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Zahid MH, Van Wyk H, Morrison AC, Coloma J, Lee GO, Cevallos V, Ponce P, Eisenberg JNS. The biting rate of Aedes aegypti and its variability: A systematic review (1970-2022). PLoS Negl Trop Dis 2023; 17:e0010831. [PMID: 37552669 PMCID: PMC10456196 DOI: 10.1371/journal.pntd.0010831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 08/25/2023] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND Transmission models have a long history in the study of mosquito-borne disease dynamics. The mosquito biting rate (MBR) is an important parameter in these models, however, estimating its value empirically is complex. Modeling studies obtain biting rate values from various types of studies, each of them having its strengths and limitations. Thus, understanding these study designs and the factors that contribute to MBR estimates and their variability is an important step towards standardizing these estimates. We do this for an important arbovirus vector Aedes aegypti. METHODOLOGY/PRINCIPAL FINDINGS We perform a systematic review using search terms such as 'biting rate' and 'biting frequency' combined with 'Aedes aegypti' ('Ae. aegypti' or 'A. aegypti'). We screened 3,201 articles from PubMed and ProQuest databases, of which 21 met our inclusion criteria. Two broader types of studies are identified: human landing catch (HLC) studies and multiple feeding studies. We analyze the biting rate data provided as well as the methodologies used in these studies to characterize the variability of these estimates across temporal, spatial, and environmental factors and to identify the strengths and limitations of existing methodologies. Based on these analyses, we present two approaches to estimate population mean per mosquito biting rate: one that combines studies estimating the number of bites taken per gonotrophic cycle and the gonotrophic cycle duration, and a second that uses data from histological studies. Based on one histological study dataset, we estimate biting rates of Ae. aegypti (0.41 and 0.35 bite/mosquito-day in Thailand and Puerto Rico, respectively). CONCLUSIONS/SIGNIFICANCE Our review reinforces the importance of engaging with vector biology when using mosquito biting rate data in transmission modeling studies. For Ae. aegypti, this includes understanding the variation of the gonotrophic cycle duration and the number of bites per gonotrophic cycle, as well as recognizing the potential for spatial and temporal variability. To address these variabilities, we advocate for site-specific data and the development of a standardized approach to estimate the biting rate.
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Affiliation(s)
- Mondal Hasan Zahid
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biology, University of Florida, Gainesville, Florida, United States of America and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Hannah Van Wyk
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, 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
| | - Gwenyth O. Lee
- Rutgers Global Health Institute & Department of Biostatistics and Epidemiology, School of Public Health, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Varsovia Cevallos
- Instituto Nacional de Investigación en Salud Pública, Centro de investigación en enfermedades infecciosas y vectoriales-CIREV, Quito, Ecuador
| | - Patricio Ponce
- Instituto Nacional de Investigación en Salud Pública, Centro de investigación en enfermedades infecciosas y vectoriales-CIREV, Quito, Ecuador
| | - Joseph N. S. Eisenberg
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, United States of America
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Bridging landscape ecology and urban science to respond to the rising threat of mosquito-borne diseases. Nat Ecol Evol 2022; 6:1601-1616. [DOI: 10.1038/s41559-022-01876-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 08/03/2022] [Indexed: 11/09/2022]
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3
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Vyhmeister E, Provan G, Doyle B, Bourke B, Castane G, Reyes-Bozo L. Comparison of Time Series and Mechanistic Models of Vector-Borne Diseases. Spat Spatiotemporal Epidemiol 2022; 41:100478. [DOI: 10.1016/j.sste.2022.100478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 10/21/2020] [Accepted: 01/10/2022] [Indexed: 11/24/2022]
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A Zika Endemic Model for the Contribution of Multiple Transmission Routes. Bull Math Biol 2021; 83:111. [PMID: 34581872 DOI: 10.1007/s11538-021-00945-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022]
Abstract
Zika virus disease is a viral disease primarily transmitted to humans through the bite of infected female mosquitoes. Recent evidence indicates that the virus can also be sexually transmitted in hosts and vertically transmitted in vectors. In this paper, we propose a Zika model with three transmission routes, that is, vector-borne transmission between humans and mosquitoes, sexual transmission within humans and vertical transmission within mosquitoes. The basic reproduction number [Formula: see text] is computed and shown to be a sharp threshold quantity. Namely, the disease-free equilibrium is globally asymptotically stable as [Formula: see text], whereas there exists a unique endemic equilibrium which is globally asymptotically stable as [Formula: see text]. The relative contributions of each transmission route on the reproduction number, and the short- and long-term host infections are analyzed. Numerical simulations confirm that vectorial transmission contributes the most to the initial and subsequent transmission. The role of sexual transmission in the early phase of a Zika outbreak is greater than the long term, while vertical transmission is the opposite. Reducing mosquito bites is the most effective measure in lowering the risk of Zika virus infection.
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Lim JT, Dickens BS, Tan KW, Koo JR, Seah A, Ho SH, Ong J, Rajarethinam J, Soh S, Cook AR, Ng LC. Hyperendemicity associated with increased dengue burden. J R Soc Interface 2021; 18:20210565. [PMID: 34520691 PMCID: PMC8440027 DOI: 10.1098/rsif.2021.0565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Over 105 million dengue infections are estimated to occur annually. Understanding the disease dynamics of dengue is often difficult due to multiple strains circulating within a population. Interactions between dengue serotype dynamics may result in complex cross-immunity dynamics at the population level and create difficulties in terms of formulating intervention strategies for the disease. In this study, a nationally representative 16-year time series with over 43 000 serotyped dengue infections was used to infer the long-run effects of between and within strain interactions and their impacts on past outbreaks. We used a novel identification strategy incorporating sign-identified Bayesian vector autoregressions, using structural impulse responses, historical decompositions and counterfactual analysis to conduct inference on dengue dynamics post-estimation. We found that on the population level: (i) across-serotype interactions on the population level were highly persistent, with a one time increase in any other serotype associated with long run decreases in the serotype of interest (range: 0.5–2.5 years) and (ii) over 38.7% of dengue cases of any serotype were associated with across-serotype interactions. The findings in this paper will substantially impact public health policy interventions with respect to dengue.
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Affiliation(s)
- Jue Tao Lim
- Environmental Health Institute, National Environmental Agency, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Borame Sue Dickens
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Ken Wei Tan
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Joel Ruihan Koo
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Annabel Seah
- Environmental Health Institute, National Environmental Agency, Singapore
| | - Soon Hoe Ho
- Environmental Health Institute, National Environmental Agency, Singapore
| | - Janet Ong
- Environmental Health Institute, National Environmental Agency, Singapore
| | | | - Stacy Soh
- Environmental Health Institute, National Environmental Agency, Singapore
| | - Alex R Cook
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Lee Ching Ng
- Environmental Health Institute, National Environmental Agency, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore
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Schimit PHT. A model based on cellular automata to estimate the social isolation impact on COVID-19 spreading in Brazil. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 200:105832. [PMID: 33213971 PMCID: PMC7836885 DOI: 10.1016/j.cmpb.2020.105832] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/04/2020] [Indexed: 05/11/2023]
Abstract
Background and objective Many countries around the world experienced a high increase in the number of COVID-19 cases after a few weeks of the first case, and along with it, excessive pressure on the healthcare systems. While medicines, drugs, and vaccines against the COVID-19 are being developed, social isolation has become the most used method for controlling the virus spreading. With the social isolation, authorities aimed to slow down the spreading, avoiding saturation of the healthcare system, and allowing that all critical COVID-19 cases could be appropriately treated. By tuning the proposed model to fit Brazil's initial COVID-19 data, the objectives of the paper are to analyze the impact of the social isolation features on the population dynamics; simulate the number of deaths due to COVID-19 and due to the lack of healthcare infrastructure; study combinations of the features for the healthcare system does not collapse; and analyze healthcare system responses for the crisis. Methods In this paper, a Susceptible-Exposed-Infected-Removed model is described in terms of probabilistic cellular automata and ordinary differential equations for the transmission of COVID-19, flexible enough for simulating different scenarios of social isolation according to the following features: the start day for the social isolation after the first death, the period for the social isolation campaign, and the percentage of the population committed to the campaign. Results Results showed that efforts in the social isolation campaign must be concentrated both on the isolation percentage and campaign duration to delay the healthcare system failure. For the hospital situation in Brazil at the beginning of the pandemic outbreak, a rate of 200 purchases per day of intensive care units and mechanical ventilators is the minimum rate to prevent the collapse of the healthcare system. Conclusions By using the model for different scenarios, it is possible to estimate the impact of social isolation campaign adhesion. For instance, if the social isolation percentage increased from 40% to 50% in Brazil, the purchase rate of 150 intensive care units and mechanical ventilators per day would be enough to prevent the healthcare system to collapse. Moreover, results showed that a premature relaxation of the social isolation campaign can lead to subsequent waves of contamination.
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Affiliation(s)
- P H T Schimit
- Informatics and Knowledge Management Graduate Program Universidade Nove de Julho Rua Vergueiro, 235/249 São Paulo, CEP: 05001-001, SP, Brazil.
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Núñez-López M, Alarcón Ramos L, Velasco-Hernández JX. Migration rate estimation in an epidemic network. APPLIED MATHEMATICAL MODELLING 2021; 89:1949-1964. [PMID: 32952269 PMCID: PMC7486824 DOI: 10.1016/j.apm.2020.08.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 05/07/2023]
Abstract
Most of the recent epidemic outbreaks in the world have as a trigger, a strong migratory component as has been evident in the recent Covid-19 pandemic. In this work we address the problem of migration of human populations and its effect on pathogen reinfections in the case of Dengue, using a Markov-chain susceptible-infected-susceptible (SIS) metapopulation model over a network. Our model postulates a general contact rate that represents a local measure of several factors: the population size of infected hosts that arrive at a given location as a function of total population size, the current incidence at neighboring locations, and the connectivity of the network where the disease spreads. This parameter can be interpreted as an indicator of outbreak risk at a given location. This parameter is tied to the fraction of individuals that move across boundaries (migration). To illustrate our model capabilities, we estimate from epidemic Dengue data in Mexico the dynamics of migration at a regional scale incorporating climate variability represented by an index based on precipitation data.
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Affiliation(s)
- M Núñez-López
- Department of Mathematics, ITAM Río Hondo 1, Ciudad de México 01080, México
| | - L Alarcón Ramos
- Departamento de Matemáticas Aplicadas y Sistemas, Universidad Autónoma Metropolitana, Cuajimalpa, Av. Vasco de Quiroga 4871, Cuajimalpa de Morelos, 05300, México
| | - J X Velasco-Hernández
- Instituto de Matemáticas, Universidad Nacional Autónoma de México, Boulevard Juriquilla No. 3001, Juriquilla, 76230, México
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ROY PARIMITA, UPADHYAY RANJITKUMAR, CAUR JASMINE. MODELING ZIKA TRANSMISSION DYNAMICS: PREVENTION AND CONTROL. J BIOL SYST 2020. [DOI: 10.1142/s021833902050014x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Zika virus (ZIKV) epidemic is depicted to have high spatial diversity and slow growth, attributable to the dynamics of the mosquito vector and mobility of the human populations. In an effort to understand the transmission dynamics of Zika virus, we formulate a new compartmental epidemic model with a system of seven differential equations and 11 parameters incorporating the decaying transmission rate and study the impact of protection measure on basic public health. We do not fit the model to the observed pattern of spread, rather we use parameter values estimated in the past and examine the extent to which the designed model prediction agrees with the pattern of spread seen in Brazil, via reaction–diffusion modeling. Our work includes estimation of key epidemiological parameters such as basic reproduction number ([Formula: see text], and gives a rough estimate of how many individuals can be typically infected during an outbreak if it occurs in India. We used partial rank correlation coefficient method for global sensitivity analysis to identify the most influential model parameters. Using optimal control theory and Pontryagin’s maximum principle, a control model has been proposed and conditions for the optimal control are determined for the deterministic model of Zika virus. The control functions for the strategies (i) vector-to-human contact reduction and (ii) vector elimination are introduced into the system. Numerical simulations are also performed. This work aimed at understanding the potential extent and timing of the ZIKV epidemic can be used as a template for the analysis of future mosquito-borne epidemics.
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Affiliation(s)
- PARIMITA ROY
- School of Mathematics, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India
| | - RANJIT KUMAR UPADHYAY
- Department of Mathematics & Computing, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, Jharkhand, India
| | - JASMINE CAUR
- School of Mathematics, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India
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Análisis de costo-efectividad del uso del programa VECTOS en el control rutinario de enfermedades transmitidas por Aedes aegypti en dos municipios de Santander, Colombia. BIOMÉDICA 2020; 40:270-282. [PMID: 32673456 PMCID: PMC7505512 DOI: 10.7705/biomedica.4658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Indexed: 12/04/2022]
Abstract
Introducción. Las enfermedades transmitidas por Aedes aegypti son un problema de salud pública. VECTOS es un programa novedoso de integración de estrategias de control de vectores. Objetivo. Evaluar el costo-efectividad del uso del VECTOS en los programas de control rutinario de enfermedades transmitidas por el vector Aedes aegypti en el municipio de San Juan de Girón (Santander). Materiales y métodos. Se evaluó el costo-efectividad del programa empleando un modelo de análisis de decisiones desde la perspectiva de las autoridades locales de salud. Se estudió la integración de las estrategias de control de vectores mediante el programa VECTOS utilizado en el municipio de San Juan de Girón durante el 2016, con el control rutinario llevado a cabo sin VECTOS en el municipio de Floridablanca. Se calculó la razón incremental del costo-efectividad (RICE), usando como medida de efectividad los años de vida ajustados por discapacidad (AVAD). Resultados. El uso del programa VECTOS fue rentable a una tasa de ahorro de USD$ 660,4 por cada AVAD evitado en comparación con el control de rutina en Floridablanca. El modelo probabilístico indicó que el sistema fue costo-efectivo en el 70 % de las 10.000 iteraciones para un umbral entre 1 y 3 PIB per cápita. Conclusiones. El programa VECTOS fue muy costo-efectivo en el municipio de San Juan de Girón. Su uso puede adoptarse en otros municipios del país donde las enfermedades transmitidas por A. aegypti son endémicas.
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Latent Infectious Capacities of Dengue Fever: Mathematical Modeling and Eco-Friendly Prevention Strategy. Symmetry (Basel) 2020. [DOI: 10.3390/sym12020263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The main aim of this article is to propose a method for exploring the latent values about the capacities of spreading dengue for each potential site. First, a mathematical model connecting the observable public data and the capacities of spreading dengue is provided based on the split feasibility problem (SFP). Then, a proper iterative scheme for the SFP is presented to approach the values of infectious capacities (ICs) of potential sites—the capacities of spreading. The performance of our proposed method is demonstrated using public data from Kaohsiung City for 2014 and 2015. The results presented in this paper show that our proposed method is reliable and the sites with a high capacity of spreading are only a small portion of thousands of all potential sites and could be an alternative strategy for preventing the outbreak of dengue fever whilst also avoiding the damage of ecosystems caused by chemical insecticides.
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Ortigoza G, Brauer F, Neri I. Modelling and simulating Chikungunya spread with an unstructured triangular cellular automata. Infect Dis Model 2020; 5:197-220. [PMID: 32021947 PMCID: PMC6993010 DOI: 10.1016/j.idm.2019.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/16/2019] [Accepted: 12/16/2019] [Indexed: 12/22/2022] Open
Abstract
In this work we propose a mathematical model to simulate Chikungunya spread; the spread model is implemented in a C++ cellular automata code defined on unstructured triangular grids and space visualizations are performed with Python. In order to simulate the time space spread of the Chikungunya diseases we include assumptions such as: heterogeneous human and vector densities, population mobility, geographically localized points of infection using geographical information systems, changes in the probabilities of infection, extrinsic incubation and mosquito death rate due to environmental variables. Numerical experiments reproduce the qualitative behavior of diseases spread and provide an insight to develop strategies to prevent the diseases spread.
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Affiliation(s)
- Gerardo Ortigoza
- Facultad de Ingeniería,Universidad Veracruzana, Boca Del Río, Ver, Mexico
| | - Fred Brauer
- Mathematics Department, University of British Columbia, Vancouver, B.C, Canada
| | - Iris Neri
- Maestría en Gestión Integrada de Cuencas, Universidad Autónoma de Querétaro, Mexico
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Dodero-Rojas E, Ferreira LG, Leite VBP, Onuchic JN, Contessoto VG. Modeling Chikungunya control strategies and Mayaro potential outbreak in the city of Rio de Janeiro. PLoS One 2020; 15:e0222900. [PMID: 31990920 PMCID: PMC6986714 DOI: 10.1371/journal.pone.0222900] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/02/2020] [Indexed: 12/15/2022] Open
Abstract
Mosquito-borne diseases have become a significant health issue in many regions around the world. For tropical countries, diseases such as Dengue, Zika, and Chikungunya, became epidemic in the last decades. Health surveillance reports during this period were crucial in providing scientific-based information to guide decision making and resources allocation to control outbreaks. In this work, we perform data analysis of the last Chikungunya epidemics in the city of Rio de Janeiro by applying a compartmental mathematical model. Sensitivity analyses were performed in order to describe the contribution of each parameter to the outbreak incidence. We estimate the "basic reproduction number" for those outbreaks and predict the potential epidemic outbreak of the Mayaro virus. We also simulated several scenarios with different public interventions to decrease the number of infected people. Such scenarios should provide insights about possible strategies to control future outbreaks.
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Affiliation(s)
- Esteban Dodero-Rojas
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States of America
- Theoretical and Computational Physics Laboratory, University of Costa Rica, San José, Costa Rica
| | - Luiza G. Ferreira
- Department of Chemistry, Rice University, Houston, TX, United States of America
| | - Vitor B. P. Leite
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences, São Paulo State University - UNESP, São José do Rio Preto, SP, Brazil
| | - José N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States of America
- Department of Chemistry, Rice University, Houston, TX, United States of America
- Department of Physics & Astronomy, Rice University, Houston, TX, United States of America
- Department of Biosciences, Rice University, Houston, TX, United States of America
| | - Vinícius G. Contessoto
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States of America
- Brazilian Biorenewables National Laboratory - LNBR, Brazilian Center for Research in Energy and Materials - CNPEM, Campinas, SP, Brazil
- * E-mail:
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Assessing the interplay between human mobility and mosquito borne diseases in urban environments. Sci Rep 2019; 9:16911. [PMID: 31729435 PMCID: PMC6858332 DOI: 10.1038/s41598-019-53127-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/17/2019] [Indexed: 12/21/2022] Open
Abstract
Urbanization drives the epidemiology of infectious diseases to many threats and new challenges. In this research, we study the interplay between human mobility and dengue outbreaks in the complex urban environment of the city-state of Singapore. We integrate both stylized and mobile phone data-driven mobility patterns in an agent-based transmission model in which humans and mosquitoes are represented as agents that go through the epidemic states of dengue. We monitor with numerical simulations the system-level response to the epidemic by comparing our results with the observed cases reported during the 2013 and 2014 outbreaks. Our results show that human mobility is a major factor in the spread of vector-borne diseases such as dengue even on the short scale corresponding to intra-city distances. We finally discuss the advantages and the limits of mobile phone data and potential alternatives for assessing valuable mobility patterns for modeling vector-borne diseases outbreaks in cities.
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Effect of active case finding on dengue control: Implications from a mathematical model. J Theor Biol 2018; 464:50-62. [PMID: 30582932 DOI: 10.1016/j.jtbi.2018.12.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 11/21/2022]
Abstract
Dengue control in India is a challenging task due to complex healthcare settings. In yesteryears, an amplification of dengue infections in India posed the need for introspection of existing dengue control policies. Prior understanding of the impacts of control interventions is necessary for their future implementation. In this paper, we propose and analyze a compartmental model of dengue to assess the impact of active case finding (ACF) on dengue disease transmission. Currently, primary prevention of dengue is possible only with vector control and personal protection from the bites of infected mosquitoes. Although a few experimental studies are performed to assess ACF in dengue disease, but this is the first attempt to represent and study the dynamics of disease using ACF as a control strategy. Local and global dynamics of the system are studied. We use sensitivity analysis to see the effects of controllable parameters of the model on the basic reproduction number and total number of infective population. We find that decrease in the biting rate of mosquitoes, and increase in the rate of hospitalization and/or notification, death rate of mosquitoes and ACF for asymptomatic and symptomatic individuals play crucial role for the reduction of disease prevalence. We calibrate our model to the yearly dengue cases in eight dengue endemic states of India. The results of our study show that ACF of symptomatic individuals will have significant effect on dengue case reduction but ACF of asymptomatic individuals cannot be ignored. Our findings indicate that the healthcare organizations must focus on ACF of symptomatic as well as asymptomatic individuals along with personal protection and mosquitoes control to achieve rapid reduction of dengue cases in India.
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Modeling the Spread of Zika Virus in a Stage-Structured Population: Effect of Sexual Transmission. Bull Math Biol 2018; 80:3038-3067. [DOI: 10.1007/s11538-018-0510-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 09/07/2018] [Indexed: 10/28/2022]
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Eder M, Cortes F, Teixeira de Siqueira Filha N, Araújo de França GV, Degroote S, Braga C, Ridde V, Turchi Martelli CM. Scoping review on vector-borne diseases in urban areas: transmission dynamics, vectorial capacity and co-infection. Infect Dis Poverty 2018; 7:90. [PMID: 30173661 PMCID: PMC6120094 DOI: 10.1186/s40249-018-0475-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/02/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transmission dynamics, vectorial capacity, and co-infections have substantial impacts on vector-borne diseases (VBDs) affecting urban and suburban populations. Reviewing key factors can provide insight into priority research areas and offer suggestions for potential interventions. MAIN BODY Through a scoping review, we identify knowledge gaps on transmission dynamics, vectorial capacity, and co-infections regarding VBDs in urban areas. Peer-reviewed and grey literature published between 2000 and 2016 was searched. We screened abstracts and full texts to select studies. Using an extraction grid, we retrieved general data, results, lessons learned and recommendations, future research avenues, and practice implications. We classified studies by VBD and country/continent and identified relevant knowledge gaps. Of 773 articles selected for full-text screening, 50 were included in the review: 23 based on research in the Americas, 15 in Asia, 10 in Africa, and one each in Europe and Australia. The largest body of evidence concerning VBD epidemiology in urban areas concerned dengue and malaria. Other arboviruses covered included chikungunya and West Nile virus, other parasitic diseases such as leishmaniasis and trypanosomiasis, and bacterial rickettsiosis and plague. Most articles retrieved in our review combined transmission dynamics and vectorial capacity; only two combined transmission dynamics and co-infection. The review identified significant knowledge gaps on the role of asymptomatic individuals, the effects of co-infection and other host factors, and the impacts of climatic, environmental, and socioeconomic factors on VBD transmission in urban areas. Limitations included the trade-off from narrowing the search strategy (missing out on classical modelling studies), a lack of studies on co-infections, most studies being only descriptive, and few offering concrete public health recommendations. More research is needed on transmission risk in homes and workplaces, given increasingly dynamic and mobile populations. The lack of studies on co-infection hampers monitoring of infections transmitted by the same vector. CONCLUSIONS Strengthening VBD surveillance and control, particularly in asymptomatic cases and mobile populations, as well as using early warning tools to predict increasing transmission, were key strategies identified for public health policy and practice.
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Affiliation(s)
- Marcus Eder
- Public Health England Sierra Leone Country Office, Freetown, Sierra Leone
- Aggeu Magalhaes Institute (IAM) / Oswaldo Cruz Foundation (Fiocruz), Avenida Professor Moraes Rego, s/n. Cidade Universitaria. CEP 50, Recife, Pernambuco 740-465 Brazil
| | - Fanny Cortes
- Universidade de Pernambuco (UPE), Recife, Pernambuco Brazil
| | | | | | - Stéphanie Degroote
- University of Montreal School of Public Health (ESPUM), Montreal, Quebec Canada
| | - Cynthia Braga
- Aggeu Magalhaes Institute (IAM) / Oswaldo Cruz Foundation (Fiocruz), Avenida Professor Moraes Rego, s/n. Cidade Universitaria. CEP 50, Recife, Pernambuco 740-465 Brazil
| | - Valéry Ridde
- University of Montreal School of Public Health (ESPUM), Montreal, Quebec Canada
- IRD (French Institute For Research on Sustainable Development), CEPED (IRD-Université Paris Descartes), Universités Paris Sorbonne Cités, ERL INSERM SAGESUD, Paris, France
| | - Celina Maria Turchi Martelli
- Aggeu Magalhaes Institute (IAM) / Oswaldo Cruz Foundation (Fiocruz), Avenida Professor Moraes Rego, s/n. Cidade Universitaria. CEP 50, Recife, Pernambuco 740-465 Brazil
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Dias JCA, Monteiro LHA. Clustered Breeding Sites: Shelters for Vector-Borne Diseases. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2018; 2018:2575017. [PMID: 30112017 PMCID: PMC6077366 DOI: 10.1155/2018/2575017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/03/2018] [Indexed: 11/17/2022]
Abstract
Here, the propagation of vector-borne diseases is modeled by using a probabilistic cellular automaton. Numerical simulations considering distinct spatial distributions and time variations of the vector abundance are performed, in order to investigate their impacts on the number of infected individuals of the host population. The main conclusion is as follows: in the clustered distributions, the prevalence is lower, but the eradication is more difficult to be achieved, as compared to homogeneous distributions. This result can be relevant in the implementation of preventive surveillance measures.
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Affiliation(s)
- J. C. A. Dias
- Universidade Presbiteriana Mackenzie, PPGEEC, São Paulo, SP, Brazil
| | - L. H. A. Monteiro
- Universidade Presbiteriana Mackenzie, PPGEEC, São Paulo, SP, Brazil
- Universidade de São Paulo, Escola Politécnica, São Paulo, SP, Brazil
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18
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Wen TH, Hsu CS, Hu MC. Evaluating neighborhood structures for modeling intercity diffusion of large-scale dengue epidemics. Int J Health Geogr 2018; 17:9. [PMID: 29724243 PMCID: PMC5934834 DOI: 10.1186/s12942-018-0131-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/26/2018] [Indexed: 11/18/2022] Open
Abstract
Background Dengue fever is a vector-borne infectious disease that is transmitted by contact between vector mosquitoes and susceptible hosts. The literature has addressed the issue on quantifying the effect of individual mobility on dengue transmission. However, there are methodological concerns in the spatial regression model configuration for examining the effect of intercity-scale human mobility on dengue diffusion. The purposes of the study are to investigate the influence of neighborhood structures on intercity epidemic progression from pre-epidemic to epidemic periods and to compare definitions of different neighborhood structures for interpreting the spread of dengue epidemics. Methods We proposed a framework for assessing the effect of model configurations on dengue incidence in 2014 and 2015, which were the most severe outbreaks in 70 years in Taiwan. Compared with the conventional model configuration in spatial regression analysis, our proposed model used a radiation model, which reflects population flow between townships, as a spatial weight to capture the structure of human mobility. Results The results of our model demonstrate better model fitting performance, indicating that the structure of human mobility has better explanatory power in dengue diffusion than the geometric structure of administration boundaries and geographic distance between centroids of cities. We also identified spatial–temporal hierarchy of dengue diffusion: dengue incidence would be influenced by its immediate neighboring townships during pre-epidemic and epidemic periods, and also with more distant neighbors (based on mobility) in pre-epidemic periods. Conclusions Our findings suggest that the structure of population mobility could more reasonably capture urban-to-urban interactions, which implies that the hub cities could be a “bridge” for large-scale transmission and make townships that immediately connect to hub cities more vulnerable to dengue epidemics. Electronic supplementary material The online version of this article (10.1186/s12942-018-0131-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tzai-Hung Wen
- Department of Geography, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City, 10617, Taiwan.
| | - Ching-Shun Hsu
- Department of Geography, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City, 10617, Taiwan
| | - Ming-Che Hu
- Department of Bioenvironmental Systems Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City, 10617, Taiwan
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19
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Enduri MK, Jolad S. Dynamics of dengue disease with human and vector mobility. Spat Spatiotemporal Epidemiol 2018; 25:57-66. [PMID: 29751893 DOI: 10.1016/j.sste.2018.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 10/30/2017] [Accepted: 03/03/2018] [Indexed: 10/17/2022]
Abstract
Dengue is a vector borne disease transmitted to humans by Aedes aegypti mosquitoes carrying virus of different serotypes. Dengue exhibits complex spatial and temporal dynamics, influenced by various biological, human and environmental factors. In this work, we study the dengue spread for a single serotype (DENV-1) including statistical models of human mobility with exponential step length distribution, by using reaction-diffusion equations and Stochastic Cellular Automata (SCA) approach. We analyze the spatial and temporal spreading of the disease using parameters from field studies. We choose mosquito density data from Ahmedabad city as a proxy for climate data in our SCA model. We find an interesting result that although human mobility makes the infection spread faster, there is an apparent early suppression of the epidemic compared to immobile humans. The disease extinction time is lesser when human mobility is included.
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Affiliation(s)
| | - Shivakumar Jolad
- Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 380005, India.
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20
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Laureano-Rosario AE, Duncan AP, Mendez-Lazaro PA, Garcia-Rejon JE, Gomez-Carro S, Farfan-Ale J, Savic DA, Muller-Karger FE. Application of Artificial Neural Networks for Dengue Fever Outbreak Predictions in the Northwest Coast of Yucatan, Mexico and San Juan, Puerto Rico. Trop Med Infect Dis 2018; 3:tropicalmed3010005. [PMID: 30274404 PMCID: PMC6136605 DOI: 10.3390/tropicalmed3010005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/18/2017] [Accepted: 01/02/2018] [Indexed: 11/16/2022] Open
Abstract
Modelling dengue fever in endemic areas is important to mitigate and improve vector-borne disease control to reduce outbreaks. This study applied artificial neural networks (ANNs) to predict dengue fever outbreak occurrences in San Juan, Puerto Rico (USA), and in several coastal municipalities of the state of Yucatan, Mexico, based on specific thresholds. The models were trained with 19 years of dengue fever data for Puerto Rico and six years for Mexico. Environmental and demographic data included in the predictive models were sea surface temperature (SST), precipitation, air temperature (i.e., minimum, maximum, and average), humidity, previous dengue cases, and population size. Two models were applied for each study area. One predicted dengue incidence rates based on population at risk (i.e., numbers of people younger than 24 years), and the other on the size of the vulnerable population (i.e., number of people younger than five years and older than 65 years). The predictive power was above 70% for all four model runs. The ANNs were able to successfully model dengue fever outbreak occurrences in both study areas. The variables with the most influence on predicting dengue fever outbreak occurrences for San Juan, Puerto Rico, included population size, previous dengue cases, maximum air temperature, and date. In Yucatan, Mexico, the most important variables were population size, previous dengue cases, minimum air temperature, and date. These models have predictive skills and should help dengue fever mitigation and management to aid specific population segments in the Caribbean region and around the Gulf of Mexico.
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Affiliation(s)
- Abdiel E Laureano-Rosario
- Institute for Marine Remote Sensing, University of South Florida, College of Marine Science, 140 7th Avenue South, Saint Petersburg, FL 33701, USA.
| | - Andrew P Duncan
- Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter EX4 4QF, UK.
| | - Pablo A Mendez-Lazaro
- Environmental Health Department, Graduate School of Public Health, University of Puerto Rico, Medical Sciences Campus, P.O. Box 365067, San Juan, PR 00936, USA.
| | - Julian E Garcia-Rejon
- Centro de Investigaciones Regionales, Lab de Arbovirologia, Unidad Inalámbrica, Universidad Autonoma de Yucatan, Calle 43 No. 613 x Calle 90, Colonia Inalambrica, Merida C.P. 97069, Yucatan, Mexico.
| | - Salvador Gomez-Carro
- Servicios de Salud de Yucatan, Hospital General Agustin O'Horan Unidad de Vigilancia Epidemiologica, Avenida Itzaes s/n Av. Jacinto Canek, Centro, Merida C.P. 97000, Yucatan, Mexico.
| | - Jose Farfan-Ale
- Centro de Investigaciones Regionales, Lab de Arbovirologia, Unidad Inalámbrica, Universidad Autonoma de Yucatan, Calle 43 No. 613 x Calle 90, Colonia Inalambrica, Merida C.P. 97069, Yucatan, Mexico.
| | - Dragan A Savic
- Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter EX4 4QF, UK.
| | - Frank E Muller-Karger
- Institute for Marine Remote Sensing, University of South Florida, College of Marine Science, 140 7th Avenue South, Saint Petersburg, FL 33701, USA.
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Hernandez-Morales I, Van Loock M. An Industry Perspective on Dengue Drug Discovery and Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:333-353. [DOI: 10.1007/978-981-10-8727-1_23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Wang L, Zhao H, Oliva SM, Zhu H. Modeling the transmission and control of Zika in Brazil. Sci Rep 2017; 7:7721. [PMID: 28798323 PMCID: PMC5552773 DOI: 10.1038/s41598-017-07264-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 06/28/2017] [Indexed: 01/18/2023] Open
Abstract
Zika virus, a reemerging mosquito-borne flavivirus, started spread across Central and Southern America and more recently to North America. The most serious impacted country is Brazil. Based on the transmission mechanism of the virus and assessment of the limited data on the reported suspected cases, we establish a dynamical model which allows us to estimate the basic reproduction number R 0 = 2.5020. The wild spreading of the virus make it a great challenge to public health to control and prevention of the virus. We formulate two control models to study the impact of releasing transgenosis mosquitoes (introducing bacterium Wolbachia into Aedes aegypti) on the transmission of Zika virus in Brazil. Our models and analysis suggest that simultaneously releasing Wolbachia-harboring female and male mosquitoes will achieve the target of population replacement, while releasing only Wolbachia-harboring male mosquitoes will suppress or even eradicate wild mosquitoes eventually. We conclude that only releasing male Wolbachia mosquitoes is a better strategy for control the spreading of Zika virus in Brazil.
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Affiliation(s)
- Liping Wang
- Department of Mathematics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, P.R. China
| | - Hongyong Zhao
- Department of Mathematics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, P.R. China.
| | - Sergio Muniz Oliva
- Departamento de Matemática Aplicada, Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, 1010, Cidade Universitária, CEP 05508-090, São Paulo, SP, Brazil
| | - Huaiping Zhu
- Lamps and Department of Mathematics and Statistics, York University, Toronto, ON, M3J 1P3, Canada
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23
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The Influence of Spatial Configuration of Residential Area and Vector Populations on Dengue Incidence Patterns in an Individual-Level Transmission Model. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14070792. [PMID: 28714879 PMCID: PMC5551230 DOI: 10.3390/ijerph14070792] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/07/2017] [Accepted: 07/11/2017] [Indexed: 11/22/2022]
Abstract
Dengue is a mosquito-borne infectious disease that is endemic in tropical and subtropical countries. Many individual-level simulation models have been developed to test hypotheses about dengue virus transmission. Often these efforts assume that human host and mosquito vector populations are randomly or uniformly distributed in the environment. Although, the movement of mosquitoes is affected by spatial configuration of buildings and mosquito populations are highly clustered in key buildings, little research has focused on the influence of the local built environment in dengue transmission models. We developed an agent-based model of dengue transmission in a village setting to test the importance of using realistic environments in individual-level models of dengue transmission. The results from one-way ANOVA analysis of simulations indicated that the differences between scenarios in terms of infection rates as well as serotype-specific dominance are statistically significant. Specifically, the infection rates in scenarios of a realistic environment are more variable than those of a synthetic spatial configuration. With respect to dengue serotype-specific cases, we found that a single dengue serotype is more often dominant in realistic environments than in synthetic environments. An agent-based approach allows a fine-scaled analysis of simulated dengue incidence patterns. The results provide a better understanding of the influence of spatial heterogeneity on dengue transmission at a local scale.
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24
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Mendenhall IH, Manuel M, Moorthy M, Lee TTM, Low DHW, Missé D, Gubler DJ, Ellis BR, Ooi EE, Pompon J. Peridomestic Aedes malayensis and Aedes albopictus are capable vectors of arboviruses in cities. PLoS Negl Trop Dis 2017. [PMID: 28650959 PMCID: PMC5501678 DOI: 10.1371/journal.pntd.0005667] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Dengue and chikungunya are global re-emerging mosquito-borne diseases. In Singapore, sustained vector control coupled with household improvements reduced domestic mosquito populations for the past 45 years, particularly the primary vector Aedes aegypti. However, while disease incidence was low for the first 30 years following vector control implementation, outbreaks have re-emerged in the past 15 years. Epidemiological observations point to the importance of peridomestic infection in areas not targeted by control programs. We investigated the role of vectors in peri-domestic areas. METHODS We carried out entomological surveys to identify the Aedes species present in vegetated sites in highly populated areas and determine whether mosquitoes were present in open-air areas frequented by people. We compared vector competence of Aedes albopictus and Aedes malayensis with Ae. aegypti after oral infection with sympatric dengue serotype 2 and chikungunya viruses. Mosquito saliva was tested for the presence of infectious virus particles as a surrogate for transmission following oral infection. RESULTS We identified Aedes albopictus and Aedes malayensis throughout Singapore and quantified their presence in forested and opened grassy areas. Both Ae. albopictus and Ae. malayensis can occupy sylvatic niches and were highly susceptible to both arboviruses. A majority of saliva of infected Ae. malayensis contained infectious particles for both viruses. CONCLUSIONS Our study reveals the prevalence of competent vectors in peri-domestic areas, including Ae. malayensis for which we established the vector status. Epidemics can be driven by infection foci, which are epidemiologically enhanced in the context of low herd immunity, selective pressure on arbovirus transmission and the presence of infectious asymptomatic persons, all these conditions being present in Singapore. Learning from Singapore's vector control success that reduced domestic vector populations, but has not sustainably reduced arboviral incidence, we suggest including peri-domestic vectors in the scope of vector management.
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Affiliation(s)
- Ian H. Mendenhall
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
- * E-mail: (IHM); (JP)
| | - Menchie Manuel
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
| | - Mahesh Moorthy
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
- Department of Clinical Virology, Christian Medical College, Vellore, Tamilnadu, India
| | - Theodore T. M. Lee
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Dolyce H. W. Low
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
| | - Dorothée Missé
- MIVEGEC, UMR IRD 224-CNRS5290-Université de Montpellier, Montpellier, France
| | - Duane J. Gubler
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
| | - Brett R. Ellis
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
| | - Eng Eong Ooi
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
| | - Julien Pompon
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore
- MIVEGEC, UMR IRD 224-CNRS5290-Université de Montpellier, Montpellier, France
- * E-mail: (IHM); (JP)
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25
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Kumar N, Abdullah M, Faizan MI, Ahmed A, Alsenaidy HA, Dohare R, Parveen S. Progression dynamics of Zika fever outbreak in El Salvador during 2015–2016: a mathematical modeling approach. Future Virol 2017. [DOI: 10.2217/fvl-2017-0119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim: The aim of the study was to utilize mathematical modeling to investigate effect of different parameters that affected mosquito-borne transmission of Zika virus during 2015–2016 outbreak in El Salvador. The model can be used to predict outbreaks at various geographical regions utilizing different conditions. Materials & methods: A susceptible-exposed-infectious-recovered mathematical model was generated for disease progression. Results: The model correlated with actual number of reported cases and stability analysis. The value of reproduction number (Ro = 4.5537) indicated rapid spread of viral infection suggestive of an outbreak. Simulations revealed that transitional parameters affected disease progression. Conclusion: Investigation of progression of infection in a given population using mathematical models may assist in prediction of outbreaks and in formulation of control measures.
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Affiliation(s)
- Narender Kumar
- Department of Mathematics, Gargi College, University of Delhi, New Delhi, India
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Mohd Abdullah
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
- School of Life Sciences, Jaipur National University, Rajasthan, India
| | - Md Imam Faizan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Anwar Ahmed
- Protein Research Chair, Department of Biochemistry, King Saud University, Riyadh, Saudi Arabia
| | | | - Ravins Dohare
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Shama Parveen
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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Kim S, Masud M, Cho G, Jung IH. Analysis of a vector-bias effect in the spread of malaria between two different incidence areas. J Theor Biol 2017; 419:66-76. [DOI: 10.1016/j.jtbi.2017.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 02/01/2017] [Accepted: 02/04/2017] [Indexed: 11/28/2022]
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Sardar T, Saha B. Mathematical analysis of a power-law form time dependent vector-borne disease transmission model. Math Biosci 2017; 288:109-123. [PMID: 28274854 DOI: 10.1016/j.mbs.2017.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/28/2017] [Accepted: 03/01/2017] [Indexed: 11/17/2022]
Abstract
In the last few years, fractional order derivatives have been used in epidemiology to capture the memory phenomena. However, these models do not have proper biological justification in most of the cases and lack a derivation from a stochastic process. In this present manuscript, using theory of a stochastic process, we derived a general time dependent single strain vector borne disease model. It is shown that under certain choice of time dependent transmission kernel this model can be converted into the classical integer order system. When the time-dependent transmission follows a power law form, we showed that the model converted into a vector borne disease model with fractional order transmission. We explicitly derived the disease-free and endemic equilibrium of this new fractional order vector borne disease model. Using mathematical properties of nonlinear Volterra type integral equation it is shown that the unique disease-free state is globally asymptotically stable under certain condition. We define a threshold quantity which is epidemiologically known as the basic reproduction number (R0). It is shown that if R0 > 1, then the derived fractional order model has a unique endemic equilibrium. We analytically derived the condition for the local stability of the endemic equilibrium. To test the model capability to capture real epidemic, we calibrated our newly proposed model to weekly dengue incidence data of San Juan, Puerto Rico for the time period 30th April 1994 to 23rd April 1995. We estimated several parameters, including the order of the fractional derivative of the proposed model using aforesaid data. It is shown that our proposed fractional order model can nicely capture real epidemic.
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Affiliation(s)
- Tridip Sardar
- Agricultural and Ecological Research Unit, Indian Statistical Institute, 203, B. T. Road, Kolkata, 700108, West Bengal, India.
| | - Bapi Saha
- Govt. College of Engineering and Textile Technology, Berhampore, 742101, West Bengal, India.
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Falcón-Lezama JA, Martínez-Vega RA, Kuri-Morales PA, Ramos-Castañeda J, Adams B. Day-to-Day Population Movement and the Management of Dengue Epidemics. Bull Math Biol 2016; 78:2011-2033. [PMID: 27704330 PMCID: PMC5069346 DOI: 10.1007/s11538-016-0209-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 09/21/2016] [Indexed: 12/03/2022]
Abstract
Dengue is a growing public health problem in tropical and subtropical cities. It is transmitted by mosquitoes, and the main strategy for epidemic prevention and control is insecticide fumigation. Effective management is, however, proving elusive. People’s day-to-day movement about the city is believed to be an important factor in the epidemiological dynamics. We use a simple model to examine the fundamental roles of broad demographic and spatial structures in epidemic initiation, growth and control. We show that the key factors are local dilution, characterised by the vector–host ratio, and spatial connectivity, characterised by the extent of habitually variable movement patterns. Epidemic risk in the population is driven by the demographic groups that frequent the areas with the highest vector–host ratio, even if they only spend some of their time there. Synchronisation of epidemic trajectories in different demographic groups is governed by the vector–host ratios to which they are exposed and the strength of connectivity. Strategies for epidemic prevention and management may be made more effective if they take into account the fluctuating landscape of transmission intensity associated with spatial heterogeneity in the vector–host ratio and people’s day-to-day movement patterns.
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Affiliation(s)
- Jorge A Falcón-Lezama
- Centro de Investigaciones sobre Enfermedades Infecciosas, Instituto Nacional de Salud Publica, Universidad 655, Colonia Sta. Maria Ahuacatitlán, Cerrada Los Pinos y Caminera. C.P., 62100, Cuernavaca, Morelos, Mexico.,Carlos Slim Health Institute, Lago Zurich 245, Edif. Presa Falcón piso 20, Ampliación Granada. Del. Miguel Hidalgo, C.P. 11529, Ciudad de Mexico, Mexico
| | - Ruth A Martínez-Vega
- Organizacion Latinoamericana de Fomento a la Investigacion en Salud, Calle 110 No. 21-30, Of. 604, Bucaramanga, Santander, Colombia
| | - Pablo A Kuri-Morales
- Subsecretaría de Prevención y Promoción de la Salud, Lieja 7, 1er piso, Colonia Juárez, Del. Cuauhtémoc, C.P. 06600, Ciudad de Mexico, Mexico
| | - José Ramos-Castañeda
- Centro de Investigaciones sobre Enfermedades Infecciosas, Instituto Nacional de Salud Publica, Universidad 655, Colonia Sta. Maria Ahuacatitlán, Cerrada Los Pinos y Caminera. C.P., 62100, Cuernavaca, Morelos, Mexico.,UTMB Center for Tropical Diseases, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77555-0435, USA
| | - Ben Adams
- Department of Mathematical Sciences, University of Bath, Bath, BA27AY, UK.
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de Lima TFM, Lana RM, de Senna Carneiro TG, Codeço CT, Machado GS, Ferreira LS, de Castro Medeiros LC, Davis Junior CA. DengueME: A Tool for the Modeling and Simulation of Dengue Spatiotemporal Dynamics. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:E920. [PMID: 27649226 PMCID: PMC5036753 DOI: 10.3390/ijerph13090920] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 08/17/2016] [Accepted: 09/01/2016] [Indexed: 12/31/2022]
Abstract
The prevention and control of dengue are great public health challenges for many countries, particularly since 2015, as other arboviruses have been observed to interact significantly with dengue virus. Different approaches and methodologies have been proposed and discussed by the research community. An important tool widely used is modeling and simulation, which help us to understand epidemic dynamics and create scenarios to support planning and decision making processes. With this aim, we proposed and developed DengueME, a collaborative open source platform to simulate dengue disease and its vector's dynamics. It supports compartmental and individual-based models, implemented over a GIS database, that represent Aedes aegypti population dynamics, human demography, human mobility, urban landscape and dengue transmission mediated by human and mosquito encounters. A user-friendly graphical interface was developed to facilitate model configuration and data input, and a library of models was developed to support teaching-learning activities. DengueME was applied in study cases and evaluated by specialists. Other improvements will be made in future work, to enhance its extensibility and usability.
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Affiliation(s)
- Tiago França Melo de Lima
- Departamento de Computação e Sistemas (DECSI), Instituto de Ciências Exatas e Aplicadas (ICEA), Universidade Federal de Ouro Preto (UFOP) - Campus João Monlevade, João Monlevade, MG 35931-008, Brasil.
| | - Raquel Martins Lana
- Programa Pós-Graduação em Epidemiologia em Saúde Pública, Escola Nacional de Saúde Pública Sérgio Arouca (ENSP), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ 21045-900, Brasil.
| | - Tiago Garcia de Senna Carneiro
- Departamento de Computação (DECOM), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP) - Campus Morro do Cruzeiro, Ouro Preto, MG 35400-000, Brasil.
| | - Cláudia Torres Codeço
- Programa de Computação Científica (PROCC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ 21045-900, Brasil.
| | - Gabriel Souza Machado
- Departamento de Computação e Sistemas (DECSI), Instituto de Ciências Exatas e Aplicadas (ICEA), Universidade Federal de Ouro Preto (UFOP) - Campus João Monlevade, João Monlevade, MG 35931-008, Brasil.
| | - Lucas Saraiva Ferreira
- Departamento de Computação e Sistemas (DECSI), Instituto de Ciências Exatas e Aplicadas (ICEA), Universidade Federal de Ouro Preto (UFOP) - Campus João Monlevade, João Monlevade, MG 35931-008, Brasil.
| | - Líliam César de Castro Medeiros
- Instituto de Ciência e Tecnologia, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), São José dos Campos, SP 12247-004, Brasil.
| | - Clodoveu Augusto Davis Junior
- Departamento de Ciência da Computação (DCC), Instituto de Ciências Exatas (ICEx), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG 31270-010, Brasil.
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Prevention and Control of Zika as a Mosquito-Borne and Sexually Transmitted Disease: A Mathematical Modeling Analysis. Sci Rep 2016; 6:28070. [PMID: 27312324 PMCID: PMC4911567 DOI: 10.1038/srep28070] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022] Open
Abstract
The ongoing Zika virus (ZIKV) epidemic in the Americas poses a major global public health emergency. While ZIKV is transmitted from human to human by bites of Aedes mosquitoes, recent evidence indicates that ZIKV can also be transmitted via sexual contact with cases of sexually transmitted ZIKV reported in Argentina, Canada, Chile, France, Italy, New Zealand, Peru, Portugal, and the USA. Yet, the role of sexual transmission on the spread and control of ZIKV infection is not well-understood. We introduce a mathematical model to investigate the impact of mosquito-borne and sexual transmission on the spread and control of ZIKV and calibrate the model to ZIKV epidemic data from Brazil, Colombia, and El Salvador. Parameter estimates yielded a basic reproduction number 0 = 2.055 (95% CI: 0.523–6.300), in which the percentage contribution of sexual transmission is 3.044% (95% CI: 0.123–45.73). Our sensitivity analyses indicate that 0 is most sensitive to the biting rate and mortality rate of mosquitoes while sexual transmission increases the risk of infection and epidemic size and prolongs the outbreak. Prevention and control efforts against ZIKV should target both the mosquito-borne and sexual transmission routes.
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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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Knipl D, Moghadas SM. The Potential Impact of Vaccination on the Dynamics of Dengue Infections. Bull Math Biol 2015; 77:2212-30. [PMID: 26585748 DOI: 10.1007/s11538-015-0120-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 10/22/2015] [Indexed: 12/01/2022]
Abstract
Dengue, classified as a 'neglected topical disease', is currently regarded globally as the most important mosquito-borne viral disease, which inflicts substantial socioeconomic and health burden in many tropical and subtropical regions of the world. While efforts continue towards developing and improving the efficacy of a tetravalent vaccine to protect individuals against all dengue virus serotypes, the long-term epidemiological impact of vaccination remains elusive. We develop a serotype-specific, vector-host compartmental model to evaluate the effect of vaccination in the presence of antibody-dependent enhancement and cross-protection following recovery from primary infection. Reproducing the reported multi-annual patterns of dengue infection, our model projects that vaccination can dramatically reduce the overall incidence of the disease. However, if the duration of vaccine-induced protection is shorter than the average lifetime of the human population, vaccination can potentially increase the incidence of severe infection of dengue haemorrhagic fever due to the effects of antibody-dependent enhancement. The magnitude and timelines for this increase depend strongly on the efficacy and duration of the vaccine-induced protection. Corresponding to the current estimates of vaccine efficacy, we show that dengue eradication is infeasible using an imperfect vaccine. Furthermore, for a vaccine that induces lifetime protection, a nearly full coverage of infant vaccination is required for dengue elimination. Our findings suggest that other vector control measures may still play a significant role in dengue prevention even when a vaccine with high protection efficacy becomes available.
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Affiliation(s)
- Diána Knipl
- Agent-Based Modelling Laboratory, York University, 4700 Keele St., Toronto, ON, M3J 1P3, Canada. .,MTA-SZTE Analysis and Stochastic Research Group, University of Szeged, Aradi vértanúk tere 1, Szeged, 6720, Hungary.
| | - Seyed M Moghadas
- Agent-Based Modelling Laboratory, York University, 4700 Keele St., Toronto, ON, M3J 1P3, Canada.
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Parham PE, Waldock J, Christophides GK, Hemming D, Agusto F, Evans KJ, Fefferman N, Gaff H, Gumel A, LaDeau S, Lenhart S, Mickens RE, Naumova EN, Ostfeld RS, Ready PD, Thomas MB, Velasco-Hernandez J, Michael E. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2013.0551. [PMID: 25688012 DOI: 10.1098/rstb.2013.0551] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems.
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Affiliation(s)
- Paul E Parham
- Department of Public Health and Policy, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3GL, UK Grantham Institute for Climate Change, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Joanna Waldock
- The Cyprus Institute, Nicosia, Cyprus Imperial College London, London SW7 2AZ, UK
| | | | - Deborah Hemming
- Meteorological Office Hadley Centre, UK Meteorological Office, Fitzroy Road, Exeter, EX1 3PB, UK
| | - Folashade Agusto
- Department of Mathematics, Austin Peay State University, Clarksville, TN 37044, USA
| | - Katherine J Evans
- Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, USA
| | - Nina Fefferman
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA
| | - Holly Gaff
- Department of Biological Sciences, Old Dominium University, Norfolk, VA 23529, USA
| | - Abba Gumel
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ 85287-1904, USA School of Mathematical and Natural Sciences, Arizona State University, Phoenix, AZ 85069-7100, USA
| | - Shannon LaDeau
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN 37996-1300, USA
| | - Ronald E Mickens
- Department of Physics, Clark Atlanta University, PO Box 172, Atlanta, GA 30314, USA
| | - Elena N Naumova
- Department of Civil and Environmental Engineering, Tufts University School of Engineering, Medford, MA 02155, USA
| | - Richard S Ostfeld
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Paul D Ready
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Matthew B Thomas
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jorge Velasco-Hernandez
- Universidad Nacional Autnoma de Mexico Institute of Mathematics Mexico City, Distrito Federal, Mexico
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
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WILLIAMS CR, GILL BS, MINCHAM G, MOHD ZAKI AH, ABDULLAH N, MAHIYUDDIN WRW, AHMAD R, SHAHAR MK, HARLEY D, VIENNET E, AZIL A, KAMALUDDIN A. Testing the impact of virus importation rates and future climate change on dengue activity in Malaysia using a mechanistic entomology and disease model. Epidemiol Infect 2015; 143:2856-64. [PMID: 25591942 PMCID: PMC9151082 DOI: 10.1017/s095026881400380x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/19/2014] [Accepted: 12/12/2014] [Indexed: 11/07/2022] Open
Abstract
We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.
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Affiliation(s)
- C. R. WILLIAMS
- Sansom Institute for Health Research, University of South Australia, Adelaide, Australia
| | - B. S. GILL
- Disease Control Division, Ministry of Health Malaysia
| | - G. MINCHAM
- Sansom Institute for Health Research, University of South Australia, Adelaide, Australia
| | | | - N. ABDULLAH
- Epidemiology and Biostatistics Unit, Institute for Medical Research, Malaysia
| | - W. R. W. MAHIYUDDIN
- Epidemiology and Biostatistics Unit, Institute for Medical Research, Malaysia
| | - R. AHMAD
- Medical Entomology Unit & WHO Collaborating Centre, Institute for Medical Research, Malaysia
| | - M. K. SHAHAR
- Medical Entomology Unit & WHO Collaborating Centre, Institute for Medical Research, Malaysia
| | - D. HARLEY
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - E. VIENNET
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - A. AZIL
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia, Malaysia
| | - A. KAMALUDDIN
- Environmental Health Research Centre, Institute for Medical Research, Malaysia
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35
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Regis LN, Acioli RV, Silveira JC, de Melo-Santos MAV, da Cunha MCS, Souza F, Batista CAV, Barbosa RMR, de Oliveira CMF, Ayres CFJ, Monteiro AMV, Souza WV. Characterization of the spatial and temporal dynamics of the dengue vector population established in urban areas of Fernando de Noronha, a Brazilian oceanic island. Acta Trop 2014; 137:80-7. [PMID: 24832009 DOI: 10.1016/j.actatropica.2014.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 04/02/2014] [Accepted: 04/05/2014] [Indexed: 11/15/2022]
Abstract
Aedes aegypti has played a major role in the dramatic expansion of dengue worldwide. The failure of control programs in reducing the rhythm of global dengue expansion through vector control suggests the need for studies to support more appropriated control strategies. We report here the results of a longitudinal study on Ae. aegypti population dynamics through continuous egg sampling aiming to characterize the infestation of urban areas of a Brazilian oceanic island, Fernando de Noronha. The spatial and temporal distribution of the dengue vector population in urban areas of the island was described using a monitoring system (SMCP-Aedes) based on a 103-trap network for Aedes egg sampling, using GIS and spatial statistics analysis tools. Mean egg densities were estimated over a 29-month period starting in 2011 and producing monthly maps of mosquito abundance. The system detected continuous Ae. aegypti oviposition in most traps. The high global positive ovitrap index (POI=83.7% of 2815 events) indicated the frequent presence of blood-fed-egg laying females at every sampling station. Egg density (eggs/ovitrap/month) reached peak values of 297.3 (0 - 2020) in May and 295 (0 - 2140) in August 2012. The presence of a stable Ae. aegypti population established throughout the inhabited areas of the island was demonstrated. A strong association between egg abundance and rainfall with a 2-month lag was observed, which combined with a first-order autocorrelation observed in the series of egg counts can provide an important forecasting tool. This first description of the characteristics of the island infestation by the dengue vector provides baseline information to analyze relationships between the spatial distribution of the vector and dengue cases, and to the development of integrated vector control strategies.
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Affiliation(s)
- Lêda N Regis
- Departamento de Entomologia, Fiocruz-PE, Recife, Brazil.
| | | | | | | | | | - Fátima Souza
- Health Department of the District of Fernando de Noronha-PE, Brazil
| | | | | | | | | | - Antonio Miguel Vieira Monteiro
- Centro de Ciência do Sistema Terrestre, Instituto Nacional de Pesquisas Espaciais, INPE, São José dos Campos, SP, Brazil
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36
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Rodrigues HS, Monteiro MTT, Torres DFM. Vaccination models and optimal control strategies to dengue. Math Biosci 2014; 247:1-12. [PMID: 24513243 DOI: 10.1016/j.mbs.2013.10.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 05/21/2013] [Accepted: 10/14/2013] [Indexed: 02/05/2023]
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37
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Pepin KM, Marques-Toledo C, Scherer L, Morais MM, Ellis B, Eiras AE. Cost-effectiveness of novel system of mosquito surveillance and control, Brazil. Emerg Infect Dis 2013; 19:542-50. [PMID: 23628282 PMCID: PMC3647717 DOI: 10.3201/eid1904.120117] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Of all countries in the Western Hemisphere, Brazil has the highest economic losses caused by dengue fever. We evaluated the cost-effectiveness of a novel system of vector surveillance and control, Monitoramento Inteligente da Dengue (Intelligent Dengue Monitoring System [MID]), which was implemented in 21 cities in Minas Gerais, Brazil. Traps for adult female mosquitoes were spaced at 300-m intervals throughout each city. In cities that used MID, vector control was conducted specifically at high-risk sites (indicated through daily updates by MID). In control cities, vector control proceeded according to guidelines of the Brazilian government. We estimated that MID prevented 27,191 cases of dengue fever and saved an average of $227 (median $58) per case prevented, which saved approximately $364,517 in direct costs (health care and vector control) and $7,138,940 in lost wages (societal effect) annually. MID was more effective in cities with stronger economies and more cost-effective in cities with higher levels of mosquito infestation.
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Affiliation(s)
- Kim M Pepin
- National Institutes of Health, Bethesda, Maryland, USA
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38
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Regis LN, Acioli RV, Silveira JC, Melo-Santos MAV, Souza WV, Ribeiro CMN, da Silva JCS, Monteiro AMV, Oliveira CMF, Barbosa RMR, Braga C, Rodrigues MAB, Silva MGNM, Ribeiro PJ, Bonat WH, de Castro Medeiros LC, Carvalho MS, Furtado AF. Sustained reduction of the dengue vector population resulting from an integrated control strategy applied in two Brazilian cities. PLoS One 2013; 8:e67682. [PMID: 23844059 PMCID: PMC3701045 DOI: 10.1371/journal.pone.0067682] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/20/2013] [Indexed: 11/30/2022] Open
Abstract
Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008-2009, with 96.8%-100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program's success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program.
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Affiliation(s)
- Lêda N Regis
- Departameto de Entomologia, Fundação Oswaldo Cruz-Fiocruz-Pe, Recife-PE, Brazil.
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Abstract
We present a stochastic dynamical model for the transmission of dengue that considers the co-evolution of the spatial dynamics of the vectors (Aedes aegypti) and hosts (human population), allowing the simulation of control strategies adapted to the actual evolution of an epidemic outbreak. We observed that imposing restrictions on the movement of infected humans is not a highly effective strategy. In contrast, isolating infected individuals with high levels of compliance by the human population is efficient even when implemented with delays during an ongoing outbreak. We also studied insecticide-spraying strategies assuming different (hypothetical) efficiencies. We observed that highly efficient fumigation strategies seem to be effective during an outbreak. Nevertheless, taking into account the controversial results on the use of spraying as a single control strategy, we suggest that carrying out combined strategies of fumigation and isolation during an epidemic outbreak should account for a suitable strategy for the attenuation of epidemic outbreaks.
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40
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Padilla-Torres SD, Ferraz G, Luz SLB, Zamora-Perea E, Abad-Franch F. Modeling dengue vector dynamics under imperfect detection: three years of site-occupancy by Aedes aegypti and Aedes albopictus in urban Amazonia. PLoS One 2013; 8:e58420. [PMID: 23472194 PMCID: PMC3589427 DOI: 10.1371/journal.pone.0058420] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/05/2013] [Indexed: 12/04/2022] Open
Abstract
Aedes aegypti and Ae. albopictus are the vectors of dengue, the most important arboviral disease of humans. To date, Aedes ecology studies have assumed that the vectors are truly absent from sites where they are not detected; since no perfect detection method exists, this assumption is questionable. Imperfect detection may bias estimates of key vector surveillance/control parameters, including site-occupancy (infestation) rates and control intervention effects. We used a modeling approach that explicitly accounts for imperfect detection and a 38-month, 55-site detection/non-detection dataset to quantify the effects of municipality/state control interventions on Aedes site-occupancy dynamics, considering meteorological and dwelling-level covariates. Ae. aegypti site-occupancy estimates (mean 0.91; range 0.79–0.97) were much higher than reported by routine surveillance based on ‘rapid larval surveys’ (0.03; 0.02–0.11) and moderately higher than directly ascertained with oviposition traps (0.68; 0.50–0.91). Regular control campaigns based on breeding-site elimination had no measurable effects on the probabilities of dwelling infestation by dengue vectors. Site-occupancy fluctuated seasonally, mainly due to the negative effects of high maximum (Ae. aegypti) and minimum (Ae. albopictus) summer temperatures (June-September). Rainfall and dwelling-level covariates were poor predictors of occupancy. The marked contrast between our estimates of adult vector presence and the results from ‘rapid larval surveys’ suggests, together with the lack of effect of local control campaigns on infestation, that many Aedes breeding sites were overlooked by vector control agents in our study setting. Better sampling strategies are urgently needed, particularly for the reliable assessment of infestation rates in the context of control program management. The approach we present here, combining oviposition traps and site-occupancy models, could greatly contribute to that crucial aim.
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Affiliation(s)
- Samael D. Padilla-Torres
- Graduate Program in Ecology, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil
| | - Gonçalo Ferraz
- Graduate Program in Ecology, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil
- Biological Dynamics of Forest Fragments Project, Smithsonian Tropical Research Institute/Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil
| | - Sergio L. B. Luz
- Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Amazonas, Brazil
| | - Elvira Zamora-Perea
- Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Amazonas, Brazil
| | - Fernando Abad-Franch
- Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Amazonas, Brazil
- * E-mail:
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Predictive Dynamics: Modeling for Virological Surveillance and Clinical Management of Dengue. DYNAMIC MODELS OF INFECTIOUS DISEASES 2013. [PMCID: PMC7121019 DOI: 10.1007/978-1-4614-3961-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dengue fever is a flu-like illness spread by the bite of an infected mosquito and is fast emerging as a major public health concern. Timely and cost-effective diagnosis would reduce the mortality rates besides providing better grounds for clinical management and disease surveillance. Identifying the clinical features for early diagnosis of dengue would be useful in reducing the virus transmission in a community. In addition to the clinical features, obtaining the influential laboratory attributes and their range would aid in quick identification of disease severity in the suspected individuals. In this chapter a new alternating decision tree methodology which generates more accurate and simplified decision tree structures with simplified classification rules is discussed. This approach helps one to obtain the influential clinical and laboratory features which would aid in identifying the suspected dengue individuals and assess the severity of infection in them.
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42
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Andraud M, Hens N, Marais C, Beutels P. Dynamic epidemiological models for dengue transmission: a systematic review of structural approaches. PLoS One 2012; 7:e49085. [PMID: 23139836 PMCID: PMC3490912 DOI: 10.1371/journal.pone.0049085] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 10/07/2012] [Indexed: 02/05/2023] Open
Abstract
Dengue is a vector-borne disease recognized as the major arbovirose with four immunologically distant dengue serotypes coexisting in many endemic areas. Several mathematical models have been developed to understand the transmission dynamics of dengue, including the role of cross-reactive antibodies for the four different dengue serotypes. We aimed to review deterministic models of dengue transmission, in order to summarize the evolution of insights for, and provided by, such models, and to identify important characteristics for future model development. We identified relevant publications using PubMed and ISI Web of Knowledge, focusing on mathematical deterministic models of dengue transmission. Model assumptions were systematically extracted from each reviewed model structure, and were linked with their underlying epidemiological concepts. After defining common terms in vector-borne disease modelling, we generally categorised fourty-two published models of interest into single serotype and multiserotype models. The multi-serotype models assumed either vector-host or direct host-to-host transmission (ignoring the vector component). For each approach, we discussed the underlying structural and parameter assumptions, threshold behaviour and the projected impact of interventions. In view of the expected availability of dengue vaccines, modelling approaches will increasingly focus on the effectiveness and cost-effectiveness of vaccination options. For this purpose, the level of representation of the vector and host populations seems pivotal. Since vector-host transmission models would be required for projections of combined vaccination and vector control interventions, we advocate their use as most relevant to advice health policy in the future. The limited understanding of the factors which influence dengue transmission as well as limited data availability remain important concerns when applying dengue models to real-world decision problems.
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Affiliation(s)
- Mathieu Andraud
- Centre for Health Economics Research and Modelling of Infectious Diseases (CHERMID), Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerpen, Belgium.
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Padmanabha H, Durham D, Correa F, Diuk-Wasser M, Galvani A. The interactive roles of Aedes aegypti super-production and human density in dengue transmission. PLoS Negl Trop Dis 2012; 6:e1799. [PMID: 22953017 PMCID: PMC3429384 DOI: 10.1371/journal.pntd.0001799] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/16/2012] [Indexed: 11/29/2022] Open
Abstract
Background A. aegypti production and human density may vary considerably in dengue endemic areas. Understanding how interactions between these factors influence the risk of transmission could improve the effectiveness of the allocation of vector control resources. To evaluate the combined impacts of variation in A. aegypti production and human density we integrated field data with simulation modeling. Methodology/Principal Findings Using data from seven censuses of A. aegypti pupae (2007–2009) and from demographic surveys, we developed an agent-based transmission model of the dengue transmission cycle across houses in 16 dengue-endemic urban ‘patches’ (1–3 city blocks each) of Armenia, Colombia. Our field data showed that 92% of pupae concentrated in only 5% of houses, defined as super-producers. Average secondary infections (R0) depended on infrequent, but highly explosive transmission events. These super-spreading events occurred almost exclusively when the introduced infectious person infected mosquitoes that were produced in super-productive containers. Increased human density favored R0, and when the likelihood of human introduction of virus was incorporated into risk, a strong interaction arose between vector production and human density. Simulated intervention of super-productive containers was substantially more effective in reducing dengue risk at higher human densities. Significance/Conclusions These results show significant interactions between human population density and the natural regulatory pattern of A. aegypti in the dynamics of dengue transmission. The large epidemiological significance of super-productive containers suggests that they have the potential to influence dengue viral adaptation to mosquitoes. Human population density plays a major role in dengue transmission, due to its potential impact on human-A. aegypti contact, both within a person's home and when visiting others. The large variation in population density within typical dengue endemic cities suggests that it should be a major consideration in dengue control policy. In the urban dengue system the life history of the mosquito vector, Aedes aegypti, transpires mainly inside and around human residences. In this study we integrated field data from an endemic city of Colombia into a simulation model to assess how natural variation in A. aegypti production and household human density influence dengue transmission. Contrary to traditional models, we show that the basic reproductive rate of dengue (Ro) is more likely to be positively correlated with human density. Moreover, the natural regulatory pattern of A. aegypti production, where a few super-productive houses dominate vector recruitment, caused a "super-spreading" pattern, whereby the large majority of viral introductions did not generate secondary infections, and Ro depended on sporadic, highly explosive transmission events. These events were dependent on the introduced infectious human infecting mosquitoes produced in super-productive vessels. When the likelihood of human introduction was incorporated into our risk indicator, a significant interaction emerged between human density and A. aegypti super production, such that removal of these containers had a much larger impact on reducing dengue in areas of higher human density. These results show that knowledge of interactions between human population density, social interactions and the natural regulatory pattern of A. aegypti can improve the design of dengue control efforts.
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Affiliation(s)
- Harish Padmanabha
- Yale School of Public Health, New Haven, Connecticut, United States of America.
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Chen SC, Hsieh MH. Modeling the transmission dynamics of dengue fever: implications of temperature effects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 431:385-391. [PMID: 22705874 DOI: 10.1016/j.scitotenv.2012.05.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/04/2012] [Accepted: 05/04/2012] [Indexed: 06/01/2023]
Abstract
The purpose of this study was to investigate the transmission dynamic modeling of dengue fever in subtropical Taiwan by the contributing temperature-dependent entomological parameters of Aedes aegypti. A vector-host transmission model was used to explore the temperature variation of pre-adult mosquito maturation, oviposition rate, adult mosquito death rate, and virus incubation rate in the mosquito. Sensitivity analysis, by transmissible biting rate and the initial mosquito population, was adapted to observe features of the epidemic. This study showed that the entomological parameter estimates are positively correlated with a gradual temperature increase, but not with pre-adult mosquito maturation rate and mosquito death rate, indicating the limitation of pre-adult mosquito maturation rate. Results show that the temperature climate factor was indeed important and influenced the dynamic modeling of the vector-host interaction. Results from our simulation also suggest that the greatest risk of dengue transmission occurs at temperatures equal to 28 °C. In the future, these results could be used for control measures modeling and cost-effectiveness analysis.
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Affiliation(s)
- Szu-Chieh Chen
- Department of Public Health, Chung Shan Medical University, Taichung 40201, Taiwan, ROC.
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Arboleda S, Jaramillo-O N, Peterson AT. Spatial and temporal dynamics of Aedes aegypti larval sites in Bello, Colombia. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2012; 37:37-48. [PMID: 22548535 DOI: 10.1111/j.1948-7134.2012.00198.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Counts of immature stages of the mosquito Aedes aegypti have been used to calculate several entomological indices of dengue vector abundance. Some studies have concluded that these indices can be used as indicators of dengue epidemic risk, while other studies have failed to find a predictive relationship. Ecological niche models have been able to predict distributional patterns in space and time, not only of vectors, but also of the diseases that they transmit. In this study, we used Landsat 7 ETM+ images and two niche-modeling algorithms to estimate the local-landscape ecological niche and the dynamics of Ae. aegypti larval habitats in Bello, Colombia, and to evaluate their potential spatial and temporal distribution. Our models showed low omission error with high confidence levels: about 13.4% of the area presents conditions consistently suitable for breeding across the entire study period (2002-2008). The proportion of neighborhoods predicted to be suitable showed a positive association with dengue case rates, whereas the vector-focused Bretau index had no relationship to case rates. As a consequence, niche models appear to offer a superior option for predictive evaluation of dengue transmission risk and anticipating the potential for outbreaks.
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Affiliation(s)
- Sair Arboleda
- Grupo de Biología y Control de Enfermedades Infecciosas (BCEI), Instituto de Biología, Universidad de Antioquia, Sede de Investigaciones Universitarias, Medellín, Colombia.
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