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Williams RJ, Brintz BJ, Ribeiro Dos Santos G, Huang AT, Buddhari D, Kaewhiran S, Iamsirithaworn S, Rothman AL, Thomas S, Farmer A, Fernandez S, Cummings DAT, Anderson KB, Salje H, Leung DT. Integration of population-level data sources into an individual-level clinical prediction model for dengue virus test positivity. SCIENCE ADVANCES 2024; 10:eadj9786. [PMID: 38363842 PMCID: PMC10871531 DOI: 10.1126/sciadv.adj9786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/17/2024] [Indexed: 02/18/2024]
Abstract
The differentiation of dengue virus (DENV) infection, a major cause of acute febrile illness in tropical regions, from other etiologies, may help prioritize laboratory testing and limit the inappropriate use of antibiotics. While traditional clinical prediction models focus on individual patient-level parameters, we hypothesize that for infectious diseases, population-level data sources may improve predictive ability. To create a clinical prediction model that integrates patient-extrinsic data for identifying DENV among febrile patients presenting to a hospital in Thailand, we fit random forest classifiers combining clinical data with climate and population-level epidemiologic data. In cross-validation, compared to a parsimonious model with the top clinical predictors, a model with the addition of climate data, reconstructed susceptibility estimates, force of infection estimates, and a recent case clustering metric significantly improved model performance.
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Affiliation(s)
- Robert J. Williams
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Ben J. Brintz
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | | | - Angkana T. Huang
- Department of Genetics, University of Cambridge, Cambridge, UK
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Darunee Buddhari
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | | | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI, USA
| | - Stephen Thomas
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Aaron Farmer
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Derek A. T. Cummings
- Department of Biology, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Kathryn B. Anderson
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Henrik Salje
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Daniel T. Leung
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT, USA
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Williams RJ, Brintz BJ, Santos GRD, Huang A, Buddhari D, Kaewhiran S, Iamsirithaworn S, Rothman AL, Thomas S, Farmer A, Fernandez S, Cummings DAT, Anderson KB, Salje H, Leung DT. Integration of population-level data sources into an individual-level clinical prediction model for dengue virus test positivity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.08.23293840. [PMID: 37609267 PMCID: PMC10441499 DOI: 10.1101/2023.08.08.23293840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The differentiation of dengue virus (DENV) infection, a major cause of acute febrile illness in tropical regions, from other etiologies, may help prioritize laboratory testing and limit the inappropriate use of antibiotics. While traditional clinical prediction models focus on individual patient-level parameters, we hypothesize that for infectious diseases, population-level data sources may improve predictive ability. To create a clinical prediction model that integrates patient-extrinsic data for identifying DENV among febrile patients presenting to a hospital in Thailand, we fit random forest classifiers combining clinical data with climate and population-level epidemiologic data. In cross validation, compared to a parsimonious model with the top clinical predictors, a model with the addition of climate data, reconstructed susceptibility estimates, force of infection estimates, and a recent case clustering metric, significantly improved model performance.
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Affiliation(s)
- RJ Williams
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, USA
| | - Ben J. Brintz
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, USA
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, USA
| | | | - Angkana Huang
- Department of Genetics, University of Cambridge, United Kingdom
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Darunee Buddhari
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | | | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, USA
| | - Stephen Thomas
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, USA
| | - Aaron Farmer
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Derek A T Cummings
- Department of Biology, University of Florida, Gainesville, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, USA
| | - Kathryn B Anderson
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, USA
| | - Henrik Salje
- Department of Genetics, University of Cambridge, United Kingdom
| | - Daniel T. Leung
- Division of Infectious Diseases, Department of Internal Medicine, University of Utah, Salt Lake City, USA
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, USA
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Man O, Kraay A, Thomas R, Trostle J, Lee GO, Robbins C, Morrison AC, Coloma J, Eisenberg JNS. Characterizing dengue transmission in rural areas: A systematic review. PLoS Negl Trop Dis 2023; 17:e0011333. [PMID: 37289678 PMCID: PMC10249895 DOI: 10.1371/journal.pntd.0011333] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023] Open
Abstract
Dengue has historically been considered an urban disease associated with dense human populations and the built environment. Recently, studies suggest increasing dengue virus (DENV) transmission in rural populations. It is unclear whether these reports reflect recent spread into rural areas or ongoing transmission that was previously unnoticed, and what mechanisms are driving this rural transmission. We conducted a systematic review to synthesize research on dengue in rural areas and apply this knowledge to summarize aspects of rurality used in current epidemiological studies of DENV transmission given changing and mixed environments. We described how authors defined rurality and how they defined mechanisms for rural dengue transmission. We systematically searched PubMed, Web of Science, and Embase for articles evaluating dengue prevalence or cumulative incidence in rural areas. A total of 106 articles published between 1958 and 2021 met our inclusion criteria. Overall, 56% (n = 22) of the 48 estimates that compared urban and rural settings reported rural dengue incidence as being as high or higher than in urban locations. In some rural areas, the force of infection appears to be increasing over time, as measured by increasing seroprevalence in children and thus likely decreasing age of first infection, suggesting that rural dengue transmission may be a relatively recent phenomenon. Authors characterized rural locations by many different factors, including population density and size, environmental and land use characteristics, and by comparing their context to urban areas. Hypothesized mechanisms for rural dengue transmission included travel, population size, urban infrastructure, vector and environmental factors, among other mechanisms. Strengthening our understanding of the relationship between rurality and dengue will require a more nuanced definition of rurality from the perspective of DENV transmission. Future studies should focus on characterizing details of study locations based on their environmental features, exposure histories, and movement dynamics to identify characteristics that may influence dengue transmission.
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Affiliation(s)
- Olivia Man
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alicia Kraay
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois, United States of America
- Institution for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
| | - Ruth Thomas
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - James Trostle
- Department of Anthropology, Trinity College, Hartford, Connecticut, United States of America
| | - Gwenyth O. Lee
- Rutgers Global Health Institute, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States of America
- Rutgers Department of Biostatistics and Epidemiology, School of Public Health, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States of America
| | - Charlotte Robbins
- Department of Anthropology, Trinity College, Hartford, Connecticut, United States of America
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Josefina Coloma
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Joseph N. S. Eisenberg
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
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Pereira FMM, Schimit PHT. Spatial dynamics of dengue fever spreading for the coexistence of two serotypes with an application to the city of São Paulo, Brazil. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 219:106758. [PMID: 35398620 DOI: 10.1016/j.cmpb.2022.106758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 02/08/2022] [Accepted: 03/12/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Dengue fever is a disease in which individuals' spatial distribution and Aedes aegypti mosquitoes breeding places are important factors for the disease dynamics. Typically urban, dengue is a problem for least developed countries due to the ineffectiveness in controlling the vector and disorderly urbanization processes. The result is a composition of urban sanitation problems and areas with high demographic densities and intense flows of people. This paper explores the spatial distribution of vector breeding places to evaluate introducing a new dengue serotype to a population at equilibrium for a pre-existing serotype. The paper's objective is to analyze the spatial dynamics of dengue using variations of the basic reproduction number. METHODS A model based on probabilistic cellular automata is proposed to permitting the necessary flexibility to consider some spatial distributions of vector breeding places. Then, ordinary differential equations are used as a mean-field approach of the model, and the basic reproduction number (R0) is derived considering the next-generation matrix method. A spatial approach for R0 is also proposed, and the model is tested in a neighbourhood from the city of São Paulo, Brazil, to examine the potential risks of vector breeding cells distribution. RESULTS The results indicated that the more spread out these places, the higher are the values of R0. When the model is applied to a neighbourhood in São Paulo, residential areas may boost the infections and must be under public vigilance to combat vector breeding sites. CONCLUSIONS Considering the mean-field approximation of the cellular automata model by ordinary differential equations, the basic reproduction number derived returned an estimative of the disease dynamics in the population. However, the spatial basic reproduction number was more assertive in showing areas with a higher disease incidence. Moreover, the model could be easily adapted to be used in real maps enabling simulations closer to real problems.
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Affiliation(s)
- F M M Pereira
- Informatics and Knowledge Management Graduate Program, Universidade Nove de Julho, Rua Vergueiro, 235/249 São Paulo, 01525-000, SP, Brazil.
| | - P H T Schimit
- Informatics and Knowledge Management Graduate Program, Universidade Nove de Julho, Rua Vergueiro, 235/249 São Paulo, 01525-000, SP, Brazil.
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Ribeiro Dos Santos G, Buddhari D, Iamsirithaworn S, Khampaen D, Ponlawat A, Fansiri T, Farmer A, Fernandez S, Thomas S, Barraquer IR, Srikiatkhachorn A, Huang AT, Cummings DAT, Endy T, Rothman AL, Salje H, Anderson K. Individual, household and community drivers of dengue virus infection risk in Kamphaeng Phet province, Thailand. J Infect Dis 2022; 226:1348-1356. [PMID: 35512137 PMCID: PMC9574660 DOI: 10.1093/infdis/jiac177] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/02/2022] [Indexed: 11/14/2022] Open
Abstract
Dengue virus (DENV) often circulates endemically. In such settings with high levels of transmission, it remains unclear whether there are risk factors that alter individual infection risk. We tested blood taken from individuals living in multigenerational households in Kamphaeng Phet province, Thailand for DENV antibodies (N = 2364, mean age 31y). Seropositivity ranged from 45.4% among those 1-5y to 99.5% for those >30y. Using spatially explicit catalytic models, we estimated 11.8% of the susceptible population gets infected annually. We found 37.5% of the variance in seropositivity was explained by unmeasured household-level effects with only 4.2% explained by spatial differences between households. The serostatus of individuals from the same household remained significantly correlated even when separated by up to 15 years in age. These findings show that despite highly endemic transmission, persistent differences in infection risk exist across households, the reasons for which remain unclear.
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Affiliation(s)
| | - Darunee Buddhari
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Thailand
| | - Sopon Iamsirithaworn
- Department of Disease Control, Ministry of Public Health, Tiwanond, Nonthaburi, Thailand
| | - Direk Khampaen
- Department of Disease Control, Ministry of Public Health, Tiwanond, Nonthaburi, Thailand
| | - Alongkot Ponlawat
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Thailand
| | - Thanyalak Fansiri
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Thailand
| | - Aaron Farmer
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Thailand
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Thailand
| | | | | | - Anon Srikiatkhachorn
- Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI 02903, USA.,Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Angkana T Huang
- Department of Genetics, University of Cambridge, UK.,Department of Virology, Armed Forces Research Institute of Medical Sciences, Thailand
| | - Derek A T Cummings
- Department of Biology, University of Florida, USA.,Emerging Pathogens Institute, University of Florida, USA
| | - Timothy Endy
- SUNY upstate, State of New York, USA.,Coalition for Epidemic Preparedness Innovations (CEPI), Washington DC, USA
| | - Alan L Rothman
- Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI 02903, USA
| | - Henrik Salje
- Department of Genetics, University of Cambridge, UK.,Department of Biology, University of Florida, USA
| | - Kathryn Anderson
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Thailand.,SUNY upstate, State of New York, USA
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6
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Sekarrini CE, Sumarmi S, Bachri S, Taryana D, Giofandi EA. Euclidean Distance Modeling of Musi River in Controlling the Dengue Epidemic Transmission in Palembang City. Open Access Maced J Med Sci 2022. [DOI: 10.3889/oamjms.2022.9125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND: Various attempts have been made to control the population of Aedes aegypti with the help of chemicals or by engineering Wolbachia pipentis, an obligate intracellular bacterium that is passed down through DENV and arbovirus infections to manipulate the monthly average reproductive yield. This study reviews the phenomenon of the river border area which is one of the habitats for the Aedes aegypti mosquito in the Musi River, Palembang City.
AIM: The application of the euclidean distance method in this study was carried out to determine the environmental exposure of settlements along the river basin area.
METHODS: The research methodology was carried out objectively related to data on dengue incidence in 2019. It was carried out by taking location coordinates through the application of geographic information systems and the use of satellite imagery for data acquisition of existing buildings. This stage is followed by bivariate statistical calculations using the application of WoE where the probability value of the measurement is described using the Area Under Curve. Processing and accumulation carried out with existing buildings will result in a calculation of the estimated size of the exposure area.
RESULTS: The results obtained provide information, where the natural breaks jeanks value of 0.007-0.016 range results in 1465ha of heavily exposed building area. The value of the temporary bivariate statistical calculation will produce an AUC probability number of 0.44 which describes the relationship between the Musi river and the findings of dengue symptoms in the sub-districts around the Musi river border area, Palembang City. Swamp soil conditions are vulnerable to being a habitat where Aedes aegypti larvae are found.
CONCLUSIONS: Based on the analysis that we obtained from the population of dengue incidence and the condition of the river basin area showed a significant structure with the distribution of dengue incidence, it is known that the presence of buildings on the river Musi banks has a greater risk of infectious diseases transmissions and natural disasters ranging from sanitation, hygiene, flooding to river erosion.
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Fansiri T, Buddhari D, Pathawong N, Pongsiri A, Klungthong C, Iamsirithaworn S, Jones AR, Fernandez S, Srikiatkhachorn A, Rothman AL, Anderson KB, Thomas SJ, Endy TP, Ponlawat A. Entomological Risk Assessment for Dengue Virus Transmission during 2016-2020 in Kamphaeng Phet, Thailand. Pathogens 2021; 10:pathogens10101234. [PMID: 34684183 PMCID: PMC8538081 DOI: 10.3390/pathogens10101234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
Individual houses with high risks of dengue virus (DENV) transmission might be a source of virus transmission within the neighborhood. We conducted an entomological risk assessment for DENV transmission at the household level, comprising family cohort members residing in the same location, to assess the risk for dengue virus transmitted by mosquito vectors. The studies were conducted in Kamphaeng Phet Province, Thailand, during 2016-2020. Entomological investigations were performed in 35 cohort families on day 1 and day 14 after receiving dengue case reports. DENV was found in 22 Aedes samples (4.9%) out of 451 tested samples. A significantly higher DENV infection rate was detected in vectors collected on day 1 (6.64%) compared to those collected on day 14 (1.82%). Annual vector surveillance was carried out in 732 houses, with 1002 traps catching 3653 Aedes females. The majority of the 13,228 water containers examined were made from plastic and clay, with used tires serving as a primary container, with 59.55% larval abundance. Larval indices, as indicators of dengue epidemics and to evaluate disease and vector control approaches, were calculated. As a result, high values of larval indices indicated the considerably high risk of dengue transmission in these communities.
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Affiliation(s)
- Thanyalak Fansiri
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (T.F.); (N.P.); (A.P.)
| | - Darunee Buddhari
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (D.B.); (C.K.); (A.R.J.); (S.F.)
| | - Nattaphol Pathawong
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (T.F.); (N.P.); (A.P.)
| | - Arissara Pongsiri
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (T.F.); (N.P.); (A.P.)
| | - Chonticha Klungthong
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (D.B.); (C.K.); (A.R.J.); (S.F.)
| | - Sopon Iamsirithaworn
- Department of Disease Control, Ministry of Public Health, Nonthaburi 11000, Thailand;
| | - Anthony R. Jones
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (D.B.); (C.K.); (A.R.J.); (S.F.)
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (D.B.); (C.K.); (A.R.J.); (S.F.)
| | - Anon Srikiatkhachorn
- Faculty of Medicine, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand;
- Department of Cell and Molecular Biology, Institute for Immunology and Informatics, University of Rhode Island, Providence, RI 02903, USA;
| | - Alan L. Rothman
- Department of Cell and Molecular Biology, Institute for Immunology and Informatics, University of Rhode Island, Providence, RI 02903, USA;
| | - Kathryn B. Anderson
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210, USA; (K.B.A.); (S.J.T.); (T.P.E.)
| | - Stephen J. Thomas
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210, USA; (K.B.A.); (S.J.T.); (T.P.E.)
| | - Timothy P. Endy
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210, USA; (K.B.A.); (S.J.T.); (T.P.E.)
| | - Alongkot Ponlawat
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand; (T.F.); (N.P.); (A.P.)
- Correspondence:
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8
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Lee GO, Vasco L, Márquez S, Zuniga-Moya JC, Van Engen A, Uruchima J, Ponce P, Cevallos W, Trueba G, Trostle J, Berrocal VJ, Morrison AC, Cevallos V, Mena C, Coloma J, Eisenberg JNS. A dengue outbreak in a rural community in Northern Coastal Ecuador: An analysis using unmanned aerial vehicle mapping. PLoS Negl Trop Dis 2021; 15:e0009679. [PMID: 34570788 PMCID: PMC8475985 DOI: 10.1371/journal.pntd.0009679] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 07/23/2021] [Indexed: 11/19/2022] Open
Abstract
Dengue is recognized as a major health issue in large urban tropical cities but is also observed in rural areas. In these environments, physical characteristics of the landscape and sociodemographic factors may influence vector populations at small geographic scales, while prior immunity to the four dengue virus serotypes affects incidence. In 2019, a rural northwestern Ecuadorian community, only accessible by river, experienced a dengue outbreak. The village is 2-3 hours by boat away from the nearest population center and comprises both Afro-Ecuadorian and Indigenous Chachi households. We used multiple data streams to examine spatial risk factors associated with this outbreak, combining maps collected with an unmanned aerial vehicle (UAV), an entomological survey, a community census, and active surveillance of febrile cases. We mapped visible water containers seen in UAV images and calculated both the green-red vegetation index (GRVI) and household proximity to public spaces like schools and meeting areas. To identify risk factors for symptomatic dengue infection, we used mixed-effect logistic regression models to account for the clustering of symptomatic cases within households. We identified 55 dengue cases (9.5% of the population) from 37 households. Cases peaked in June and continued through October. Rural spatial organization helped to explain disease risk. Afro-Ecuadorian (versus Indigenous) households experience more symptomatic dengue (OR = 3.0, 95%CI: 1.3, 6.9). This association was explained by differences in vegetation (measured by GRVI) near the household (OR: 11.3 95% 0.38, 38.0) and proximity to the football field (OR: 13.9, 95% 4.0, 48.4). The integration of UAV mapping with other data streams adds to our understanding of these dynamics.
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Affiliation(s)
- Gwenyth O. Lee
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Luis Vasco
- Instituto de Geografía, Universidad San Francisco de Quito, Quito, Ecuador
| | - Sully Márquez
- Instituto de Microbiología, Universidad San Francisco de Quito, Quito, Ecuador
| | - Julio C. Zuniga-Moya
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Amanda Van Engen
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jessica Uruchima
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Patricio Ponce
- Gestión de Investigación, desarrollo e Innovación, Instituto Nacional de Investigación en Salud Pública (INSPI), Quito, Ecuador
| | - William Cevallos
- Instituto de Biomedicina, Universidad Central del Ecuador, Quito, Ecuador
| | - Gabriel Trueba
- Instituto de Microbiología, Universidad San Francisco de Quito, Quito, Ecuador
| | - James Trostle
- Department of Anthropology, Trinity College, Hartford, Connecticut, United States of America
| | - Veronica J. Berrocal
- Department of Statistics, University of California, Irvine, California, United States of America
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicince, University of California, San Diego, California, United States
| | - Varsovia Cevallos
- Gestión de Investigación, desarrollo e Innovación, Instituto Nacional de Investigación en Salud Pública (INSPI), Quito, Ecuador
| | - Carlos Mena
- Instituto de Geografía, Universidad San Francisco de Quito, Quito, Ecuador
| | - Josefina Coloma
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, California, United States of America
| | - Joseph N. S. Eisenberg
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
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9
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Berry IM, Melendrez MC, Pollett S, Figueroa K, Buddhari D, Klungthong C, Nisalak A, Panciera M, Thaisomboonsuk B, Li T, Vallard TG, Macareo L, Yoon IK, Thomas SJ, Endy T, Jarman RG. Precision Tracing of Household Dengue Spread Using Inter- and Intra-Host Viral Variation Data, Kamphaeng Phet, Thailand. Emerg Infect Dis 2021; 27:1637-1644. [PMID: 34013878 PMCID: PMC8153871 DOI: 10.3201/eid2706.204323] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dengue control approaches are best informed by granular spatial epidemiology of these viruses, yet reconstruction of inter- and intra-household transmissions is limited when analyzing case count, serologic, or genomic consensus sequence data. To determine viral spread on a finer spatial scale, we extended phylogenomic discrete trait analyses to reconstructions of house-to-house transmissions within a prospective cluster study in Kamphaeng Phet, Thailand. For additional resolution and transmission confirmation, we mapped dengue intra-host single nucleotide variants on the taxa of these time-scaled phylogenies. This approach confirmed 19 household transmissions and revealed that dengue disperses an average of 70 m per day between households in these communities. We describe an evolutionary biology framework for the resolution of dengue transmissions that cannot be differentiated based on epidemiologic and consensus genome data alone. This framework can be used as a public health tool to inform control approaches and enable precise tracing of dengue transmissions.
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10
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Pollington TM, Tildesley MJ, Hollingsworth TD, Chapman LA. Developments in statistical inference when assessing spatiotemporal disease clustering with the tau statistic. SPATIAL STATISTICS 2021; 42:100438. [PMID: 33816096 PMCID: PMC7985614 DOI: 10.1016/j.spasta.2020.100438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 03/06/2020] [Accepted: 03/07/2020] [Indexed: 06/12/2023]
Abstract
The tau statistic τ uses geolocation and, usually, symptom onset time to assess global spatiotemporal clustering from epidemiological data. We test different methods that could bias the clustering range estimate based on the statistic or affect its apparent precision, by comparison with a baseline analysis of an open access measles dataset. From re-analysing this data we find evidence against no clustering and no inhibition, p -value ∈ [ 0 , 0 ⋅ 022 ] (global envelope test). We develop a tau-specific modification of the Loh & Stein spatial bootstrap sampling method, which gives bootstrap tau estimates with 24% lower sampling error and a 110% higher estimated clustering endpoint than previously published (61⋅0 m vs. 29 m) and an equivalent increase in the clustering area of elevated disease odds by 342%. These differences could have important consequences for control efforts. Correct practice of graphical hypothesis testing of no clustering and clustering range estimation of the tau statistic are illustrated in the online Graphical abstract. We advocate proper implementation of this useful statistic, ultimately to reduce inaccuracies in control policy decisions made during disease clustering analysis.
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Affiliation(s)
- Timothy M. Pollington
- MathSys CDT, University of Warwick, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, UK
| | - Michael J. Tildesley
- Zeeman Institute (SBIDER), School of Life Sciences, and Mathematics Institute, University of Warwick, UK
| | - T. Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, UK
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Wat'senga Tezzo F, Fasine S, Manzambi Zola E, Marquetti MDC, Binene Mbuka G, Ilombe G, Mundeke Takasongo R, Smitz N, Bisset JA, Van Bortel W, Vanlerberghe V. High Aedes spp. larval indices in Kinshasa, Democratic Republic of Congo. Parasit Vectors 2021; 14:92. [PMID: 33522947 PMCID: PMC7852359 DOI: 10.1186/s13071-021-04588-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 01/08/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Dengue, yellow fever, chikungunya and Zika are among the most important emerging infectious vector-borne diseases worldwide. In the Democratic Republic of Congo (DRC), increases in cases of dengue and outbreaks of yellow fever and chikungunya have been reported since 2010. The main vectors of these arboviruses, Aedes aegypti and Aedes albopictus, have been reported in DRC, but there is a lack of detailed information on their presence and spread to guide disease control efforts. METHODS In 2018, two cross-sectional surveys were conducted in Kinshasa province (DRC), one in the rainy (January/February) and one in the dry season (July). Four hundred houses were visited in each of the four selected communes (N'Djili, Mont Ngafula, Lingwala and Kalamu). Within the peri-domestic area of each household, searches were conducted for larval habitats, which were then surveyed for the presence of Aedes larvae and pupae. A subset of the immature specimens were reared to adults for morphological identification followed by DNA barcoding of the specimens to validate identifications. RESULTS The most rural commune (Mont Ngafula) had the highest pupal index (number of Aedes spp. pupae per 100 inspected houses) at 246 (20) pupae/100 houses, and Breteau index (BI; number of containers positive for immature stages of Aedes spp. per 100 households) at 82.2 (19.5) positive containers/100 houses for the rainy (and dry) season, respectively. The BI was 21.5 (4.7), 36.7 (9.8) and 41.7 (7.5) in Kalamu, Lingwala and N'Djili in the rainy (and dry) season, respectively. The house index (number of houses positive for at least one container with immature stages of Aedes spp. per 100 inspected houses) was, on average, across all communes, 27.5% (7.6%); and the container index (number of containers positive for immature stages of Aedes spp. per 100 inspected containers) was 15.0% (10.0%) for the rainy (and dry) season, respectively. The vast majority of Aedes-positive containers were found outside the houses [adjusted odds ratio 27.4 (95% confidence interval 14.9-50.1)]. During the dry season, the most productive containers were the ones used for water storage, whereas in the rainy season rubbish and tires constituted key habitats. Both Ae. aegypti and Ae. albopictus were found. Anopheles larvae were found in different types of Aedes larval habitats, especially during the rainy season. CONCLUSIONS In both surveys and in all communes, the larval indices (BI) were higher than the arbovirus transmission threshold values established by the World Health Organization. Management strategies for controlling Aedes in Kinshasa need to target the key types of containers for Aedes larvae, which are mainly located in outdoor spaces, for larval habitat destruction or reduction.
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Affiliation(s)
- Francis Wat'senga Tezzo
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Sylvie Fasine
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Emile Manzambi Zola
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Maria Del Carmen Marquetti
- Department of Vector Control, Instituto Medicina Tropical Pedro Kourí (IPK), Avenida Novia del Mediodía, KM 6 1/2, La Lisa, Havana, Cuba
| | - Guillaume Binene Mbuka
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Gillon Ilombe
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Richard Mundeke Takasongo
- Unit of Entomology, Department of Parasitology, National Institute of Biomedical Research, 5345 Avenue De la Démocratie, Gombe, Kinshasa, Democratic Republic of the Congo
| | - Nathalie Smitz
- Department of Biology, Royal Museum for Central Africa (BopCo), Leuvensesteenweg 13-17, Tervuren, Belgium
| | - Juan Andre Bisset
- Department of Vector Control, Instituto Medicina Tropical Pedro Kourí (IPK), Avenida Novia del Mediodía, KM 6 1/2, La Lisa, Havana, Cuba
| | - Wim Van Bortel
- Outbreak Research Team, Institute of Tropical Medicine (ITM), Nationalestraat 155, Antwerp, Belgium
- Unit of Entomology, Biomedical Science Department, Institute of Tropical Medicine (ITM), Nationalestraat 155, Antwerp, Belgium
| | - Veerle Vanlerberghe
- Tropical Infectious Disease Group, Public Health Department, Institute of Tropical Medicine (ITM), Nationalestraat 155, Antwerp, Belgium.
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Fustec B, Phanitchat T, Hoq MI, Aromseree S, Pientong C, Thaewnongiew K, Ekalaksananan T, Bangs MJ, Corbel V, Alexander N, Overgaard HJ. Complex relationships between Aedes vectors, socio-economics and dengue transmission-Lessons learned from a case-control study in northeastern Thailand. PLoS Negl Trop Dis 2020; 14:e0008703. [PMID: 33001972 PMCID: PMC7553337 DOI: 10.1371/journal.pntd.0008703] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 10/13/2020] [Accepted: 08/12/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/OBJECTIVES Dengue fever is an important public health concern in most tropical and subtropical countries, and its prevention and control rest on vector surveillance and control. However, many aspects of dengue epidemiology remain unclear; in particular, the relationship between Aedes vector abundance and dengue transmission risk. This study aims to identify entomological and immunological indices capable of discriminating between dengue case and control (non-case) houses, based on the assessment of candidate indices, as well as individual and household characteristics, as potential risk factors for acquiring dengue infection. METHODS This prospective, hospital-based, case-control study was conducted in northeastern Thailand between June 2016 and August 2019. Immature and adult stage Aedes were collected at the houses of case and control patients, recruited from district hospitals, and at patients' neighboring houses. Blood samples were tested by RDT and PCR to detect dengue cases, and were processed with the Nterm-34 kDa salivary peptide to measure the human immune response to Aedes bites. Socioeconomic status, and other individual and household characteristics were analyzed as potential risk factors for dengue. RESULTS Study findings showed complex relationships between entomological indices and dengue risk. The presence of DENV-infected Aedes at the patient house was associated with 4.2-fold higher odds of dengue. On the other hand, Aedes presence (irrespective of infectious status) in the patient's house was negatively associated with dengue. In addition, the human immune response to Aedes bites, was higher in control than in case patients and Aedes adult abundance and immature indices were higher in control than in case houses at the household and the neighboring level. Multivariable analysis showed that children aged 10-14 years old and those aged 15-25 years old had respectively 4.5-fold and 2.9-fold higher odds of dengue infection than those older than 25 years. CONCLUSION DENV infection in female Aedes at the house level was positively associated with dengue infection, while adult Aedes presence in the household was negatively associated. This study highlights the potential benefit of monitoring dengue viruses in Aedes vectors. Our findings suggest that monitoring the presence of DENV-infected Aedes mosquitoes could be a better indicator of dengue risk than the traditional immature entomological indices.
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Affiliation(s)
- Benedicte Fustec
- University of Montpellier, Montpellier, France
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Institut de Recherche pour le Developpement, Montpellier, France
| | - Thipruethai Phanitchat
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mohammad Injamul Hoq
- School of Public Health, Epidemiology and Social Medicine at the Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Sirinart Aromseree
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen, Thailand
| | - Chamsai Pientong
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen, Thailand
| | | | - Tipaya Ekalaksananan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen, Thailand
| | - Michael J. Bangs
- Public Health & Malaria Control, PT Freeport Indonesia/International SOS, Mimika, Papua, Indonesia
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Vincent Corbel
- University of Montpellier, Montpellier, France
- Institut de Recherche pour le Developpement, Montpellier, France
| | - Neal Alexander
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
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13
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Teissier Y, Paul R, Aubry M, Rodo X, Dommar C, Salje H, Sakuntabhai A, Cazelles B, Cao-Lormeau VM. Long-term persistence of monotypic dengue transmission in small size isolated populations, French Polynesia, 1978-2014. PLoS Negl Trop Dis 2020; 14:e0008110. [PMID: 32142511 PMCID: PMC7080275 DOI: 10.1371/journal.pntd.0008110] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 03/18/2020] [Accepted: 02/02/2020] [Indexed: 01/18/2023] Open
Abstract
Understanding the transition of epidemic to endemic dengue transmission remains a challenge in regions where serotypes co-circulate and there is extensive human mobility. French Polynesia, an isolated group of 117 islands of which 72 are inhabited, distributed among five geographically separated subdivisions, has recorded mono-serotype epidemics since 1944, with long inter-epidemic periods of circulation. Laboratory confirmed cases have been recorded since 1978, enabling exploration of dengue epidemiology under monotypic conditions in an isolated, spatially structured geographical location. A database was constructed of confirmed dengue cases, geolocated to island for a 35-year period. Statistical analyses of viral establishment, persistence and fade-out as well as synchrony among subdivisions were performed. Seven monotypic and one heterotypic dengue epidemic occurred, followed by low-level viral circulation with a recrudescent epidemic occurring on one occasion. Incidence was asynchronous among the subdivisions. Complete viral die-out occurred on several occasions with invasion of a new serotype. Competitive serotype replacement has been observed previously and seems to be characteristic of the South Pacific. Island population size had a strong impact on the establishment, persistence and fade-out of dengue cases and endemicity was estimated achievable only at a population size in excess of 175 000. Despite island remoteness and low population size, dengue cases were observed somewhere in French Polynesia almost constantly, in part due to the spatial structuration generating asynchrony among subdivisions. Long-term persistence of dengue virus in this group of island populations may be enabled by island hopping, although could equally be explained by a reservoir of sub-clinical infections on the most populated island, Tahiti. Dengue virus is the most significant arthropod-borne virus infecting man. Understanding how long dengue virus can persist in populations of varying size is key to understanding its epidemiology. This is, however, impossible to achieve in settings where dengue is endemic, because of continued human movement and is further complexified by the occurrence of several co-circulating serotypes. By contrast, French Polynesia, an isolated group of 72 inhabited islands in the South Pacific, has had intermittent majoritarily monotypic dengue epidemics since the 1940s and offers a unique opportunity to address questions of viral persistence, turnover and the importance of spatial sub-structure in determining dengue epidemiology. Collating and analyzing a database of laboratory-confirmed dengue cases from across French Polynesia over a 35 year period we were able to show that dengue virus die-out can occur with or without replacement by a new serotype, monotypic transmission of dengue viruses fails to be maintained within small island populations but can persist for years among isolated islands connected via air and sea links. This remarkable long-term persistence of dengue virus in French Polynesia could be maintained by asynchronous viral transmission among connected islands and/or by repeated seeding from a reservoir of sub-clinical infections in the most populated island, Tahiti.
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Affiliation(s)
- Yoann Teissier
- Laboratoire de recherche sur les maladies infectieuses à transmission vectorielle, Institut Louis Malardé, Papeete, Tahiti, French Polynesia
- Université Paris Descartes, PSL University, Paris, France
| | - Richard Paul
- Institut Pasteur, Unité de Génétique Fonctionnelle des Maladies Infectieuses, UMR 2000 CNRS, Paris, France
- Pasteur Kyoto International Joint Research Unit for Integrative Vaccinomics, Kyoto, Japan
- * E-mail: (RP); (VMCL)
| | - Maite Aubry
- Laboratoire de recherche sur les maladies infectieuses à transmission vectorielle, Institut Louis Malardé, Papeete, Tahiti, French Polynesia
| | - Xavier Rodo
- ICREA, Barcelona, Spain
- CLIMA (Climate and Health) Program, ISGlobal, Barcelona, Spain
| | - Carlos Dommar
- CLIMA (Climate and Health) Program, ISGlobal, Barcelona, Spain
| | - Henrik Salje
- Institut Pasteur, Mathematical Modelling of Infectious Diseases Unit, UMR 2000, Centre National de la Recherche Scientifique, Paris, France
| | - Anavaj Sakuntabhai
- Institut Pasteur, Unité de Génétique Fonctionnelle des Maladies Infectieuses, UMR 2000 CNRS, Paris, France
- Pasteur Kyoto International Joint Research Unit for Integrative Vaccinomics, Kyoto, Japan
| | - Bernard Cazelles
- International Center for Mathematical and Computational Modeling of Complex Systems (UMMISCO), UMI 209, Sorbonne Université - IRD, Bondy cedex, France
- iGLOBE, UMI CNRS 3157, University of Arizona, Tucson, Arizona, United States of America
- IBENS, UMR 8197 CNRS-ENS Ecole Normale Supérieure, Paris, France
| | - Van-Mai Cao-Lormeau
- Laboratoire de recherche sur les maladies infectieuses à transmission vectorielle, Institut Louis Malardé, Papeete, Tahiti, French Polynesia
- * E-mail: (RP); (VMCL)
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14
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Xu Z, Bambrick H, Pongsumpun P, Ming Tang I, Yakob L, Devine G, Frentiu FD, Williams G, Hu W. Does Bangkok have a central role in the dengue dynamics of Thailand? Parasit Vectors 2020; 13:22. [PMID: 31931886 PMCID: PMC6958813 DOI: 10.1186/s13071-020-3892-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 01/07/2020] [Indexed: 01/28/2023] Open
Abstract
Background Bangkok plays a central role in the commerce of Thailand. This study aimed to characterize the district-level spatial-temporal patterns of dengue in Thailand and explore if a dengue peak in Bangkok led the peaks of dengue in other Thai provinces. Methods Monthly dengue data at district level in Thailand from January 2004 to December 2017 were obtained and used to assess the spatial and seasonal patterns of dengue in Thailand. As our seasonal decomposition and cross-correlation analyses showed that dengue in Bangkok peaked in November, which was a few months after the dengue peak in most other provinces, we used a time-series generalized linear model to explore if there was another province in which the dengue case number was most predictive of dengue case numbers in other Thai provinces. Results The highest district-level annual dengue incidence rates (per 10,000) in the three time periods (i.e. 2004–2008, 2009–2013 and 2014–2017) were 58.08 (Samphanthawong), 85.93 (Mueang Krabi), and 66.60 (Mae Sariang), respectively. Dengue incidence rates in the western part of Northern Thailand, southern part of Central Thailand, southern part of Eastern Thailand, and Southern Thailand were higher than in other regions. Dengue in most districts of Thailand peaked in June, July or August, but dengue peaks in all districts of Bangkok occurred in November. The number of dengue cases in Nakhon Ratchasima was most predictive of the number of dengue cases in other provinces in Thailand by a one-month lag. Conclusions Our results suggest that the dengue peak in Bangkok did not lead the peaks of dengue in other Thai provinces. Future research exploring how changes in socio-ecological factors (e.g. road network and climate factors) in Nakhon Ratchasima have affected the transmission of dengue in Thailand might shed some new light on the prevention and control of dengue.
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Affiliation(s)
- Zhiwei Xu
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, 4059, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, 4059, Australia.,School of Public Health, Faculty of Medicine, University of Queensland, Brisbane, 4006, Australia
| | - Hilary Bambrick
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, 4059, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, 4059, Australia
| | - Puntani Pongsumpun
- Department of Mathematics, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, 10520, Thailand
| | - I Ming Tang
- Computational & Applied Science for Smart Innovation Cluster (CLASSIC), Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, WC1H 9SH, UK
| | - Gregor Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, 4006, Australia
| | - Francesca D Frentiu
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, 4059, Australia.,School of Biomedical Sciences, Queensland University of Technology, Brisbane, 4059, Australia
| | - Gail Williams
- School of Public Health, Faculty of Medicine, University of Queensland, Brisbane, 4006, Australia
| | - Wenbiao Hu
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, 4059, Australia. .,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, 4059, Australia.
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15
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Distribution and Spatial Pattern Analysis on Dengue Cases in Seremban District, Negeri Sembilan, Malaysia. SUSTAINABILITY 2019. [DOI: 10.3390/su11133572] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dengue fever disease increases alongside urbanization rate in tropical countries. Hence, the need to visualize the distribution pattern of increases is vital for the management of dengue cases, especially in Malaysia. Thus, the dengue surveillance system is proposed for the monitoring of dengue cases using computer-generated modeling for spatial distribution patterns, which is important for management and control. The present study performed distribution and spatial pattern analysis of dengue cases reported in the growing Seremban district in Negeri Sembilan, Malaysia in 2008 and 2009. The purpose of the study is to evaluate the pattern of distribution and determine whether it is clustered or dispersed. A total of 1401 and 1056 cases for dengue-related diseases were reported by the Ministry of Health Malaysia in Seremban district in the years 2008 and 2009, respectively. Three spatial statistical analysis were conducted: Spatial mean center, directional distribution, and standard distant on distribution of dengue cases reported. This study found that the distribution pattern for dengue cases is clustered. Spatial mean center and directional distribution for both sets of years have slight differences. Meanwhile, standard distance for dengue cases reported in the year 2008 is 22,085.82 m, which is bigger than dengue cases reported in 2009, showing a standard distance of 20,318.35 m. More sets of cases throughout years are required in further studies to identify factors that contribute to dengue epidemiology in the Seremban district undergoing urbanization.
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16
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Churakov M, Villabona-Arenas CJ, Kraemer MUG, Salje H, Cauchemez S. Spatio-temporal dynamics of dengue in Brazil: Seasonal travelling waves and determinants of regional synchrony. PLoS Negl Trop Dis 2019; 13:e0007012. [PMID: 31009460 PMCID: PMC6497439 DOI: 10.1371/journal.pntd.0007012] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 05/02/2019] [Accepted: 03/29/2019] [Indexed: 12/18/2022] Open
Abstract
Dengue continues to be the most important vector-borne viral disease globally and in Brazil, where more than 1.4 million cases and over 500 deaths were reported in 2016. Mosquito control programmes and other interventions have not stopped the alarming trend of increasingly large epidemics in the past few years. Here, we analyzed monthly dengue cases reported in Brazil between 2001 and 2016 to better characterise the key drivers of dengue epidemics. Spatio-temporal analysis revealed recurring travelling waves of disease occurrence. Using wavelet methods, we characterised the average seasonal pattern of dengue in Brazil, which starts in the western states of Acre and Rondônia, then travels eastward to the coast before reaching the northeast of the country. Only two states in the north of Brazil (Roraima and Amapá) did not follow the countrywide pattern and had inconsistent timing of dengue epidemics throughout the study period. We also explored epidemic synchrony and timing of annual dengue cycles in Brazilian regions. Using gravity style models combined with climate factors, we showed that both human mobility and vector ecology contribute to spatial patterns of dengue occurrence. This study offers a characterization of the spatial dynamics of dengue in Brazil and its drivers, which could inform intervention strategies against dengue and other arboviruses.
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Affiliation(s)
- Mikhail Churakov
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris, France
| | - Christian J. Villabona-Arenas
- UMI233 TransVIHMI, Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Moritz U. G. Kraemer
- Department of Pediatrics, Harvard Medical School, 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, Oxford, United Kingdom
| | - Henrik Salje
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris, France
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris, France
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Benante JP, Fox J, Lawrence K, Fansiri T, Pongsiri A, Ponlawat A, Chaskopoulou A. A Comparative Study of Mosquito and Sand Fly (Diptera: Psychodidae: Phlebotominae) Sampling Using Dry Ice and Chemically Generated Carbon Dioxide From Three Different Prototype CO2 Generators. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:494-498. [PMID: 30321387 DOI: 10.1093/jee/toy319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Indexed: 06/08/2023]
Abstract
A comparative study was conducted to test the efficiency of Centers for Disease Control and Prevention (CDC) light traps baited with either dry ice or carbon dioxide (CO2) produced from one of three different sources in collecting mosquitoes (Diptera: Culicidae) in Thailand. Treatments consisted of dry ice pellets, CO2 gas produced from one of three prototype CO2 generator systems (TDA, CUBE, Moustiq-Air Med-e-Cell - MEC), and a CDC light trap without a CO2 source. The best performing prototype from Thailand was then tested in collecting sand flies (Diptera: Psychodidae: Phlebotominae) in Greece. A total of 12,798 mosquitoes and 8,329 sand flies were sampled during the experimentation. The most prevalent mosquito species collected in Thailand were: Culex vishnui Theobald > Anopheles minimus Theobald > Culex tritaeniorhynchus Giles > Anopheles sawadwongporni Rattanarithikul & Green. By far the most prevalent sand fly species collected in Thessaloniki was Phlebotomus perfiliewi Parrot followed by Phlebotomus tobbi Adler and Theodor and Phlebotomus simici Nitzulescu. In general, the TDA treatment was the only treatment with no significant difference from the dry ice-treatment in mean trap catches. Although dry ice-baited traps caught higher numbers of mosquitoes and sand flies than the TDA-baited traps, there was no difference in the number of species collected. Results indicate that the traps baited with the TDA CO2 generator were as attractive as traps supplied with dry ice and, therefore, the TDA CO2 generator is a suitable alternative to dry ice as a source of carbon dioxide for use with adult mosquito and sand fly traps.
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Affiliation(s)
- John Paul Benante
- Entomology Branch, Walter Reed Army Institute of Research (WRAIR), Silver Spring, MD
| | - James Fox
- Medical Support Systems Project Management Office, US Army Medical Materiel Development Activity (USAMMDA), Fort Detrick, MD
| | - Kendra Lawrence
- Pharmaceutical Systems Project Management Office, US Army Medical Materiel Development Activity (USAMMDA), Fort Detrick, MD
| | - Thanyalak Fansiri
- Vector Biology and Control Section, Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Arissara Pongsiri
- Vector Biology and Control Section, Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Alongkot Ponlawat
- Vector Biology and Control Section, Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
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18
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Truelove SA, Graham M, Moss WJ, Metcalf CJE, Ferrari MJ, Lessler J. Characterizing the impact of spatial clustering of susceptibility for measles elimination. Vaccine 2019; 37:732-741. [PMID: 30579756 PMCID: PMC6348711 DOI: 10.1016/j.vaccine.2018.12.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 12/07/2018] [Accepted: 12/11/2018] [Indexed: 01/16/2023]
Abstract
Measles elimination efforts are primarily focused on achieving and maintaining national vaccination coverage goals, based on estimates of the critical vaccination threshold (Vc): the proportion of the population that must be immune to prevent sustained epidemics. Traditionally, Vc estimates assume evenly mixing populations, an invalid assumption. If susceptible individuals preferentially contact one another, communities may remain vulnerable to epidemics even when vaccination coverage targets are met at the national level. Here we present a simple method to estimate Vc and the effective reproductive number, R, while accounting for spatial clustering of susceptibility. For measles, assuming R0 = 15 and 95% population immunity, adjustment for high clustering of susceptibility increases R from 0.75 to 1.29, Vc from 93% to 96%, and outbreak probability after a single introduction from <1% to 23%. The impact of clustering remains minimal until vaccination coverage nears elimination levels. We illustrate our approach using Demographic and Health Survey data from Tanzania and show how non-vaccination clustering potentially contributed to continued endemic transmission of measles virus during the last two decades. Our approach demonstrates why high national vaccination coverage sometimes fails to achieve measles elimination, and that a shift from national to subnational focus is needed as countries approach elimination.
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Affiliation(s)
- Shaun A Truelove
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Matthew Graham
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; The Hospital for Tropical Diseases, Wellcome Trust Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA; Office of Population Research, Woodrow Wilson School, Princeton University, Princeton, NJ, USA
| | - Matthew J Ferrari
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA; Department of Biology, The Pennsylvania State University, University Park, PA, USA
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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Comprehensive evaluation of demographic, socio-economic and other associated risk factors affecting the occurrence of dengue incidence among Colombo and Kandy Districts of Sri Lanka: a cross-sectional study. Parasit Vectors 2018; 11:478. [PMID: 30143051 PMCID: PMC6109346 DOI: 10.1186/s13071-018-3060-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/13/2018] [Indexed: 11/11/2022] Open
Abstract
Background Comprehensive understanding of risk factors related to socio-economic and demographic status and knowledge, attitudes and practices (KAP) of local communities play a key role in the design and implementation of community-based vector management programmes, along with the identification of gaps in existing control activities. Methods A total of 10 Medical Officers of Health (MOH) areas recording high dengue incidence over the last five years were selected from Colombo (n = 5) and Kandy (n = 5) Districts, Sri Lanka. From each MOH area, 200 houses reporting past dengue incidence were selected randomly as test group (n = 1000 for each district) based on the dengue case records available at relevant MOH offices. Information on socio-economic and demographic status and knowledge, attitudes and practices were gathered using an interviewer administered questionnaire. The control group contained 200 households from each MOH area that had not reported any dengue case and the same questionnaire was used for the assessment (n = 1000 for each district). Statistical comparisons between the test and control groups were carried out using the Chi-square test of independence, cluster analysis, analysis of similarities (ANOSIM) and multi-dimensional scaling (MDS) analysis. Results Significant differences among the test and control groups in terms of basic demographic and socio-economic factors, living standards, knowledge, attitude and practices, were recognized (P < 0.05 at 95% level of confidence). The test group indicated similar risk factors, while the control group also shared more or less similar characteristics as depicted by the findings of cluster analysis and ANOSIM. Findings of the present study highlight the importance of further improvement in community education, motivation and communication gaps, proper coordination and integration of control programmes with relevant entities. Key infrastructural risk factors such as urbanization and waste collection, should be further improved, while vector controlling entities should focus more on the actual conditions represented by the public on knowledge, attitudes and personal protective practices. Conclusions The design of flexible and community friendly intervention programmes to ensure the efficacy and sustainability of controlling dengue vectors through community based integrated vector management strategies, is recommended.
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Anders KL, Indriani C, Ahmad RA, Tantowijoyo W, Arguni E, Andari B, Jewell NP, Rances E, O'Neill SL, Simmons CP, Utarini A. The AWED trial (Applying Wolbachia to Eliminate Dengue) to assess the efficacy of Wolbachia-infected mosquito deployments to reduce dengue incidence in Yogyakarta, Indonesia: study protocol for a cluster randomised controlled trial. Trials 2018; 19:302. [PMID: 29855331 PMCID: PMC5984439 DOI: 10.1186/s13063-018-2670-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 05/03/2018] [Indexed: 11/10/2022] Open
Abstract
Background Dengue and other arboviruses transmitted by Aedes aegypti mosquitoes, including Zika and chikungunya, present an increasing public health challenge in tropical regions. Current vector control strategies have failed to curb disease transmission, but continue to be employed despite the absence of robust evidence for their effectiveness or optimal implementation. The World Mosquito Program has developed a novel approach to arbovirus control using Ae. aegypti stably transfected with Wolbachia bacterium, with a significantly reduced ability to transmit dengue, Zika and chikungunya in laboratory experiments. Modelling predicts this will translate to local elimination of dengue in most epidemiological settings. This study protocol describes the first trial to measure the efficacy of Wolbachia in reducing dengue virus transmission in the field. Methods/design The study is a parallel, two-arm, non-blinded cluster randomised controlled trial conducted in a single site in Yogyakarta, Indonesia. The aim is to determine whether large-scale deployment of Wolbachia-infected Ae. aegypti mosquitoes leads to a measurable reduction in dengue incidence in treated versus untreated areas. The primary endpoint is symptomatic, virologically confirmed dengue virus infection of any severity. The 26 km2 study area was subdivided into 24 contiguous clusters, allocated randomly 1:1 to receive Wolbachia deployments or no intervention. We use a novel epidemiological study design, the cluster-randomised test-negative design trial, in which dengue cases and arbovirus-negative controls are sampled concurrently from among febrile patients presenting to a network of primary care clinics, with case or control status classified retrospectively based on the results of laboratory diagnostic testing. Efficacy is estimated from the odds ratio of Wolbachia exposure distribution (probability of living in a Wolbachia-treated area) among virologically confirmed dengue cases compared to test-negative controls. A secondary per-protocol analysis allows for individual Wolbachia exposure levels to be assessed to account for movements outside the cluster and the heterogeneity in local Wolbachia prevalence among treated clusters. Discussion The findings from this study will provide the first experimental evidence for the efficacy of Wolbachia in reducing dengue incidence. Together with observational evidence that is accumulating from pragmatic deployments of Wolbachia in other field sites, this will provide valuable data to estimate the effectiveness of this novel approach to arbovirus control, inform future cost-effectiveness estimates, and guide plans for large-scale deployments in other endemic settings. Trial registration ClinicalTrials.gov, identifier: NCT03055585. Registered on 14 February 2017. Electronic supplementary material The online version of this article (10.1186/s13063-018-2670-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katherine L Anders
- World Mosquito Program, Institute of Vector Borne Disease, Monash University, Melbourne, Australia.
| | - Citra Indriani
- Department of Biostatistics, Epidemiology and Population Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia.,Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Riris Andono Ahmad
- Department of Biostatistics, Epidemiology and Population Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia.,Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Warsito Tantowijoyo
- Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Eggi Arguni
- Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia.,Department of Pediatrics, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Bekti Andari
- Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | | | - Edwige Rances
- World Mosquito Program, Institute of Vector Borne Disease, Monash University, Melbourne, Australia
| | - Scott L O'Neill
- World Mosquito Program, Institute of Vector Borne Disease, Monash University, Melbourne, Australia
| | - Cameron P Simmons
- World Mosquito Program, Institute of Vector Borne Disease, Monash University, Melbourne, Australia
| | - Adi Utarini
- Eliminate Dengue Project, Centre for Tropical Medicine, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia.,Department of Health Policy and Management, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
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21
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Katzelnick LC, Harris E. The use of longitudinal cohorts for studies of dengue viral pathogenesis and protection. Curr Opin Virol 2018; 29:51-61. [PMID: 29597086 PMCID: PMC5996389 DOI: 10.1016/j.coviro.2018.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/12/2018] [Indexed: 12/31/2022]
Abstract
In this review, we describe how longitudinal prospective community-based, school-based, and household-based cohort studies contribute to improving our knowledge of viral disease, focusing specifically on contributions to understanding and preventing dengue. We describe how longitudinal cohorts enable measurement of essential disease parameters and risk factors; provide insights into biological correlates of protection and disease risk; enable rapid application of novel biological and statistical technologies; lead to development of new interventions and inform vaccine trial design; serve as sentinels in outbreak conditions and facilitate development of critical diagnostic assays; enable holistic studies on disease in the context of other infections, comorbidities, and environmental risk factors; and build research capacity that strengthens national and global public health response and disease surveillance.
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Affiliation(s)
- Leah C Katzelnick
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, 185 Li Ka Shing Center, 1951 Oxford Street, Berkeley, CA 94720-3370, United States
| | - Eva Harris
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, 185 Li Ka Shing Center, 1951 Oxford Street, Berkeley, CA 94720-3370, United States.
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22
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Salje H, Lessler J, Maljkovic Berry I, Melendrez MC, Endy T, Kalayanarooj S, A-Nuegoonpipat A, Chanama S, Sangkijporn S, Klungthong C, Thaisomboonsuk B, Nisalak A, Gibbons RV, Iamsirithaworn S, Macareo LR, Yoon IK, Sangarsang A, Jarman RG, Cummings DAT. Dengue diversity across spatial and temporal scales: Local structure and the effect of host population size. Science 2017; 355:1302-1306. [PMID: 28336667 DOI: 10.1126/science.aaj9384] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 12/15/2016] [Accepted: 02/16/2017] [Indexed: 12/30/2022]
Abstract
A fundamental mystery for dengue and other infectious pathogens is how observed patterns of cases relate to actual chains of individual transmission events. These pathways are intimately tied to the mechanisms by which strains interact and compete across spatial scales. Phylogeographic methods have been used to characterize pathogen dispersal at global and regional scales but have yielded few insights into the local spatiotemporal structure of endemic transmission. Using geolocated genotype (800 cases) and serotype (17,291 cases) data, we show that in Bangkok, Thailand, 60% of dengue cases living <200 meters apart come from the same transmission chain, as opposed to 3% of cases separated by 1 to 5 kilometers. At distances <200 meters from a case (encompassing an average of 1300 people in Bangkok), the effective number of chains is 1.7. This number rises by a factor of 7 for each 10-fold increase in the population of the "enclosed" region. This trend is observed regardless of whether population density or area increases, though increases in density over 7000 people per square kilometer do not lead to additional chains. Within Thailand these chains quickly mix, and by the next dengue season viral lineages are no longer highly spatially structured within the country. In contrast, viral flow to neighboring countries is limited. These findings are consistent with local, density-dependent transmission and implicate densely populated communities as key sources of viral diversity, with home location the focal point of transmission. These findings have important implications for targeted vector control and active surveillance.
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Affiliation(s)
- Henrik Salje
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA. .,Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France.,CNRS, URA3012, Paris 75015, France.,Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Irina Maljkovic Berry
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA
| | - Melanie C Melendrez
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA
| | - Timothy Endy
- Department of Medicine, Upstate Medical University of New York, Syracuse, New York, NY, 13210, USA
| | | | | | - Sumalee Chanama
- National Institute of Health, Department of Medical Sciences, Nonthaburi, Thailand
| | - Somchai Sangkijporn
- National Institute of Health, Department of Medical Sciences, Nonthaburi, Thailand
| | - Chonticha Klungthong
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Butsaya Thaisomboonsuk
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Ananda Nisalak
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Robert V Gibbons
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | - Louis R Macareo
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - In-Kyu Yoon
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,International Vaccine Institute, Seoul, South Korea
| | - Areerat Sangarsang
- National Institute of Health, Department of Medical Sciences, Nonthaburi, Thailand
| | - Richard G Jarman
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA
| | - Derek A T Cummings
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA. .,Department of Biology, University of Florida, Gainesville, FL 32610, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
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23
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Ponlawat A, Harwood JF, Putnam JL, Nitatsukprasert C, Pongsiri A, Kijchalao U, Linthicum KJ, Kline DL, Clark GG, Obenauer PJ, Doud CW, Mccardle PW, Richardson AG, Szumlas DE, Richardson JH. Field Evaluation of Indoor Thermal Fog and Ultra-Low Volume Applications For Control of Aedes aegypti in Thailand. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2017; 33:116-127. [PMID: 28590217 DOI: 10.2987/16-6594.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Efficacies of a handheld thermal fogger (Patriot™) and a backpack ultra-low volume (ULV) sprayer (Twister™) with combinations of 2 different adulticides (pyrethrin, deltamethrin) and an insect growth regulator (pyriproxyfen) were field-tested and compared for their impact on reducing indoor Aedes aegypti populations in Thailand. The effectiveness of the indoor space sprays was evaluated by sampling the natural Ae. aegypti population in houses and determining their physiological status, by monitoring mortality of sentinel caged mosquitoes (AFRIMS strain) and by assessing larval mortality in laboratory bioassays using water exposed to the spray. A total of 14,742 Ae. aegypti were collected from Biogents Sentinel traps in this study. The combination of ULD® BP-300 (3% pyrethrin) and NyGuard® (10% pyriproxyfen) sprayed either by the Patriot or Twister significantly reduced some Ae. aegypti populations up to 20 days postspray relative to the control clusters. The addition of pyriproxyfen to the adulticide extended how long household mosquito populations were suppressed. In 2 of the 4 products being compared, the Twister resulted in higher mortality of caged mosquitoes compared with the Patriot. However, neither machine was able to achieve high mortality among Ae. aegypti placed in hidden (protected) cages. The larval bioassay results demonstrated that the Twister ULV provided better adult emergence inhibition than the Patriot (thermal fogger), likely due to larger droplet size.
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Vanlerberghe V, Gómez-Dantés H, Vazquez-Prokopec G, Alexander N, Manrique-Saide P, Coelho G, Toledo ME, Ocampo CB, Van der Stuyft P. Changing paradigms in Aedes control: considering the spatial heterogeneity of dengue transmission. REVISTA PANAMERICANA DE SALUD PUBLICA = PAN AMERICAN JOURNAL OF PUBLIC HEALTH 2017; 41:e16. [PMID: 31391815 PMCID: PMC6660874 DOI: 10.26633/rpsp.2017.16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 05/18/2016] [Indexed: 12/13/2022]
Abstract
Current dengue vector control strategies, focusing on reactive implementation of insecticide-based interventions in response to clinically apparent disease manifestations, tend to be inefficient, short-lived, and unsustainable within the worldwide epidemiological scenario of virus epidemic recrudescence. As a result of a series of expert meetings and deliberations, a paradigm shift is occurring and a new strategy, using risk stratification at the city level in order to concentrate proactive, sustained efforts in areas at high risk for transmission, has emerged. In this article, the authors 1) outline this targeted, proactive intervention strategy, within the context of dengue epidemiology, the dynamics of its transmission, and current Aedes control strategies, and 2) provide support from published literature for the need to empirically test its impact on dengue transmission as well as on the size of disease outbreaks. As chikungunya and Zika viruses continue to expand their range, the need for a science-based, proactive approach for control of urban Aedes spp. mosquitoes will become a central focus of integrated disease management planning.
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Affiliation(s)
- Veerle Vanlerberghe
- General Epidemiology and Disease Control Unit Institute of Tropical Medicine Antwerp Belgium General Epidemiology and Disease Control Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Hector Gómez-Dantés
- Instituto Nacional de Salud Publica CuernavacaMorelos Mexico Instituto Nacional de Salud Publica, Cuernavaca, Morelos, Mexico
| | - Gonzalo Vazquez-Prokopec
- Department of Environmental Sciences Emory University AtlantaGeorgia United States of America Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Neal Alexander
- London School of Hygiene and Tropical Medicine London United Kingdom London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Pablo Manrique-Saide
- Entomological Bioassays Unit Universidad Autónoma de Yucatán, Merida Yucatán Mexico Entomological Bioassays Unit, Universidad Autónoma de Yucatán, Merida, Yucatán, Mexico
| | - Giovanini Coelho
- National Dengue Control Program Brazilian Ministry of Health Brasília Brazil National Dengue Control Program, Brazilian Ministry of Health, Brasília, Brazil
| | - Maria Eugenia Toledo
- Department of Epidemiology Institute of Tropical Medicine "Pedro Kourí," Havana Cuba Department of Epidemiology, Institute of Tropical Medicine "Pedro Kourí," Havana, Cuba
| | - Clara B Ocampo
- International Training and Medical Research Center Cali Colombia International Training and Medical Research Center, Cali, Colombia
| | - Patrick Van der Stuyft
- Department of Public Health Ghent University Ghent Belgium Department of Public Health, Ghent University, Ghent, Belgium
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Kittayapong P, Olanratmanee P, Maskhao P, Byass P, Logan J, Tozan Y, Louis V, Gubler DJ, Wilder-Smith A. Mitigating Diseases Transmitted by Aedes Mosquitoes: A Cluster-Randomised Trial of Permethrin-Impregnated School Uniforms. PLoS Negl Trop Dis 2017; 11:e0005197. [PMID: 28103255 PMCID: PMC5245776 DOI: 10.1371/journal.pntd.0005197] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 11/17/2016] [Indexed: 11/23/2022] Open
Abstract
Background Viral diseases transmitted via Aedes mosquitoes are on the rise, such as Zika, dengue, and chikungunya. Novel tools to mitigate Aedes mosquitoes-transmitted diseases are urgently needed. We tested whether commercially insecticide-impregnated school uniforms can reduce dengue incidence in school children. Methods We designed a cluster-randomised controlled trial in Thailand. The primary endpoint was laboratory-confirmed dengue infections. Secondary endpoints were school absenteeism; and impregnated uniforms’ 1-hour knock-down and 24 hour mosquito mortality as measured by standardised WHOPES bioassay cone tests at baseline and after repeated washing. Furthermore, entomological assessments inside classrooms and in outside areas of schools were conducted. Results We enrolled 1,811 pupils aged 6–17 from 5 intervention and 5 control schools. Paired serum samples were obtained from 1,655 pupils. In the control schools, 24/641 (3.7%) and in the intervention schools 33/1,014 (3.3%) students had evidence of new dengue infections during one school term (5 months). There was no significant difference in proportions of students having incident dengue infections between the intervention and control schools, with adjustment for clustering by school. WHOPES cone tests showed a 100% knock down and mortality of Aedes aegypti mosquitoes exposed to impregnated clothing at baseline and up to 4 washes, but this efficacy rapidly declined to below 20% after 20 washes, corresponding to a weekly reduction in knock-down and mosquito mortality by 4.7% and 4.4% respectively. Results of the entomological assessments showed that the mean number of Aedes aegypti mosquitoes caught inside the classrooms of the intervention schools was significantly reduced in the month following the introduction of the impregnated uniforms, compared to those collected in classrooms of the control schools (p = 0.04) Conclusions Entomological assessments showed that the intervention had some impact on the number of Aedes mosquitoes inside treatment schools immediately after impregnation and before insecticidal activity declined. However, there was no serological evidence of protection against dengue infections over the five months school term, best explained by the rapid washing-out of permethrin after 4 washes. If rapid washing-out of permethrin could be overcome by novel technological approaches, insecticide-treated clothes might become a potentially cost-effective and scalable intervention to protect against diseases transmitted by Aedes mosquitoes such as dengue, Zika, and chikungunya. Trial Registration ClinicalTrials.gov NCT01563640 Viral diseases transmitted via Aedes mosquitoes are on the rise, such as Zika, dengue, and chikungunya. Novel tools to mitigate Aedes mosquitoes-transmitted diseases are urgently needed. We tested whether commercially available insecticide-impregnated school uniforms can reduce dengue incidence in school children. To test this hypothesis we designed a school based randomized controlled trial where we enrolled 1,811 school children aged 6–17. For study monitoring, we also measured the effect of the impregnated uniforms on the survival of Aedes mosquitoes based on a standard bioassay test called WHOPES cone test. Furthermore, we counted the number of Aedes mosquitoes in classrooms and outside areas of classrooms. In the control schools, 3.7% and in the intervention schools 3.3% of the students had evidence of new dengue infections during the 5 month long school term, which indicates that there was no protection against dengue infections despite the fact that the knockdown effect of the impregnated uniforms was very high in the laboratory. We also showed a significant reduction of Aedes mosquitoes in the classrooms of the intervention schools. So why did this not translate into clinical protection against dengue? We assume the reason was the rapid wash-out effect of permethrin. Despite the company’s claim that impregnated clothing would withstand up to 70 launderings, we found a rapid decline in permethrin efficacy already after 4 washes, with the efficacy to below 20% after 20 washes. If rapid washing-out of permethrin could be overcome by novel technological approaches, insecticide-treated clothes might become a potentially cost-effective and scalable intervention to protect against diseases transmitted by Aedes mosquitoes such as dengue, Zika, and chikungunya.
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Affiliation(s)
- Pattamaporn Kittayapong
- Center of Excellence for Vectors and Vector-Borne Diseases, Faculty of Science, Mahidol University at Salaya, Nakhon Phatom, Thailand
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- * E-mail: (AWS); (PK)
| | - Phanthip Olanratmanee
- Faculty of Science and Technology, Rajabhat Rajanagarindra University, Chachoengsao, Thailand
| | - Pongsri Maskhao
- Faculty of Humanities and Social Sciences, Rajabhat Rajanagarindra University, Chachoengsao, Thailand
| | - Peter Byass
- Umeå Centre for Global Health Research, Epidemiology and Global Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - James Logan
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Yesim Tozan
- Institute of Public Health, Heidelberg University Medical School, Germany
- College of Global Public Health, New York University, New York, United States
| | - Valérie Louis
- Institute of Public Health, Heidelberg University Medical School, Germany
| | - Duane J. Gubler
- Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, Singapore
| | - Annelies Wilder-Smith
- Umeå Centre for Global Health Research, Epidemiology and Global Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany
- * E-mail: (AWS); (PK)
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Synchrony of Dengue Incidence in Ho Chi Minh City and Bangkok. PLoS Negl Trop Dis 2016; 10:e0005188. [PMID: 28033384 PMCID: PMC5199033 DOI: 10.1371/journal.pntd.0005188] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 11/15/2016] [Indexed: 01/07/2023] Open
Abstract
Background Ho Chi Minh City and Bangkok are highly dengue endemic. The extent to which disease patterns are attributable to local versus regional dynamics remains unclear. To address this gap we compared key transmission parameters across the locations. Methods and Principal Findings We used 2003–2009 age-stratified case data to inform catalytic transmission models. Further, we compared the spatial clustering of serotypes within each city. We found that annual case numbers were highly consistent across the two cities (correlation of 0.77, 95% CI: 0.74–0.79) as was the annual force of infection (correlation of 0.57, 95% CI: 0.46–0.68). Serotypes were less similar with serotype-specific correlations ranging from 0.65 for DENV1 to -0.14 for DENV4. Significant spatial clustering of serotypes was observed in HCMC at distances <500m, similar to previous observations from Bangkok. Discussions Dengue dynamics are comparable across these two hubs. Low correlation in serotype distribution suggests that similar built environments, vector populations and climate, rather than viral flow drives these observations. All four serotypes of dengue have circulated endemically throughout Southeast Asia for decades. However, despite the enormous burden of disease, there remains poor understanding of the similarity in disease patterns across the region. We analyzed data from over 100,000 cases of dengue from two of the largest cities in the region, Bangkok and Ho Chi Minh City between 2001 and 2009. We use basic statistical methods to reconstruct the annual probability of infection in the two cities during this time period using methods that are robust to differences in reporting mechanisms. We find that both the epidemic curves and annual probabilities of infection were highly correlated across the cities, however, serotype-specific correlations were far more variable. Finally, we used geocoded case homes from Ho Chi Minh to demonstrate that cases in the city clustered at spatial scales (<500m) similar to that previously observed in Bangkok. These findings show that dengue dynamics are highly comparable across these two urban hubs; however, the low correlation in serotype distribution suggests that similar built environments and climate, rather than viral flow drives these observations.
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Disparities in influenza mortality and transmission related to sociodemographic factors within Chicago in the pandemic of 1918. Proc Natl Acad Sci U S A 2016; 113:13839-13844. [PMID: 27872284 DOI: 10.1073/pnas.1612838113] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Social factors have been shown to create differential burden of influenza across different geographic areas. We explored the relationship between potential aggregate-level social determinants and mortality during the 1918 influenza pandemic in Chicago using a historical dataset of 7,971 influenza and pneumonia deaths. Census tract-level social factors, including rates of illiteracy, homeownership, population, and unemployment, were assessed as predictors of pandemic mortality in Chicago. Poisson models fit with generalized estimating equations (GEEs) were used to estimate the association between social factors and the risk of influenza and pneumonia mortality. The Poisson model showed that influenza and pneumonia mortality increased, on average, by 32.2% for every 10% increase in illiteracy rate adjusted for population density, homeownership, unemployment, and age. We also found a significant association between transmissibility and population density, illiteracy, and unemployment but not homeownership. Lastly, analysis of the point locations of reported influenza and pneumonia deaths revealed fine-scale spatiotemporal clustering. This study shows that living in census tracts with higher illiteracy rates increased the risk of influenza and pneumonia mortality during the 1918 influenza pandemic in Chicago. Our observation that disparities in structural determinants of neighborhood-level health lead to disparities in influenza incidence in this pandemic suggests that disparities and their determinants should remain targets of research and control in future pandemics.
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Salje H, Cummings DAT, Lessler J. Estimating infectious disease transmission distances using the overall distribution of cases. Epidemics 2016; 17:10-18. [PMID: 27744095 DOI: 10.1016/j.epidem.2016.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 10/06/2016] [Accepted: 10/06/2016] [Indexed: 11/19/2022] Open
Abstract
The average spatial distance between transmission-linked cases is a fundamental property of infectious disease dispersal. However, the distance between a case and their infector is rarely measurable. Contact-tracing investigations are resource intensive or even impossible, particularly when only a subset of cases are detected. Here, we developed an approach that uses onset dates, the generation time distribution and location information to estimate the mean transmission distance. We tested our method using outbreak simulations. We then applied it to the 2001 foot-and-mouth outbreak in Cumbria, UK, and compared our results to contact-tracing activities. In simulations with a true mean distance of 106m, the average mean distance estimated was 109m when cases were fully observed (95% range of 71-142). Estimates remained consistent with the true mean distance when only five percent of cases were observed, (average estimate of 128m, 95% range 87-165). Estimates were robust to spatial heterogeneity in the underlying population. We estimated that both the mean and the standard deviation of the transmission distance during the 2001 foot-and-mouth outbreak was 8.9km (95% CI: 8.4km-9.7km). Contact-tracing activities found similar values of 6.3km (5.2km-7.4km) and 11.2km (9.5km-12.8km), respectively. We were also able to capture the drop in mean transmission distance over the course of the outbreak. Our approach is applicable across diseases, robust to under-reporting and can inform interventions and surveillance.
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Affiliation(s)
- Henrik Salje
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA; Mathematical Modeling of Infectious Diseases Unit, Institut Pasteur, Paris, France; CNRS, URA3012, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France.
| | - Derek A T Cummings
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA; Mathematical Modeling of Infectious Diseases Unit, Institut Pasteur, Paris, France; Department of Biology, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA; Department of Biology, University of Florida, Gainesville, FL, USA
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Wijayanti SPM, Porphyre T, Chase-Topping M, Rainey SM, McFarlane M, Schnettler E, Biek R, Kohl A. The Importance of Socio-Economic Versus Environmental Risk Factors for Reported Dengue Cases in Java, Indonesia. PLoS Negl Trop Dis 2016; 10:e0004964. [PMID: 27603137 PMCID: PMC5014450 DOI: 10.1371/journal.pntd.0004964] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/09/2016] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Dengue is a major mosquito-borne viral disease and an important public health problem. Identifying which factors are important determinants in the risk of dengue infection is critical in supporting and guiding preventive measures. In South-East Asia, half of all reported fatal infections are recorded in Indonesia, yet little is known about the epidemiology of dengue in this country. METHODOLOGY/PRINCIPAL FINDINGS Hospital-reported dengue cases in Banyumas regency, Central Java were examined to build Bayesian spatial and spatio-temporal models assessing the influence of climatic, demographic and socio-economic factors on the risk of dengue infection. A socio-economic factor linking employment type and economic status was the most influential on the risk of dengue infection in the Regency. Other factors such as access to healthcare facilities and night-time temperature were also found to be associated with higher risk of reported dengue infection but had limited explanatory power. CONCLUSIONS/SIGNIFICANCE Our data suggest that dengue infections are triggered by indoor transmission events linked to socio-economic factors (employment type, economic status). Preventive measures in this area should therefore target also specific environments such as schools and work areas to attempt and reduce dengue burden in this community. Although our analysis did not account for factors such as variations in immunity which need further investigation, this study can advise preventive measures in areas with similar patterns of reported dengue cases and environment.
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Affiliation(s)
- Siwi P. M. Wijayanti
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
- Public Health Department, Faculty of Health Sciences, University of Jenderal Soedirman, Purwokerto, Indonesia
- * E-mail: (SPMW); (TP); (AK)
| | - Thibaud Porphyre
- Centre for Immunity, Infection and Evolution (CIIE), Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (SPMW); (TP); (AK)
| | - Margo Chase-Topping
- Centre for Immunity, Infection and Evolution (CIIE), Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephanie M. Rainey
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
| | - Melanie McFarlane
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
| | - Esther Schnettler
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
| | - Roman Biek
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
- Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alain Kohl
- MRC–University of Glasgow Centre for Virus Research, Glasgow, Scotland, United Kingdom
- * E-mail: (SPMW); (TP); (AK)
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Robert MA, Christofferson RC, Silva NJB, Vasquez C, Mores CN, Wearing HJ. Modeling Mosquito-Borne Disease Spread in U.S. Urbanized Areas: The Case of Dengue in Miami. PLoS One 2016; 11:e0161365. [PMID: 27532496 PMCID: PMC4988691 DOI: 10.1371/journal.pone.0161365] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/04/2016] [Indexed: 11/18/2022] Open
Abstract
Expansion of mosquito-borne pathogens into more temperate regions of the world necessitates tools such as mathematical models for understanding the factors that contribute to the introduction and emergence of a disease in populations naïve to the disease. Often, these models are not developed and analyzed until after a pathogen is detected in a population. In this study, we develop a spatially explicit stochastic model parameterized with publicly available U.S. Census data for studying the potential for disease spread in Urbanized Areas of the United States. To illustrate the utility of the model, we specifically study the potential for introductions of dengue to lead to autochthonous transmission and outbreaks in a population representative of the Miami Urbanized Area, where introductions of dengue have occurred frequently in recent years. We describe seasonal fluctuations in mosquito populations by fitting a population model to trap data provided by the Miami-Dade Mosquito Control Division. We show that the timing and location of introduced cases could play an important role in determining both the probability that local transmission occurs as well as the total number of cases throughout the entire region following introduction. We show that at low rates of clinical presentation, small outbreaks of dengue could go completely undetected during a season, which may confound mitigation efforts that rely upon detection. We discuss the sensitivity of the model to several critical parameter values that are currently poorly characterized and motivate the collection of additional data to strengthen the predictive power of this and similar models. Finally, we emphasize the utility of the general structure of this model in studying mosquito-borne diseases such as chikungunya and Zika virus in other regions.
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Affiliation(s)
- Michael A. Robert
- Department of Biology, University of New Mexico, Albuquerque, NM, United States of America
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM, United States of America
- * E-mail:
| | - Rebecca C. Christofferson
- Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Noah J. B. Silva
- Department of Biology, University of New Mexico, Albuquerque, NM, United States of America
| | - Chalmers Vasquez
- Miami-Dade County Mosquito Control Division, Miami, FL, United States of America
| | - Christopher N. Mores
- Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Helen J. Wearing
- Department of Biology, University of New Mexico, Albuquerque, NM, United States of America
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM, United States of America
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Kraemer MUG, Perkins TA, Cummings DAT, Zakar R, Hay SI, Smith DL, Reiner RC. Big city, small world: density, contact rates, and transmission of dengue across Pakistan. J R Soc Interface 2016; 12:20150468. [PMID: 26468065 PMCID: PMC4614486 DOI: 10.1098/rsif.2015.0468] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Macroscopic descriptions of populations commonly assume that encounters between individuals are well mixed; i.e. each individual has an equal chance of coming into contact with any other individual. Relaxing this assumption can be challenging though, due to the difficulty of acquiring detailed knowledge about the non-random nature of encounters. Here, we fitted a mathematical model of dengue virus transmission to spatial time-series data from Pakistan and compared maximum-likelihood estimates of 'mixing parameters' when disaggregating data across an urban-rural gradient. We show that dynamics across this gradient are subject not only to differing transmission intensities but also to differing strengths of nonlinearity due to differences in mixing. Accounting for differences in mobility by incorporating two fine-scale, density-dependent covariate layers eliminates differences in mixing but results in a doubling of the estimated transmission potential of the large urban district of Lahore. We furthermore show that neglecting spatial variation in mixing can lead to substantial underestimates of the level of effort needed to control a pathogen with vaccines or other interventions. We complement this analysis with estimates of the relationships between dengue transmission intensity and other putative environmental drivers thereof.
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Affiliation(s)
- M U G Kraemer
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - T A Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - D A T Cummings
- Department of Epidemiology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - R Zakar
- Department of Public Health, University of Punjab, Lahore 54590, Pakistan
| | - S I Hay
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA 98121, USA
| | - D L Smith
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA Sanaria Institute for Global Health and Tropical Medicine, Rockville, MD 20850, USA
| | - R C Reiner
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN 47405, USA
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Measuring Spatial Dependence for Infectious Disease Epidemiology. PLoS One 2016; 11:e0155249. [PMID: 27196422 PMCID: PMC4873007 DOI: 10.1371/journal.pone.0155249] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 04/26/2016] [Indexed: 12/01/2022] Open
Abstract
Global spatial clustering is the tendency of points, here cases of infectious disease, to occur closer together than expected by chance. The extent of global clustering can provide a window into the spatial scale of disease transmission, thereby providing insights into the mechanism of spread, and informing optimal surveillance and control. Here the authors present an interpretable measure of spatial clustering, τ, which can be understood as a measure of relative risk. When biological or temporal information can be used to identify sets of potentially linked and likely unlinked cases, this measure can be estimated without knowledge of the underlying population distribution. The greater our ability to distinguish closely related (i.e., separated by few generations of transmission) from more distantly related cases, the more closely τ will track the true scale of transmission. The authors illustrate this approach using examples from the analyses of HIV, dengue and measles, and provide an R package implementing the methods described. The statistic presented, and measures of global clustering in general, can be powerful tools for analysis of spatially resolved data on infectious diseases.
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Padmanabha H, Correa F, Rubio C, Baeza A, Osorio S, Mendez J, Jones JH, Diuk-Wasser MA. Human Social Behavior and Demography Drive Patterns of Fine-Scale Dengue Transmission in Endemic Areas of Colombia. PLoS One 2015; 10:e0144451. [PMID: 26656072 PMCID: PMC4684369 DOI: 10.1371/journal.pone.0144451] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/18/2015] [Indexed: 01/09/2023] Open
Abstract
Dengue is known to transmit between humans and A. aegypti mosquitoes living in neighboring houses. Although transmission is thought to be highly heterogeneous in both space and time, little is known about the patterns and drivers of transmission in groups of houses in endemic settings. We carried out surveys of PCR positivity in children residing in 2-block patches of highly endemic cities of Colombia. We found high levels of heterogeneity in PCR positivity, varying from less than 30% in 8 of the 10 patches to 56 and 96%, with the latter patch containing 22 children simultaneously PCR positive (PCR22) for DEN2. We then used an agent-based model to assess the likely eco-epidemiological context of this observation. Our model, simulating daily dengue dynamics over a 20 year period in a single two block patch, suggests that the observed heterogeneity most likely derived from variation in the density of susceptible people. Two aspects of human adaptive behavior were critical to determining this density: external social relationships favoring viral introduction (by susceptible residents or infectious visitors) and immigration of households from non-endemic areas. External social relationships generating frequent viral introduction constituted a particularly strong constraint on susceptible densities, thereby limiting the potential for explosive outbreaks and dampening the impact of heightened vectorial capacity. Dengue transmission can be highly explosive locally, even in neighborhoods with significant immunity in the human population. Variation among neighborhoods in the density of local social networks and rural-to-urban migration is likely to produce significant fine-scale heterogeneity in dengue dynamics, constraining or amplifying the impacts of changes in mosquito populations and cross immunity between serotypes.
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Affiliation(s)
- Harish Padmanabha
- Centro de Investigaciones en el Desarrollo Humano (CIDHUM), Universidad del Norte, Km 5 Via Puerto Colombia, Puerto Colombia, Colombia
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, 1 Park Place, Suite 300, Annapolis, Maryland, 21401, United States of America
- * E-mail:
| | - Fabio Correa
- Instituto Nacional de Salud de Colombia, Avenida/calle 26 No. 51–20 - Zona 6 CAN, Bogotá, D.C., Colombia
| | - Camilo Rubio
- Instituto Nacional de Salud de Colombia, Avenida/calle 26 No. 51–20 - Zona 6 CAN, Bogotá, D.C., Colombia
| | - Andres Baeza
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, 1 Park Place, Suite 300, Annapolis, Maryland, 21401, United States of America
| | - Salua Osorio
- Instituto Nacional de Salud de Colombia, Avenida/calle 26 No. 51–20 - Zona 6 CAN, Bogotá, D.C., Colombia
| | - Jairo Mendez
- Instituto Nacional de Salud de Colombia, Avenida/calle 26 No. 51–20 - Zona 6 CAN, Bogotá, D.C., Colombia
| | - James Holland Jones
- Department of Anthropology/Woods Institute of the Environment, Stanford University, 450 Serra Mall, Building 50, Stanford, California, 94305–2034, United States of America
| | - Maria A Diuk-Wasser
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Ave, New York, New York, 10027, United States of America
- Department of Epidemiology of Microbial Diseases, Yale University, 60 College St, New Haven, Connecticut, 06520, United States of America
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Salje H, Cauchemez S, Alera MT, Rodriguez-Barraquer I, Thaisomboonsuk B, Srikiatkhachorn A, Lago CB, Villa D, Klungthong C, Tac-An IA, Fernandez S, Velasco JM, Roque VG, Nisalak A, Macareo LR, Levy JW, Cummings D, Yoon IK. Reconstruction of 60 Years of Chikungunya Epidemiology in the Philippines Demonstrates Episodic and Focal Transmission. J Infect Dis 2015; 213:604-10. [PMID: 26410592 PMCID: PMC4721913 DOI: 10.1093/infdis/jiv470] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/16/2015] [Indexed: 11/15/2022] Open
Abstract
Proper understanding of the long-term epidemiology of chikungunya has been hampered by poor surveillance. Outbreak years are unpredictable and cases often misdiagnosed. Here we analyzed age-specific data from 2 serological studies (from 1973 and 2012) in Cebu, Philippines, to reconstruct both the annual probability of infection and population-level immunity over a 60-year period (1952–2012). We also explored whether seroconversions during 2012–2013 were spatially clustered. Our models identified 4 discrete outbreaks separated by an average delay of 17 years. On average, 23% (95% confidence interval [CI], 16%–37%) of the susceptible population was infected per outbreak, with >50% of the entire population remaining susceptible at any point. Participants who seroconverted during 2012–2013 were clustered at distances of <230 m, suggesting focal transmission. Large-scale outbreaks of chikungunya did not result in sustained multiyear transmission. Nevertheless, we estimate that >350 000 infections were missed by surveillance systems. Serological studies could supplement surveillance to provide important insights on pathogen circulation.
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Affiliation(s)
- Henrik Salje
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland Mathematical Modeling Unit, Institut Pasteur, Paris, France
| | | | | | | | - Butsaya Thaisomboonsuk
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Anon Srikiatkhachorn
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester
| | - Catherine B Lago
- Virology Research Unit, Armed Forces Research Institute of Medical Sciences
| | | | - Chonticha Klungthong
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - John Mark Velasco
- Virology Research Unit, Armed Forces Research Institute of Medical Sciences
| | - Vito G Roque
- Department of Health, National Epidemiology Center, Manila, Philippines
| | - Ananda Nisalak
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Louis R Macareo
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Jens W Levy
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Derek Cummings
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland Department of Biology, University of Florida, Gainesville
| | - In-Kyu Yoon
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand International Vaccine Institute, Seoul, Republic of Korea
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Abstract
Dengue is currently the most rapidly spreading vector-borne disease, with an increasing burden over recent decades. Currently, neither a licensed vaccine nor an effective anti-viral therapy is available, and treatment largely remains supportive. Current vector control strategies to prevent and reduce dengue transmission are neither efficient nor sustainable as long-term interventions. Increased globalization and climate change have been reported to influence dengue transmission. In this article, we reviewed the non-climatic and climatic risk factors which facilitate dengue transmission. Sustainable and effective interventions to reduce the increasing threat from dengue would require the integration of these risk factors into current and future prevention strategies, including dengue vaccination, as well as the continuous support and commitment from the political and environmental stakeholders.
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Affiliation(s)
- Pang Junxiong
- Communicable Disease Center, Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, IIDE, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
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