51
|
Vieira Machado AA, Estevan AO, Sales A, Brabes KCDS, Croda J, Negrão FJ. Direct costs of dengue hospitalization in Brazil: public and private health care systems and use of WHO guidelines. PLoS Negl Trop Dis 2014; 8:e3104. [PMID: 25188295 PMCID: PMC4154670 DOI: 10.1371/journal.pntd.0003104] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 07/08/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dengue, an arboviral disease, is a public health problem in tropical and subtropical regions worldwide. In Brazil, epidemics have become increasingly important, with increases in the number of hospitalizations and the costs associated with the disease. This study aimed to describe the direct costs of hospitalized dengue cases, the financial impact of admissions and the use of blood products where current protocols for disease management were not followed. METHODS AND RESULTS To analyze the direct costs of dengue illness and platelet transfusion in Brazil based on the World Health Organization (WHO) guidelines, we conducted a retrospective cross-sectional census study on hospitalized dengue patients in the public and private Brazilian health systems in Dourados City, Mato Grosso do Sul State, Brazil. The analysis involved cases that occurred from January through December during the 2010 outbreak. In total, we examined 8,226 mandatorily reported suspected dengue cases involving 507 hospitalized patients. The final sample comprised 288 laboratory-confirmed dengue patients, who accounted for 56.8% of all hospitalized cases. The overall cost of the hospitalized dengue cases was US $210,084.30, in 2010, which corresponded to 2.5% of the gross domestic product per capita in Dourados that year. In 35.2% of cases, blood products were used in patients who did not meet the blood transfusion criteria. The overall median hospitalization cost was higher (p = 0.002) in the group that received blood products (US $1,622.40) compared with the group that did not receive blood products (US $550.20). CONCLUSION The comparative costs between the public and the private health systems show that both the hospitalization of and platelet transfusion in patients who do not meet the WHO and Brazilian dengue guidelines increase the direct costs, but not the quality, of health care.
Collapse
Affiliation(s)
| | - Anderson Oliveira Estevan
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
| | - Antonio Sales
- Faculty of Math, State University of Mato Grosso do Sul, Nova Andradina, Mato Grosso do Sul, Brazil
| | | | - Júlio Croda
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
| | - Fábio Juliano Negrão
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, Mato Grosso do Sul, Brazil
- * E-mail:
| |
Collapse
|
52
|
Carrington LB, Simmons CP. Human to mosquito transmission of dengue viruses. Front Immunol 2014; 5:290. [PMID: 24987394 PMCID: PMC4060056 DOI: 10.3389/fimmu.2014.00290] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 06/03/2014] [Indexed: 12/01/2022] Open
Abstract
The successful transmission of dengue virus from a human host to a mosquito vector requires a complex set of factors to align. It is becoming increasingly important to improve our understanding of the parameters that shape the human to mosquito component of the transmission cycle so that vaccines and therapeutic antivirals can be fully evaluated and epidemiological models refined. Here we describe these factors, and discuss the biological and environmental impacts and demographic changes that are influencing these dynamics. Specifically, we examine features of the human infection required for the mosquito to acquire the virus via natural blood feeding, as well as the biological and environmental factors that influence a mosquito's susceptibility to infection, up to the point that they are capable of transmitting the virus to a new host.
Collapse
Affiliation(s)
- Lauren B. Carrington
- Dengue Group, Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
| | - Cameron P. Simmons
- Dengue Group, Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine, University of Oxford, Oxford, UK
| |
Collapse
|
53
|
Abstract
Because of the increasing incidence, geographic expansion and economic burden of dengue transmission, dengue poses major challenges to policy makers. A vaccine against dengue is urgently needed, but vaccine development has been hampered by the lack of an appropriate animal model, poor understanding of correlates of successful human immunity, the fear of immune enhancement, and viral interference in tetravalent combinations. The most suitable target epitopes for vaccines, as well as the role of nonstructural proteins remain elusive. The chimeric yellow fever bone-based live attenuated dengue vaccine is furthest in development, but initial efficacy results have been disappointing. Lessons learnt from this failure will affect the design of future trials, and increase the urgency to identify the best epitope and immune correlates. Dengue vaccine introduction will not be the only strategy to combat dengue, but needs to be "packaged" with novel vector control approaches, with community-based interventions to reduce the number of breeding sites, and reducing the case fatality rate by improving case management.
Collapse
Affiliation(s)
- Annelies Wilder-Smith
- Lee Kong Chian School of Medicine, Nanyang Technological University, Mandalay Road 11, Singapore, Singapore,
| | | |
Collapse
|
54
|
Bowman LR, Runge-Ranzinger S, McCall PJ. Assessing the relationship between vector indices and dengue transmission: a systematic review of the evidence. PLoS Negl Trop Dis 2014; 8:e2848. [PMID: 24810901 PMCID: PMC4014441 DOI: 10.1371/journal.pntd.0002848] [Citation(s) in RCA: 201] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 03/27/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite doubts about methods used and the association between vector density and dengue transmission, routine sampling of mosquito vector populations is common in dengue-endemic countries worldwide. This study examined the evidence from published studies for the existence of any quantitative relationship between vector indices and dengue cases. METHODOLOGY/PRINCIPAL FINDINGS From a total of 1205 papers identified in database searches following Cochrane and PRISMA Group guidelines, 18 were included for review. Eligibility criteria included 3-month study duration and dengue case confirmation by WHO case definition and/or serology. A range of designs were seen, particularly in spatial sampling and analyses, and all but 3 were classed as weak study designs. Eleven of eighteen studies generated Stegomyia indices from combined larval and pupal data. Adult vector data were reported in only three studies. Of thirteen studies that investigated associations between vector indices and dengue cases, 4 reported positive correlations, 4 found no correlation and 5 reported ambiguous or inconclusive associations. Six out of 7 studies that measured Breteau Indices reported dengue transmission at levels below the currently accepted threshold of 5. CONCLUSIONS/SIGNIFICANCE There was little evidence of quantifiable associations between vector indices and dengue transmission that could reliably be used for outbreak prediction. This review highlighted the need for standardized sampling protocols that adequately consider dengue spatial heterogeneity. Recommendations for more appropriately designed studies include: standardized study design to elucidate the relationship between vector abundance and dengue transmission; adult mosquito sampling should be routine; single values of Breteau or other indices are not reliable universal dengue transmission thresholds; better knowledge of vector ecology is required.
Collapse
Affiliation(s)
- Leigh R. Bowman
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Silvia Runge-Ranzinger
- The Special Programme for Research and Training in Tropical Diseases of the World Health Organization (WHO/TDR), Geneva, Switzerland
| | - P. J. McCall
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| |
Collapse
|
55
|
Abstract
Dengue is an expanding public health problem in the tropics and subtropical areas. Millions of people, most from resource-constrained countries, seek treatment every year for dengue-related disease. Despite more than 70 years of effort, a safe and efficacious vaccine remains unavailable. Antidengue antiviral drugs also do not exist despite attempts to develop or repurpose drug compounds. Gaps in the knowledge of dengue immunology, absence of a validated animal or human model of disease, and suboptimal assay platforms to measure immune responses following infection or experimental vaccination are obstacles to drug and vaccine development efforts. The limited success of one vaccine candidate in a recent clinical endpoint efficacy trial challenges commonly held beliefs regarding potential correlates of protection. If a dengue vaccine is to become a reality in the near term, vaccine developers should expand development pathway explorations beyond those typically required to demonstrate safety and efficacy.
Collapse
|
56
|
Ortega L. World Health Day 2014: an opportunity to promote research on vectors & vector-borne diseases. Indian J Med Res 2014; 139:481-3. [PMID: 24927335 PMCID: PMC4078485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Leonard Ortega
- Regional Adviser, Malaria WHO Regional Office for South East Asia World Health House, Indraprastha Estate, Mahatma Gandhi Marg, New Delhi 110 002, India
| |
Collapse
|
57
|
Naish S, Dale P, Mackenzie JS, McBride J, Mengersen K, Tong S. Climate change and dengue: a critical and systematic review of quantitative modelling approaches. BMC Infect Dis 2014; 14:167. [PMID: 24669859 PMCID: PMC3986908 DOI: 10.1186/1471-2334-14-167] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/20/2014] [Indexed: 12/19/2022] Open
Abstract
Background Many studies have found associations between climatic conditions and dengue transmission. However, there is a debate about the future impacts of climate change on dengue transmission. This paper reviewed epidemiological evidence on the relationship between climate and dengue with a focus on quantitative methods for assessing the potential impacts of climate change on global dengue transmission. Methods A literature search was conducted in October 2012, using the electronic databases PubMed, Scopus, ScienceDirect, ProQuest, and Web of Science. The search focused on peer-reviewed journal articles published in English from January 1991 through October 2012. Results Sixteen studies met the inclusion criteria and most studies showed that the transmission of dengue is highly sensitive to climatic conditions, especially temperature, rainfall and relative humidity. Studies on the potential impacts of climate change on dengue indicate increased climatic suitability for transmission and an expansion of the geographic regions at risk during this century. A variety of quantitative modelling approaches were used in the studies. Several key methodological issues and current knowledge gaps were identified through this review. Conclusions It is important to assemble spatio-temporal patterns of dengue transmission compatible with long-term data on climate and other socio-ecological changes and this would advance projections of dengue risks associated with climate change.
Collapse
Affiliation(s)
- Suchithra Naish
- School of Public Health and Social Work & Institute of Health and Biomedical Innovation, Queensland University of Technology, Victoria Park Road, Brisbane, Queensland, Australia.
| | | | | | | | | | | |
Collapse
|
58
|
Jindal H, Bhatt B, Malik JS, SK S. Dengue vaccine: a valuable asset for the future. Hum Vaccin Immunother 2014; 10:2245-6. [PMID: 25424928 PMCID: PMC4896803 DOI: 10.4161/hv.28953] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/20/2014] [Indexed: 11/19/2022] Open
Abstract
Dengue has emerged as one of the major global public health problems. The disease has broken out of its shell and has spread due to increased international travel and climatic changes. Globally, over 2.5 billion people accounting for >40% of the world's population are at risk from dengue. Since the 1940s, dengue vaccines have been under investigation. A live-attenuated tetravalent vaccine based on chimeric yellow fever-dengue virus (CYD-TDV) has progressed to phase III efficacy studies. Dengue vaccine has been found to be a cost-effective intervention to reduce morbidity and mortality. Current dengue vaccine candidates aim to protect against the 4 dengue serotypes, but the recent discovery of a fifth serotype could complicate vaccine development. In recent years, an urgent need has been felt for a vaccine to prevent the morbidity and mortality from this disease in a cost-effective way.
Collapse
Affiliation(s)
| | - Bhumika Bhatt
- Department of Community Medicine; PGIMS; Rohtak, Haryana, India
| | | | - Shashikantha SK
- Department of Community Medicine; PGIMS; Rohtak, Haryana, India
| |
Collapse
|
59
|
McArthur MA, Sztein MB, Edelman R. Dengue vaccines: recent developments, ongoing challenges and current candidates. Expert Rev Vaccines 2013; 12:933-53. [PMID: 23984962 PMCID: PMC3773977 DOI: 10.1586/14760584.2013.815412] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dengue is among the most prevalent and important arbovirus diseases of humans. To effectively control this rapidly spreading disease, control of the vector mosquito and a safe and efficacious vaccine are critical. Despite considerable efforts, the development of a successful vaccine has remained elusive. Multiple factors have complicated the creation of a successful vaccine, not the least of which are the complex, immune-mediated responses against four antigenically distinct serotypes necessitating a tetravalent vaccine providing long-lasting protective immunity. Despite the multiple impediments, there are currently many promising vaccine candidates in preclinical and clinical development. Here, the recent advances in dengue virus vaccine development are reviewed and the challenges associated with the use of these vaccines as a public health tool are briefly discussed.
Collapse
Affiliation(s)
- Monica A. McArthur
- Department of Pediatrics, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
| | - Marcelo B. Sztein
- Department of Pediatrics, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
| | - Robert Edelman
- Department of Medicine, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Room 480, Baltimore, MD 21201, USA
| |
Collapse
|
60
|
Villabona-Arenas CJ, Zanotto PMDA. Worldwide spread of Dengue virus type 1. PLoS One 2013; 8:e62649. [PMID: 23675416 PMCID: PMC3652851 DOI: 10.1371/journal.pone.0062649] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/24/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND DENV-1 is one of the four viral serotypes that causes Dengue, the most common mosquito-borne viral disease of humans. The prevalence of these viruses has grown in recent decades and is now present in more than 100 countries. Limited studies document the spread of DENV-1 over the world despite its importance for human health. METHODOLOGY/PRINCIPAL FINDINGS We used representative DENV-1 envelope gene sequences to unravel the dynamics of viral diffusion under a Bayesian phylogeographic approach. Data included strains from 45 distinct geographic locations isolated from 1944 to 2009. The estimated mean rate of nucleotide substitution was 6.56 × 10⁻⁴ substitutions/site/year. The larger genotypes (I, IV and V) had a distinctive phylogenetic structure and since 1990 they experienced effective population size oscillations. Thailand and Indonesia represented the main sources of strains for neighboring countries. Besides, Asia broadcast lineages into the Americas and the Pacific region that diverged in isolation. Also, a transmission network analysis revealed the pivotal role of Indochina in the global diffusion of DENV-1 and of the Caribbean in the diffusion over the Americas. CONCLUSIONS/SIGNIFICANCE The study summarizes the spatiotemporal DENV-1 worldwide spread that may help disease control.
Collapse
Affiliation(s)
- Christian Julián Villabona-Arenas
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil
| | - Paolo Marinho de Andrade Zanotto
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil
| |
Collapse
|
61
|
Villabona-Arenas CJ, Mondini A, Bosch I, Schimitt D, Calzavara-Silva CE, de A Zanotto PM, Nogueira ML. Dengue virus type 3 adaptive changes during epidemics in São Jose de Rio Preto, Brazil, 2006-2007. PLoS One 2013; 8:e63496. [PMID: 23667626 PMCID: PMC3646734 DOI: 10.1371/journal.pone.0063496] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/03/2013] [Indexed: 12/26/2022] Open
Abstract
Global dengue virus spread in tropical and sub-tropical regions has become a major international public health concern. It is evident that DENV genetic diversity plays a significant role in the immunopathology of the disease and that the identification of polymorphisms associated with adaptive responses is important for vaccine development. The investigation of naturally occurring genomic variants may play an important role in the comprehension of different adaptive strategies used by these mutants to evade the human immune system. In order to elucidate this role we sequenced the complete polyprotein-coding region of thirty-three DENV-3 isolates to characterize variants circulating under high endemicity in the city of São José de Rio Preto, Brazil, during the onset of the 2006-07 epidemic. By inferring the evolutionary history on a local-scale and estimating rates of synonymous (dS) and nonsynonimous (dN) substitutions, we have documented at least two different introductions of DENV-3 into the city and detected 10 polymorphic codon sites under significant positive selection (dN/dS > 1) and 8 under significant purifying selection (dN/dS < 1). We found several polymorphic amino acid coding sites in the envelope (15), NS1 (17), NS2A (11), and NS5 (24) genes, which suggests that these genes may be experiencing relatively recent adaptive changes. Furthermore, some polymorphisms correlated with changes in the immunogenicity of several epitopes. Our study highlights the existence of significant and informative DENV variability at the spatio-temporal scale of an urban outbreak.
Collapse
Affiliation(s)
- Christian Julian Villabona-Arenas
- Laboratório de Evolução Molecular e Bioinformática (LEMB), Departamento de Microbiologia, Instituto de Ciências Biomédicas. Universidade de São Paulo, São Paulo, Brazil
| | - Adriano Mondini
- Laboratório de Saúde Pública. Departamento de Ciências Biológicas. Faculdade de Ciências Farmacêuticas - Universidade Estadual Paulista “Júlio de Mesquita Filho” Araraquara/SP, Brazil
| | - Irene Bosch
- Division of Heath Science and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Diane Schimitt
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, United States of America
| | - Carlos E. Calzavara-Silva
- Laboratório de Imunologia Celular e Molecular (LICM), Centro de Pesquisas Rene Rachou (CPqRR), Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, MG, Brazil
| | - Paolo M. de A Zanotto
- Laboratório de Evolução Molecular e Bioinformática (LEMB), Departamento de Microbiologia, Instituto de Ciências Biomédicas. Universidade de São Paulo, São Paulo, Brazil
| | - Maurício L. Nogueira
- Laboratório de Pesquisas em Virologia, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP, Brazil
| |
Collapse
|
62
|
Thomas SJ. Dengue human infection model: re-establishing a tool for understanding dengue immunology and advancing vaccine development. Hum Vaccin Immunother 2013; 9:1587-90. [PMID: 23466948 DOI: 10.4161/hv.24188] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Dengue is an emerging and re-emerging disease of the tropics and sub-tropics. Millions of infections occur annually exacting a significant social, financial, and health care resource toll. Widespread use of a safe and efficacious dengue vaccine in cooperation with strategic vector control is the best hope for reducing the global dengue burden. Despite over 100 y of research exploring dengue immunology, pathogenesis, animal models, and vaccine and drug development there is no licensed vaccine or dengue anti-viral. No correlate of protection or validated animal model of disease has been defined. Experimental human infection with partially attenuated dengue viruses are documented as early as 1902 and have facilitated research efforts resulting in seminal discoveries and observations. It is time to explore re-invigorating the dengue human infection model to support dengue vaccine development.
Collapse
Affiliation(s)
- Stephen J Thomas
- Director, Viral Diseases Branch; Walter Reed Army Institute of Research; Silver Spring, MD USA
| |
Collapse
|
63
|
Shepard DS, Undurraga EA, Halasa YA. Economic and disease burden of dengue in Southeast Asia. PLoS Negl Trop Dis 2013; 7:e2055. [PMID: 23437406 PMCID: PMC3578748 DOI: 10.1371/journal.pntd.0002055] [Citation(s) in RCA: 281] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 12/26/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dengue poses a substantial economic and disease burden in Southeast Asia (SEA). Quantifying this burden is critical to set policy priorities and disease-control strategies. METHODS AND FINDINGS We estimated the economic and disease burden of dengue in 12 countries in SEA: Bhutan, Brunei, Cambodia, East-Timor, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Viet Nam. We obtained reported cases from multiple sources--surveillance data, World Health Organization (WHO), and published studies--and adjusted for underreporting using expansion factors from previous literature. We obtained unit costs per episode through a systematic literature review, and completed missing data using linear regressions. We excluded costs such as prevention and vector control, and long-term sequelae of dengue. Over the decade of 2001-2010, we obtained an annual average of 2.9 million (m) dengue episodes and 5,906 deaths. The annual economic burden (with 95% certainty levels) was US$950m (US$610m-US$1,384m) or about US$1.65 (US$1.06-US$2.41) per capita. The annual number of disability-adjusted life years (DALYs), based on the original 1994 definition, was 214,000 (120,000-299,000), which is equivalent to 372 (210-520) DALYs per million inhabitants. CONCLUSION Dengue poses a substantial economic and disease burden in SEA with a DALY burden per million inhabitants in the region. This burden is higher than that of 17 other conditions, including Japanese encephalitis, upper respiratory infections, and hepatitis B.
Collapse
Affiliation(s)
- Donald S Shepard
- Schneider Institutes for Health Policy, Heller School for Social Policy and Management, Brandeis University, Waltham, Massachusetts, USA.
| | | | | |
Collapse
|
64
|
Timoshevskiy VA, Severson DW, deBruyn BS, Black WC, Sharakhov IV, Sharakhova MV. An integrated linkage, chromosome, and genome map for the yellow fever mosquito Aedes aegypti. PLoS Negl Trop Dis 2013; 7:e2052. [PMID: 23459230 PMCID: PMC3573077 DOI: 10.1371/journal.pntd.0002052] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/21/2012] [Indexed: 11/18/2022] Open
Abstract
Background Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito's ability to transmit various pathogens. However, linking the QTLs to Ae. aegypti chromosomes and genomic sequences has been challenging because of the poor quality of polytene chromosomes and the highly fragmented genome assembly for this species. Methodology/Principal Findings Based on the approach developed in our previous study, we constructed idiograms for mitotic chromosomes of Ae. aegypti based on their banding patterns at early metaphase. These idiograms represent the first cytogenetic map developed for mitotic chromosomes of Ae. aegypti. One hundred bacterial artificial chromosome clones carrying major genetic markers were hybridized to the chromosomes using fluorescent in situ hybridization. As a result, QTLs related to the transmission of the filarioid nematode Brugia malayi, the avian malaria parasite Plasmodium gallinaceum, and the dengue virus, as well as sex determination locus and 183 Mbp of genomic sequences were anchored to the exact positions on Ae. aegypti chromosomes. A linear regression analysis demonstrated a good correlation between positions of the markers on the physical and linkage maps. As a result of the recombination rate variation along the chromosomes, 12 QTLs on the linkage map were combined into five major clusters of QTLs on the chromosome map. Conclusion This study developed an integrated linkage, chromosome, and genome map—iMap—for the yellow fever mosquito. Our discovery of the localization of multiple QTLs in a few major chromosome clusters suggests a possibility that the transmission of various pathogens is controlled by the same genomic loci. Thus, the iMap will facilitate the identification of genomic determinants of traits responsible for susceptibility or refractoriness of the mosquito to diverse pathogens. About half of the human population is under risk of dengue infection. Because of the absence of a vaccine or drug treatment, the prevention of this disease largely relies on controlling its major vector mosquito Aedes aegypti. Availability of the complete genome sequence for this mosquito offers the potential to help in the identification of novel disease control strategies. An efficient vector of arboviruses, Ae. aegypti is also a convenient model for laboratory studies. A number of genetic loci related to the remarkable ability of this mosquito to transmit various pathogens were genetically mapped to the three linkage groups corresponding to the three individual chromosomes of the mosquito. However, the exact physical positions of the genetic loci and genomic sequences on the chromosomes were unknown. In this study, we developed maps for mitotic chromosomes of Ae. aegypti and localized 100 clones carrying major genetic markers, which were previously used for mapping genetic loci associated with the pathogens' transmission. Finally, linkage, chromosome, and genome maps of Ae. aegypti were integrated. Anchoring of the genomic sequences associated with genetic markers to the chromosomes of Ae. aegypti will help to identify candidate genes that might be utilized for developing advanced genome-based strategies for vector control.
Collapse
Affiliation(s)
- Vladimir A. Timoshevskiy
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - David W. Severson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Becky S. deBruyn
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - William C. Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Igor V. Sharakhov
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Maria V. Sharakhova
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
| |
Collapse
|
65
|
Castañeda-Orjuela C, Díaz H, Alvis-Guzman N, Olarte A, Rodriguez H, Camargo G, De la Hoz-Restrepo F. Burden of Disease and Economic Impact of Dengue and Severe Dengue in Colombia, 2011. Value Health Reg Issues 2012; 1:123-128. [DOI: 10.1016/j.vhri.2012.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
66
|
Shepard DS, Undurraga EA, Lees RS, Halasa Y, Lum LCS, Ng CW. Use of multiple data sources to estimate the economic cost of dengue illness in Malaysia. Am J Trop Med Hyg 2012; 87:796-805. [PMID: 23033404 PMCID: PMC3516253 DOI: 10.4269/ajtmh.2012.12-0019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 06/29/2012] [Indexed: 01/16/2023] Open
Abstract
Dengue represents a substantial burden in many tropical and sub-tropical regions of the world. We estimated the economic burden of dengue illness in Malaysia. Information about economic burden is needed for setting health policy priorities, but accurate estimation is difficult because of incomplete data. We overcame this limitation by merging multiple data sources to refine our estimates, including an extensive literature review, discussion with experts, review of data from health and surveillance systems, and implementation of a Delphi process. Because Malaysia has a passive surveillance system, the number of dengue cases is under-reported. Using an adjusted estimate of total dengue cases, we estimated an economic burden of dengue illness of US$56 million (Malaysian Ringgit MYR196 million) per year, which is approximately US$2.03 (Malaysian Ringgit 7.14) per capita. The overall economic burden of dengue would be even higher if we included costs associated with dengue prevention and control, dengue surveillance, and long-term sequelae of dengue.
Collapse
Affiliation(s)
- Donald S. Shepard
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts; Centre for Research in Biotechnology for Agriculture, and Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | | | | | | | | |
Collapse
|
67
|
Affiliation(s)
- Duane J. Gubler
- *Address correspondence to Duane J. Gubler, Signature Research Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857. E-mail:
| |
Collapse
|