901
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A survey of the 2014 dengue fever epidemic in Guangzhou, China. Emerg Microbes Infect 2015; 4:e57. [PMID: 26954995 PMCID: PMC5176085 DOI: 10.1038/emi.2015.57] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/22/2015] [Accepted: 07/27/2015] [Indexed: 12/03/2022]
Abstract
In 2014, a serious dengue outbreak in Guangzhou occurred, consisting of 37 354 laboratory confirmed cases of infection. In this study, the clinical picture of dengue fever due to dengue virus (DENV) type 1 in Guangzhou was described. Clinical and laboratory data collected by studying 726 sera of suspected clinical cases from hospitals and 328 sera of healthy persons from two residence communities were analyzed during the outbreak, and 484 patients were diagnosed with an acute dengue infection. Fever, headache, congestion of the throat, and myalgia were the most typical symptoms in DENV-infected patients. Thrombocytopenia, leukopenia, and an increase in liver enzymes were significantly more common in the infected patients than in the healthy controls. Fourteen cases of silent infection were discovered among the 328 healthy persons, suggesting a DENV inapparent infection rate of 4.27% among healthy individuals. The data obtained by analyzing 212 positive sera with three methods indicated different results with different detection methods. DENV RNA should be used for early diagnoses during days 1–6 after symptom onset, immunoglobulin M (IgM) can be easily recognized after four days have passed since symptom onset and DENV isolation has a peak positive rate during days 1–3 after the onset of symptoms. A phylogenetic analysis of viral NS1 gene sequences from this outbreak indicated that the predominant isolates could be categorized as DENV-1 genotype III and had the highest homology with the India genotypes from 2009 to 2011. However, this analysis also revealed a co-epidemic of the 2013 Zhongshan and 2003 Singapore genotypes, both belonging to DENV-1 genotype I, which suggested multiple geographic origins for the 2014 epidemic of dengue 1 strains in Guangzhou.
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902
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L'Azou M, Succo T, Kamagaté M, Ouattara A, Gilbernair E, Adjogoua E, Luxemburger C. Dengue: etiology of acute febrile illness in Abidjan, Côte d'Ivoire, in 2011-2012. Trans R Soc Trop Med Hyg 2015; 109:717-22. [PMID: 26385938 PMCID: PMC4603269 DOI: 10.1093/trstmh/trv076] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/20/2015] [Indexed: 01/22/2023] Open
Abstract
Background The burden of dengue in Africa is not well understood. A prospective study was conducted in Abidjan, Côte d'Ivoire from December 2011 to December 2012 to estimate the proportion of dengue and malaria cases among febrile patients during a period when dengue was not known to be circulating in the region, and to describe the clinical and virological characteristics of laboratory-diagnosed dengue cases. Methods Blood samples were taken from febrile patients (body temperature ≥38°C) at two study sites. Patients with fever lasting more than 7 days, with fever of known origin and with jaundice were excluded. Thick blood film tests, ELISA for anti-dengue IgM and reverse transcription-PCR (RT-PCR) were performed. Results A total of 812 patients were enrolled (51.7% male [48.3% female]; 46.4% aged <10 years) of whom 796 (98.0%) provided IgM ELISA and RT-PCR data, and 807 (99.4%) had thick blood film results. Three (0.4%) patients had laboratory-diagnosed dengue (one with DENV-3 serotype), none of whom were diagnosed clinically, and 234 (28.8%) had confirmed malaria. Conclusions This study suggests that dengue virus circulates in Abidjan outside an epidemic and that there should be an increase in awareness of dengue as a possible diagnosis in cases of undifferentiated fever. These results stress the importance of implementing laboratory capacity to assess dengue burden in Africa.
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Affiliation(s)
- Maïna L'Azou
- Global Epidemiology Department, Sanofi Pasteur, Avenue Pont Pasteur 69367 Lyon cedex 07, France
| | - Tiphanie Succo
- Global Epidemiology Department, Sanofi Pasteur, Avenue Pont Pasteur 69367 Lyon cedex 07, France
| | | | - Abdoulaye Ouattara
- Epidemiology and Clinical Research Department, Pasteur Institute, Abidjan, Côte d'Ivoire
| | | | - Edgar Adjogoua
- Endemic Viruses Department, Pasteur Institute, Abidjan, Côte d'Ivoire
| | - Christine Luxemburger
- Global Epidemiology Department, Sanofi Pasteur, Avenue Pont Pasteur 69367 Lyon cedex 07, France
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903
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Lower Low-Density Lipoprotein Cholesterol Levels Are Associated with Severe Dengue Outcome. PLoS Negl Trop Dis 2015; 9:e0003904. [PMID: 26334914 PMCID: PMC4559460 DOI: 10.1371/journal.pntd.0003904] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 06/11/2015] [Indexed: 11/24/2022] Open
Abstract
Dengue virus (DENV) is a flavivirus of worldwide importance, with approximately 4 billion people across 128 countries at risk of infection, and up to 390 million infections and 96 million clinically apparent cases estimated annually. Previous in vitro studies have shown that lipids and lipoproteins play a role in modifying virus infectivity. However, the relationship between development of severe dengue and total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, is unclear. We analyzed data from 789 laboratory-confirmed dengue cases and 447 other febrile illnesses (OFI) in a prospective pediatric hospital-based study in Managua, Nicaragua between August 2005 and January 2013, using three different classifications of dengue severity: World Health Organization (WHO) 1997, WHO 2009, and standardized intervention categories. Total serum cholesterol and LDL-C levels decreased over the course of illness and were generally lower with increasing dengue severity, regardless of classification scheme. Greater decreases in LDL-C than HDL-C were observed among dengue-positive patients compared to patients with OFI and among severe dengue compared to mild dengue cases. Furthermore, daily cholesterol levels declined with daily albumin blood levels. To examine the effect of cholesterol at presentation on subsequent risk of development of severe dengue, relative risks and 95% confidence intervals were calculated using multivariable modified Poisson models. We found that lower total serum cholesterol and LDL-C levels at presentation were associated with subsequent risk of developing dengue hemorrhagic fever/dengue shock syndrome using the WHO 1997 dengue severity classification, and thus that the reduction in LDL-C is likely driving the decreases observed in total serum cholesterol levels among dengue-positive patients. Our results suggest that cholesterol blood levels are important correlates of dengue pathophysiology and should be explored as part of a prognostic biomarker panel for severe dengue. Dengue is a viral infection of worldwide importance with up to 96 million cases annually. Cholesterol, a type of lipid, may play a role in dengue virus infectivity and severity, but changes in cholesterol levels over the course of illness are not well-understood. To investigate the relationship between development of severe dengue and total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), we analyzed data from a prospective hospital-based study of pediatric dengue in Managua, Nicaragua (August 2005–January 2013). Because different classifications of dengue severity are used, we performed analyses using three different classifications. Cholesterol decreased over the course of illness and differed across disease outcome, regardless of classification scheme. Greater decreases in LDL-C than HDL-C were observed among dengue-positive patients versus patients with other febrile illnesses and among severe versus mild dengue cases. In multivariate models, lower total serum cholesterol and LDL-C levels at presentation were associated with subsequent risk of developing dengue hemorrhagic fever/dengue shock syndrome (World Health Organization 1997 classification). Our results suggest that reduction in LDL-C is likely driving decreases observed in total serum cholesterol levels among dengue-positive patients and should be explored as part of a prognostic biomarker panel for severe dengue.
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904
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Kirkpatrick BD, Durbin AP, Pierce KK, Carmolli MP, Tibery CM, Grier PL, Hynes N, Diehl SA, Elwood D, Jarvis AP, Sabundayo BP, Lyon CE, Larsson CJ, Jo M, Lovchik JM, Luke CJ, Walsh MC, Fraser EA, Subbarao K, Whitehead SS. Robust and Balanced Immune Responses to All 4 Dengue Virus Serotypes Following Administration of a Single Dose of a Live Attenuated Tetravalent Dengue Vaccine to Healthy, Flavivirus-Naive Adults. J Infect Dis 2015; 212:702-10. [PMID: 25801652 PMCID: PMC4612392 DOI: 10.1093/infdis/jiv082] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/19/2014] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The 4 serotypes of dengue virus, DENV-1-4, are the leading cause of arboviral disease globally. The ideal dengue vaccine would provide protection against all serotypes after a single dose. METHODS Two randomized, placebo-controlled trials were performed with 168 flavivirus-naive adults to demonstrate the safety and immunogenicity of a live attenuated tetravalent dengue vaccine (TV003), compared with those of a second tetravalent vaccine with an enhanced DENV-2 component (TV005), and to evaluate the benefit of a booster dose at 6 months. Safety data, viremia, and neutralizing antibody titers were evaluated. RESULTS A single dose of TV005 elicited a tetravalent response in 90% of vaccinees by 3 months after vaccination and a trivalent response in 98%. Compared with TV003, the higher-dose DENV-2 component increased the observed frequency of immunogenicity to DENV-2 in the TV005 trial. Both the first and second doses were well tolerated. Neither vaccine viremia, rash, nor a significant antibody boost were observed following a second dose. CONCLUSIONS A single subcutaneous dose of TV005 dengue vaccine is safe and induces a tetravalent antibody response at an unprecedented frequency among vaccinees. A second dose has limited benefit and appears to be unnecessary. Studies to confirm these findings and assess vaccine efficacy will now move to populations in regions where DENV transmission is endemic. CLINICAL TRIALS REGISTRATION NCT01072786 and NCT01436422.
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Affiliation(s)
- Beth D. Kirkpatrick
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Anna P. Durbin
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Kristen K. Pierce
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Marya P. Carmolli
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Cecilia M. Tibery
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Palmtama L. Grier
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Noreen Hynes
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Sean A. Diehl
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Dan Elwood
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Adrienne P. Jarvis
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Beulah P. Sabundayo
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Caroline E. Lyon
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Catherine J. Larsson
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Matthew Jo
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Janece M. Lovchik
- Center for Immunization Research, Johns Hopkins University School of Public Health,Baltimore
| | - Catherine J. Luke
- National Institutes of Allergy and Infectious Diseases, Bethesda, Maryland
| | - Mary C. Walsh
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Ellen A. Fraser
- Department of Medicine, Vaccine Testing Center, University of Vermont College of Medicine,Burlington
| | - Kanta Subbarao
- National Institutes of Allergy and Infectious Diseases, Bethesda, Maryland
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905
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Conroy AL, Gélvez M, Hawkes M, Rajwans N, Tran V, Liles WC, Villar-Centeno LA, Kain KC. Host biomarkers are associated with progression to dengue haemorrhagic fever: a nested case-control study. Int J Infect Dis 2015; 40:45-53. [PMID: 26255888 DOI: 10.1016/j.ijid.2015.07.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVES Dengue represents the most important arboviral infection worldwide. Onset of circulatory collapse can be unpredictable. Biomarkers that can identify individuals at risk of plasma leakage may facilitate better triage and clinical management. DESIGN Using a nested case-control design, we randomly selected subjects from a prospective cohort study of dengue in Colombia (n=1582). Using serum collected within 96 hours of fever onset, we tested 19 biomarkers by ELISA in cases (developed dengue hemorrhagic fever or dengue shock syndrome (DHF/DSS); n=46), and controls (uncomplicated dengue fever (DF); n=65) and healthy controls (HC); n=15. RESULTS Ang-1 levels were lower and angptl3, sKDR, sEng, sICAM-1, CRP, CXCL10/IP-10, IL-18 binding protein, CHI3L1, C5a and Factor D levels were increased in dengue compared to HC. sICAM-1, sEng and CXCL10/IP-10 were further elevated in subjects who subsequently developed DHF/DSS (p=0.008, p=0.028 and p=0.025, respectively). In a logistic regression model, age (odds ratio (OR) (95% CI): 0.95 (0.92-0.98), p=0.001), hyperesthesia/hyperalgesia (OR; 3.8 (1.4-10.4), p=0.008) and elevated sICAM-1 (>298ng/mL: OR; 6.3 (1.5-25.7), p=0.011) at presentation were independently associated with progression to DHF/DSS. CONCLUSIONS These results suggest that inflammation and endothelial activation are important pathways in the pathogenesis of dengue and sICAM-1 levels may identify individuals at risk of plasma leakage.
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Affiliation(s)
- Andrea L Conroy
- Sandra A. Rotman Laboratories, Sandra Rotman Centre, University Health Network-Toronto General Hospital, University of Toronto, Toronto, ON, M5G 1L7, Canada.
| | - Margarita Gélvez
- Centro de Investigaciones Epidemiológicas, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia.
| | - Michael Hawkes
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
| | - Nimerta Rajwans
- Sandra A. Rotman Laboratories, Sandra Rotman Centre, University Health Network-Toronto General Hospital, University of Toronto, Toronto, ON, M5G 1L7, Canada.
| | - Vanessa Tran
- Sandra A. Rotman Laboratories, Sandra Rotman Centre, University Health Network-Toronto General Hospital, University of Toronto, Toronto, ON, M5G 1L7, Canada.
| | - W Conrad Liles
- University of Washington, Department of Medicine, Seattle, WA, 98195, USA.
| | - Luis Angel Villar-Centeno
- Centro de Investigaciones Epidemiológicas, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia.
| | - Kevin C Kain
- Sandra A. Rotman Laboratories, Sandra Rotman Centre, University Health Network-Toronto General Hospital, University of Toronto, Toronto, ON, M5G 1L7, Canada; Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, M5G 2C4, Canada.
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906
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Govindarajan D, Meschino S, Guan L, Clements DE, ter Meulen JH, Casimiro DR, Coller BAG, Bett AJ. Preclinical development of a dengue tetravalent recombinant subunit vaccine: Immunogenicity and protective efficacy in nonhuman primates. Vaccine 2015; 33:4105-16. [DOI: 10.1016/j.vaccine.2015.06.067] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/06/2015] [Accepted: 06/14/2015] [Indexed: 11/27/2022]
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907
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Messina JP, Pigott DM, Golding N, Duda KA, Brownstein JS, Weiss DJ, Gibson H, Robinson TP, Gilbert M, William Wint GR, Nuttall PA, Gething PW, Myers MF, George DB, Hay SI. The global distribution of Crimean-Congo hemorrhagic fever. Trans R Soc Trop Med Hyg 2015; 109:503-13. [PMID: 26142451 PMCID: PMC4501401 DOI: 10.1093/trstmh/trv050] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne infection caused by a virus (CCHFV) from the Bunyaviridae family. Domestic and wild vertebrates are asymptomatic reservoirs for the virus, putting animal handlers, slaughter-house workers and agricultural labourers at highest risk in endemic areas, with secondary transmission possible through contact with infected blood and other bodily fluids. Human infection is characterized by severe symptoms that often result in death. While it is known that CCHFV transmission is limited to Africa, Asia and Europe, definitive global extents and risk patterns within these limits have not been well described. METHODS We used an exhaustive database of human CCHF occurrence records and a niche modeling framework to map the global distribution of risk for human CCHF occurrence. RESULTS A greater proportion of shrub or grass land cover was the most important contributor to our model, which predicts highest levels of risk around the Black Sea, Turkey, and some parts of central Asia. Sub-Saharan Africa shows more focalized areas of risk throughout the Sahel and the Cape region. CONCLUSIONS These new risk maps provide a valuable starting point for understanding the zoonotic niche of CCHF, its extent and the risk it poses to humans.
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Affiliation(s)
| | | | - Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - John S Brownstein
- Department of Pediatrics, Harvard Medical School and Children's Hospital Informatics Program, Boston Children's Hospital, Boston, MA, USA
| | | | - Harry Gibson
- Department of Zoology, University of Oxford, Oxford, UK
| | - Timothy P Robinson
- Livestock Systems and Environment (LSE), International Livestock Research Institute (ILRI),Nairobi, Kenya
| | - Marius Gilbert
- Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium Fonds National de la Recherche Scientifique, Brussels, Belgium
| | | | | | | | | | - Dylan B George
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Simon I Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK Fogarty International Center, National Institutes of Health, Bethesda, MD, USA Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
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908
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Campbell KM, Haldeman K, Lehnig C, Munayco CV, Halsey ES, Laguna-Torres VA, Yagui M, Morrison AC, Lin CD, Scott TW. Weather Regulates Location, Timing, and Intensity of Dengue Virus Transmission between Humans and Mosquitoes. PLoS Negl Trop Dis 2015. [PMID: 26222979 PMCID: PMC4519153 DOI: 10.1371/journal.pntd.0003957] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Background Dengue is one of the most aggressively expanding mosquito-transmitted viruses. The human burden approaches 400 million infections annually. Complex transmission dynamics pose challenges for predicting location, timing, and magnitude of risk; thus, models are needed to guide prevention strategies and policy development locally and globally. Weather regulates transmission-potential via its effects on vector dynamics. An important gap in understanding risk and roadblock in model development is an empirical perspective clarifying how weather impacts transmission in diverse ecological settings. We sought to determine if location, timing, and potential-intensity of transmission are systematically defined by weather. Methodology/Principal Findings We developed a high-resolution empirical profile of the local weather-disease connection across Peru, a country with considerable ecological diversity. Applying 2-dimensional weather-space that pairs temperature versus humidity, we mapped local transmission-potential in weather-space by week during 1994-2012. A binary classification-tree was developed to test whether weather data could classify 1828 Peruvian districts as positive/negative for transmission and into ranks of transmission-potential with respect to observed disease. We show that transmission-potential is regulated by temperature-humidity coupling, enabling epidemics in a limited area of weather-space. Duration within a specific temperature range defines transmission-potential that is amplified exponentially in higher humidity. Dengue-positive districts were identified by mean temperature >22°C for 7+ weeks and minimum temperature >14°C for 33+ weeks annually with 95% sensitivity and specificity. In elevated-risk locations, seasonal peak-incidence occurred when mean temperature was 26-29°C, coincident with humidity at its local maximum; highest incidence when humidity >80%. We profile transmission-potential in weather-space for temperature-humidity ranging 0-38°C and 5-100% at 1°C x 2% resolution. Conclusions/Significance Local duration in limited areas of temperature-humidity weather-space identifies potential locations, timing, and magnitude of transmission. The weather-space profile of transmission-potential provides needed data that define a systematic and highly-sensitive weather-disease connection, demonstrating separate but coupled roles of temperature and humidity. New insights regarding natural regulation of human-mosquito transmission across diverse ecological settings advance our understanding of risk locally and globally for dengue and other mosquito-borne diseases and support advances in public health policy/operations, providing an evidence-base for modeling, predicting risk, and surveillance-prevention planning. Timing and spatial-extent of diseases such as dengue and malaria that result from transmission between humans and mosquitoes are regulated by weather in complicated ways. For Aedes aegypti mosquitoes, the primary vector of dengue, slight changes in different components of weather have important effects on population dynamics, lifespan, biting-frequency, virus incubation period and capacity to transmit the virus, thus inducing changes in transmission probability. These complicated dynamics produce a weather-disease connection that is not well-defined for different ecological settings. Understanding this connection is important to critical elements of policy development and operational control of dengue such as predicting risk, developing human-vector transmission models, and planning surveillance-intervention strategies locally and globally. The empirical profile of the weather-disease connection for dengue developed in this study provides a needed understanding of how temperature and humidity work together in regulating human-mosquito transmission. The observed likelihood of low to epidemic-level transmission was highly sensitive to local seasonal duration in limited areas of this two-dimensional weather-space. Data presented represent a resource for estimating where and when transmission-potential supports epidemics of varying magnitude. This high-resolution weather-disease profile for dengue reveals systematic relationships that are informative for mosquito-borne diseases in general and discussions of consequences of global warming.
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Affiliation(s)
- Karen M. Campbell
- Computational Science Research Center, San Diego State University, San Diego, California, United States of America
- * E-mail:
| | - Kristin Haldeman
- Computational Science Research Center, San Diego State University, San Diego, California, United States of America
| | - Chris Lehnig
- Computational Science Research Center, San Diego State University, San Diego, California, United States of America
| | - Cesar V. Munayco
- Department of Preventive Medicine and Biometrics, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | | | | | | | - Amy C. Morrison
- Department of Entomology, University of California, Davis, Davis, California, United States of America
| | - Chii-Dean Lin
- Department of Mathematics and Statistics, San Diego State University, San Diego, California, United States of America
| | - Thomas W. Scott
- Department of Entomology, University of California, Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
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909
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Anholeti MC, Duprat RC, Figueiredo MR, Kaplan MA, Santos MG, Gonzalez MS, Ratcliffe NA, Feder D, Paiva SR, Mello CB. Biocontrol evaluation of extracts and a major component, clusianone, from Clusia fluminensis Planch. & Triana against Aedes aegypti. Mem Inst Oswaldo Cruz 2015. [PMID: 26200711 PMCID: PMC4569826 DOI: 10.1590/0074-02760150103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Studies evaluated the effects of hexanic extracts from the fruits and flowers
ofClusia fluminensis and the main component of the flower
extract, a purified benzophenone (clusianone), against Aedes
aegypti. The treatment of larvae with the crude fruit or flower extracts
from C. fluminensis did not affect the survival ofAe.
aegypti (50 mg/L), however, the flower extracts significantly delayed
development of Ae. aegypti. In contrast, the clusianone (50 mg/L) isolate from the
flower extract, representing 54.85% of this sample composition, showed a highly
significant inhibition of survival, killing 93.3% of the larvae and completely
blocking development of Ae. aegypti. The results showed, for the first time, high
activity of clusianone against Ae. aegypti that both killed and inhibited mosquito
development. Therefore, clusianone has potential for development as a biopesticide
for controlling insect vectors of tropical diseases. Future work will elucidate the
mode of action of clusianone isolated from C. fluminensis.
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Affiliation(s)
- Maria C Anholeti
- Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Rodrigo C Duprat
- Laboratório de Biologia de Insetos, Universidade Federal Fluminense, Niterói, RJ, BR
| | - Maria R Figueiredo
- Laboratório de Química de Produtos Naturais, Farmanguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, BR
| | - Maria Ac Kaplan
- nstituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Marcelo Guerra Santos
- Departamento de Ciências, Faculdade de Formação de Professores, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Marcelo S Gonzalez
- Laboratório de Biologia de Insetos, Universidade Federal Fluminense, Niterói, RJ, BR
| | - Norman A Ratcliffe
- Laboratório de Biologia de Insetos, Universidade Federal Fluminense, Niterói, RJ, BR
| | - Denise Feder
- Laboratório de Biologia de Insetos, Universidade Federal Fluminense, Niterói, RJ, BR
| | - Selma R Paiva
- Laboratório de Botânica Estrutural e Funcional, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, BR
| | - Cicero B Mello
- Laboratório de Biologia de Insetos, Universidade Federal Fluminense, Niterói, RJ, BR
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910
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Andersson N, Nava-Aguilera E, Arosteguí J, Morales-Perez A, Suazo-Laguna H, Legorreta-Soberanis J, Hernandez-Alvarez C, Fernandez-Salas I, Paredes-Solís S, Balmaseda A, Cortés-Guzmán AJ, Serrano de Los Santos R, Coloma J, Ledogar RJ, Harris E. Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial. BMJ 2015; 351:h3267. [PMID: 26156323 PMCID: PMC4495677 DOI: 10.1136/bmj.h3267] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To test whether community mobilization adds effectiveness to conventional dengue control. DESIGN Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. SETTING Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. PARTICIPANTS Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85,182 residents in 18,838 households. INTERVENTIONS A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention-chemical-free prevention of mosquito reproduction-to its own circumstances. All clusters continued the government run dengue control program. MAIN OUTCOME MEASURES Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. RESULTS With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of dengue illness (24.7%, 1.8% to 51.2%), fewer houses with larvae or pupae among houses visited (house index) (44.1%, 13.6% to 74.7%), fewer containers with larvae or pupae among containers examined (container index) (36.7%, 24.5% to 44.8%), fewer containers with larvae or pupae among houses visited (Breteau index) (35.1%, 16.7% to 55.5%), and fewer pupae per person (51.7%, 36.2% to 76.1%). The numbers needed to treat were 30 (95% confidence interval 20 to 59) for a lower risk of infection in children, 71 (48 to 143) for fewer reports of dengue illness, 17 (14 to 20) for the house index, 37 (35 to 67) for the container index, 10 (6 to 29) for the Breteau index, and 12 (7 to 31) for fewer pupae per person. Secondary per protocol analysis showed no serological evidence of a protective effect of temephos. CONCLUSIONS Evidence based community mobilization can add effectiveness to dengue vector control. Each site implementing the intervention in its own way has the advantage of local customization and strong community engagement. TRIAL REGISTRATION ISRCTN27581154.
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Affiliation(s)
- Neil Andersson
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico Department of Family Medicine, McGill University, 5858 Côte-des-Neiges, Montreal, Canada
| | - Elizabeth Nava-Aguilera
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico
| | | | - Arcadio Morales-Perez
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico
| | | | - José Legorreta-Soberanis
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico
| | | | | | - Sergio Paredes-Solís
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico
| | - Angel Balmaseda
- Laboratorio Nacional de Virología, Centro Nacional de Diagnóstico y Referencia, Ministerio de Salud, Managua, Nicaragua
| | - Antonio Juan Cortés-Guzmán
- Departamento de Prevención y Control de Enfermedades Transmisibles por Vector, Servicios Estatales de Salud Guerrero, Av Rufo Figueroa 6, Colonia Burócratas, Chilpancingo, Mexico
| | - René Serrano de Los Santos
- Centro de Investigación de Enfermedades Tropicales (CIET), Universidad Autónoma de Guerrero, Acapulco, Mexico
| | - Josefina Coloma
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | | | - Eva Harris
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
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911
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Kraemer MUG, Sinka ME, Duda KA, Mylne A, Shearer FM, Brady OJ, Messina JP, Barker CM, Moore CG, Carvalho RG, Coelho GE, Van Bortel W, Hendrickx G, Schaffner F, Wint GRW, Elyazar IRF, Teng HJ, Hay SI. The global compendium of Aedes aegypti and Ae. albopictus occurrence. Sci Data 2015; 2:150035. [PMID: 26175912 PMCID: PMC4493829 DOI: 10.1038/sdata.2015.35] [Citation(s) in RCA: 213] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/23/2015] [Indexed: 01/21/2023] Open
Abstract
Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit.
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Affiliation(s)
- Moritz U G Kraemer
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS, UK
| | - Marianne E Sinka
- Wellcome Trust Centre for Human Genetics,University of Oxford , Oxford, UK ; Institute for Health Metrics and Evaluation, University of Washington , Seattle, USA
| | - Kirsten A Duda
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS, UK
| | - Adrian Mylne
- Wellcome Trust Centre for Human Genetics,University of Oxford , Oxford, UK ; Institute for Health Metrics and Evaluation, University of Washington , Seattle, USA
| | - Freya M Shearer
- Wellcome Trust Centre for Human Genetics,University of Oxford , Oxford, UK ; Institute for Health Metrics and Evaluation, University of Washington , Seattle, USA
| | - Oliver J Brady
- Wellcome Trust Centre for Human Genetics,University of Oxford , Oxford, UK ; Institute for Health Metrics and Evaluation, University of Washington , Seattle, USA
| | - Jane P Messina
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS, UK
| | - Christopher M Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California , Davis, CA, USA ; Center for Vectorborne Diseases, University of California , Davis, CA, USA ; Fogarty International Center, National Institutes of Health , Bethesda, Maryland 20892, USA
| | - Chester G Moore
- Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, CO, USA
| | - Roberta G Carvalho
- National Dengue Control Program, Ministry of Health , Brasilia, DF, Brazil
| | - Giovanini E Coelho
- National Dengue Control Program, Ministry of Health , Brasilia, DF, Brazil
| | - Wim Van Bortel
- European Centre for Disease Prevention and Control , Stockholm, Sweden
| | | | | | - G R William Wint
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS, UK ; Environmental Research Group Oxford Ltd, Department of Zoology , South Parks Road, Oxford OX1 3PS, UK
| | | | - Hwa-Jen Teng
- Center for Research, Diagnostics and Vaccine Development, Centers for Disease Control , Taipei, Taiwan (ROC)
| | - Simon I Hay
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS, UK ; Fogarty International Center, National Institutes of Health , Bethesda, Maryland 20892, USA
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912
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Kraemer MUG, Sinka ME, Duda KA, Mylne AQN, Shearer FM, Barker CM, Moore CG, Carvalho RG, Coelho GE, Van Bortel W, Hendrickx G, Schaffner F, Elyazar IRF, Teng HJ, Brady OJ, Messina JP, Pigott DM, Scott TW, Smith DL, Wint GRW, Golding N, Hay SI. The global distribution of the arbovirus vectors Aedes aegypti and Ae. albopictus. eLife 2015; 4:e08347. [PMID: 26126267 PMCID: PMC4493616 DOI: 10.7554/elife.08347] [Citation(s) in RCA: 1134] [Impact Index Per Article: 126.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/18/2015] [Indexed: 02/06/2023] Open
Abstract
Dengue and chikungunya are increasing global public health concerns due to their rapid geographical spread and increasing disease burden. Knowledge of the contemporary distribution of their shared vectors, Aedes aegypti and Aedes albopictus remains incomplete and is complicated by an ongoing range expansion fuelled by increased global trade and travel. Mapping the global distribution of these vectors and the geographical determinants of their ranges is essential for public health planning. Here we compile the largest contemporary database for both species and pair it with relevant environmental variables predicting their global distribution. We show Aedes distributions to be the widest ever recorded; now extensive in all continents, including North America and Europe. These maps will help define the spatial limits of current autochthonous transmission of dengue and chikungunya viruses. It is only with this kind of rigorous entomological baseline that we can hope to project future health impacts of these viruses.
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Affiliation(s)
- Moritz UG Kraemer
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Marianne E Sinka
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kirsten A Duda
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Adrian QN Mylne
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Freya M Shearer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Christopher M Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, United States
| | - Chester G Moore
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, United States
| | | | | | - Wim Van Bortel
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | | | | | | | - Hwa-Jen Teng
- Center for Research, Diagnostics and Vaccine Development, Centers for Disease Control, Taipei, Taiwan
| | - Oliver J Brady
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Jane P Messina
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - David M Pigott
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Thomas W Scott
- Fogarty International Center, National Institutes of Health, Bethesda, United States
- Department of Entomology and Nematology, University of California, Davis, Davis, United States
| | - David L Smith
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Fogarty International Center, National Institutes of Health, Bethesda, United States
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, United States
| | - GR William Wint
- Environmental Research Group Oxford, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Simon I Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Fogarty International Center, National Institutes of Health, Bethesda, United States
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, United States
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913
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Jaenisch T, Junghanss T, Wills B, Brady OJ, Eckerle I, Farlow A, Hay SI, McCall PJ, Messina JP, Ofula V, Sall AA, Sakuntabhai A, Velayudhan R, Wint GRW, Zeller H, Margolis HS, Sankoh O. Dengue expansion in Africa-not recognized or not happening? Emerg Infect Dis 2015; 20. [PMID: 25271370 PMCID: PMC4193177 DOI: 10.3201/eid2010.140487] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Addressing this expansion is essential before control and prevention of dengue are implemented. An expert conference on Dengue in Africa was held in Accra, Ghana, in February 2013 to consider key questions regarding the possible expansion of dengue in Africa. Four key action points were highlighted to advance our understanding of the epidemiology of dengue in Africa. First, dengue diagnostic tools must be made more widely available in the healthcare setting in Africa. Second, representative data need to be collected across Africa to uncover the true burden of dengue. Third, established networks should collaborate to produce these types of data. Fourth, policy needs to be informed so the necessary steps can be taken to provide dengue vector control and health services.
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914
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Abstract
Background Increasing volumes of data and computational capacity afford unprecedented opportunities to scale up infectious disease (ID) mapping for public health uses. Whilst a large number of IDs show global spatial variation, comprehensive knowledge of these geographic patterns is poor. Here we use an objective method to prioritise mapping efforts to begin to address the large deficit in global disease maps currently available. Methodology/Principal Findings Automation of ID mapping requires bespoke methodological adjustments tailored to the epidemiological characteristics of different types of diseases. Diseases were therefore grouped into 33 clusters based upon taxonomic divisions and shared epidemiological characteristics. Disability-adjusted life years, derived from the Global Burden of Disease 2013 study, were used as a globally consistent metric of disease burden. A review of global health stakeholders, existing literature and national health priorities was undertaken to assess relative interest in the diseases. The clusters were ranked by combining both metrics, which identified 44 diseases of main concern within 15 principle clusters. Whilst malaria, HIV and tuberculosis were the highest priority due to their considerable burden, the high priority clusters were dominated by neglected tropical diseases and vector-borne parasites. Conclusions/Significance A quantitative, easily-updated and flexible framework for prioritising diseases is presented here. The study identifies a possible future strategy for those diseases where significant knowledge gaps remain, as well as recognising those where global mapping programs have already made significant progress. For many conditions, potential shared epidemiological information has yet to be exploited. Maps have long been used to not only visualise, but also to inform infectious disease control efforts, identify and predict areas of greatest risk of specific diseases, and better understand the epidemiology of disease over various spatial scales. In spite of the utilities of such outputs, globally comprehensive maps have been produced for only a handful of infectious diseases. Due to limited resources, it is necessary to define a framework to prioritise which diseases to consider mapping globally. This paper outlines a framework which compares each disease’s global burden with its associated interest from the policy community in a data-driven manner which can be used to determine the relative priority of each condition. Malaria, HIV and TB are, unsurprisingly, ranked highest due to their considerable health burden, while the other priority diseases are dominated by neglected tropical diseases and vector-borne diseases. For some conditions, global mapping efforts are already in place, however, for many neglected conditions there still remains a need for high resolution spatial surveys.
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915
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Quam MB, Khan K, Sears J, Hu W, Rocklöv J, Wilder-Smith A. Estimating air travel-associated importations of dengue virus into Italy. J Travel Med 2015; 22:186-93. [PMID: 25756472 DOI: 10.1111/jtm.12192] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 11/24/2014] [Accepted: 12/01/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Southern Europe is increasingly at risk for dengue emergence, given the seasonal presence of relevant mosquito vectors and suitable climatic conditions. For example, Aedes mosquitoes, the main vector for both dengue and chikungunya, are abundant in Italy, and Italy experienced the first ever outbreak of chikungunya in Europe in 2007. We set out to estimate the extent of dengue virus importations into Italy via air travelers. METHODS We attempted to quantify the number of dengue virus importations based on modeling of published estimates on dengue incidence in the countries of disembarkation and analysis of data on comprehensive air travel from these countries into Italy's largest international airport in Rome. RESULTS From 2005 to 2012, more than 7.3 million air passengers departing from 100 dengue-endemic countries arrived in Rome. Our Importation Model, which included air traveler volume, estimated the incidence of dengue infections in the countries of disembarkation, and the probability of infection coinciding with travel accounted for an average of 2,320 (1,621-3,255) imported dengue virus infections per year, of which 572 (381-858) were "apparent" dengue infections and 1,747 (1,240-2,397) "inapparent." CONCLUSIONS Between 2005 and 2012, we found an increasing trend of dengue virus infections imported into Rome via air travel, which may pose a potential threat for future emergence of dengue in Italy, given that the reoccurring pattern of peak importations corresponds seasonally with periods of relevant mosquito vector activity. The observed increasing annual trends of dengue importation and the consistent peaks in late summer underpin the urgency in determining the threshold levels for the vector and infected human populations that could facilitate novel autochthonous transmission of dengue in Europe.
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Affiliation(s)
- Mikkel B Quam
- Department of Public Health and Clinical Medicine, Epidemiology and Global Health Unit, Umeå University, Umeå, Västerbotten, Sweden; Institute of Public Health, University of Heidelberg, Heidelberg, Germany
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916
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Lai S, Huang Z, Zhou H, Anders KL, Perkins TA, Yin W, Li Y, Mu D, Chen Q, Zhang Z, Qiu Y, Wang L, Zhang H, Zeng L, Ren X, Geng M, Li Z, Tatem AJ, Hay SI, Yu H. The changing epidemiology of dengue in China, 1990-2014: a descriptive analysis of 25 years of nationwide surveillance data. BMC Med 2015; 13:100. [PMID: 25925417 PMCID: PMC4431043 DOI: 10.1186/s12916-015-0336-1] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/24/2015] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Dengue has been a notifiable disease in China since 1 September 1989. Cases have been reported each year during the past 25 years of dramatic socio-economic changes in China, and reached a historical high in 2014. This study describes the changing epidemiology of dengue in China during this period, to identify high-risk areas and seasons and to inform dengue prevention and control activities. METHODS We describe the incidence and distribution of dengue in mainland China using notifiable surveillance data from 1990-2014, which includes classification of imported and indigenous cases from 2005-2014. RESULTS From 1990-2014, 69,321 cases of dengue including 11 deaths were reported in mainland China, equating to 2.2 cases per one million residents. The highest number was recorded in 2014 (47,056 cases). The number of provinces affected has increased, from a median of three provinces per year (range: 1 to 5 provinces) during 1990-2000 to a median of 14.5 provinces per year (range: 5 to 26 provinces) during 2001-2014. During 2005-2014, imported cases were reported almost every month and 28 provinces (90.3%) were affected. However, 99.8% of indigenous cases occurred between July and November. The regions reporting indigenous cases have expanded from the coastal provinces of southern China and provinces adjacent to Southeast Asia to the central part of China. Dengue virus serotypes 1, 2, 3, and 4 were all detected from 2009-2014. CONCLUSIONS In China, the area affected by dengue has expanded since 2000 and the incidence has increased steadily since 2012, for both imported and indigenous dengue. Surveillance and control strategies should be adjusted to account for these changes, and further research should explore the drivers of these trends.
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Affiliation(s)
- Shengjie Lai
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. .,Department of Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Zhuojie Huang
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Hang Zhou
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Katherine L Anders
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, 764 Vo Van Kiet, District 5, Ho Chi Minh City, Vietnam. .,Centre for Tropical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK. .,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
| | - T Alex Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA. .,Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Wenwu Yin
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Yu Li
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Di Mu
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Qiulan Chen
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Zike Zhang
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Yanzi Qiu
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Liping Wang
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Honglong Zhang
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Linjia Zeng
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Xiang Ren
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Mengjie Geng
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Zhongjie Li
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
| | - Andrew J Tatem
- Department of Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK. .,Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. .,Flowminder Foundation, Roslagsgatan 17 SE-11355, Stockholm, Sweden.
| | - Simon I Hay
- Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. .,Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
| | - Hongjie Yu
- Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
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917
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Perumalsamy H, Jang MJ, Kim JR, Kadarkarai M, Ahn YJ. Larvicidal activity and possible mode of action of four flavonoids and two fatty acids identified in Millettia pinnata seed toward three mosquito species. Parasit Vectors 2015; 8:237. [PMID: 25928224 PMCID: PMC4410478 DOI: 10.1186/s13071-015-0848-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/08/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity and mechanism of action of four flavonoids and two fatty acids from Millettia pinnata (Fabaceae) seed as well as six pure fatty acids and four fatty acid esters toward third instar larvae from insecticide-susceptible C. pipiens pallens and A. aegypti as well as wild A. albopictus. Efficacy of 12 experimental liquid formulations containing M. pinnata seed methanol extract and hydrodistillate (0.5-10.0% liquids) was also assessed. METHODS The contact toxicities of all compounds and 12 formulations were compared with those of two larvicides, temephos and fenthion and the commercial temephos 200 g/L emulsifiable concentrate (EC). The possible mode of larvicidal action of the constituents was elucidated using biochemical methods. Larval mortality and cAMP level were analyzed by the Bonferroni multiple-comparison method. RESULTS Potent toxicity was produced by karanjin, oleic acid, karanjachromene, linoleic acid, linolenic acid, pongamol, pongarotene, and elaidic acid toward C. pipiens pallens larvae (24 h LC50, 14.61-28.22 mg/L) and A. aegypti larvae (16.13-37.61 mg/L). Against wild A. albopictus larvae, oleic acid (LC50, 18.79 mg/L) and karanjin (35.26 mg/L) exhibited potent toxicity. All constituents were less toxic than either temephos or fenthion. Structure-activity relationship indicates that the degree of saturation, the side chain length, and the geometric isomerism of fatty acids appear to play a role in determining the fatty acid toxicity. Acetylcholinesterase (AChE) is the main site of action of the flavonoids, oleic acid, and palmitic acid. The mechanism of larvicidal action of elaidic acid, arachidic acid, and behenic acid might be due to interference with the octopaminergic system. Linoleic acid and linolenic acid might act on both AChE and octopaminergic receptor. M. pinnata seed extract or hydrodistillate applied as 10% liquid provided 100% mortality toward the three mosquito species larvae and the efficacy of the liquids was comparable to that of temephos 200 g/L EC. CONCLUSION Further studies will warrant possible applications of M. pinnata seed-derived products as potential larvicides for the control of mosquito populations.
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Affiliation(s)
- Haribalan Perumalsamy
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea.
| | - Myung Jin Jang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, Republic of Korea.
| | - Jun-Ran Kim
- National Academy of Agricultural Science, Rural Development Administration, Wanju, 565-851, Jeollabuk-do, Republic of Korea.
| | - Murugan Kadarkarai
- Department of Zoology, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
| | - Young-Joon Ahn
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, Republic of Korea.
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918
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A global compendium of human Crimean-Congo haemorrhagic fever virus occurrence. Sci Data 2015; 2:150016. [PMID: 25977820 PMCID: PMC4409013 DOI: 10.1038/sdata.2015.16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/13/2015] [Indexed: 11/08/2022] Open
Abstract
In order to map global disease risk, a geographic database of human Crimean-Congo haemorrhagic fever virus (CCHFV) occurrence was produced by surveying peer-reviewed literature and case reports, as well as informal online sources. Here we present this database, comprising occurrence data linked to geographic point or polygon locations dating from 1953 to 2013. We fully describe all data collection, geo-positioning, database management and quality-control procedures. This is the most comprehensive database of confirmed CCHF occurrence in humans to-date, containing 1,721 geo-positioned occurrences in total.
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919
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CD8+ T Cells Can Mediate Short-Term Protection against Heterotypic Dengue Virus Reinfection in Mice. J Virol 2015; 89:6494-505. [PMID: 25855749 DOI: 10.1128/jvi.00036-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 04/06/2015] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED Dengue virus (DENV) is a major public health threat worldwide. Infection with one of the four serotypes of DENV results in a transient period of protection against reinfection with all serotypes (cross-protection), followed by lifelong immunity to the infecting serotype. While a protective role for neutralizing antibody responses is well established, the contribution of T cells to reinfection is less clear, especially during heterotypic reinfection. This study investigates the role of T cells during homotypic and heterotypic DENV reinfection. Mice were sequentially infected with homotypic or heterotypic DENV serotypes, and T cell subsets were depleted before the second infection to assess the role of DENV-primed T cells during reinfection. Mice primed nonlethally with DENV were protected against reinfection with either a homotypic or heterotypic serotype 2 weeks later. Homotypic priming induced a robust neutralizing antibody response, whereas heterotypic priming elicited binding, but nonneutralizing antibodies. CD8(+) T cells were required for protection against heterotypic, but not homotypic, reinfection. These results suggest that T cells can contribute crucially to protection against heterotypic reinfection in situations where humoral responses alone may not be protective. Our findings have important implications for vaccine design, as they suggest that inducing both humoral and cellular responses during vaccination may maximize protective efficacy across all DENV serotypes. IMPORTANCE Dengue virus is present in more than 120 countries in tropical and subtropical regions. Infection with dengue virus can be asymptomatic, but it can also progress into the potentially lethal severe dengue disease. There are four closely related dengue virus serotypes. Infection with one serotype results in a transient period of resistance against all serotypes (cross-protection), followed by lifelong resistance to the infecting serotype, but not the other ones. The duration and mechanisms of the transient cross-protection period remain elusive. This study investigates the contribution of cellular immunity to cross-protection using mouse models of DENV infection. Our results demonstrate that cellular immunity is crucial to mediate cross-protection against reinfection with a different serotype, but not for protection against reinfection with the same serotype. A better understanding of the mediators responsible for the cross-protection period is important for vaccine design, as an ideal vaccine against dengue virus should efficiently protect against all serotypes.
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920
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Saied KG, Al-Taiar A, Altaire A, Alqadsi A, Alariqi EF, Hassaan M. Knowledge, attitude and preventive practices regarding dengue fever in rural areas of Yemen. Int Health 2015; 7:420-5. [PMID: 25858280 DOI: 10.1093/inthealth/ihv021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 03/16/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In recent years there have been several reports of outbreaks of dengue fever (DF) in Yemen. This study aimed to describe the prevailing knowledge, attitude and preventive practices regarding DF, and to investigate the factors associated with poor preventive practices in rural areas of Yemen. METHODS A population-based, cross-sectional study was conducted on 804 randomly selected heads of household. A pretested, structured questionnaire was administered through face-to-face interviews. Logistic regression was used to investigate factors independently associated with poor practice. RESULTS Out of 804 participants, 753 (93.7%) were aware of the symptoms of DF and 671 (83.4%) knew that DF was transmitted by mosquito bites. Only 420 (52.2%) knew that direct person-to-person transmission was not possible. Furthermore, 205 (25.5%) thought that someone with DF should be avoided and 460 (57.2%) thought the elimination of breeding sites was the responsibility of health authorities. Poor knowledge of DF and a low level of education were significantly associated with poor preventive practices. CONCLUSIONS In rural areas of Yemen, people have a vague understanding of DF transmission and a negative attitude towards preventative practices. Efforts should be made to correct misconceptions about transmission of the disease and to highlight the importance of community participation in control activities.
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Affiliation(s)
- Khaled G Saied
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 2583 Al-Tahreer Post Office, Sana'a, Yemen
| | - Abdullah Al-Taiar
- Department Community Medicine and Behavioural Sciences, Faculty of Medicine, Kuwait University, Box 24923 Safat, 13110 Kuwait, Kuwait
| | - Abdulrahman Altaire
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 2583 Al-Tahreer Post Office, Sana'a, Yemen
| | - Ala Alqadsi
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 2583 Al-Tahreer Post Office, Sana'a, Yemen
| | - Enas F Alariqi
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 2583 Al-Tahreer Post Office, Sana'a, Yemen
| | - Maha Hassaan
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 2583 Al-Tahreer Post Office, Sana'a, Yemen
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921
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Acosta POA, Granja F, Meneses CA, Nascimento IAS, Sousa DD, Lima Júnior WP, Naveca FG. False-negative dengue cases in Roraima, Brazil: an approach regarding the high number of negative results by NS1 ag kits. Rev Inst Med Trop Sao Paulo 2015; 56:447-50. [PMID: 25229228 PMCID: PMC4172119 DOI: 10.1590/s0036-46652014000500014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 03/13/2014] [Indexed: 11/22/2022] Open
Abstract
Serum samples from 150 NS1-negative (Platelia ELISA)
patients presumptively diagnosed with dengue were analyzed by the TaqMan probed
real-time reverse transcription PCR (TaqMan qRT-PCR) method. The
qRT-PCR positive samples were tested for serotype by semi-nested RT-PCR and a
qualitative immunochromatographic assay for IgG and IgM. Molecular detection
methods showed 33 (22%) positive samples out of 150 NS1-antigen
negative samples. Of these, 72% were collected up to day 2 after the onset
of symptoms, when diagnostic sensitivity of NS1-antigen test assays is
significantly enhanced. Most of the cases were not characterized as secondary
infection. Twenty-eight samples were successfully serotyped, 75% of which
for DENV-4, 14% for DENV-2, 7% for DENV-3 and 4% for DENV-1.
These findings reaffirm the hyperendemic situation of the state of Roraima and
suggest a lower sensitivity of the NS1 test, mainly when DENV-4 is the
predominant serotype. Health care providers should therefore be aware of samples
tested negative by NS1 antigen assays, especially when clinical symptoms and
other laboratory data results show evidence of dengue infection.
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Affiliation(s)
- Pablo O A Acosta
- Laboratório de Biologia Molecular, Centro de Estudos da Biodiversidade, Universidade Federal de Roraima, Boa Vista, RR, Brasil
| | - Fabiana Granja
- Laboratório de Biologia Molecular, Centro de Estudos da Biodiversidade, Universidade Federal de Roraima, Boa Vista, RR, Brasil
| | | | - Ismael A S Nascimento
- Laboratório de Biologia Molecular, Centro de Estudos da Biodiversidade, Universidade Federal de Roraima, Boa Vista, RR, Brasil
| | - Débora D Sousa
- Laboratório de Biologia Molecular, Centro de Estudos da Biodiversidade, Universidade Federal de Roraima, Boa Vista, RR, Brasil
| | - Wilson P Lima Júnior
- Laboratório de Biologia Molecular, Centro de Estudos da Biodiversidade, Universidade Federal de Roraima, Boa Vista, RR, Brasil
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922
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Feldstein LR, Brownstein JS, Brady OJ, Hay SI, Johansson MA. Dengue on islands: a Bayesian approach to understanding the global ecology of dengue viruses. Trans R Soc Trop Med Hyg 2015; 109:303-12. [PMID: 25771261 PMCID: PMC4401210 DOI: 10.1093/trstmh/trv012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/29/2015] [Indexed: 12/14/2022] Open
Abstract
Background Transmission of dengue viruses (DENV), the most common arboviral pathogens globally, is influenced by many climatic and socioeconomic factors. However, the relative contributions of these factors on a global scale are unclear. Methods We randomly selected 94 islands stratified by socioeconomic and geographic characteristics. With a Bayesian model, we assessed factors contributing to the probability of islands having a history of any dengue outbreaks and of having frequent outbreaks. Results Minimum temperature was strongly associated with suitability for DENV transmission. Islands with a minimum monthly temperature of greater than 14.8°C (95% CI: 12.4–16.6°C) were predicted to be suitable for DENV transmission. Increased population size and precipitation were associated with increased outbreak frequency, but did not capture all of the variability. Predictions for 48 testing islands verified these findings. Conclusions This analysis clarified two key components of DENV ecology: minimum temperature was the most important determinant of suitability; and endemicity was more likely in areas with high precipitation and large, but not necessarily dense, populations. Wealth and connectivity, in contrast, had no discernable effects. This model adds to our knowledge of global determinants of dengue risk and provides a basis for understanding the ecology of dengue endemicity.
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Affiliation(s)
- Leora R Feldstein
- Children's Hospital Informatics Program, Boston Children's Hospital, 1 Autumn St., Boston, MA 02215, USA Center for Statistics and Quantitative Infectious Diseases, Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; USA
| | - John S Brownstein
- Children's Hospital Informatics Program, Boston Children's Hospital, 1 Autumn St., Boston, MA 02215, USA Department of Pediatrics, Harvard Medical School, 1 Autumn St., Boston, MA 02215, USA
| | - Oliver J Brady
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Simon I Hay
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Michael A Johansson
- Dengue Branch, Division of Vector-Borne Diseases, CDC, 1324 Calle Canada, San Juan, PR 00920, USA
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923
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Abstract
Dengue is a vector-borne disease that causes a substantial public health burden within its expanding range. Several modelling studies have attempted to predict the future global distribution of dengue. However, the resulting projections are difficult to compare and are sometimes contradictory because the models differ in their approach, in the quality of the disease data that they use and in the choice of variables that drive disease distribution. In this Review, we compare the main approaches that have been used to model the future global distribution of dengue and propose a set of minimum criteria for future projections that, by analogy, are applicable to other vector-borne diseases.
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924
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Undurraga EA, Betancourt-Cravioto M, Ramos-Castañeda J, Martínez-Vega R, Méndez-Galván J, Gubler DJ, Guzmán MG, Halstead SB, Harris E, Kuri-Morales P, Tapia-Conyer R, Shepard DS. Economic and disease burden of dengue in Mexico. PLoS Negl Trop Dis 2015; 9:e0003547. [PMID: 25786225 PMCID: PMC4364886 DOI: 10.1371/journal.pntd.0003547] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/17/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dengue imposes a substantial economic and disease burden in most tropical and subtropical countries. Dengue incidence and severity have dramatically increased in Mexico during the past decades. Having objective and comparable estimates of the economic burden of dengue is essential to inform health policy, increase disease awareness, and assess the impact of dengue prevention and control technologies. METHODS AND FINDINGS We estimated the annual economic and disease burden of dengue in Mexico for the years 2010-2011. We merged multiple data sources, including a prospective cohort study; patient interviews and macro-costing from major hospitals; surveillance, budget, and health data from the Ministry of Health; WHO cost estimates; and available literature. We conducted a probabilistic sensitivity analysis using Monte Carlo simulations to derive 95% certainty levels (CL) for our estimates. Results suggest that Mexico had about 139,000 (95%CL: 128,000-253,000) symptomatic and 119 (95%CL: 75-171) fatal dengue episodes annually on average (2010-2011), compared to an average of 30,941 symptomatic and 59 fatal dengue episodes reported. The annual cost, including surveillance and vector control, was US$170 (95%CL: 151-292) million, or $1.56 (95%CL: 1.38-2.68) per capita, comparable to other countries in the region. Of this, $87 (95%CL: 87-209) million or $0.80 per capita (95%CL: 0.62-1.12) corresponds to illness. Annual disease burden averaged 65 (95%CL: 36-99) disability-adjusted life years (DALYs) per million population. Inclusion of long-term sequelae, co-morbidities, impact on tourism, and health system disruption during outbreaks would further increase estimated economic and disease burden. CONCLUSION With this study, Mexico joins Panama, Puerto Rico, Nicaragua, and Thailand as the only countries or areas worldwide with comprehensive (illness and preventive) empirical estimates of dengue burden. Burden varies annually; during an outbreak, dengue burden may be significantly higher than that of the pre-vaccine level of rotavirus diarrhea. In sum, Mexico's potential economic benefits from dengue control would be substantial.
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Affiliation(s)
- Eduardo A. Undurraga
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | | | - José Ramos-Castañeda
- Instituto Nacional de Salud Pública, Cuernavaca, Mexico
- Center for Tropical Diseases, University of Texas-Medical Branch, Galveston, Texas, United States of America
| | - Ruth Martínez-Vega
- Instituto Nacional de Salud Pública, Cuernavaca, Mexico
- Organización Latinoamericana para el Fomento de la Investigación en Salud, Bucaramanga, Colombia
| | | | | | | | - Scott B. Halstead
- Pediatric Dengue Vaccine Initiative, Rockville, Maryland, United States of America
| | - Eva Harris
- University of California, Berkeley, Berkeley, California, United States of America
| | | | | | - Donald S. Shepard
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
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925
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Stolp ZD, Smurthwaite CA, Reed C, Williams W, Dharmawan A, Djaballah H, Wolkowicz R. A Multiplexed Cell-Based Assay for the Identification of Modulators of Pre-Membrane Processing as a Target against Dengue Virus. ACTA ACUST UNITED AC 2015; 20:616-26. [PMID: 25724189 PMCID: PMC4438100 DOI: 10.1177/1087057115571247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/14/2015] [Indexed: 12/19/2022]
Abstract
The DenV pre-membrane protein (prM) is a crucial chaperone for the viral envelope protein, preventing premature fusion with vesicles during viral export. prM molecules in immature particles are cleaved by host proteases, leading to mature fusogenic virions. Blockade of prM cleavage would restrict fusion and represents a novel druggable opportunity against DenV. We have thus established a cell-based platform to monitor prM processing that relies on an engineered two-tag scaffold that travels to the cell surface through the secretory pathway. The assay discriminates between a single cell-surface tag when prM is cleaved and two tags when it is not, as detected through fluorescent-coupled antibodies by flow cytometry. The assay, miniaturized into a 96-well plate format, was multiplexed with the HIV-1 envelope boundary, also cleaved in the same pathway. A pilot screen against 1280 compounds was executed, leading to the identification of a potential active and corroborating the robustness of our assay for large-scale screening. We describe for the first time a cell-based assay that monitors DenV prM processing within the classical secretory pathway, which was exploited to identify a potential novel drug against DenV.
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Affiliation(s)
- Zachary D Stolp
- Department of Biology, San Diego State University, San Diego, CA, USA
| | | | - Connor Reed
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Wesley Williams
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Andre Dharmawan
- Department of Biology, San Diego State University, San Diego, CA, USA
| | | | - Roland Wolkowicz
- Department of Biology, San Diego State University, San Diego, CA, USA
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926
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Khamim K, Hattasingh W, Nisalak A, Kaewkungwal J, Fernandez S, Thaisomboonsuk B, Pengsaa K, Thisyakorn U. Neutralizing dengue antibody in pregnant Thai women and cord blood. PLoS Negl Trop Dis 2015; 9:e0003396. [PMID: 25658481 PMCID: PMC4320096 DOI: 10.1371/journal.pntd.0003396] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/05/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The WHO 'Global Strategy for Dengue Prevention and Control, 2012-2020' addresses the growing need for the treatment of dengue, and targets a 25% reduction in morbidity and 50% in mortality (using 2010 estimates as baseline). Achieving these goals requires future dengue prevention strategies that will employ both potential vaccines and sustainable vector-control measures. Maternally transferred dengue antibody is an important factor in determining the optimal age for dengue vaccination. OBJECTIVES To estimate the seroprevalence of dengue antibodies among mothers living in an area of high endemicity--Ban Pong, Ratchaburi Province--and to assess maternal dengue antibodies transferred to cord blood. MATERIALS & METHODS A cross-sectional study was conducted with 141 pregnant women who delivered at Ban Pong Hospital, Ratchaburi, Thailand. Maternal-cord paired sera were tested for dengue neutralizing (NT) antibody by PRNT50 assay. A ratio of ≥ 1:10 NT titer to dengue serotype was considered seropositive. RESULTS Most mothers (137/141, 97.2%) had NT antibodies to at least one dengue serotype in their sera. At birth, the proportion of cord sera with NT antibodies to DEN-1, DEN-2, DEN-3, and DEN-4, were high and similar to the sera of their mothers, at 93.6%, 97.2%, 97.9%, and 92.2%, respectively. The dengue geometric mean titers (GMT) in cord blood were significantly higher than the maternal antibodies (p<0.001): highest in DEN-2, followed by DEN-3, and then DEN-1. The GMT of DEN-4 was the lowest among all four serotypes. CONCLUSIONS Dengue infection is highly prevalent among pregnant women in this dengue-endemic area. Most of the cord blood had transferred dengue antibodies, which may have an impact on the disease burden in this population.
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Affiliation(s)
- Kriangsak Khamim
- Department of Obstetrics and Gynecology, Ban Pong Hospital, Ratchaburi, Thailand
| | - Weerawan Hattasingh
- Department of Tropical Pediatrics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ananda Nisalak
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Thailand
| | - Jaranit Kaewkungwal
- Centre of Excellence for Biomedical & Public Health Informatics (BIOPHICS), and Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Thailand
| | - Butsaya Thaisomboonsuk
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Thailand
| | - Krisana Pengsaa
- Department of Tropical Pediatrics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Usa Thisyakorn
- Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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927
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Vairo F, Nicastri E, Yussuf SM, Cannas A, Meschi S, Mahmoud MAA, Mohamed AH, Maiko PM, De Nardo P, Bevilacqua N, Castilletti C, Di Caro A, Racalbuto V, Ippolito G. IgG against dengue virus in healthy blood donors, Zanzibar, Tanzania. Emerg Infect Dis 2015; 20:465-8. [PMID: 24572373 PMCID: PMC3944865 DOI: 10.3201/eid2003.130150] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We conducted a seroprevalence survey among 500 healthy adult donors at Zanzibar National Blood Transfusion Services. Dengue virus IgG seroprevalence was 50.6% and independently associated with age and urban residence. These data will aid in building a surveillance, preparedness, and response plan for dengue virus infections in the Zanzibar Archipelago.
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928
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Stoler J, Delimini RK, Bonney JHK, Oduro AR, Owusu-Agyei S, Fobil JN, Awandare GA. Evidence of recent dengue exposure among malaria parasite-positive children in three urban centers in Ghana. Am J Trop Med Hyg 2015; 92:497-500. [PMID: 25582693 DOI: 10.4269/ajtmh.14-0678] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Blood samples of 218 children ages 2-14 years old with confirmed malaria in hospitals across Ghana were tested for dengue virus exposure. We detected dengue-specific immunoglobulin M (IgM) antibodies in 3.2% of the children, indicating possible coinfection, and IgG antibodies in 21.6% of them, which suggests previous exposure. Correlates of exposure are discussed.
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Affiliation(s)
- Justin Stoler
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - Rupert K Delimini
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - J H Kofi Bonney
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - Abraham R Oduro
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - Seth Owusu-Agyei
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - Julius N Fobil
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
| | - Gordon A Awandare
- Department of Geography, University of Miami, Coral Gables, Florida; Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida; Kintampo Health Research Centre, Kintampo, Ghana; West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana; Virology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; Navrongo Health Research Centre, Navrongo, Ghana; Department of Biological, Environmental and Occupational Health Sciences, University of Ghana, Legon, Ghana
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929
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A systematic review and meta-analysis of dengue risk with temperature change. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 12:1-15. [PMID: 25546270 PMCID: PMC4306847 DOI: 10.3390/ijerph120100001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/08/2014] [Indexed: 01/12/2023]
Abstract
Dengue fever (DF) is the most serious mosquito-borne viral disease in the world and is significantly affected by temperature. Although associations between DF and temperatures have been reported repeatedly, conclusions have been inconsistent. Six databases were searched up to 23 March 2014, without language and geographical restrictions. The articles that studied the correlations between temperatures and dengue were selected, and a random-effects model was used to calculate the pooled odds ratio and 95% confidence intervals. Of 1589 identified articles, 137 were reviewed further, with 33 satisfying inclusion criteria. The closest associations were observed between mean temperature from the included studies (23.2–27.7 °C) and DF (OR 35.0% per 1 °C; 95% CI 18.3%–51.6%) positively. Additionally, minimum (18.1–24.2 °C) (29.5% per 1 °C; 20.9%–38.1%) and maximum temperature (28.0–34.5 °C) (28.9%; 10.3%–47.5%) were also associated with increased dengue transmission. The OR of DF incidence increased steeply from 22 °C to 29 °C, suggesting an inflexion of DF risk between these lower and upper limits of DF risk. This discovery is helpful for government decision-makers focused on preventing and controlling dengue in areas with temperatures within this range.
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930
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Elevated dengue virus nonstructural protein 1 serum levels and altered toll-like receptor 4 expression, nitric oxide, and tumor necrosis factor alpha production in dengue hemorrhagic Fever patients. J Trop Med 2014; 2014:901276. [PMID: 25580138 PMCID: PMC4279176 DOI: 10.1155/2014/901276] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/18/2014] [Accepted: 11/25/2014] [Indexed: 11/17/2022] Open
Abstract
Background. During dengue virus (DV) infection, monocytes produce tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) which might be critical to immunopathogenesis. Since intensity of DV replication may determine clinical outcomes, it is important to know the effects of viral nonstructural protein 1 (NS1) on innate immune parameters of infected patients. The present study investigates the relationships between dengue virus nonstructural protein 1 (NS1) serum levels and innate immune response (TLR4 expression and TNF-α/NO production) of DV infected patients presenting different clinical outcomes. Methodology/Principal Findings. We evaluated NO, NS1 serum levels (ELISA), TNF-α production by peripheral blood mononuclear cells (PBMCs), and TLR4 expression on CD14+ cells from 37 dengue patients and 20 healthy controls. Early in infection, increased expression of TLR4 in monocytes of patients with dengue fever (DF) was detected compared to patients with dengue hemorrhagic fever (DHF). Moreover, PBMCs of DHF patients showed higher NS1 and lower NO serum levels during the acute febrile phase and a reduced response to TLR4 stimulation by LPS (with a reduced TNF-α production) when compared to DF patients. Conclusions/Significance. During DV infection in humans, some innate immune parameters change, depending on the NS1 serum levels, and phase and severity of the disease which may contribute to development of different clinical outcomes.
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931
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932
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Semenza JC, Sudre B, Miniota J, Rossi M, Hu W, Kossowsky D, Suk JE, Van Bortel W, Khan K. International dispersal of dengue through air travel: importation risk for Europe. PLoS Negl Trop Dis 2014; 8:e3278. [PMID: 25474491 PMCID: PMC4256202 DOI: 10.1371/journal.pntd.0003278] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/18/2014] [Indexed: 12/04/2022] Open
Abstract
Background The worldwide distribution of dengue is expanding, in part due to globalized traffic and trade. Aedes albopictus is a competent vector for dengue viruses (DENV) and is now established in numerous regions of Europe. Viremic travellers arriving in Europe from dengue-affected areas of the world can become catalysts of local outbreaks in Europe. Local dengue transmission in Europe is extremely rare, and the last outbreak occurred in 1927–28 in Greece. However, autochthonous transmission was reported from France in September 2010, and from Croatia between August and October 2010. Methodology We compiled data on areas affected by dengue in 2010 from web resources and surveillance reports, and collected national dengue importation data. We developed a hierarchical regression model to quantify the relationship between the number of reported dengue cases imported into Europe and the volume of airline travellers arriving from dengue-affected areas internationally. Principal Findings In 2010, over 5.8 million airline travellers entered Europe from dengue-affected areas worldwide, of which 703,396 arrived at 36 airports situated in areas where Ae. albopictus has been recorded. The adjusted incidence rate ratio for imported dengue into European countries was 1.09 (95% CI: 1.01–1.17) for every increase of 10,000 travellers; in August, September, and October the rate ratios were 1.70 (95%CI: 1.23–2.35), 1.46 (95%CI: 1.02–2.10), and 1.35 (95%CI: 1.01–1.81), respectively. Two Italian cities where the vector is present received over 50% of all travellers from dengue-affected areas, yet with the continuing vector expansion more cities will be implicated in the future. In fact, 38% more travellers arrived in 2013 into those parts of Europe where Ae. albopictus has recently been introduced, compared to 2010. Conclusions The highest risk of dengue importation in 2010 was restricted to three months and can be ranked according to arriving traveller volume from dengue-affected areas into cities where the vector is present. The presence of the vector is a necessary, but not sufficient, prerequisite for DENV onward transmission, which depends on a number of additional factors. However, our empirical model can provide spatio-temporal elements to public health interventions. The global disease burden of dengue is staggering. Continuous expansion and vaccine failures illustrate the limitations of current dengue control efforts. Novel approaches and additional tools are required to combat and contain the disease. In Europe, dengue infections are rare and the last outbreak of dengue occurred in the late 1920s, in Greece. In 2010, however, local transmission occurred in France and Croatia. Based on 2010 data, we present a novel quantitative model of the risk of dengue importation for Europe. The 2010 model predicts the risk of dengue importation to be greatest for Milan, Rome and Barcelona in August, September and October, precisely when vector activity is the highest. With the current expansion of the vector in Europe, more cities are projected to be at risk in the future. Thus, the model based on 2010 data quantifies the likelihood and timing of importation. This approach employs global travel data to assess dengue importation risk in the EU and illustrates how quantitative models could tailor infectious disease control to certain regions and time periods.
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Affiliation(s)
- Jan C. Semenza
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
- * E-mail:
| | - Bertrand Sudre
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Jennifer Miniota
- Division of Infectious Diseases, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Massimiliano Rossi
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Wei Hu
- Division of Infectious Diseases, St. Michael's Hospital, Toronto, Ontario, Canada
| | - David Kossowsky
- Division of Infectious Diseases, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Jonathan E. Suk
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Wim Van Bortel
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Kamran Khan
- Division of Infectious Diseases, St. Michael's Hospital, Toronto, Ontario, Canada
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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933
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Horstick O, Morrison AC. Dengue disease surveillance: improving data for dengue control. PLoS Negl Trop Dis 2014; 8:e3311. [PMID: 25375232 PMCID: PMC4222865 DOI: 10.1371/journal.pntd.0003311] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Olaf Horstick
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany
| | - Amy C. Morrison
- Department of Entomology, University of California, Davis, Davis, California, United States of America
- Naval Medical Research Unit No. 6, Washington, D.C., United States of America
- * E-mail:
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934
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Shepard DS, Undurraga EA, Betancourt-Cravioto M, Guzmán MG, Halstead SB, Harris E, Mudin RN, Murray KO, Tapia-Conyer R, Gubler DJ. Approaches to refining estimates of global burden and economics of dengue. PLoS Negl Trop Dis 2014; 8:e3306. [PMID: 25412506 PMCID: PMC4238988 DOI: 10.1371/journal.pntd.0003306] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 10/01/2014] [Indexed: 11/24/2022] Open
Abstract
Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools for diagnosis, vaccination, vector control, and treatment are being developed, these recommended steps should improve objective, systematic measures of dengue burden to strengthen health policy decisions.
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Affiliation(s)
- Donald S. Shepard
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | - Eduardo A. Undurraga
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | | | | | - Scott B. Halstead
- Dengue Vaccine Initiative, Rockville, Maryland, United States of America
| | - Eva Harris
- University of California, Berkeley, California, United States of America
| | | | - Kristy O. Murray
- Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, United States of America
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935
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Salyer SJ, Ellis EM, Salomon C, Bron C, Juin S, Hemme RR, Hunsperger E, Jentes ES, Magloire R, Tomashek KM, Desormeaux AM, Muñoz-Jordán JL, Etienne L, Beltran M, Sharp TM, Moffett D, Tappero J, Margolis HS, Katz MA. Dengue virus infections among Haitian and expatriate non-governmental organization workers--Léogane and Port-au-Prince, Haiti, 2012. PLoS Negl Trop Dis 2014; 8:e3269. [PMID: 25356592 PMCID: PMC4214624 DOI: 10.1371/journal.pntd.0003269] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 09/14/2014] [Indexed: 11/30/2022] Open
Abstract
In October 2012, the Haitian Ministry of Health and the US CDC were notified of 25 recent dengue cases, confirmed by rapid diagnostic tests (RDTs), among non-governmental organization (NGO) workers. We conducted a serosurvey among NGO workers in Léogane and Port-au-Prince to determine the extent of and risk factors for dengue virus infection. Of the total 776 staff from targeted NGOs in Léogane and Port-au-Prince, 173 (22%; 52 expatriates and 121 Haitians) participated. Anti-dengue virus (DENV) IgM antibody was detected in 8 (15%) expatriates and 9 (7%) Haitians, and DENV non-structural protein 1 in one expatriate. Anti-DENV IgG antibody was detected in 162 (94%) participants (79% of expatriates; 100% of Haitians), and confirmed by microneutralization testing as DENV-specific in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 pupae collected from 68 containers, 65% were Aedes aegypti; 27% were Ae. albopictus. Few NGO workers reported undertaking mosquito-avoidance action. Our findings underscore the risk of dengue in expatriate workers in Haiti and Haitians themselves. Dengue is the most common mosquito-borne viral disease in the world, and caused an estimated 390 million infections and 96 million cases in the tropics and subtropics in 2010. Over the last decade, the number of cases of dengue and the severity of dengue virus infections have increased in the Americas, including the Caribbean, yet little is still known about dengue in Haiti. Following an outbreak of dengue in mostly expatriate NGO workers, the investigators of this study took blood samples from expatriate and Haitian NGO workers living in two cities in Haiti and tested them for evidence of current, recent, and past dengue virus infection. They also investigated the amount and kinds of mosquitoes at homes and work sites. The study found recent infections among some Haitians and expatriates and widespread past infections among all Haitians and most expatriates. It also found that many people were not doing basic things to avoid mosquito bites, like applying mosquito repellent multiple times a day and wearing long sleeves or pants. These findings highlight the likely endemicity of dengue virus in Haiti, and the need to improve knowledge and awareness of dengue prevention among expatriates visiting Haiti and local Haitians.
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Affiliation(s)
- Stephanie J. Salyer
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
| | - Esther M. Ellis
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | - Corvil Salomon
- Ministry of Public Health and Population, Port-au-Prince, Haiti
| | - Christophe Bron
- International Federation of Red Cross and Red Crescent Societies, Port-au-Prince, Haiti
| | - Stanley Juin
- Centers for Disease Control and Prevention, Port-au-Prince, Haiti
| | - Ryan R. Hemme
- Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | | | - Emily S. Jentes
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Roc Magloire
- Ministry of Public Health and Population, Port-au-Prince, Haiti
| | - Kay M. Tomashek
- Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | | | | | | | - Manuela Beltran
- Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | - Tyler M. Sharp
- Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | - Daphne Moffett
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jordan Tappero
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | - Mark A. Katz
- Centers for Disease Control and Prevention, Port-au-Prince, Haiti
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936
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Advances in the understanding, management, and prevention of dengue. J Clin Virol 2014; 64:153-9. [PMID: 25453329 DOI: 10.1016/j.jcv.2014.08.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 08/25/2014] [Indexed: 01/09/2023]
Abstract
Dengue causes more human morbidity globally than any other vector-borne viral disease. Recent research has led to improved epidemiological methods that predict disease burden and factors involved in transmission, a better understanding of immune responses in infection, and enhanced animal models. In addition, a number of control measures, including preventative vaccines, are in clinical trials. However, significant gaps remain, including the need for better surveillance in large parts of the world, methods to predict which individuals will develop severe disease, and immunologic correlates of protection against dengue illness. During the next decade, dengue will likely expand its geographic reach and become an increasing burden on health resources in affected areas. Licensed vaccines and antiviral agents are needed in order to effectively control dengue and limit disease.
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937
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Cano J, Rebollo MP, Golding N, Pullan RL, Crellen T, Soler A, Kelly-Hope LA, Lindsay SW, Hay SI, Bockarie MJ, Brooker SJ. The global distribution and transmission limits of lymphatic filariasis: past and present. Parasit Vectors 2014; 7:466. [PMID: 25303991 PMCID: PMC4197264 DOI: 10.1186/s13071-014-0466-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/29/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination by 2020 and to guide elimination efforts countries have, in recent years, conducted extensive mapping surveys. Documenting the past and present distribution of LF and its environmental limits is important for a number of reasons. Here, we present an initiative to develop a global atlas of LF and present a new global map of the limits of LF transmission. METHODS We undertook a systematic search and assembly of prevalence data worldwide and used a suite of environmental and climatic data and boosted regression trees (BRT) modelling to map the transmission limits of LF. RESULTS Data were identified for 66 of the 72 countries currently endemic and for a further 17 countries where LF is no longer endemic. Our map highlights a restricted and highly heterogeneous distribution in sub-Saharan Africa, with transmission more widespread in West Africa compared to east, central and southern Africa where pockets of transmission occur. Contemporary transmission occurs across much of south and South-east Asia and the Pacific. Interestingly, the risk map reflects environmental conditions suitable for LF transmission across Central and South America, including the southern States of America, although active transmission is only known in a few isolated foci. In countries that have eliminated LF, our predictions of environmental suitability are consistent with historical distribution. CONCLUSIONS The global distribution of LF is highly heterogeneous and geographically targeted and sustained control will be required to achieve elimination. This first global map can help evaluate the progress of interventions and guide surveillance activities.
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Affiliation(s)
- Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Maria P Rebollo
- NTD Support Center, Task Force for Global Health, Emory University, Atlanta, United States of America.
- Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Nick Golding
- Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK.
| | - Rachel L Pullan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Thomas Crellen
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Anna Soler
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Louise A Kelly-Hope
- Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Steve W Lindsay
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom.
| | - Simon I Hay
- Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK.
| | - Moses J Bockarie
- Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Simon J Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
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938
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A probabilistic spatial dengue fever risk assessment by a threshold-based-quantile regression method. PLoS One 2014; 9:e106334. [PMID: 25302582 PMCID: PMC4193740 DOI: 10.1371/journal.pone.0106334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 08/04/2014] [Indexed: 11/19/2022] Open
Abstract
Understanding the spatial characteristics of dengue fever (DF) incidences is crucial for governmental agencies to implement effective disease control strategies. We investigated the associations between environmental and socioeconomic factors and DF geographic distribution, are proposed a probabilistic risk assessment approach that uses threshold-based quantile regression to identify the significant risk factors for DF transmission and estimate the spatial distribution of DF risk regarding full probability distributions. To interpret risk, return period was also included to characterize the frequency pattern of DF geographic occurrences. The study area included old Kaohsiung City and Fongshan District, two areas in Taiwan that have been affected by severe DF infections in recent decades. Results indicated that water-related facilities, including canals and ditches, and various types of residential area, as well as the interactions between them, were significant factors that elevated DF risk. By contrast, the increase of per capita income and its associated interactions with residential areas mitigated the DF risk in the study area. Nonlinear associations between these factors and DF risk were present in various quantiles, implying that water-related factors characterized the underlying spatial patterns of DF, and high-density residential areas indicated the potential for high DF incidence (e.g., clustered infections). The spatial distributions of DF risks were assessed in terms of three distinct map presentations: expected incidence rates, incidence rates in various return periods, and return periods at distinct incidence rates. These probability-based spatial risk maps exhibited distinct DF risks associated with environmental factors, expressed as various DF magnitudes and occurrence probabilities across Kaohsiung, and can serve as a reference for local governmental agencies.
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939
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Abstract
Dengue is a mosquito-borne viral disease of expanding geographical range and increasing incidence. The vast majority of dengue cases are children less than 15 years of age. Dengue causes a spectrum of illness from mild fever to severe disease with plasma leakage and shock. Infants and children with secondary heterologous dengue infections are most at risk for severe dengue disease. Laboratory diagnosis of dengue can be established within five days of disease onset by direct detection of viral components in serum. After day five, serologic diagnosis provides indirect evidence of dengue. Currently, no effective antiviral agents are available to treat dengue infection. Therefore, treatment remains supportive, with emphasis on close hematological monitoring, recognition of warning signs of severe disease and fluid-replacement therapy and/or blood transfusions when required. Development of a dengue vaccine is considered a high public health priority. A safe and efficacious dengue vaccine would also be important for travelers. This review highlights the current understanding of dengue in children, including its clinical manifestations, pathogenesis, diagnostic tests, management and prevention.
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Affiliation(s)
- Lilly M Verhagen
- Department of Pediatrics, Radboud University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
| | - Ronald de Groot
- Department of Pediatrics, Radboud University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
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940
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Regis LN, Acioli RV, Silveira JC, de Melo-Santos MAV, da Cunha MCS, Souza F, Batista CAV, Barbosa RMR, de Oliveira CMF, Ayres CFJ, Monteiro AMV, Souza WV. Characterization of the spatial and temporal dynamics of the dengue vector population established in urban areas of Fernando de Noronha, a Brazilian oceanic island. Acta Trop 2014; 137:80-7. [PMID: 24832009 DOI: 10.1016/j.actatropica.2014.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 04/02/2014] [Accepted: 04/05/2014] [Indexed: 11/15/2022]
Abstract
Aedes aegypti has played a major role in the dramatic expansion of dengue worldwide. The failure of control programs in reducing the rhythm of global dengue expansion through vector control suggests the need for studies to support more appropriated control strategies. We report here the results of a longitudinal study on Ae. aegypti population dynamics through continuous egg sampling aiming to characterize the infestation of urban areas of a Brazilian oceanic island, Fernando de Noronha. The spatial and temporal distribution of the dengue vector population in urban areas of the island was described using a monitoring system (SMCP-Aedes) based on a 103-trap network for Aedes egg sampling, using GIS and spatial statistics analysis tools. Mean egg densities were estimated over a 29-month period starting in 2011 and producing monthly maps of mosquito abundance. The system detected continuous Ae. aegypti oviposition in most traps. The high global positive ovitrap index (POI=83.7% of 2815 events) indicated the frequent presence of blood-fed-egg laying females at every sampling station. Egg density (eggs/ovitrap/month) reached peak values of 297.3 (0 - 2020) in May and 295 (0 - 2140) in August 2012. The presence of a stable Ae. aegypti population established throughout the inhabited areas of the island was demonstrated. A strong association between egg abundance and rainfall with a 2-month lag was observed, which combined with a first-order autocorrelation observed in the series of egg counts can provide an important forecasting tool. This first description of the characteristics of the island infestation by the dengue vector provides baseline information to analyze relationships between the spatial distribution of the vector and dengue cases, and to the development of integrated vector control strategies.
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Affiliation(s)
- Lêda N Regis
- Departamento de Entomologia, Fiocruz-PE, Recife, Brazil.
| | | | | | | | | | - Fátima Souza
- Health Department of the District of Fernando de Noronha-PE, Brazil
| | | | | | | | | | - Antonio Miguel Vieira Monteiro
- Centro de Ciência do Sistema Terrestre, Instituto Nacional de Pesquisas Espaciais, INPE, São José dos Campos, SP, Brazil
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941
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Schaffner F, Mathis A. Dengue and dengue vectors in the WHO European region: past, present, and scenarios for the future. THE LANCET. INFECTIOUS DISEASES 2014; 14:1271-80. [PMID: 25172160 DOI: 10.1016/s1473-3099(14)70834-5] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
After 55 years of absence, dengue has re-emerged in the WHO European region both as locally transmitted sporadic cases and as an outbreak in Madeira, driven by the introduction of people infected with the virus and the invasion of the vector mosquito species Aedes aegypti and Aedes albopictus. Models predict a further spread of A albopictus, particularly under climate change conditions. Dengue transmission models suggest a low risk in Europe, but these models too rarely include transmission by A albopictus (the main established vector). Further information gaps exist with regard to the Caucasus and central Asian countries of the WHO European region. Many European countries have implemented surveillance and control measures for invasive mosquitoes, but only a few include surveillance for dengue. As long as no dengue-specific prophylaxis or therapeutics are available, integrated vector management is the most sustainable control option. The rapid elimination of newly introduced A aegypti populations should be targeted in the European region, particularly in southern Europe and the Caucasus, where the species was present for decades until the 1950s.
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Affiliation(s)
- Francis Schaffner
- Institute of Parasitology, Swiss National Centre for Vector Entomology, University of Zurich, Zurich, Switzerland
| | - Alexander Mathis
- Institute of Parasitology, Swiss National Centre for Vector Entomology, University of Zurich, Zurich, Switzerland.
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942
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LaCon G, Morrison AC, Astete H, Stoddard ST, Paz-Soldan VA, Elder JP, Halsey ES, Scott TW, Kitron U, Vazquez-Prokopec GM. Shifting patterns of Aedes aegypti fine scale spatial clustering in Iquitos, Peru. PLoS Negl Trop Dis 2014; 8:e3038. [PMID: 25102062 PMCID: PMC4125221 DOI: 10.1371/journal.pntd.0003038] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/08/2014] [Indexed: 11/18/2022] Open
Abstract
Background Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels. Methodologies/Principal Findings Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study. Conclusions/Significance Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically high levels of transmission may be more effective than targeting Ae. aegypti hotspots. We carried out a comprehensive study of the long-term trends in household-level Aedes aegypti spatial distribution within a well-defined urban area endemic for dengue virus. By using a dataset consisting of 13,662 household entomological visits performed in two neighborhoods in Iquitos, Peru, we quantified the ∼3 year spatial clustering patterns of Ae. aegypti among houses and the temporal persistence of vector abundance hotspots. Our results provide strong support for the conclusion that Ae. aegypti distribution is highly focal and that hotspots of high vector abundance at the level of small groups of houses are common, but temporally unstable. Results from our study have implications for understanding the spatio-temporal patterns of Ae. aegypti abundance and for the design of surveillance and control activities that are based on household-level entomological data.
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Affiliation(s)
- Genevieve LaCon
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Amy C. Morrison
- Department of Entomology, University of California Davis, Davis, California, United States of America
| | - Helvio Astete
- U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
| | - Steven T. Stoddard
- Department of Entomology, University of California Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Valerie A. Paz-Soldan
- Department of Global Health Systems and Development, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - John P. Elder
- Graduate School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Eric S. Halsey
- U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
| | - Thomas W. Scott
- Department of Entomology, University of California Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gonzalo M. Vazquez-Prokopec
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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943
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Liese BH, Houghton N, Teplitskaya L. Development assistance for neglected tropical diseases: progress since 2009. Int Health 2014; 6:162-71. [PMID: 25096331 DOI: 10.1093/inthealth/ihu052] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neglected tropical diseases (NTDs) is an umbrella term for a diverse group of debilitating infections that represent the most common afflictions for 2.7 billion people living on less than US$2 per day. Major efforts have recently re-focused attention on NTDs, including structured advocacy by the Bill and Melinda Gates Foundation, technical and political support by WHO and large-scale drug donation programs by pharmaceutical companies. An analysis of the Official Development Assistance (ODA) for NTDs in 2009 showed that Development Assistance Committee members and multilateral donors had largely ignored funding NTD control projects. This study reviews the changes since 2009 and finds an increased engagement by pharmaceutical manufacturers through drug donation programs substantially increased by the 'London Declaration' in 2012, a focused effort of 77 public and private partners on control or elimination of the 10 most common NTDs, but no increase in ODA for NTDs between 2008 and 2012. The allocation of ODA still does not reflect the respective importance of these diseases.
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Affiliation(s)
- Bernhard H Liese
- Department of International Health, Georgetown University, Washington DC, USA
| | - Natalia Houghton
- Department of International Health, Georgetown University, Washington DC, USA
| | - Lyubov Teplitskaya
- Department of International Health, Georgetown University, Washington DC, USA
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944
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Halstead SB. Stumbles on the path to dengue control. THE LANCET. INFECTIOUS DISEASES 2014; 14:661-662. [DOI: 10.1016/s1473-3099(14)70770-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Progress in the identification of dengue virus entry/fusion inhibitors. BIOMED RESEARCH INTERNATIONAL 2014; 2014:825039. [PMID: 25157370 PMCID: PMC4135166 DOI: 10.1155/2014/825039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 05/09/2014] [Indexed: 01/12/2023]
Abstract
Dengue fever, a reemerging disease, is putting nearly 2.5 billion people at risk worldwide. The number of infections and the geographic extension of dengue fever infection have increased in the past decade. The disease is caused by the dengue virus, a flavivirus that uses mosquitos Aedes sp. as vectors. The disease has several clinical manifestations, from the mild cold-like illness to the more serious hemorrhagic dengue fever and dengue shock syndrome. Currently, there is no approved drug for the treatment of dengue disease or an effective vaccine to fight the virus. Therefore, the search for antivirals against dengue virus is an active field of research. As new possible receptors and biological pathways of the virus biology are discovered, new strategies are being undertaken to identify possible antiviral molecules. Several groups of researchers have targeted the initial step in the infection as a potential approach to interfere with the virus. The viral entry process is mediated by viral proteins and cellular receptor molecules that end up in the endocytosis of the virion, the fusion of both membranes, and the release of viral RNA in the cytoplasm. This review provides an overview of the targets and progress that has been made in the quest for dengue virus entry inhibitors.
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946
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Brady OJ, Golding N, Pigott DM, Kraemer MUG, Messina JP, Reiner RC, Scott TW, Smith DL, Gething PW, Hay SI. Global temperature constraints on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission. Parasit Vectors 2014; 7:338. [PMID: 25052008 PMCID: PMC4148136 DOI: 10.1186/1756-3305-7-338] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/27/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dengue is a disease that has undergone significant expansion over the past hundred years. Understanding what factors limit the distribution of transmission can be used to predict current and future limits to further dengue expansion. While not the only factor, temperature plays an important role in defining these limits. Previous attempts to analyse the effect of temperature on the geographic distribution of dengue have not considered its dynamic intra-annual and diurnal change and its cumulative effects on mosquito and virus populations. METHODS Here we expand an existing modelling framework with new temperature-based relationships to model an index proportional to the basic reproductive number of the dengue virus. This model framework is combined with high spatial and temporal resolution global temperature data to model the effects of temperature on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission. RESULTS Our model predicted areas where temperature is not expected to permit transmission and/or Aedes persistence throughout the year. By reanalysing existing experimental data our analysis indicates that Ae. albopictus, often considered a minor vector of dengue, has comparable rates of virus dissemination to its primary vector, Ae. aegypti, and when the longer lifespan of Ae. albopictus is considered its competence for dengue virus transmission far exceeds that of Ae. aegypti. CONCLUSIONS These results can be used to analyse the effects of temperature and other contributing factors on the expansion of dengue or its Aedes vectors. Our finding that Ae. albopictus has a greater capacity for dengue transmission than Ae. aegypti is contrary to current explanations for the comparative rarity of dengue transmission in established Ae. albopictus populations. This suggests that the limited capacity of Ae. albopictus to transmit DENV is more dependent on its ecology than vector competence. The recommendations, which we explicitly outlined here, point to clear targets for entomological investigation.
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Affiliation(s)
- Oliver J Brady
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford, United Kingdom.
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Stoddard ST, Wearing HJ, Reiner RC, Morrison AC, Astete H, Vilcarromero S, Alvarez C, Ramal-Asayag C, Sihuincha M, Rocha C, Halsey ES, Scott TW, Kochel TJ, Forshey BM. Long-term and seasonal dynamics of dengue in Iquitos, Peru. PLoS Negl Trop Dis 2014; 8:e3003. [PMID: 25033412 PMCID: PMC4102451 DOI: 10.1371/journal.pntd.0003003] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/02/2014] [Indexed: 12/02/2022] Open
Abstract
Introduction Long-term disease surveillance data provide a basis for studying drivers of pathogen transmission dynamics. Dengue is a mosquito-borne disease caused by four distinct, but related, viruses (DENV-1-4) that potentially affect over half the world's population. Dengue incidence varies seasonally and on longer time scales, presumably driven by the interaction of climate and host susceptibility. Precise understanding of dengue dynamics is constrained, however, by the relative paucity of laboratory-confirmed longitudinal data. Methods We studied 10 years (2000–2010) of laboratory-confirmed, clinic-based surveillance data collected in Iquitos, Peru. We characterized inter and intra-annual patterns of dengue dynamics on a weekly time scale using wavelet analysis. We explored the relationships of case counts to climatic variables with cross-correlation maps on annual and trimester bases. Findings Transmission was dominated by single serotypes, first DENV-3 (2001–2007) then DENV-4 (2008–2010). After 2003, incidence fluctuated inter-annually with outbreaks usually occurring between October and April. We detected a strong positive autocorrelation in case counts at a lag of ∼70 weeks, indicating a shift in the timing of peak incidence year-to-year. All climatic variables showed modest seasonality and correlated weakly with the number of reported dengue cases across a range of time lags. Cases were reduced after citywide insecticide fumigation if conducted early in the transmission season. Conclusions Dengue case counts peaked seasonally despite limited intra-annual variation in climate conditions. Contrary to expectations for this mosquito-borne disease, no climatic variable considered exhibited a strong relationship with transmission. Vector control operations did, however, appear to have a significant impact on transmission some years. Our results indicate that a complicated interplay of factors underlie DENV transmission in contexts such as Iquitos. Description of long-term temporal patterns in disease occurrence improves our understanding of pathogen transmission dynamics and facilitates predicting new epidemics. Dengue, the most prevalent mosquito-borne, viral disease of humans, typically varies seasonally and on longer, inter-annual time scales. In most studies of these patterns, however, only a fraction of putative dengue cases are confirmed with laboratory diagnostics. Here we analyzed 10 years of fully confirmed dengue cases reported to a sentinel surveillance system in Iquitos, Peru. We describe the inter and intra-annual patterns of weekly case counts and relate these to climate and local vector control efforts. We show that dengue case counts vary seasonally in Iquitos despite very little variation in key climatic conditions, such as temperature and humidity. Overall, transmission correlated poorly with climate regardless of time lag. In seasons when vector control was conducted early, there was an apparent decline in cases later that season. We speculate that the relationships between climatic conditions and transmission of DENV in Iquitos are complex and non-linear, and that other factors, such as herd immunity, virus diversity, and vector control efforts, play key roles determining the timing and intensity of transmission.
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Affiliation(s)
- Steven T. Stoddard
- Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Helen J. Wearing
- University of New Mexico, Albuquerque, Albuquerque, New Mexico, United States of America
| | - Robert C. Reiner
- Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Amy C. Morrison
- Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America
- U.S. Naval Medical Research Unit No. 6, Lima, Peru
| | | | | | | | | | | | | | | | - Thomas W. Scott
- Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tadeusz J. Kochel
- U.S. Naval Medical Research Center, Silver Spring, Maryland, United States of America
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Cauchemez S, Ledrans M, Poletto C, Quenel P, de Valk H, Colizza V, Boëlle PY. Local and regional spread of chikungunya fever in the Americas. ACTA ACUST UNITED AC 2014; 19:20854. [PMID: 25060573 DOI: 10.2807/1560-7917.es2014.19.28.20854] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chikungunya fever (CHIKV), a viral disease transmitted by mosquitoes, is currently affecting several areas in the Caribbean. The vector is found in the Americas from southern Florida to Brazil, and the Caribbean is a highly connected region in terms of population movements. There is therefore a significant risk for the epidemic to quickly expand to a wide area in the Americas. Here, we describe the spread of CHIKV in the first three areas to report cases and between areas in the region. Local transmission of CHIKV in the Caribbean is very effective, the mean number of cases generated by a human case ranging from two to four. There is a strong spatial signature in the regional epidemic, with the risk of transmission between areas estimated to be inversely proportional to the distance rather than driven by air transportation. So far, this simple distance-based model has successfully predicted observed patterns of spread. The spatial structure allows ranking areas according to their risk of invasion. This characterisation may help national and international agencies to optimise resource allocation for monitoring and control and encourage areas with elevated risks to act.
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Affiliation(s)
- S Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France
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Knowledge, attitude and practice regarding dengue fever among the healthy population of highland and lowland communities in central Nepal. PLoS One 2014; 9:e102028. [PMID: 25007284 PMCID: PMC4090170 DOI: 10.1371/journal.pone.0102028] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 06/13/2014] [Indexed: 12/30/2022] Open
Abstract
Background Dengue fever (DF) is the most rapidly spreading mosquito-borne viral disease in the world. In this decade it has expanded to new countries and from urban to rural areas. Nepal was regarded DF free until 2004. Since then dengue virus (DENV) has rapidly expanded its range even in mountain regions of Nepal, and major outbreaks occurred in 2006 and 2010. However, no data on the local knowledge, attitude and practice (KAP) of DF in Nepal exist although such information is required for prevention and control measures. Methods We conducted a community based cross-sectional survey in five districts of central Nepal between September 2011 and February 2012. We collected information on the socio-demographic characteristics of the participants and their knowledge, attitude and practice regarding DF using a structured questionnaire. We then statistically compared highland and lowland communities to identify possible causes of observed differences. Principal Findings Out of 589 individuals interviewed, 77% had heard of DF. Only 12% of the sample had good knowledge of DF. Those living in the lowlands were five times more likely to possess good knowledge than highlanders (P<0.001). Despite low knowledge levels, 83% of the people had good attitude and 37% reported good practice. We found a significantly positive correlation among knowledge, attitude and practice (P<0.001). Among the socio-demographic variables, the education level of the participants was an independent predictor of practice level (P<0.05), and education level and interaction between the sex and age group of the participants were independent predictors of attitude level (P<0.05). Conclusion Despite the rapid expansion of DENV in Nepal, the knowledge of people about DF was very low. Therefore, massive awareness programmes are urgently required to protect the health of people from DF and to limit its further spread in this country.
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950
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Cranial imaging findings in dengue virus infection. J Neurol Sci 2014; 342:36-41. [DOI: 10.1016/j.jns.2014.04.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/10/2014] [Accepted: 04/11/2014] [Indexed: 11/22/2022]
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