substantially. Similarly, in the US, particularly in the military populations, rates of hepatitis A disease have dropped with the use of hepatitis A vaccine. Studies of the pathogenesis of dengue infections have increased understanding of the role of cellular immunity in responding to these infections, and epidemiological studies have prepared the province for studies of dengue vaccines. Approximately 80 publications resulted from this collaboration. Studies conducted in Kamphaeng Phet provided experience that contributed to clinical trials of hepatitis E and HIV vaccines, conducted elsewhere. To provide a base for continuing studies, The Kamphaeng Phet-AFRIMS Virology Research Unit (KAVRU) was established. This paper reviews the origins of the collaboration and the scientific observations made between 1982 and 2012.
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Affiliation(s)
- Robert V Gibbons
- Armed Forces Research Institute of Medical Science, Department of Virology, Bangkok, Thailand.
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Guzman MG, Alvarez M, Halstead SB. Secondary infection as a risk factor for dengue hemorrhagic fever/dengue shock syndrome: an historical perspective and role of antibody-dependent enhancement of infection. Arch Virol 2013; 158:1445-59. [PMID: 23471635 DOI: 10.1007/s00705-013-1645-3] [Citation(s) in RCA: 469] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/17/2013] [Indexed: 01/06/2023]
Abstract
Today, dengue viruses are the most prevalent arthropod-borne viruses in the world. Since the 1960s, numerous reports have identified a second heterologous dengue virus (DENV) infection as a principal risk factor for severe dengue disease (dengue hemorrhagic fever/dengue shock syndrome, DHF/DSS). Modifiers of dengue disease response include the specific sequence of two DENV infections, the interval between infections, and contributions from the human host, such as age, ethnicity, chronic illnesses and genetic background. Antibody-dependent enhancement (ADE) of dengue virus infection has been proposed as the early mechanism underlying DHF/DSS. Dengue cross-reactive antibodies raised following a first dengue infection combine with a second infecting virus to form infectious immune complexes that enter Fc-receptor-bearing cells. This results in an increased number of infected cells and increased viral output per cell. At the late illness stage, high levels of cytokines, possibly the result of T cell elimination of infected cells, result in vascular permeability, leading to shock and death. This review is focused on the etiological role of secondary infections (SI) and mechanisms of ADE.
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Affiliation(s)
- Maria G Guzman
- Institute of Tropical Medicine Pedro Kouri, Havana, Cuba.
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19
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Behura SK, Severson DW. Nucleotide substitutions in dengue virus serotypes from Asian and American countries: insights into intracodon recombination and purifying selection. BMC Microbiol 2013; 13:37. [PMID: 23410119 PMCID: PMC3598932 DOI: 10.1186/1471-2180-13-37] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 01/21/2013] [Indexed: 01/26/2023] Open
Abstract
Background Dengue virus (DENV) infection represents a significant public health problem in many subtropical and tropical countries. Although genetically closely related, the four serotypes of DENV differ in antigenicity for which cross protection among serotypes is limited. It is also believed that both multi-serotype infection as well as the evolution of viral antigenicity may have confounding effects in increased dengue epidemics. Numerous studies have been performed that investigated genetic diversity of DENV, but the precise mechanism(s) of dengue virus evolution are not well understood. Results We investigated genome-wide genetic diversity and nucleotide substitution patterns in the four serotypes among samples collected from different countries in Asia and Central and South America and sequenced as part of the Genome Sequencing Center for Infectious Diseases at the Broad Institute. We applied bioinformatics, statistical and coalescent simulation methods to investigate diversity of codon sequences of DENV samples representing the four serotypes. We show that fixation of nucleotide substitutions is more prominent among the inter-continental isolates (Asian and American) of serotypes 1, 2 and 3 compared to serotype 4 isolates (South and Central America) and are distributed in a non-random manner among the genes encoded by the virus. Nearly one third of the negatively selected sites are associated with fixed mutation sites within serotypes. Our results further show that of all the sites showing evidence of recombination, the majority (~84%) correspond to sites under purifying selection in the four serotypes. The analysis further shows that genetic recombination occurs within specific codons, albeit with low frequency (< 5% of all recombination sites) throughout the DENV genome of the four serotypes and reveals significant enrichment (p < 0.05) among sites under purifying selection in the virus. Conclusion The study provides the first evidence for intracodon recombination in DENV and suggests that within codons, genetic recombination has a significant role in maintaining extensive purifying selection of DENV in natural populations. Our study also suggests that fixation of beneficial mutations may lead to virus evolution via translational selection of specific sites in the DENV genome.
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Affiliation(s)
- Susanta K Behura
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, 46556, Notre Dame, IN, USA
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Schein CH, Bowen DM, Lewis JA, Choi K, Paul A, van der Heden van Noort GJ, Lu W, Filippov DV. Physicochemical property consensus sequences for functional analysis, design of multivalent antigens and targeted antivirals. BMC Bioinformatics 2012; 13 Suppl 13:S9. [PMID: 23320474 PMCID: PMC3426803 DOI: 10.1186/1471-2105-13-s13-s9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background Analysis of large sets of biological sequence data from related strains or organisms is complicated by superficial redundancy in the set, which may contain many members that are identical except at one or two positions. Thus a new method, based on deriving physicochemical property (PCP)-consensus sequences, was tested for its ability to generate reference sequences and distinguish functionally significant changes from background variability. Methods The PCP consensus program was used to automatically derive consensus sequences starting from sequence alignments of proteins from Flaviviruses (from the Flavitrack database) and human enteroviruses, using a five dimensional set of Eigenvectors that summarize over 200 different scalar values for the PCPs of the amino acids. A PCP-consensus protein of a Dengue virus envelope protein was produced recombinantly and tested for its ability to bind antibodies to strains using ELISA. Results PCP-consensus sequences of the flavivirus family could be used to classify them into five discrete groups and distinguish areas of the envelope proteins that correlate with host specificity and disease type. A multivalent Dengue virus antigen was designed and shown to bind antibodies against all four DENV types. A consensus enteroviral VPg protein had the same distinctive high pKa as wild type proteins and was recognized by two different polymerases. Conclusions The process for deriving PCP-consensus sequences for any group of aligned similar sequences, has been validated for sequences with up to 50% diversity. Ongoing projects have shown that the method identifies residues that significantly alter PCPs at a given position, and might thus cause changes in function or immunogenicity. Other potential applications include deriving target proteins for drug design and diagnostic kits.
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Affiliation(s)
- Catherine H Schein
- Institute for Translational Sciences, Computational Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Texas 77555-0857, USA.
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Cox J, Mota J, Sukupolvi-Petty S, Diamond MS, Rico-Hesse R. Mosquito bite delivery of dengue virus enhances immunogenicity and pathogenesis in humanized mice. J Virol 2012; 86:7637-49. [PMID: 22573866 PMCID: PMC3416288 DOI: 10.1128/jvi.00534-12] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/01/2012] [Indexed: 01/18/2023] Open
Abstract
Dengue viruses (DENV) are transmitted to humans by the bite of Aedes aegypti or Aedes albopictus mosquitoes, with millions of infections annually in over 100 countries. The diseases they produce, which occur exclusively in humans, are dengue fever (DF) and dengue hemorrhagic fever (DHF). We previously developed a humanized mouse model of DF in which mice transplanted with human hematopoietic stem cells produced signs of DENV disease after injection with low-passage, wild-type isolates. Using these mice, but now allowing infected A. aegypti to transmit dengue virus during feeding, we observed signs of more severe disease (higher and more sustained viremia, erythema, and thrombocytopenia). Infected mice mounted innate (gamma interferon [IFN-γ] and soluble interleukin 2 receptor alpha [sIL-2Rα]) and adaptive (anti-DENV antibodies) immune responses that failed to clear viremia until day 56, while a mosquito bite alone induced strong immunomodulators (tumor necrosis factor alpha [TNF-α], IL-4, and IL-10) and thrombocytopenia. This is the first animal model that allows an evaluation of human immunity to DENV infection after mosquito inoculation.
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Affiliation(s)
- Jonathan Cox
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Javier Mota
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Soila Sukupolvi-Petty
- Departments of Medicine, Molecular Microbiology, Pathology, and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael S. Diamond
- Departments of Medicine, Molecular Microbiology, Pathology, and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rebeca Rico-Hesse
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
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OhAinle M, Balmaseda A, Macalalad AR, Tellez Y, Zody MC, Saborío S, Nuñez A, Lennon NJ, Birren BW, Gordon A, Henn MR, Harris E. Dynamics of dengue disease severity determined by the interplay between viral genetics and serotype-specific immunity. Sci Transl Med 2012; 3:114ra128. [PMID: 22190239 DOI: 10.1126/scitranslmed.3003084] [Citation(s) in RCA: 223] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The rapid spread of dengue is a worldwide public health problem. In two clinical studies of dengue in Managua, Nicaragua, we observed an abrupt increase in disease severity across several epidemic seasons of dengue virus serotype 2 (DENV-2) transmission. Waning DENV-1 immunity appeared to increase the risk of severe disease in subsequent DENV-2 infections after a period of cross-protection. The increase in severity coincided with replacement of the Asian/American DENV-2 NI-1 clade with a new virus clade, NI-2B. In vitro analyses of viral isolates from the two clades and analysis of viremia in patient blood samples support the emergence of a fitter virus in later, relative to earlier, epidemic seasons. In addition, the NI-1 clade of viruses was more virulent specifically in children who were immune to DENV-1, whereas DENV-3 immunity was associated with more severe disease among NI-2B infections. Our data demonstrate that the complex interaction between viral genetics and population dynamics of serotype-specific immunity contributes to the risk of severe dengue disease. Furthermore, this work provides insights into viral evolution and the interaction between viral and immunological determinants of viral fitness and virulence.
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Affiliation(s)
- Molly OhAinle
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA 94720-7354, USA
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Méndez JA, Usme-Ciro JA, Domingo C, Rey GJ, Sánchez JA, Tenorio A, Gallego-Gomez JC. Phylogenetic reconstruction of dengue virus type 2 in Colombia. Virol J 2012; 9:64. [PMID: 22405440 PMCID: PMC3349600 DOI: 10.1186/1743-422x-9-64] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 03/09/2012] [Indexed: 12/31/2022] Open
Abstract
Background Dengue fever is perhaps the most important viral re-emergent disease especially in tropical and sub-tropical countries, affecting about 50 million people around the world yearly. In Colombia, dengue virus was first detected in 1971 and still remains as a major public health issue. Although four viral serotypes have been recurrently identified, dengue virus type 2 (DENV-2) has been involved in the most important outbreaks during the last 20 years, including 2010 when the fatality rate highly increased. As there are no major studies reviewing virus origin and genotype distribution in this country, the present study attempts to reconstruct the phylogenetic history of DENV-2 using a sequence analysis from a 224 bp PCR-amplified product corresponding to the carboxyl terminus of the envelope (E) gene from 48 Colombian isolates. Results As expected, the oldest isolates belonged to the American genotype (subtype V), but the strains collected since 1990 represent the American/Asian genotype (subtype IIIb) as previously reported in different American countries. Interestingly, the introduction of this genotype coincides with the first report of dengue hemorrhagic fever in Colombia at the end of 1989 and the increase of cases during the next years. Conclusion After replacement of the American genotype, several lineages of American/Asian subtype have rapidly spread all over the country evolving in new clades. Nevertheless, the direct association of these new variants in the raise of lethality rate observed during the last outbreak has to be demonstrated.
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Affiliation(s)
- Jairo A Méndez
- Laboratorio de Virología, Instituto Nacional de Salud, Avenida/Calle 26 No, 51-20, Bogotá, D.C.,Colombia.
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Chen R, Vasilakis N. Dengue--quo tu et quo vadis? Viruses 2011; 3:1562-608. [PMID: 21994796 PMCID: PMC3187692 DOI: 10.3390/v3091562] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/12/2011] [Accepted: 08/12/2011] [Indexed: 02/08/2023] Open
Abstract
Dengue viruses (DENV) are by far the most important arboviral pathogens in the tropics around the world, putting at risk of infection nearly a third of the global human population. DENV are members of the genus Flavivirus in the Family Flaviviridae and comprise four antigenically distinct serotypes (DENV-1-4). Although they share almost identical epidemiological features, they are genetically distinct. Phylogenetic analyses have revealed valuable insights into the origins, epidemiology and the forces that shape DENV evolution in nature. In this review, we examine the current status of DENV evolution, including but not limited to rates of evolution, selection pressures, population sizes and evolutionary constraints, and we discuss how these factors influence transmission, pathogenesis and emergence.
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Affiliation(s)
- Rubing Chen
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA; E-Mail:
| | - Nikos Vasilakis
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA; E-Mail:
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA
- Institute for Human Infection and Immunity, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA
- Center for Tropical Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA
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Co-existence of major and minor viral populations from two different origins in patients secondarily infected with dengue virus serotype 2 in Bangkok. Biochem Biophys Res Commun 2011; 413:136-42. [PMID: 21872571 DOI: 10.1016/j.bbrc.2011.08.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 08/15/2011] [Indexed: 11/22/2022]
Abstract
Generally, RNA viruses exhibit significant genetic diversity that sometimes effect viral fitness in infected hosts and probably also pathogenesis. Dengue viruses (DENVs) consist of four antigenically distinct serotypes. All the serotypes of DENV can cause mild to severe dengue illnesses. In this study, we examined the sequence variation of DENV in plasma obtained from four patients living in Bangkok who had been secondarily infected with serotype 2 (DENV-2) in 2010. The plasma-derived RNA was directly subjected to reverse transcriptase (RT)-polymerase chain reaction (PCR) at a region including most of domain III of the envelope (E) protein gene, and the PCR products obtained were subjected to clonal sequencing. Using 19-20 clones sequenced from each patient (78 total) plus 601 corresponding sequences from a public database, phylogenetic analysis revealed that the nucleic acid sequences fell into two clusters with clearly different origins. Interestingly, all patients gave sequences indicating that they carried viral populations containing 2, 3 or 5 genetic variants that consisted of one major variant plus one or more minor variants. Three patients showed a major variant from one cluster plus one or more minor components from the other while one showed major and minor variants from a single cluster. Thus, it can be concluded that DENV belonging to two different genetic lineages were co-circulated in Bangkok in 2010. For these two genotype clusters there was also a clear difference in H or Y at the deduced amino acid position 346 (i.e. H346Y) that was consistent for our sequences and 601 sequences from the public database. Thus, one among the mixed viral genotypes introduced into human individuals seems to be variably selected as the predominant component of the carried viral population, and it is possible that the dynamics of this process could influence virus evolution and disease severity.
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Kelley JF, Kaufusi PH, Volper EM, Nerurkar VR. Maturation of dengue virus nonstructural protein 4B in monocytes enhances production of dengue hemorrhagic fever-associated chemokines and cytokines. Virology 2011; 418:27-39. [PMID: 21810535 DOI: 10.1016/j.virol.2011.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/25/2011] [Accepted: 07/03/2011] [Indexed: 11/19/2022]
Abstract
High levels of viremia and chemokines and cytokines underlie the progression of severe dengue disease. Dengue virus (DENV) preferentially infects peripheral blood monocytes, which secrete elevated levels of immunomediators in patients with severe disease. Further, DENV nonstructural proteins (NS) are capable of modifying intracellular signaling, including interferon inhibition. We demonstrate that peak secretions of immunomediators such as IL-6, IL-8, IP-10, TNFα or IFNγ in DENV-infected monocytes correlate with maximum virus production and NS4B and NS5 are primarily responsible for the induction of immunomediators. Furthermore, we demonstrate that sequential NS4AB processing initiated by the viral protease NS2B3(pro) and via the intermediate 2KNS4B significantly enhances immunomediator induction. While the 2K-signal peptide is not essential for immunomediator induction, it plays a synergistic role with NS4B. These data suggest that NS4B maturation is important during innate immune signaling in DENV-infected monocytes. Given similar NS4B topologies and polyprotein processing across flaviviruses, NS4B may be an attractive target for developing Flavivirus-wide therapeutic interventions.
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Affiliation(s)
- James F Kelley
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
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Molecular epidemiology of autochthonous dengue virus strains circulating in Mexico. J Clin Microbiol 2011; 49:3370-4. [PMID: 21775538 DOI: 10.1128/jcm.00950-11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dengue virus (DENV) is the most important arthropod-borne viral infection in humans. Here, the genetic relatedness among autochthonous DENV Mexican isolates was assessed. Phylogenetic and median-joining network analyses showed that viral strains recovered from different geographic locations are genetically related and relatively homogeneous, exhibiting limited nucleotide diversity.
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Phylogenetic characterization of dengue virus type 2 in Espírito Santo, Brazil. Mol Biol Rep 2011; 39:71-80. [DOI: 10.1007/s11033-011-0711-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 04/23/2011] [Indexed: 10/18/2022]
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Abstract
Dengue is an acute emerging infectious disease transmitted by Aedes mosquitoes and has become a serious global public health problem. In mainland China, a number of large dengue outbreaks with serious consequences have been reported as early as 1978. In the three decades from 1978 to 2008, a total of 655,324 cases were reported, resulting in 610 deaths. Since the 1990s, dengue epidemics have spread gradually from Guangdong, Hainan, and Guangxi provinces in the southern coastal regions to the relatively northern and western regions including Fujian, Zhejiang, and Yunnan provinces. As the major transmission vectors of dengue viruses, the biological behavior and vectorial capacity of Aedes mosquitoes have undergone significant changes in the last two decades in mainland China, most likely the result of urbanization and global climate changes. In this review, we summarize the geographic and temporal distributions, the serotype and genotype distributions of dengue viruses in mainland China, and analyze the current status of surveillance and control of vectors for dengue transmission.
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Affiliation(s)
- Jin-Ya Wu
- School of Public Health and Tropical Medicine, Southern Medical University, Guangdong, People's Republic of China.
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Mendez JA, Usme-Ciro JA, Domingo C, Rey GJ, Sanchez JA, Tenorio A, Gallego-Gomez JC. Phylogenetic history demonstrates two different lineages of dengue type 1 virus in Colombia. Virol J 2010; 7:226. [PMID: 20836894 PMCID: PMC2944171 DOI: 10.1186/1743-422x-7-226] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Accepted: 09/14/2010] [Indexed: 11/10/2022] Open
Abstract
Background Dengue Fever is one of the most important viral re-emergent diseases affecting about 50 million people around the world especially in tropical and sub-tropical countries. In Colombia, the virus was first detected in the earliest 70's when the disease became a major public health concern. Since then, all four serotypes of the virus have been reported. Although most of the huge outbreaks reported in this country have involved dengue virus serotype 1 (DENV-1), there are not studies about its origin, genetic diversity and distribution. Results We used 224 bp corresponding to the carboxyl terminus of envelope (E) gene from 74 Colombian isolates in order to reconstruct phylogenetic relationships and to estimate time divergences. Analyzed DENV-1 Colombian isolates belonged to the formerly defined genotype V. Only one virus isolate was clasified in the genotype I, likely representing a sole introduction that did not spread. The oldest strains were closely related to those detected for the first time in America in 1977 from the Caribbean and were detected for two years until their disappearance about six years later. Around 1987, a split up generated 2 lineages that have been evolving separately, although not major aminoacid changes in the analyzed region were found. Conclusion DENV-1 has been circulating since 1978 in Colombia. Yet, the phylogenetic relationships between strains isolated along the covered period of time suggests that viral strains detected in some years, although belonging to the same genotype V, have different recent origins corresponding to multiple re-introduction events of viral strains that were circulating in neighbor countries. Viral strains used in the present study did not form a monophyletic group, which is evidence of a polyphyletic origin. We report the rapid spread patterns and high evolution rate of the different DENV-1 lineages.
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Affiliation(s)
- Jairo A Mendez
- Laboratorio de Virología, Instituto Nacional de Salud, Avenida/Calle 26 No, Bogotá D.C., Colombia.
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Abstract
Much remains to be learned about the pathogenesis of the different manifestations of dengue virus (DENV) infections in humans. They may range from subclinical infection to dengue fever, dengue hemorrhagic fever (DHF), and eventually dengue shock syndrome (DSS). As both cell tropism and tissue tropism of DENV are considered major determinants in the pathogenesis of dengue, there is a critical need for adequate tropism assays, animal models, and human autopsy data. More than 50 years of research on dengue has resulted in a host of literature, which strongly suggests that the pathogenesis of DHF and DSS involves viral virulence factors and detrimental host responses, collectively resulting in abnormal hemostasis and increased vascular permeability. Differential targeting of specific vascular beds is likely to trigger the localized vascular hyperpermeability underlying DSS. A personalized approach to the study of pathogenesis will elucidate the basis of individual risk for development of DHF and DSS as well as identify the genetic and environmental bases for differences in risk for development of severe disease.
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Danecek P, Lu W, Schein CH. PCP consensus sequences of flaviviruses: correlating variance with vector competence and disease phenotype. J Mol Biol 2009; 396:550-63. [PMID: 19969003 DOI: 10.1016/j.jmb.2009.11.070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 11/18/2009] [Accepted: 11/30/2009] [Indexed: 01/11/2023]
Abstract
BACKGROUND Computational methods are needed to design multivalent vaccines against flaviviruses (FVs) such as the West Nile virus or the dengue virus (DENV). OBJECTIVE We aimed to use physicochemical property (PCP) consensus sequences of FV strains to delineate conserved motifs, areas of maximum variability, and specific loci that correlate with arthropod vector, serotype, and disease severity. METHODS PCP consensus sequences for 27 species were prepared from 928 annotated sequences catalogued in Flavitrack. Alignments of these correlated well with the known structures of the NS3 protease domain and envelope (E) proteins. The PCPMer suite was used to identify motifs common to all FVs. Areas of PCP variability that correlated with phenotype were plotted on the structures. RESULTS Despite considerable diversity at the amino acid level, PCPs for both proteins were well conserved throughout the FVs. A series of insertions in E separated tick- from mosquito-borne viruses and all arthropod-borne viruses from isolates with no known vector or directly from insects. Comparison of a PCP consensus sequence of E derived from 600 DENV strains (DENV600) with individual ones for DENV1-DENV4 showed that most major serotype-specific variation occurs near these insertions. The DENV600 differed from one prepared from eight hemorrhagic or fatal strains from four DENV serotypes at only three positions, two of which overlap known escape mutant sites. CONCLUSIONS Comparing consensus sequences showed that substantial changes occur in only a few areas of the E protein. PCP consensus sequences can contribute to the design of multivalent vaccines.
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Affiliation(s)
- Petr Danecek
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0857, USA
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Weaver SC, Vasilakis N. Molecular evolution of dengue viruses: contributions of phylogenetics to understanding the history and epidemiology of the preeminent arboviral disease. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2009; 9:523-40. [PMID: 19460319 PMCID: PMC3609037 DOI: 10.1016/j.meegid.2009.02.003] [Citation(s) in RCA: 302] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/04/2009] [Accepted: 02/05/2009] [Indexed: 12/31/2022]
Abstract
Dengue viruses (DENV) are the most important arboviral pathogens in tropical and subtropical regions throughout the world, putting at risk of infection nearly a third of the global human population. Evidence from the historical record suggests a long association between these viruses and humans. The transmission of DENV includes a sylvatic, enzootic cycle between nonhuman primates and arboreal mosquitoes of the genus Aedes, and an urban, endemic/epidemic cycle between Aedes aegypti, a mosquito with larval development in peridomestic water containers, and human reservoir hosts. DENV are members of the genus Flavivirus in the Family Flaviviridae and comprise of 4 antigenically distinct serotypes (DENV-1-4). Although they are nearly identical epidemiologically, the 4 DENV serotypes are genetically quite distinct. Utilization of phylogenetic analyses based on partial and/or complete genomic sequences has elucidated the origins, epidemiology (genetic diversity, transmission dynamics and epidemic potential), and the forces that shape DENV molecular evolution (rates of evolution, selection pressures, population sizes, putative recombination and evolutionary constraints) in nature. In this review, we examine how phylogenetics have improved understanding of DENV population dynamics and sizes at various stages of infection and transmission, and how this information may influence pathogenesis and improve our ability to understand and predict DENV emergence.
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Affiliation(s)
- Scott C Weaver
- Department of Pathology, Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609, USA.
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Abstract
Dengue is one of the most important emerging diseases of humans, with no preventative vaccines or antiviral cures available at present. Although one-third of the world's population live at risk of infection, little is known about the pattern and dynamics of dengue virus (DENV) within outbreak situations. By exploiting genomic data from an intensively studied major outbreak, we are able to describe the molecular epidemiology of DENV at a uniquely fine-scaled temporal and spatial resolution. Two DENV serotypes (DENV-1 and DENV-3), and multiple component genotypes, spread concurrently and with similar epidemiological and evolutionary profiles during the initial outbreak phase of a major dengue epidemic that took place in Singapore during 2005. Although DENV-1 and DENV-3 differed in viremia and clinical outcome, there was no evidence for adaptive evolution before, during, or after the outbreak, indicating that ecological or immunological rather than virological factors were the key determinants of epidemic dynamics.
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Abstract
Dengue is a spectrum of disease caused by four serotypes of the most prevalent arthropod-borne virus affecting humans today, and its incidence has increased dramatically in the past 50 years. Due in part to population growth and uncontrolled urbanization in tropical and subtropical countries, breeding sites for the mosquitoes that transmit dengue virus have proliferated, and successful vector control has proven problematic. Dengue viruses have evolved rapidly as they have spread worldwide, and genotypes associated with increased virulence have expanded from South and Southeast Asia into the Pacific and the Americas. This review explores the human, mosquito, and viral factors that contribute to the global spread and persistence of dengue, as well as the interaction between the three spheres, in the context of ecological and climate changes. What is known, as well as gaps in knowledge, is emphasized in light of future prospects for control and prevention of this pandemic disease.
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Affiliation(s)
- Jennifer L Kyle
- Division of Infectious Diseases, School of Public Health, and Graduate Group in Microbiology, University of California, Berkeley, California 94720-7354, USA.
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Seligman SJ. Constancy and diversity in the flavivirus fusion peptide. Virol J 2008; 5:27. [PMID: 18275613 PMCID: PMC2275255 DOI: 10.1186/1743-422x-5-27] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 02/14/2008] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Flaviviruses include the mosquito-borne dengue, Japanese encephalitis, yellow fever and West Nile and the tick-borne encephalitis viruses. They are responsible for considerable world-wide morbidity and mortality. Viral entry is mediated by a conserved fusion peptide containing 16 amino acids located in domain II of the envelope protein E. Highly orchestrated conformational changes initiated by exposure to acidic pH accompany the fusion process and are important factors limiting amino acid changes in the fusion peptide that still permit fusion with host cell membranes in both arthropod and vertebrate hosts. The cell-fusing related agents, growing only in mosquitoes or insect cell lines, possess a different homologous peptide. RESULTS Analysis of 46 named flaviviruses deposited in the Entrez Nucleotides database extended the constancy in the canonical fusion peptide sequences of mosquito-borne, tick-borne and viruses with no known vector to include more recently-sequenced viruses. The mosquito-borne signature amino acid, G104, was also found in flaviviruses with no known vector and with the cell-fusion related viruses. Despite the constancy in the canonical sequences in pathogenic flaviviruses, mutations were surprisingly frequent with a 27% prevalence of nonsynonymous mutations in yellow fever virus fusion peptide sequences, and 0 to 7.4% prevalence in the others. Six of seven yellow fever patients whose virus had fusion peptide mutations died. In the cell-fusing related agents, not enough sequences have been deposited to estimate reliably the prevalence of fusion peptide mutations. However, the canonical sequences homologous to the fusion peptide and the pattern of disulfide linkages in protein E differed significantly from the other flaviviruses. CONCLUSION The constancy of the canonical fusion peptide sequences in the arthropod-borne flaviviruses contrasts with the high prevalence of mutations in most individual viruses. The discrepancy may be the result of a survival advantage accompanying sequence diversity (quasispecies) involving the fusion peptide. Limited clinical data with yellow fever virus suggest that the presence of fusion peptide mutants is not associated with a decreased case fatality rate. The cell-fusing related agents may have substantial differences from other flaviviruses in their mechanism of viral entry into the host cell.
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Affiliation(s)
- Stephen J Seligman
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, USA.
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Zaki A, Perera D, Jahan SS, Cardosa MJ. Phylogeny of dengue viruses circulating in Jeddah, Saudi Arabia: 1994 to 2006. Trop Med Int Health 2008; 13:584-92. [PMID: 18248565 DOI: 10.1111/j.1365-3156.2008.02037.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The nucleotide sequence of the 240 bp E/NS1 junction of 81 dengue viruses isolated from cases in Jeddah, Saudi Arabia was determined and used to serotype the viruses. The nucleotide sequences of the complete Envelope (E) genes of 19 isolates were used for a phylogenetic analysis of the dengue viruses circulating in Saudi Arabia from 1994 to 2006. Three of the four dengue serotypes (DENV-1, DENV-2 and DENV-3) were found to circulate, often with more than one serotype in each outbreak. There was a major outbreak caused by DENV-1 and DENV-2 in 1994 while DENV-3 emerged in 1997. In the summer of 2004, all three serotypes were isolated and this gave way to an extended outbreak of DENV-1 that stretched from the summer of 2005 through early 2006. In the 1994 outbreak, the DENV-1 circulating was from the America-Africa genotype (lineage India-2) while the most recent outbreak in 2005 and 2006 was caused by a different DENV-1 strain from genotype Asia (lineage Asia-2), suggesting a re-introduction of DENV-1 a decade after the first introduction in 1994. There has been no change in the genotypes of DENV-2 (cosmopolitan genotype) and DENV-3 (genotype III) circulating since introduction in 1994 and 1997, respectively.
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Affiliation(s)
- Ali Zaki
- Dr Soliman Fakeeh Hospital, Jeddah, Saudi Arabia
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Kurane I. Dengue hemorrhagic fever with special emphasis on immunopathogenesis. Comp Immunol Microbiol Infect Dis 2007; 30:329-40. [PMID: 17645944 DOI: 10.1016/j.cimid.2007.05.010] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Accepted: 05/16/2007] [Indexed: 10/23/2022]
Abstract
Dengue virus infections are a serious cause of morbidity and mortality in most tropical and subtropical areas of the world; Southeast and South Asia, Central and South America, and the Caribbean. Dengue virus infection can be asymptomatic or causes two forms of illness, dengue fever (DF) and dengue hemorrhagic fever (DHF), which is the severe form of dengue illness and often fatal. Pathogenesis of DHF has been analyzed, and two mechanisms are considered to be responsible. These include dengue serotype cross-reactive immune responses and virulence of the virus. The immunopathological mechanisms include a complex series of immune responses. Rapid increase in the levels of cytokines, especially TNF-alpha, and chemical mediators play a key role in inducing unique clinical manifestations of DHF such as plasma leakage, shock, and hemorrhagic manifestations. It is understood that the process is initiated by infection with a virulent dengue virus, often in the presence of antibodies that enhance dengue virus infection in secondary infection, and then triggered by rapidly elevated cytokines and chemical mediators that were produced by intense immune activation. However, complete understanding of the entire pathological mechanism is far from complete, and further studies are still needed.
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Affiliation(s)
- Ichiro Kurane
- Department of Virology 1, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
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CHUANSUMRIT AMPAIWAN, TANGNARARATCHAKIT KANCHANA. Pathophysiology and management of dengue hemorrhagic fever. ACTA ACUST UNITED AC 2006. [DOI: 10.1111/j.1778-428x.2006.00025.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yeh WT, Chen RF, Wang L, Liu JW, Shaio MF, Yang KD. Implications of previous subclinical dengue infection but not virus load in dengue hemorrhagic fever. ACTA ACUST UNITED AC 2006; 48:84-90. [PMID: 16965355 DOI: 10.1111/j.1574-695x.2006.00127.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a study comparing the virus load and immune reaction between patients with primary and secondary dengue-2 (DEN-2) infections in a hospital-based analysis, we found that 40.7% (55/135) of the 135 patients had secondary DEN-2 infection following a DEN-2 outbreak in southern Taiwan. Most of the secondary infections had subclinical primary dengue infections (78.2%; 43/55). Patients with secondary DEN-2 infections had lower platelet counts, and blood interferon-alpha and virus load, but significantly higher interleukin-10 (P=0.030) and anti-DEN-1 neutralization titers (P=0.013) than those with primary infection. Patients with secondary DEN-2 infection also had a higher rate of dengue hemorrhagic fever (DHF) (61.7% vs. 36.3%). A previous subclinical dengue infection is involved in the secondary DEN-2 infection associated with altered immune reaction and higher DHF rate, but lower blood virus load.
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Affiliation(s)
- Wen-Ting Yeh
- Department of Medical Research, Chang Gung Memorial Hospital at Kaohsiung, Chang Gung University College of Medicine, Niau-Sung, Kaohsiung, Taiwan
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Bennett SN, Holmes EC, Chirivella M, Rodriguez DM, Beltran M, Vorndam V, Gubler DJ, McMillan WO. Molecular evolution of dengue 2 virus in Puerto Rico: positive selection in the viral envelope accompanies clade reintroduction. J Gen Virol 2006; 87:885-893. [PMID: 16528038 DOI: 10.1099/vir.0.81309-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dengue virusis a circumtropical, mosquito-borne flavivirus that infects 50–100 million people each year and is expanding in both range and prevalence. Of the four co-circulating viral serotypes (DENV-1 to DENV-4) that cause mild to severe febrile disease, DENV-2 has been implicated in the onset of dengue haemorrhagic fever (DHF) in the Americas in the early 1980s. To identify patterns of genetic change since DENV-2's reintroduction into the region, molecular evolution in DENV-2 from Puerto Rico (PR) and surrounding countries was examined over a 20 year period of fluctuating disease incidence. Structural genes (over 20 % of the viral genome), which affect viral packaging, host-cell entry and immune response, were sequenced for 91 DENV-2 isolates derived from both low- and high-prevalence years. Phylogenetic analyses indicated that DENV-2 outbreaks in PR have been caused by viruses assigned to subtype IIIb, originally from Asia. Variation amongst DENV-2 viruses in PR has since largely arisenin situ, except for a lineage-replacement event in 1994 that appears to have non-PR New World origins. Although most structural genes have remained relatively conserved since the 1980s, strong evidence was found for positive selection acting on a number of amino acid sites in the envelope gene, which have also been important in defining phylogenetic structure. Some of these changes are exhibited by the multiple lineages present in 1994, during the largest Puerto Rican outbreak of dengue, suggesting that they may have altered disease dynamics, although their functional significance will require further investigation.
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Affiliation(s)
- Shannon N Bennett
- Department of Biology, University of Puerto Rico - Rio Piedras, San Juan, PR, USA
| | - Edward C Holmes
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - Maritza Chirivella
- Centers for Disease Control and Prevention, Dengue Branch, San Juan, PR, USA
| | - Dania M Rodriguez
- Department of Biology, University of Puerto Rico - Rio Piedras, San Juan, PR, USA
| | - Manuela Beltran
- Centers for Disease Control and Prevention, Dengue Branch, San Juan, PR, USA
| | - Vance Vorndam
- Centers for Disease Control and Prevention, Dengue Branch, San Juan, PR, USA
| | - Duane J Gubler
- Asia-Pacific Institute of Tropical Medicine and Infectious Diseases, Honolulu, HI, USA
| | - W Owen McMillan
- Department of Biology, University of Puerto Rico - Rio Piedras, San Juan, PR, USA
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Cummings DAT, Schwartz IB, Billings L, Shaw LB, Burke DS. Dynamic effects of antibody-dependent enhancement on the fitness of viruses. Proc Natl Acad Sci U S A 2005; 102:15259-64. [PMID: 16217017 PMCID: PMC1257724 DOI: 10.1073/pnas.0507320102] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Indexed: 01/10/2023] Open
Abstract
Antibody-dependent enhancement (ADE), a phenomenon in which viral replication is increased rather than decreased by immune sera, has been observed in vitro for a large number of viruses of public health importance, including flaviviruses, coronaviruses, and retroviruses. The most striking in vivo example of ADE in humans is dengue hemorrhagic fever, a disease in which ADE is thought to increase the severity of clinical manifestations of dengue virus infection by increasing virus replication. We examine the epidemiological impact of ADE on the prevalence and persistence of viral serotypes. Using a dynamical system model of n cocirculating dengue serotypes, we find that ADE may provide a competitive advantage to those serotypes that undergo enhancement compared with those that do not, and that this advantage increases with increasing numbers of cocirculating serotypes. Paradoxically, there are limits to the selective advantage provided by increasing levels of ADE, because greater levels of enhancement induce large amplitude oscillations in incidence of all dengue virus infections, threatening the persistence of both the enhanced and nonenhanced serotypes. Although the models presented here are specifically designed for dengue, our results are applicable to any epidemiological system in which partial immunity increases pathogen replication rates. Our results suggest that enhancement is most advantageous in settings where multiple serotypes circulate and where a large host population is available to support pathogen persistence during the deep troughs of ADE-induced large amplitude oscillations of virus replication.
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Affiliation(s)
- Derek A T Cummings
- Department of International Health, Bloomberg School of Public Health, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA
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Medin CL, Fitzgerald KA, Rothman AL. Dengue virus nonstructural protein NS5 induces interleukin-8 transcription and secretion. J Virol 2005; 79:11053-61. [PMID: 16103156 PMCID: PMC1193580 DOI: 10.1128/jvi.79.17.11053-11061.2005] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Elevated circulating levels of chemokines have been reported in patients with dengue fever and are proposed to contribute to the pathogenesis of dengue disease. To establish in vitro models for chemokine induction by dengue 2 virus (DEN2V), we studied a variety of human cell lines and primary cells. DEN2V infection of HepG2 and primary dendritic cells induced the production of interleukin-8 (IL-8), RANTES, MIP-1alpha, and MIP-1beta, whereas only IL-8 and RANTES were induced following dengue virus infection of HEK293 cells. Chemokine secretion was accompanied by an increase in steady-state mRNA levels. No chemokine induction was observed in HEK293 cells treated with poly(I:C) or alpha interferon, suggesting a direct effect of virus infection. To determine the mechanism(s) involved in the induction of chemokine production by DEN2V, individual dengue virus genes were cloned into plasmids and expressed in HEK293 cells. Transfection of a plasmid expressing NS5 or a dengue virus replicon induced IL-8 gene expression and secretion. RANTES expression was not induced under these conditions, however. Reporter assays showed that IL-8 induction by NS5 was principally through CAAT/enhancer binding protein, whereas DEN2V infection also induced NF-kappaB. These results indicate a role for the dengue virus NS5 protein in the induction of IL-8 by DEN2V infection. Recruitment and activation of potential target cells to sites of DEN2V replication by virus-induced chemokine production may contribute to viral replication as well as to the inflammatory components of dengue virus disease.
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Affiliation(s)
- Carey L Medin
- Center for Infectious Disease and Vaccine Research, University of Massachusetts Medical School, Worcester, 01655, USA
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Navarro-Sánchez E, Desprès P, Cedillo-Barrón L. Innate immune responses to dengue virus. Arch Med Res 2005; 36:425-35. [PMID: 16099317 DOI: 10.1016/j.arcmed.2005.04.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 04/29/2005] [Indexed: 01/12/2023]
Abstract
Dengue fever/dengue hemorrhagic fever (DF/DHF) has emerged as the most important mosquito-borne viral diseases in tropical areas. The dengue virus (DV) has become endemic in most tropical urban centers throughout the world, and DHF has appeared concomitantly with this expansion. Given the fact that intensity of DV replication during the early times of infection could determine clinical outcomes, which ranges from febrile illness (DF) to life-threatening disease (DHF), it is important to understand the impact of DV infection on innate immunity. Interstitial dendritic cells (DCs) are believed to constitute the first line of the innate host defense against invading DV at the anatomical sites where it replicates after the initial bite by infected mosquito. Early activation of natural killer (NK) cells and type-I interferon-dependent immunity may be also important in limiting viral replication at the early times of dengue infection. The ability of infecting DV to counter the innate antiviral immunity might account for differences in virulence observed between viral strains.
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Affiliation(s)
- Erika Navarro-Sánchez
- Unité des Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, France
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Pires Neto RJ, Lima DM, de Paula SO, Lima CM, Rocco IM, Fonseca BAL. Molecular epidemiology of type 1 and 2 dengue viruses in Brazil from 1988 to 2001. Braz J Med Biol Res 2005; 38:843-52. [PMID: 15933777 DOI: 10.1590/s0100-879x2005000600005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dengue is a mosquito-borne viral infection that in recent decades has become a major international public health concern. Epidemic dengue fever reemerged in Brazil in 1981. Since 1990 more than one dengue virus serotype has been circulating in this tropical country and increasing rates of dengue hemorrhagic fever and dengue shock syndrome have been detected every year. Some evidence supports the association between the introduction of a new serotype and/or genotype in a region and the appearance of dengue hemorrhagic fever. In order to study the evolutionary relationships and possible detection of the introduction of new dengue virus genotypes in Brazil in the last years, we analyzed partial nucleotide sequences of 52 Brazilian samples of both dengue type 1 and dengue type 2 isolated from 1988 to 2001 from highly endemic regions. A 240-nucleotide-long sequence from the envelope/nonstructural protein 1 gene junction was used for phylogenetic analysis. After comparing the nucleotide sequences originally obtained in this study to those previously studied by others, and analyzing the phylogenetic trees, we conclude that, after the initial introduction of the currently circulating dengue-1 and dengue-2 genotypes in Brazil, there has been no evidence of introduction of new genotypes since 1988. The increasing number of dengue hemorrhagic fever cases seen in Brazil in the last years is probably associated with secondary infections or with the introduction of new serotypes but not with the introduction of new genotypes.
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Affiliation(s)
- R J Pires Neto
- Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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Abstract
The evolution of dengue viruses has had a major impact on their virulence for humans and on the epidemiology of dengue disease around the world. Although antigenic and genetic differences in virus strains had become evident, it is mainly due to the lack of animal models of disease that has made it difficult to detect differences in virulence of dengue viruses. However, phylogenetic studies of many different dengue virus samples have led to the association between specific genotypes (within serotypes) and the presentation of more or less severe disease. Currently, dengue viruses can be classified as being of epidemiologically low, medium, or high impact; i.e., some viruses may remain in sylvatic cycles of little or low transmissibility to humans, others produce dengue fever (DF) only, and some genotypes have been associated with the potential to cause the more severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) in addition to DF. Although the factors that contribute to dengue virus epidemiology are complex, studies have suggested that specific viral structures may contribute to increased replication in human target cells and to increased transmission by the mosquito vector; however, the immune status and possibly the genetic background of the host are also determinants of virulence or disease presentation. As to the question of whether dengue viruses are evolving toward virulence as they continue to spread throughout the world, phylogenetic and epidemiological analyses suggest that the more virulent genotypes are now displacing those that have lower epidemiological impact; there is no evidence for the transmission of antigenically aberrant, new strains.
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Affiliation(s)
- Rebeca Rico-Hesse
- Southwest Foundation for Biomedical Research, San Antonio, Texas 78227, USA
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Edgil D, Diamond MS, Holden KL, Paranjape SM, Harris E. Translation efficiency determines differences in cellular infection among dengue virus type 2 strains. Virology 2004; 317:275-90. [PMID: 14698666 DOI: 10.1016/j.virol.2003.08.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the molecular basis for differences in the ability of natural variants of dengue virus type 2 (DEN2) to replicate in primary human cells. The rates of virus binding, virus entry, input strand translation, and RNA stability of low-passage Thai and Nicaraguan and prototype DEN2 strains were compared. All strains exhibited equivalent binding, entry, and uncoating, and displayed comparable stability of positive strand viral RNA over time in primary cells. However, the low-passage Nicaraguan isolates were much less efficient in their ability to translate viral proteins. Sequence analysis of the full-length low-passage Nicaraguan and Thai viral genomes identified specific differences in the 3' untranslated region (3'UTR). Substitution of the different sequences into chimeric RNA reporter constructs demonstrated that the changes in the 3'UTR directly affected the efficiency of viral translation. Thus, differences in infectivity among closely related DEN2 strains correlate with efficiency of translation of input viral RNA.
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Affiliation(s)
- Dianna Edgil
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, CA 94720-7360, USA
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Avilés G, Meissner J, Mantovani R, St Jeor S. Complete coding sequences of dengue-1 viruses from Paraguay and Argentina. Virus Res 2004; 98:75-82. [PMID: 14609632 DOI: 10.1016/j.virusres.2003.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have determined the complete coding sequences of six dengue-1 (DEN-1) viruses isolated from Paraguay and Argentina in 2000 from patients with dengue fever. Sequences of strains 259par00, 280par00, 295arg00, 297arg00 and 301arg00 can encode a polyprotein of 3392 amino acids. Strain 293arg00 circulated as a "wild type+deletion mutant" quasispecies, with a subpopulation characterized by a 3-nucleotide deletion in the NS4A region. This variant, which would encode a three amino acid change in the NS4A protein, was found as a minority population in one additional partially-sequenced isolate from the same outbreak. These six South American strains group into two different clades of the "American-African" DEN-1 genotype-one clade is most closely related to strains isolated from Brazil in 1997, the other to a Peruvian strain isolated in 1991 for which only partial sequence information is available. DEN-1 viruses isolated worldwide comprise at least four different genotypes according to previously defined classification criteria.
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Affiliation(s)
- G Avilés
- Department of Microbiology, University of Nevada, Reno, MS 200, Reno, NV 89557, USA.
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Affiliation(s)
- Scott B Halstead
- Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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