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Poongavanan J, Lourenço J, Tsui JLH, Colizza V, Ramphal Y, Baxter C, Kraemer MUG, Dunaiski M, de Oliveira T, Tegally H. Dengue virus importation risks in Africa: a modelling study. Lancet Planet Health 2024; 8:e1043-e1054. [PMID: 39674194 DOI: 10.1016/s2542-5196(24)00272-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 10/18/2024] [Accepted: 10/18/2024] [Indexed: 12/16/2024]
Abstract
BACKGROUND Dengue is a significant global public health concern that poses a threat in Africa. Particularly, African countries are at risk of viral introductions through air travel connectivity with areas of South America and Asia in which explosive dengue outbreaks frequently occur. Limited reporting and diagnostic capacity hinder a comprehensive assessment of continent-wide transmission dynamics and deployment of surveillance strategies in Africa. In this study, we aimed to identify African airports at high risk of receiving passengers with dengue from Asia, Latin America, and other African countries with high dengue incidence. METHODS For this modelling study, air travel flow data were obtained from the International Air Transport Association database for 2019. Data comprised monthly passenger volumes from 14 high-incidence countries outside of Africa and 18 countries within the African continent that reported dengue outbreaks in the past 10 years to 54 African countries, encompassing all 197 commercial airports in both the source and destination regions. The risk of dengue introduction into Africa from countries of high incidence in Asia, Latin America, and within Africa was estimated based on origin-destination air travel flows and epidemic activity at origin. We produced a novel proxy for local dengue epidemic activity using a composite index of theoretical climate-driven transmission suitability and population density, which we used, in addition to travel information in a risk flow model, to estimate importation risk. FINDINGS Countries in eastern Africa had a high estimated risk of dengue importation from Asia and other east African countries, whereas for west African countries, the risk of importation was higher from within the region than from countries outside of Africa. Some countries with high risk of importation had low local transmission suitability, which is likely to hamper the risk that dengue importations would lead to local transmission and establishment of a dengue outbreak. Mauritius, Uganda, Côte d'Ivoire, Senegal, and Kenya were identified as countries susceptible to dengue introductions during periods of persistent transmission suitability. INTERPRETATION Our study improves data-driven allocation of surveillance resources, in regions of Africa that are at high risk of dengue introduction and establishment, including from regional circulation. Improvements in resource allocation will be crucial in detecting and managing imported cases and could improve local responses to dengue outbreaks. FUNDING Rockefeller Foundation, National Institute of Health, EDCTP3 and Horizon Europe Research and Innovation, World Bank Group, Medical Research Foundation, Wellcome Trust, Google, Oxford Martin School Pandemic Genomics programme, and John Fell Fund.
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Affiliation(s)
- Jenicca Poongavanan
- Centre for Epidemic Response and Innovation, Stellenbosch University, Stellenbosch, South Africa
| | - José Lourenço
- Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal; Medical School, Biomedical Research Center, Catholic University of Portugal, Lisbon, Portugal
| | - Joseph L-H Tsui
- Department of Biology and Pandemic Sciences Institute, University of Oxford, Oxford, UK
| | - Vittoria Colizza
- Institut Pierre Louis d'Epidémiologie et de Santé Publique, Sorbonne Université, INSERM, Paris, France; Department of Biology, Georgetown University, Washington, DC, USA
| | - Yajna Ramphal
- Centre for Epidemic Response and Innovation, Stellenbosch University, Stellenbosch, South Africa
| | - Cheryl Baxter
- Centre for Epidemic Response and Innovation, Stellenbosch University, Stellenbosch, South Africa
| | - Moritz U G Kraemer
- Department of Biology and Pandemic Sciences Institute, University of Oxford, Oxford, UK
| | - Marcel Dunaiski
- Department of Mathematical Sciences, Computer Science Division, Stellenbosch University, Stellenbosch, South Africa
| | - Tulio de Oliveira
- Centre for Epidemic Response and Innovation, Stellenbosch University, Stellenbosch, South Africa; KwaZulu-Natal Research Innovation and Sequencing Platform, University of KwaZulu-Natal, Durban, South Africa
| | - Houriiyah Tegally
- Centre for Epidemic Response and Innovation, Stellenbosch University, Stellenbosch, South Africa.
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Poongavanan J, Lourenço J, Tsui JLH, Colizza V, Ramphal Y, Baxter C, Kraemer MU, Dunaiski M, de Oliveira T, Tegally H. Assessing Dengue Virus Importation Risks in Africa: A Climate and Travel-Based Model. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.07.24306997. [PMID: 39574849 PMCID: PMC11581072 DOI: 10.1101/2024.05.07.24306997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/09/2024]
Abstract
Background Dengue is a significant global public health concern that poses a threat to Africa. Particularly, African countries are at risk of viral introductions through air travel connectivity with areas of South America and Asia that experience frequent explosive outbreaks. Limited reporting and diagnostic capacity hinder a comprehensive assessment of continent-wide transmission dynamics and deployment of surveillance strategies in Africa. This study aimed to identify African airports at high risk of receiving dengue infected passengers from Asia, Latin America and other African countries with high dengue incidence. Methods The risk of dengue introduction into Africa from countries of high incidence in Africa, Latin America and within Africa was estimated based on origin-destination air travel flows and epidemic activity at origin. We produced a novel proxy for local dengue epidemic activity using a composite index of theoretical climate-driven transmission suitability and population density, which we used, along with travel information in a risk flow model, to estimate importation risk. Findings We find that countries in East Africa face higher estimated risk of importation from Asia and other East African countries, whereas for West African countries, larger risk of importation is estimated from within the region. Some countries with high risk of importation experience low local transmission suitability which likely hampers the chances that importations lead to local transmission and establishment. Conversely, Mauritius, Uganda, Ivory Coast, Senegal, and Kenya are identified as countries susceptible to dengue introductions during periods of persistent transmission suitability. Interpretation Our work improves data driven allocation of surveillance resources, in regions of Africa that are at high risk of dengue introduction and establishment, including from regional circulation. This will be critical in detecting and managing imported cases and can improve local response to dengue outbreaks. Funding Rockefeller Foundation, National Institute of Health, EDCTP3 and Horizon Europe Research and Innovation, World Bank Group, Medical Research Foundation, Wellcome Trust, Google.org, Oxford Martin School Pandemic Genomics programme, John Fell Fund.
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Affiliation(s)
- Jenicca Poongavanan
- Centre for Epidemic Response and innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
| | - José Lourenço
- BioISI (Biosystems and Integrative Sciences Institute), University of Lisbon, Lisbon, Portugal
- Universidade Católica Portuguesa, Medical School, Biomedical Research Center, Lisboa, Portugal
| | | | - Vittoria Colizza
- Sorbonne Université, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique (IPLESP), Paris, France
- Department of Biology, Georgetown University, Washington, District of Columbia, USA
| | - Yajna Ramphal
- Centre for Epidemic Response and innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
| | - Cheryl Baxter
- Centre for Epidemic Response and innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
| | - Moritz U.G. Kraemer
- Department of Biology, University of Oxford, Oxford,UK
- Pandemic Sciences Institute, University of Oxford, UK
| | - Marcel Dunaiski
- Computer Science Division, Department of Mathematical Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Tulio de Oliveira
- Centre for Epidemic Response and innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), University of KwaZulu-Natal, Durban, South Africa
| | - Houriiyah Tegally
- Centre for Epidemic Response and innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
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Viennet E, Frentiu FD, McKenna E, Torres Vasconcelos F, Flower RLP, Faddy HM. Arbovirus Transmission in Australia from 2002 to 2017. BIOLOGY 2024; 13:524. [PMID: 39056717 PMCID: PMC11273437 DOI: 10.3390/biology13070524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024]
Abstract
Arboviruses pose a significant global public health threat, with Ross River virus (RRV), Barmah Forest virus (BFV), and dengue virus (DENV) being among the most common and clinically significant in Australia. Some arboviruses, including those prevalent in Australia, have been reported to cause transfusion-transmitted infections. This study examined the spatiotemporal variation of these arboviruses and their potential impact on blood donation numbers across Australia. Using data from the Australian Department of Health on eight arboviruses from 2002 to 2017, we retrospectively assessed the distribution and clustering of incidence rates in space and time using Geographic Information System mapping and space-time scan statistics. Regression models were used to investigate how weather variables, their lag months, space, and time affect case and blood donation counts. The predictors' importance varied with the spatial scale of analysis. Key predictors were average rainfall, minimum temperature, daily temperature variation, and relative humidity. Blood donation number was significantly associated with the incidence rate of all viruses and its interaction with local transmission of DENV, overall. This study, the first to cover eight clinically relevant arboviruses at a fine geographical level in Australia, identifies regions at risk for transmission and provides valuable insights for public health intervention.
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Affiliation(s)
- Elvina Viennet
- Research and Development, Strategy and Growth, Australian Red Cross Lifeblood, Kelvin Grove, QLD 4059, Australia; (E.M.); (F.T.V.); (R.L.P.F.); (H.M.F.)
- School of Biomedical Sciences, Centre for Immunology and Infection Control, Queensland University of Technology, Brisbane, QLD 4001, Australia;
| | - Francesca D. Frentiu
- School of Biomedical Sciences, Centre for Immunology and Infection Control, Queensland University of Technology, Brisbane, QLD 4001, Australia;
| | - Emilie McKenna
- Research and Development, Strategy and Growth, Australian Red Cross Lifeblood, Kelvin Grove, QLD 4059, Australia; (E.M.); (F.T.V.); (R.L.P.F.); (H.M.F.)
- School of Biomedical Sciences, Centre for Immunology and Infection Control, Queensland University of Technology, Brisbane, QLD 4001, Australia;
| | - Flavia Torres Vasconcelos
- Research and Development, Strategy and Growth, Australian Red Cross Lifeblood, Kelvin Grove, QLD 4059, Australia; (E.M.); (F.T.V.); (R.L.P.F.); (H.M.F.)
- School of Health, University of the Sunshine Coast, Petrie, QLD 4052, Australia
| | - Robert L. P. Flower
- Research and Development, Strategy and Growth, Australian Red Cross Lifeblood, Kelvin Grove, QLD 4059, Australia; (E.M.); (F.T.V.); (R.L.P.F.); (H.M.F.)
- School of Biomedical Sciences, Centre for Immunology and Infection Control, Queensland University of Technology, Brisbane, QLD 4001, Australia;
| | - Helen M. Faddy
- Research and Development, Strategy and Growth, Australian Red Cross Lifeblood, Kelvin Grove, QLD 4059, Australia; (E.M.); (F.T.V.); (R.L.P.F.); (H.M.F.)
- School of Health, University of the Sunshine Coast, Petrie, QLD 4052, Australia
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Spatial Analysis of Mosquito-Borne Diseases in Europe: A Scoping Review. SUSTAINABILITY 2022. [DOI: 10.3390/su14158975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mosquito-borne infections are increasing in endemic areas and previously unaffected regions. In 2020, the notification rate for Dengue was 0.5 cases per 100,000 population, and for Chikungunya <0.1/100,000. In 2019, the rate for Malaria was 1.3/100,000, and for West Nile Virus, 0.1/100,000. Spatial analysis is increasingly used in surveillance and epidemiological investigation, but reviews about their use in this research topic are scarce. We identify and describe the methodological approaches used to investigate the distribution and ecological determinants of mosquito-borne infections in Europe. Relevant literature was extracted from PubMed, Scopus, and Web of Science from inception until October 2021 and analysed according to PRISMA-ScR protocol. We identified 110 studies. Most used geographical correlation analysis (n = 50), mainly applying generalised linear models, and the remaining used spatial cluster detection (n = 30) and disease mapping (n = 30), mainly conducted using frequentist approaches. The most studied infections were Dengue (n = 32), Malaria (n = 26), Chikungunya (n = 26), and West Nile Virus (n = 24), and the most studied ecological determinants were temperature (n = 39), precipitation (n = 24), water bodies (n = 14), and vegetation (n = 11). Results from this review may support public health programs for mosquito-borne disease prevention and may help guide future research, as we recommended various good practices for spatial epidemiological studies.
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Mostafiz MM, Ryu J, Akintola AA, Choi KS, Hwang UW, Hassan E, Lee KY. Larvicidal Activity of Methyl Benzoate, a Volatile Organic Compound, Against the Mosquitoes Aedes albopictus and Culex pipiens (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:788-794. [PMID: 35043202 DOI: 10.1093/jme/tjab230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Indexed: 06/14/2023]
Abstract
Methyl benzoate (MBe) is a volatile organic molecule found in various plants; it is used as an insect semiochemical. MBe also has a biorational insecticidal effect against various agricultural and urban arthropod pests. The present study was the first to assess the larvicidal potential of MBe against fourth-instar larvae of the mosquitoes Aedes albopictus (Skuse) and Culex pipiens (L.). A positive association was observed between MBe concentrations and larval mortality in both the species. The highest mortality recorded was 100% for Ae. albopictus and 56% for Cx. pipiens after 24 h of exposure to 200 ppm MBe. The lethal median concentration (LC50) values of MBe against fourth-instar larvae of Ae. albopictus and Cx. pipiens were 61 ppm and 185 ppm, respectively. These results suggest that MBe has great potential for use as an environmentally friendly larvicidal agent for mosquito control.
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Affiliation(s)
- Md Munir Mostafiz
- Division of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Korea
| | - Jihun Ryu
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | | | - Kwang Shik Choi
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
- Research Institute for Dok-do and Ulleung-do Island, Kyungpook National University, Daegu, Korea
| | - Ui Wook Hwang
- Biomedical Convergence Science and Technology, Kyungpook National University, Daegu, Korea
| | - Errol Hassan
- School of Agriculture and Food Sciences, The University of Queensland Gatton, Queensland, Australia
| | - Kyeong-Yeoll Lee
- Division of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Korea
- Research Institute for Dok-do and Ulleung-do Island, Kyungpook National University, Daegu, Korea
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Ding Y, Wandelt S, Sun X. TLQP: Early-stage transportation lock-down and quarantine problem. TRANSPORTATION RESEARCH. PART C, EMERGING TECHNOLOGIES 2021; 129:103218. [PMID: 36313400 PMCID: PMC9587919 DOI: 10.1016/j.trc.2021.103218] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/12/2021] [Accepted: 05/08/2021] [Indexed: 05/05/2023]
Abstract
The advent of COVID-19 is a sensible reminder of the vulnerability of our society to pandemics. We need to be better prepared for finding ways to stem such outbreaks. Except from social distancing and wearing face masks, restricting the movement of people is one important measure necessary to control the spread. Such decisions on the lock-down/reduction of movement should be made in an informed way and, accordingly, modeled as an optimization problem. We propose the Early-stage Transportation Lock-down and Quarantine Problem (TLQP), which can help to decide which parts of the transportation infrastructure of a country should be restricted in early stages. On top of the network-based Susceptible-Exposed-Infectious-Recovered (SEIR) model, we establish a decision recommendation framework, which considers the lock-down of cross-border traffic, internal traffic, and movement inside individual populations. The combinatorial optimization problem aims to find the best set of actions which minimize the social cost of a lock-down. Given the inherent intractability of this problem, we develop a highly-efficient heuristic based on the Effective Distance (ED) path and the Cost-Effective Lazy Forward (CELF) algorithm. We perform and report experiments on the global spread of COVID-19 and show how individual countries may protect their population by taking appropriate measures against the threatening pandemic. We believe that our study contributes to the orchestration of measures for dealing with current and future epidemic outbreaks.
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Affiliation(s)
- Yida Ding
- School of General Engineering, Beihang University, 100191 Beijing, China
| | - Sebastian Wandelt
- School of Electronic and Information Engineering, Beihang University, 100191 Beijing, China
| | - Xiaoqian Sun
- School of General Engineering, Beihang University, 100191 Beijing, China
- School of Electronic and Information Engineering, Beihang University, 100191 Beijing, China
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Zhang Y, Riera J, Ostrow K, Siddiqui S, de Silva H, Sarkar S, Fernando L, Gardner L. Modeling the relative role of human mobility, land-use and climate factors on dengue outbreak emergence in Sri Lanka. BMC Infect Dis 2020; 20:649. [PMID: 32883213 PMCID: PMC7469426 DOI: 10.1186/s12879-020-05369-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/25/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND More than 80,000 dengue cases including 215 deaths were reported nationally in less than 7 months between 2016 and 2017, a fourfold increase in the number of reported cases compared to the average number over 2010-2016. The region of Negombo, located in the Western province, experienced the greatest number of dengue cases in the country and is the focus area of our study, where we aim to capture the spatial-temporal dynamics of dengue transmission. METHODS We present a statistical modeling framework to evaluate the spatial-temporal dynamics of the 2016-2017 dengue outbreak in the Negombo region of Sri Lanka as a function of human mobility, land-use, and climate patterns. The analysis was conducted at a 1 km × 1 km spatial resolution and a weekly temporal resolution. RESULTS Our results indicate human mobility to be a stronger indicator for local outbreak clusters than land-use or climate variables. The minimum daily temperature was identified as the most influential climate variable on dengue cases in the region; while among the set of land-use patterns considered, urban areas were found to be most prone to dengue outbreak, followed by areas with stagnant water and then coastal areas. The results are shown to be robust across spatial resolutions. CONCLUSIONS Our study highlights the potential value of using travel data to target vector control within a region. In addition to illustrating the relative relationship between various potential risk factors for dengue outbreaks, the results of our study can be used to inform where and when new cases of dengue are likely to occur within a region, and thus help more effectively and innovatively, plan for disease surveillance and vector control.
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Affiliation(s)
- Ying Zhang
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Jefferson Riera
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21205 USA
| | - Kayla Ostrow
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Sauleh Siddiqui
- Department of Environmental Science, American University, Washington, DC 20016 USA
| | - Harendra de Silva
- Department of Pediatrics, University of Colombo, Colombo, 00900 Sri Lanka
| | - Sahotra Sarkar
- Department of Philosophy, Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712 USA
| | - Lakkumar Fernando
- Centre for Clinical Management of Dengue and Dengue Haemorrhagic Fever, Negombo, 11500 Sri Lanka
| | - Lauren Gardner
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
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Salami D, Capinha C, Martins MDRO, Sousa CA. Dengue importation into Europe: A network connectivity-based approach. PLoS One 2020; 15:e0230274. [PMID: 32163497 PMCID: PMC7067432 DOI: 10.1371/journal.pone.0230274] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/25/2020] [Indexed: 12/17/2022] Open
Abstract
The spread of dengue through global human mobility is a major public health concern. A key challenge is understanding the transmission pathways and mediating factors that characterized the patterns of dengue importation into non-endemic areas. Utilizing a network connectivity-based approach, we analyze the importation patterns of dengue fever into European countries. Seven connectivity indices were developed to characterize the role of the air passenger traffic, seasonality, incidence rate, geographical proximity, epidemic vulnerability, and wealth of a source country, in facilitating the transport and importation of dengue fever. We used generalized linear mixed models (GLMMs) to examine the relationship between dengue importation and the connectivity indices while accounting for the air transport network structure. We also incorporated network autocorrelation within a GLMM framework to investigate the propensity of a European country to receive an imported case, by virtue of its position within the air transport network. The connectivity indices and dynamical processes of the air transport network were strong predictors of dengue importation in Europe. With more than 70% of the variation in dengue importation patterns explained. We found that transportation potential was higher for source countries with seasonal dengue activity, high passenger traffic, high incidence rates, high epidemic vulnerability, and in geographical proximity to a destination country in Europe. We also found that position of a European country within the air transport network was a strong predictor of the country's propensity to receive an imported case. Our findings provide evidence that the importation patterns of dengue into Europe can be largely explained by appropriately characterizing the heterogeneities of the source, and topology of the air transport network. This contributes to the foundational framework for building integrated predictive models for bio-surveillance of dengue importation.
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Affiliation(s)
- Donald Salami
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Lisbon, Portugal
- * E-mail: (DS); (CS)
| | - César Capinha
- Centro de Estudos Geográficos, Instituto de Geografia e Ordenamento do Território, Universidade de Lisboa, Lisboa, Lisbon, Portugal
| | - Maria do Rosário Oliveira Martins
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Lisbon, Portugal
| | - Carla Alexandra Sousa
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Lisbon, Portugal
- * E-mail: (DS); (CS)
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Akhtar M, Kraemer MUG, Gardner LM. A dynamic neural network model for predicting risk of Zika in real time. BMC Med 2019; 17:171. [PMID: 31474220 PMCID: PMC6717993 DOI: 10.1186/s12916-019-1389-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 07/12/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In 2015, the Zika virus spread from Brazil throughout the Americas, posing an unprecedented challenge to the public health community. During the epidemic, international public health officials lacked reliable predictions of the outbreak's expected geographic scale and prevalence of cases, and were therefore unable to plan and allocate surveillance resources in a timely and effective manner. METHODS In this work, we present a dynamic neural network model to predict the geographic spread of outbreaks in real time. The modeling framework is flexible in three main dimensions (i) selection of the chosen risk indicator, i.e., case counts or incidence rate; (ii) risk classification scheme, which defines the high-risk group based on a relative or absolute threshold; and (iii) prediction forecast window (1 up to 12 weeks). The proposed model can be applied dynamically throughout the course of an outbreak to identify the regions expected to be at greatest risk in the future. RESULTS The model is applied to the recent Zika epidemic in the Americas at a weekly temporal resolution and country spatial resolution, using epidemiological data, passenger air travel volumes, and vector habitat suitability, socioeconomic, and population data for all affected countries and territories in the Americas. The model performance is quantitatively evaluated based on the predictive accuracy of the model. We show that the model can accurately predict the geographic expansion of Zika in the Americas with the overall average accuracy remaining above 85% even for prediction windows of up to 12 weeks. CONCLUSIONS Sensitivity analysis illustrated the model performance to be robust across a range of features. Critically, the model performed consistently well at various stages throughout the course of the outbreak, indicating its potential value at any time during an epidemic. The predictive capability was superior for shorter forecast windows and geographically isolated locations that are predominantly connected via air travel. The highly flexible nature of the proposed modeling framework enables policy makers to develop and plan vector control programs and case surveillance strategies which can be tailored to a range of objectives and resource constraints.
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Affiliation(s)
- Mahmood Akhtar
- School of Civil and Environment Engineering, UNSW Sydney, Sydney, NSW, Australia
- School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Moritz U G Kraemer
- Department of Zoology, University of Oxford, Oxford, UK
- Computational Epidemiology Group, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Lauren M Gardner
- School of Civil and Environment Engineering, UNSW Sydney, Sydney, NSW, Australia.
- Department of Civil Engineering, Johns Hopkins University, Baltimore, MD, USA.
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Meslé MMI, Hall IM, Christley RM, Leach S, Read JM. The use and reporting of airline passenger data for infectious disease modelling: a systematic review. Euro Surveill 2019; 24:1800216. [PMID: 31387671 PMCID: PMC6685100 DOI: 10.2807/1560-7917.es.2019.24.31.1800216] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 09/18/2018] [Indexed: 01/06/2023] Open
Abstract
BackgroundA variety of airline passenger data sources are used for modelling the international spread of infectious diseases. Questions exist regarding the suitability and validity of these sources.AimWe conducted a systematic review to identify the sources of airline passenger data used for these purposes and to assess validation of the data and reproducibility of the methodology.MethodsArticles matching our search criteria and describing a model of the international spread of human infectious disease, parameterised with airline passenger data, were identified. Information regarding type and source of airline passenger data used was collated and the studies' reproducibility assessed.ResultsWe identified 136 articles. The majority (n = 96) sourced data primarily used by the airline industry. Governmental data sources were used in 30 studies and data published by individual airports in four studies. Validation of passenger data was conducted in only seven studies. No study was found to be fully reproducible, although eight were partially reproducible.LimitationsBy limiting the articles to international spread, articles focussed on within-country transmission even if they used relevant data sources were excluded. Authors were not contacted to clarify their methods. Searches were limited to articles in PubMed, Web of Science and Scopus.ConclusionWe recommend greater efforts to assess validity and biases of airline passenger data used for modelling studies, particularly when model outputs are to inform national and international public health policies. We also recommend improving reporting standards and more detailed studies on biases in commercial and open-access data to assess their reproducibility.
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Affiliation(s)
- Margaux Marie Isabelle Meslé
- National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections at University of Liverpool, Liverpool, United Kingdom
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Ian Melvyn Hall
- National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections at University of Liverpool, Liverpool, United Kingdom
- School of Mathematics, University of Manchester, Manchester, United Kingdom
- Emergency Response Department, Public Health England, Salisbury, United Kingdom
- National Institute for Health Research, Health Protection Research Unit in Emergency Preparedness and Response at Kings College London, London, United Kingdom
| | - Robert Matthew Christley
- National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections at University of Liverpool, Liverpool, United Kingdom
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Steve Leach
- National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections at University of Liverpool, Liverpool, United Kingdom
- Emergency Response Department, Public Health England, Salisbury, United Kingdom
- National Institute for Health Research, Health Protection Research Unit in Emergency Preparedness and Response at Kings College London, London, United Kingdom
- National Institute for Health Research, Health Protection Research Unit in Modelling Methodology at Imperial College London, London, United Kingdom
| | - Jonathan Michael Read
- National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections at University of Liverpool, Liverpool, United Kingdom
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- Centre for Health Informatics Computation and Statistics, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
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11
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Le Tyrant M, Bley D, Leport C, Alfandari S, Guégan JF. Low to medium-low risk perception for dengue, chikungunya and Zika outbreaks by infectious diseases physicians in France, Western Europe. BMC Public Health 2019; 19:1014. [PMID: 31366341 PMCID: PMC6889449 DOI: 10.1186/s12889-019-7317-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 07/15/2019] [Indexed: 11/17/2022] Open
Abstract
Background Many tropical countries are currently experiencing dengue (DEN), chikungunya (CHIK) and also more recently Zika (ZIKA) epidemics (particularly in Latin America). Although the risk of transmission and spread of these infections in temperate regions remains a controversial issue, vector-borne diseases have been widely reported in the media and have been the focus of preventive strategies by national and international policy-makers and public health authorities. In this context, we wanted to determine the extent of risk perception in infectious diseases (ID) physicians of the current and future risk of arboviral disease introduction, autochthonous case development and epidemic scenarios in France, Western Europe. Methods To this aim, we developed an original standardized questionnaire survey which was disseminated by the French Infectious Diseases Society to ID physician members. Results We found that ID physicians perceived the risk of introduction and outbreak development of DEN, CHIK and ZIKA in France to be low to medium-low. Generalized Linear Model(s) identified medical school training, the extent of professional experience, and awareness of the French national plan regarding arboviral infections as significant predictors for lower risk perception among respondents. Conclusion Despite the fact that arboviral diseases are increasingly being imported into France, sometimes resulting in sporadic autochtonous transmission, French ID physicians do not perceive the risk as high. Better communication and education targeting health professionals and citizens will be needed to enhance the effectiveness of the French national plan to prepare against arboviral diseases. Electronic supplementary material The online version of this article (10.1186/s12889-019-7317-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marion Le Tyrant
- UMR ESPACE 7300, CNRS, Aix Marseille University, Avignon Université, Université Nice Sophia-Antipolis, F-13545, Aix-en-Provence, France.,UMR MIVEGEC, IRD, CNRS, University of Montpellier, Centre IRD de Montpellier, F-34394, Montpellier, Cedex 5, France
| | - Daniel Bley
- UMR ESPACE 7300, CNRS, Aix Marseille University, Avignon Université, Université Nice Sophia-Antipolis, F-13545, Aix-en-Provence, France
| | - Catherine Leport
- Université Paris-Diderot, Inserm 1137, UMR 1137, 16, rue Henri-Huchard, 75870, Paris, Cedex 18, France.,Mission COREB Nationale, Assistance publique - Hôpitaux de Paris, 75004, Paris, France
| | - Serge Alfandari
- Service de réanimation et maladies infectieuses, Centre hospitalier de Tourcoing, Tourcoing, France
| | - Jean-François Guégan
- UMR MIVEGEC, IRD, CNRS, University of Montpellier, Centre IRD de Montpellier, F-34394, Montpellier, Cedex 5, France. .,UMR ASTRE, INRA, Cirad, University of Montpellier, Campus international de Baillarguet, Montferrier-sur-Lez, F-34980, Montpellier, France. .,International U.N. programme FutureEarth, OneHealth global research programme, Montréal, Canada.
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12
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Lai S, Johansson MA, Yin W, Wardrop NA, van Panhuis WG, Wesolowski A, Kraemer MUG, Bogoch II, Kain D, Findlater A, Choisy M, Huang Z, Mu D, Li Y, He Y, Chen Q, Yang J, Khan K, Tatem AJ, Yu H. Seasonal and interannual risks of dengue introduction from South-East Asia into China, 2005-2015. PLoS Negl Trop Dis 2018; 12:e0006743. [PMID: 30412575 PMCID: PMC6248995 DOI: 10.1371/journal.pntd.0006743] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/21/2018] [Accepted: 10/21/2018] [Indexed: 12/19/2022] Open
Abstract
Due to worldwide increased human mobility, air-transportation data and mathematical models have been widely used to measure risks of global dispersal of pathogens. However, the seasonal and interannual risks of pathogens importation and onward transmission from endemic countries have rarely been quantified and validated. We constructed a modelling framework, integrating air travel, epidemiological, demographical, entomological and meteorological data, to measure the seasonal probability of dengue introduction from endemic countries. This framework has been applied retrospectively to elucidate spatiotemporal patterns and increasing seasonal risk of dengue importation from South-East Asia into China via air travel in multiple populations, Chinese travelers and local residents, over a decade of 2005-15. We found that the volume of airline travelers from South-East Asia into China has quadrupled from 2005 to 2015 with Chinese travelers increased rapidly. Following the growth of air traffic, the probability of dengue importation from South-East Asia into China has increased dramatically from 2005 to 2015. This study also revealed seasonal asymmetries of transmission routes: Sri Lanka and Maldives have emerged as origins; neglected cities at central and coastal China have been increasingly vulnerable to dengue importation and onward transmission. Compared to the monthly occurrence of dengue reported in China, our model performed robustly for importation and onward transmission risk estimates. The approach and evidence could facilitate to understand and mitigate the changing seasonal threat of arbovirus from endemic regions.
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Affiliation(s)
- Shengjie Lai
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
- WorldPop, Department of Geography and Environment, University of Southampton, Southampton, United Kingdom
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
- Flowminder Foundation, Stockholm, Sweden
| | - Michael A. Johansson
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, San Juan, Puerto Rico
- Center for Communicable Disease Dynamics, Harvard T.H. Chan School of Public Health, Boston, MA, United States of America
| | - Wenwu Yin
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
| | - Nicola A. Wardrop
- WorldPop, Department of Geography and Environment, University of Southampton, Southampton, United Kingdom
- Department for International Development, London, United Kingdom
| | - Willem G. van Panhuis
- Epidemiology and Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Moritz U. G. Kraemer
- Harvard Medical School, Harvard University, Boston, MA, United States of America
- Computational Epidemiology Lab, Boston Children’s Hospital, Boston, MA, United States of America
- Department of Zoology, University of Oxford, New Radcliffe House, Radcliffe Observatory Quarter, Oxford, United Kingdom
| | - Isaac I. Bogoch
- Department of Medicine, Division of Infectious Diseases, University of Toronto, Toronto, ON, Canada
- Divisions of General Internal Medicine and Infectious Diseases, University Health Network, Toronto, ON, Canada
| | - Dylain Kain
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Aidan Findlater
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Marc Choisy
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
- Oxford University Clinical Research Unit, National Hospital for Tropical Diseases, Hanoi, Vietnam
| | - Zhuojie Huang
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Di Mu
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
| | - Yu Li
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
| | - Yangni He
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Qiulan Chen
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
| | - Juan Yang
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Kamran Khan
- Department of Medicine, Division of Infectious Diseases, University of Toronto, Toronto, ON, Canada
- Li Ka Shing Knowledge Institute, St Michael’s Hospital, Toronto, Ontario, Canada
| | - Andrew J. Tatem
- WorldPop, Department of Geography and Environment, University of Southampton, Southampton, United Kingdom
- Flowminder Foundation, Stockholm, Sweden
| | - Hongjie Yu
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
- Division of Infectious Disease, Key Laboratory of Surveillance and Early–warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Changping District, Beijing, China
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Gardner LM, Bóta A, Gangavarapu K, Kraemer MUG, Grubaugh ND. Inferring the risk factors behind the geographical spread and transmission of Zika in the Americas. PLoS Negl Trop Dis 2018; 12:e0006194. [PMID: 29346387 PMCID: PMC5790294 DOI: 10.1371/journal.pntd.0006194] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 01/30/2018] [Accepted: 12/27/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND An unprecedented Zika virus epidemic occurred in the Americas during 2015-2016. The size of the epidemic in conjunction with newly recognized health risks associated with the virus attracted significant attention across the research community. Our study complements several recent studies which have mapped epidemiological elements of Zika, by introducing a newly proposed methodology to simultaneously estimate the contribution of various risk factors for geographic spread resulting in local transmission and to compute the risk of spread (or re-introductions) between each pair of regions. The focus of our analysis is on the Americas, where the set of regions includes all countries, overseas territories, and the states of the US. METHODOLOGY/PRINCIPAL FINDINGS We present a novel application of the Generalized Inverse Infection Model (GIIM). The GIIM model uses real observations from the outbreak and seeks to estimate the risk factors driving transmission. The observations are derived from the dates of reported local transmission of Zika virus in each region, the network structure is defined by the passenger air travel movements between all pairs of regions, and the risk factors considered include regional socioeconomic factors, vector habitat suitability, travel volumes, and epidemiological data. The GIIM relies on a multi-agent based optimization method to estimate the parameters, and utilizes a data driven stochastic-dynamic epidemic model for evaluation. As expected, we found that mosquito abundance, incidence rate at the origin region, and human population density are risk factors for Zika virus transmission and spread. Surprisingly, air passenger volume was less impactful, and the most significant factor was (a negative relationship with) the regional gross domestic product (GDP) per capita. CONCLUSIONS/SIGNIFICANCE Our model generates country level exportation and importation risk profiles over the course of the epidemic and provides quantitative estimates for the likelihood of introduced Zika virus resulting in local transmission, between all origin-destination travel pairs in the Americas. Our findings indicate that local vector control, rather than travel restrictions, will be more effective at reducing the risks of Zika virus transmission and establishment. Moreover, the inverse relationship between Zika virus transmission and GDP suggests that Zika cases are more likely to occur in regions where people cannot afford to protect themselves from mosquitoes. The modeling framework is not specific for Zika virus, and could easily be employed for other vector-borne pathogens with sufficient epidemiological and entomological data.
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Affiliation(s)
- Lauren M. Gardner
- School of Civil and Environmental Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - András Bóta
- School of Civil and Environmental Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Karthik Gangavarapu
- Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
| | - Moritz U. G. Kraemer
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nathan D. Grubaugh
- Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
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Carvalho BM, Rangel EF, Vale MM. Evaluation of the impacts of climate change on disease vectors through ecological niche modelling. BULLETIN OF ENTOMOLOGICAL RESEARCH 2017; 107:419-430. [PMID: 27974065 DOI: 10.1017/s0007485316001097] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Vector-borne diseases are exceptionally sensitive to climate change. Predicting vector occurrence in specific regions is a challenge that disease control programs must meet in order to plan and execute control interventions and climate change adaptation measures. Recently, an increasing number of scientific articles have applied ecological niche modelling (ENM) to study medically important insects and ticks. With a myriad of available methods, it is challenging to interpret their results. Here we review the future projections of disease vectors produced by ENM, and assess their trends and limitations. Tropical regions are currently occupied by many vector species; but future projections indicate poleward expansions of suitable climates for their occurrence and, therefore, entomological surveillance must be continuously done in areas projected to become suitable. The most commonly applied methods were the maximum entropy algorithm, generalized linear models, the genetic algorithm for rule set prediction, and discriminant analysis. Lack of consideration of the full-known current distribution of the target species on models with future projections has led to questionable predictions. We conclude that there is no ideal 'gold standard' method to model vector distributions; researchers are encouraged to test different methods for the same data. Such practice is becoming common in the field of ENM, but still lags behind in studies of disease vectors.
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Affiliation(s)
- B M Carvalho
- Laboratório de Vertebrados,Instituto de Biologia,Universidade Federal do Rio de Janeiro,Rio de Janeiro,Brazil
| | - E F Rangel
- Laboratório Interdisciplinar de Vigilância Entomológica em Diptera e Hemiptera, Instituto Oswaldo Cruz,Fundação Oswaldo Cruz,Rio de Janeiro,Brazil
| | - M M Vale
- Laboratório de Vertebrados,Instituto de Biologia,Universidade Federal do Rio de Janeiro,Rio de Janeiro,Brazil
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15
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Influenza A H5N1 and H7N9 in China: A spatial risk analysis. PLoS One 2017; 12:e0174980. [PMID: 28376125 PMCID: PMC5380336 DOI: 10.1371/journal.pone.0174980] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/19/2017] [Indexed: 11/19/2022] Open
Abstract
Background Zoonotic avian influenza poses a major risk to China, and other parts of the world. H5N1 has remained endemic in China and globally for nearly two decades, and in 2013, a novel zoonotic influenza A subtype H7N9 emerged in China. This study aimed to improve upon our current understanding of the spreading mechanisms of H7N9 and H5N1 by generating spatial risk profiles for each of the two virus subtypes across mainland China. Methods and findings In this study, we (i) developed a refined data set of H5N1 and H7N9 locations with consideration of animal/animal environment case data, as well as spatial accuracy and precision; (ii) used this data set along with environmental variables to build species distribution models (SDMs) for each virus subtype in high resolution spatial units of 1km2 cells using Maxent; (iii) developed a risk modelling framework which integrated the results from the SDMs with human and chicken population variables, which was done to quantify the risk of zoonotic transmission; and (iv) identified areas at high risk of H5N1 and H7N9 transmission. We produced high performing SDMs (6 of 8 models with AUC > 0.9) for both H5N1 and H7N9. In all our SDMs, H7N9 consistently showed higher AUC results compared to H5N1, suggesting H7N9 suitability could be better explained by environmental variables. For both subtypes, high risk areas were primarily located in south-eastern China, with H5N1 distributions found to be more diffuse and extending more inland compared to H7N9. Conclusions We provide projections of our risk models to public health policy makers so that specific high risk areas can be targeted for control measures. We recommend comparing H5N1 and H7N9 prevalence rates and survivability in the natural environment to better understand the role of animal and environmental transmission in human infections.
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16
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Gardner L, Chen N, Sarkar S. Vector status of Aedes species determines geographical risk of autochthonous Zika virus establishment. PLoS Negl Trop Dis 2017; 11:e0005487. [PMID: 28339472 PMCID: PMC5381944 DOI: 10.1371/journal.pntd.0005487] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 04/05/2017] [Accepted: 03/13/2017] [Indexed: 11/19/2022] Open
Abstract
Background The 2015-16 Zika virus pandemic originating in Latin America led to predictions of a catastrophic global spread of the disease. Since the current outbreak began in Brazil in May 2015 local transmission of Zika has been reported in over 60 countries and territories, with over 750 thousand confirmed and suspected cases. As a result of its range expansion attention has focused on possible modes of transmission, of which the arthropod vector-based disease spread cycle involving Aedes species is believed to be the most important. Additional causes of concern are the emerging new links between Zika disease and Guillain-Barre Syndrome (GBS), and a once rare congenital disease, microcephaly. Methodology/principal findings Like dengue and chikungunya, the geographic establishment of Zika is thought to be limited by the occurrence of its principal vector mosquito species, Ae. aegypti and, possibly, Ae. albopictus. While Ae. albopictus populations are more widely established than those of Ae. aegypti, the relative competence of these species as a Zika vector is unknown. The analysis reported here presents a global risk model that considers the role of each vector species independently, and quantifies the potential spreading risk of Zika into new regions. Six scenarios are evaluated which vary in the weight assigned to Ae. albopictus as a possible spreading vector. The scenarios are bounded by the extreme assumptions that spread is driven by air travel and Ae. aegypti presence alone and spread driven equally by both species. For each scenario destination cities at highest risk of Zika outbreaks are prioritized, as are source cities in affected regions. Finally, intercontinental air travel routes that pose the highest risk for Zika spread are also ranked. The results are compared between scenarios. Conclusions/significance Results from the analysis reveal that if Ae. aegypti is the only competent Zika vector, then risk is geographically limited; in North America mainly to Florida and Texas. However, if Ae. albopictus proves to be a competent vector of Zika, which does not yet appear to be the case, then there is risk of local establishment in all American regions including Canada and Chile, much of Western Europe, Australia, New Zealand, as well as South and East Asia, with a substantial increase in risk to Asia due to the more recent local establishment of Zika in Singapore. Between 1952, when the Zika virus was first found in humans, and 2007 Zika disease outbreaks were limited to small isolated epidemics in equatorial Africa and tropical Asia. However, the recent outbreak, which began in Brazil in May 2015, resulted over 750 thousand estimated cases and confirmed local transmission in more than 60 countries by October, 2016. Like dengue and chikungunya, Zika is spread by Aedes aegypti mosquitoes and possibly, other species including Aedes albopictus. Geographic spread of the virus occurs when infected travelers travel from affected regions to ones without an established local Zika disease cycle, but in which the known and potential vector species have established populations. We estimate the risk of Zika importation and establishment into new regions using air travel data and ecological vector habitat suitability models for Ae. aegypti and Ae. albopictus. Given the uncertainties surrounding the vectorial competence of Aedes mosquitoes, we compare the geographic risk profiles when spread is driven by air travel and Ae. aegypti presence alone, with spread driven by air travel and both species. We conclude that there is a much higher global risk of Zika spread under the latter scenario, although it is the least likely.
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Affiliation(s)
- Lauren Gardner
- School of Civil and Environmental Engineering, University of New South Wales (UNSW) Sydney, Sydney, NSW, Australia
- * E-mail:
| | - Nan Chen
- School of Civil and Environmental Engineering, University of New South Wales (UNSW) Sydney, Sydney, NSW, Australia
| | - Sahotra Sarkar
- Department of Integrative Biology and Department of Philosophy, University of Texas at Austin, Austin, Texas, United States of America
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Ayukekbong JA, Oyero OG, Nnukwu SE, Mesumbe HN, Fobisong CN. Value of routine dengue diagnosis in endemic countries. World J Virol 2017; 6:9-16. [PMID: 28239567 PMCID: PMC5303857 DOI: 10.5501/wjv.v6.i1.9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/24/2016] [Accepted: 12/09/2016] [Indexed: 02/05/2023] Open
Abstract
Dengue is one of the most common arthropod-borne viral diseases in humans and it is a leading cause of illness and death in the tropical and subtropical regions of the world. It is thought to account for 400 million cases annually among approximately 3.97 billion people at risk of infection in 128 endemic countries. Despite the global prevalence of the disease, the availability of a vaccine is limited in most countries in the endemic areas. Most endemic countries in South America, South East Asia and Africa serve as attractive touristic sites for people from non-endemic countries who become infected and export the virus to dengue-free regions. Dengue fever typically resembles malaria and in endemic countries most cases of dengue are treated as presumptive malaria. Consequently, routine dengue diagnosis among persons with fever will offer early treatment and reduce the burden of the disease. Also, routine testing among travellers from endemic countries will reduce importation and prevent the geographical expansion of dengue. In this essay, we seek to highlight the usefulness of routine dengue testing in endemic countries.
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Sharp TM, Tomashek KM, Read JS, Margolis HS, Waterman SH. A New Look at an Old Disease: Recent Insights into the Global Epidemiology of Dengue. CURR EPIDEMIOL REP 2017; 4:11-21. [PMID: 28251039 PMCID: PMC5306284 DOI: 10.1007/s40471-017-0095-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW By all measures, the morbidity and mortality due to dengue are continuing to worsen worldwide. Although both early and recent studies have demonstrated regional differences in how dengue affects local populations, these findings were to varying extents related to disparate surveillance approaches. RECENT FINDINGS Recent studies have broadened the recognized spectrum of disease resulting from DENV infection, particularly in adults, and have also demonstrated new mechanisms of DENV spread both within and between populations. New results regarding the frequency and duration of homo- and heterotypic anti-DENV antibodies have provided important insights relevant to vaccine design and implementation. SUMMARY These observations and findings as well as difficulties in comparing the epidemiology of dengue within and between regions of the world underscore the need for population-based dengue surveillance worldwide. Enhanced surveillance should be implemented to complement passive surveillance in countries in the tropics to establish baseline data in order to define affected populations and evaluate the impact of dengue vaccines and novel vector control interventions.
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Affiliation(s)
- Tyler M. Sharp
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, PR 00920-3860 USA
| | - Kay M. Tomashek
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, PR 00920-3860 USA
| | - Jennifer S. Read
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, PR 00920-3860 USA
| | - Harold S. Margolis
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, PR 00920-3860 USA
| | - Stephen H. Waterman
- Dengue Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 1324 Calle Cañada, San Juan, PR 00920-3860 USA
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Semenza JC, Rocklöv J, Penttinen P, Lindgren E. Observed and projected drivers of emerging infectious diseases in Europe. Ann N Y Acad Sci 2016; 1382:73-83. [PMID: 27434370 PMCID: PMC7167773 DOI: 10.1111/nyas.13132] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/12/2022]
Abstract
Emerging infectious diseases are of international concern because of the potential for, and impact of, pandemics; however, they are difficult to predict. To identify the drivers of disease emergence, we analyzed infectious disease threat events (IDTEs) detected through epidemic intelligence collected at the European Centre for Disease Prevention and Control (ECDC) between 2008 and 2013, and compared the observed results with a 2008 ECDC foresight study of projected drivers of future IDTEs in Europe. Among 10 categories of IDTEs, foodborne and waterborne IDTEs were the most common, vaccine-preventable IDTEs caused the highest number of cases, and airborne IDTEs caused the most deaths. Observed drivers for each IDTE were sorted into three main groups: globalization and environmental drivers contributed to 61% of all IDTEs, public health system drivers contributed to 21%, and social and demographic drivers to 18%. A multiple logistic regression analysis showed that four of the top five drivers for observed IDTEs were in the globalization and environment group. In the observational study, the globalization and environment group was related to all IDTE categories, but only to five of eight categories in the foresight study. Directly targeting these drivers with public health interventions may diminish the chances of IDTE occurrence from the outset.
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Affiliation(s)
- Jan C. Semenza
- European Centre for Disease Prevention and ControlStockholmSweden
| | | | - Pasi Penttinen
- European Centre for Disease Prevention and ControlStockholmSweden
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Viennet E, Ritchie SA, Williams CR, Faddy HM, Harley D. Public Health Responses to and Challenges for the Control of Dengue Transmission in High-Income Countries: Four Case Studies. PLoS Negl Trop Dis 2016; 10:e0004943. [PMID: 27643596 PMCID: PMC5028037 DOI: 10.1371/journal.pntd.0004943] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Dengue has a negative impact in low- and lower middle-income countries, but also affects upper middle- and high-income countries. Despite the efforts at controlling this disease, it is unclear why dengue remains an issue in affluent countries. A better understanding of dengue epidemiology and its burden, and those of chikungunya virus and Zika virus which share vectors with dengue, is required to prevent the emergence of these diseases in high-income countries in the future. The purpose of this review was to assess the relative burden of dengue in four high-income countries and to appraise the similarities and differences in dengue transmission. We searched PubMed, ISI Web of Science, and Google Scholar using specific keywords for articles published up to 05 May 2016. We found that outbreaks rarely occur where only Aedes albopictus is present. The main similarities between countries uncovered by our review are the proximity to dengue-endemic countries, the presence of a competent mosquito vector, a largely nonimmune population, and a lack of citizens' engagement in control of mosquito breeding. We identified important epidemiological and environmental issues including the increase of local transmission despite control efforts, population growth, difficulty locating larval sites, and increased human mobility from neighboring endemic countries. Budget cuts in health and lack of practical vaccines contribute to an increased risk. To be successful, dengue-control programs for high-income countries must consider the epidemiology of dengue in other countries and use this information to minimize virus importation, improve the control of the cryptic larval habitat, and engage the community in reducing vector breeding. Finally, the presence of a communicable disease center is critical for managing and reducing future disease risks.
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Affiliation(s)
- Elvina Viennet
- Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research and Development, Australian Red Cross Blood Service, Kelvin Grove, Queensland, Australia
| | - Scott A. Ritchie
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Cairns, Queensland, Australia
| | - Craig R. Williams
- Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia
| | - Helen M. Faddy
- Research and Development, Australian Red Cross Blood Service, Kelvin Grove, Queensland, Australia
| | - David Harley
- Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
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Gardner LM, Chughtai AA, MacIntyre CR. Risk of global spread of Middle East respiratory syndrome coronavirus (MERS-CoV) via the air transport network. J Travel Med 2016; 23:taw063. [PMID: 27601536 PMCID: PMC7531608 DOI: 10.1093/jtm/taw063] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/18/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND Middle East respiratory syndrome coronavirus (MERS-CoV) emerged from the Kingdom of Saudi Arabia (KSA) in 2012 and has since spread to 26 countries. All cases reported so far have either been in the Middle East or linked to the region through passenger air travel, with the largest outbreak outside KSA occurring in South Korea. Further international spread is likely due to the high travel volumes of global travel, as well as the occurrence of large annual mass gathering such as the Haj and Umrah pilgrimages that take place in the region. METHODS In this study, a transport network modelling framework was used to quantify the risk of MERS-CoV spreading internationally via air travellers. All regions connected to MERS-CoV affected countries via air travel are considered, and the countries at highest risk of travel-related importations of MERS-CoV were identified, ranked and compared with actual spread of MERS cases. RESULTS The model identifies all countries that have previously reported a travel acquired case to be in the top 50 at-risk countries. India, Pakistan and Bangladesh are the highest risk countries which have yet to report a case, and should be prepared for the possibility of (pilgrims and general) travellers returning infected with MERS-CoV. In addition, the UK, Egypt, Turkey and the USA are at risk of more cases. CONCLUSIONS We have demonstrated a risk-analysis approach, using travel patterns, to prioritize countries at highest risk for MERS-CoV importations. In order to prevent global outbreaks such as the one seen in South Korea, it is critical for high-risk countries to be prepared and have appropriate screening and triage protocols in place to identify travel-related cases of MERS-CoV. The results from the model can be used by countries to prioritize their airport and hospital screening and triage protocols.
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Affiliation(s)
- Lauren M Gardner
- School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052, Australia
| | - Abrar A Chughtai
- School of Public Health and Community Medicine, Faculty of Medicine, UNSW Australia, Sydney, NSW, 2052, Australia
| | - C Raina MacIntyre
- School of Public Health and Community Medicine, Faculty of Medicine, UNSW Australia, Sydney, NSW, 2052, Australia College of Public Services and Community Solutions, Arizona State University, Tempe, AZ, USA
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22
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Gardner LM, Chen N, Sarkar S. Global risk of Zika virus depends critically on vector status of Aedes albopictus. THE LANCET. INFECTIOUS DISEASES 2016; 16:522-523. [DOI: 10.1016/s1473-3099(16)00176-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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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: 1250] [Impact Index Per Article: 125.0] [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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Semenza JC. Prototype early warning systems for vector-borne diseases in Europe. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:6333-51. [PMID: 26042370 PMCID: PMC4483704 DOI: 10.3390/ijerph120606333] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/21/2015] [Accepted: 05/25/2015] [Indexed: 11/18/2022]
Abstract
Globalization and environmental change, social and demographic determinants and health system capacity are significant drivers of infectious diseases which can also act as epidemic precursors. Thus, monitoring changes in these drivers can help anticipate, or even forecast, an upsurge of infectious diseases. The European Environment and Epidemiology (E3) Network has been built for this purpose and applied to three early warning case studies: (1) The environmental suitability of malaria transmission in Greece was mapped in order to target epidemiological and entomological surveillance and vector control activities. Malaria transmission in these areas was interrupted in 2013 through such integrated preparedness and response activities. (2) Since 2010, recurrent West Nile fever outbreaks have ensued in South/eastern Europe. Temperature deviations from a thirty year average proved to be associated with the 2010 outbreak. Drivers of subsequent outbreaks were computed through multivariate logistic regression models and included monthly temperature anomalies for July and a normalized water index. (3) Dengue is a tropical disease but sustained transmission has recently emerged in Madeira. Autochthonous transmission has also occurred repeatedly in France and in Croatia mainly due to travel importation. The risk of dengue importation into Europe in 2010 was computed with the volume of international travelers from dengue affected areas worldwide.These prototype early warning systems indicate that monitoring drivers of infectious diseases can help predict vector-borne disease threats.
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Affiliation(s)
- Jan C Semenza
- European Centre for Disease Prevention and Control, Tomtebodavagen 11A, SE-171 83 Stockholm, Sweden.
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25
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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: 84] [Impact Index Per Article: 7.6] [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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26
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Fredericks AC, Fernandez-Sesma A. The burden of dengue and chikungunya worldwide: implications for the southern United States and California. Ann Glob Health 2014; 80:466-75. [PMID: 25960096 PMCID: PMC4427842 DOI: 10.1016/j.aogh.2015.02.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Dengue virus (DENV) spreads to humans through the bite of an infected Aedes aegypti or Aedes albopictus mosquito and is a growing public health threat to both industrialized and developing nations worldwide. Outbreaks of autochthonous dengue in the United States occurred extensively in the past but over the past 3 decades have again taken place in Florida, Hawaii, and Texas as well as in American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and the US Virgin Islands. As the Aedes vectors spread worldwide it is anticipated that DENV as well as other viruses also transmitted by these vectors, such as Chikungunya virus (CHKV), will invade new areas of the world, including the United States. OBJECTIVES In this review, we describe the current burden of dengue disease worldwide and the potential introduction of DENV and CHKV into different areas of the United States. Of these areas, the state of California saw the arrival and spread of the Aedes aegypti vector beginning in 2013. This invasion presents a developing situation when considering the state's number of imported dengue cases and proximity to northern Mexico as well as the rising specter of chikungunya in the Western hemisphere. FINDINGS In light of the recent arrival of Aedes aegypti mosquito vectors to California, there is now a small but appreciable risk for endemic transmission of dengue and chikungunya within the State. It is likely, however, that if DENV or CHKV were to become endemic that the public health situation would be similar to that currently found along the Texas-Mexico border. The distribution of Aedes vectors in California as well as a discussion of several factors contributing to the risk for dengue importation are discussed and evaluated. CONCLUSIONS Dengue and chikungunya viruses present real risks to states where the Aedes vector is now established. Scientists, physicians, and public health authorities should familiarize themselves with these risks and prepare appropriately.
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Affiliation(s)
- Anthony C Fredericks
- Department of Microbiology and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ana Fernandez-Sesma
- Department of Microbiology and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.
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27
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Allen KC. Tracking the traveler without a passport: perspective on surveillance of imported disease. J Travel Med 2014; 21:295-7. [PMID: 25155926 PMCID: PMC7107537 DOI: 10.1111/jtm.12143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 06/23/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Koya C Allen
- Department of Biostatistics, Environmental Health and Epidemiology, College of Public Health, Kent State University, Kent, OH, USA
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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: 166] [Impact Index Per Article: 15.1] [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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29
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Abstract
For most of human history, populations have been relatively isolated from each other, and only recently has there been extensive contact between peoples, flora and fauna from both old and new worlds. The reach, volume and speed of modern travel are unprecedented, with human mobility increasing in high income countries by over 1000-fold since 1800. This growth is putting people at risk from the emergence of new strains of familiar diseases, and from completely new diseases, while ever more cases of the movement of both disease vectors and the diseases they carry are being seen. Pathogens and their vectors can now move further, faster and in greater numbers than ever before. Equally however, we now have access to the most detailed and comprehensive datasets on human mobility and pathogen distributions ever assembled, in order to combat these threats. This short review paper provides an overview of these datasets, with a particular focus on low income regions, and covers briefly approaches used to combine them to help us understand and control some of the negative effects of population and pathogen movements.
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Affiliation(s)
- Andrew J Tatem
- Department of Geography and Environment, University of Southampton, UK
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30
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Duber HC, Kelly SM. Febrile Illness in a Young Traveler: Dengue Fever and its Complications. J Emerg Med 2013; 45:526-9. [DOI: 10.1016/j.jemermed.2013.03.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 11/02/2012] [Accepted: 03/15/2013] [Indexed: 10/26/2022]
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Gardner L, Sarkar S. A global airport-based risk model for the spread of dengue infection via the air transport network. PLoS One 2013; 8:e72129. [PMID: 24009672 PMCID: PMC3756962 DOI: 10.1371/journal.pone.0072129] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/11/2013] [Indexed: 11/19/2022] Open
Abstract
The number of travel-acquired dengue infections has seen a consistent global rise over the past decade. An increased volume of international passenger air traffic originating from regions with endemic dengue has contributed to a rise in the number of dengue cases in both areas of endemicity and elsewhere. This paper reports results from a network-based risk assessment model which uses international passenger travel volumes, travel routes, travel distances, regional populations, and predictive species distribution models (for the two vector species, Aedes aegypti and Aedes albopictus) to quantify the relative risk posed by each airport in importing passengers with travel-acquired dengue infections. Two risk attributes are evaluated: (i) the risk posed by through traffic at each stopover airport and (ii) the risk posed by incoming travelers to each destination airport. The model results prioritize optimal locations (i.e., airports) for targeted dengue surveillance. The model is easily extendible to other vector-borne diseases.
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Affiliation(s)
- Lauren Gardner
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia.
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Abstract
Dengue is currently regarded globally as the most important mosquito-borne viral disease. A history of symptoms compatible with dengue can be traced back to the Chin Dynasty of 265-420 AD. The virus and its vectors have now become widely distributed throughout tropical and subtropical regions of the world, particularly over the last half-century. Significant geographic expansion has been coupled with rapid increases in incident cases, epidemics, and hyperendemicity, leading to the more severe forms of dengue. Transmission of dengue is now present in every World Health Organization (WHO) region of the world and more than 125 countries are known to be dengue endemic. The true impact of dengue globally is difficult to ascertain due to factors such as inadequate disease surveillance, misdiagnosis, and low levels of reporting. Currently available data likely grossly underestimates the social, economic, and disease burden. Estimates of the global incidence of dengue infections per year have ranged between 50 million and 200 million; however, recent estimates using cartographic approaches suggest this number is closer to almost 400 million. The expansion of dengue is expected to increase due to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement and also viral evolution. No vaccine or specific antiviral therapy currently exists to address the growing threat of dengue. Prompt case detection and appropriate clinical management can reduce the mortality from severe dengue. Effective vector control is the mainstay of dengue prevention and control. Surveillance and improved reporting of dengue cases is also essential to gauge the true global situation as indicated in the objectives of the WHO Global Strategy for Dengue Prevention and Control, 2012-2020. More accurate data will inform the prioritization of research, health policy, and financial resources toward reducing this poorly controlled disease. The objective of this paper is to review historical and current epidemiology of dengue worldwide and, additionally, reflect on some potential reasons for expansion of dengue into the future.
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Affiliation(s)
- Natasha Evelyn Anne Murray
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany ; Population Health, Waikato District Health Board, Hamilton, New Zealand
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Huang Z, Das A, Qiu Y, Tatem AJ. Web-based GIS: the vector-borne disease airline importation risk (VBD-AIR) tool. Int J Health Geogr 2012; 11:33. [PMID: 22892045 PMCID: PMC3503742 DOI: 10.1186/1476-072x-11-33] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 08/08/2012] [Indexed: 11/10/2022] Open
Abstract
Background Over the past century, the size and complexity of the air travel network has increased dramatically. Nowadays, there are 29.6 million scheduled flights per year and around 2.7 billion passengers are transported annually. The rapid expansion of the network increasingly connects regions of endemic vector-borne disease with the rest of the world, resulting in challenges to health systems worldwide in terms of vector-borne pathogen importation and disease vector invasion events. Here we describe the development of a user-friendly Web-based GIS tool: the Vector-Borne Disease Airline Importation Risk Tool (VBD-AIR), to help better define the roles of airports and airlines in the transmission and spread of vector-borne diseases. Methods Spatial datasets on modeled global disease and vector distributions, as well as climatic and air network traffic data were assembled. These were combined to derive relative risk metrics via air travel for imported infections, imported vectors and onward transmission, and incorporated into a three-tier server architecture in a Model-View-Controller framework with distributed GIS components. A user-friendly web-portal was built that enables dynamic querying of the spatial databases to provide relevant information. Results The VBD-AIR tool constructed enables the user to explore the interrelationships among modeled global distributions of vector-borne infectious diseases (malaria. dengue, yellow fever and chikungunya) and international air service routes to quantify seasonally changing risks of vector and vector-borne disease importation and spread by air travel, forming an evidence base to help plan mitigation strategies. The VBD-AIR tool is available at http://www.vbd-air.com. Conclusions VBD-AIR supports a data flow that generates analytical results from disparate but complementary datasets into an organized cartographical presentation on a web map for the assessment of vector-borne disease movements on the air travel network. The framework built provides a flexible and robust informatics infrastructure by separating the modules of functionality through an ontological model for vector-borne disease. The VBD‒AIR tool is designed as an evidence base for visualizing the risks of vector-borne disease by air travel for a wide range of users, including planners and decisions makers based in state and local government, and in particular, those at international and domestic airports tasked with planning for health risks and allocating limited resources.
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Affiliation(s)
- Zhuojie Huang
- Department of Geography, University of Florida, Gainesville, FL, USA.
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