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Modeling transmission dynamics of Ebola virus disease

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International Journal of Biomathematics 2017年第4期10卷 297-331页

作者： Mudassar Imran Adnan Khan Ali R. Ansari Syed Touqeer Hussain Shah International Center for Applied Mathematics and Computational Bioengineering Department of Mathematics and Natural Sciences Gulf University for Science and Technology Hawally Kuwait Department of Mathematics Lahore University of Management Sciences Lahore Pakistan

Ebola virus disease （EVD） has emerged as a rapidly spreading potentially fatal disease. Several studies have been performed recently to investigate the dynamics of EVD. In this paper, we study the transmission dynamics of EVD by formulating an SEIR-type transmission model that includes isolated individuals as well as dead individuals that are not yet buried. Dynamical systems analysis of the model is performed, and it is consequently shown that the disease-free steady state is globally asymptotically stable when the basic reproduction number, R0 is less than unity. It is also shown that there exists a unique endemic equilibrium when R0 〉 1. Using optimal control theory, we propose control strategies, which will help to eliminate the Ebola disease. We use data fitting on models, with and without isolation, to estimate the basic reproductive numbers for the 2014 outbreak of EVD in Liberia and Sierra Leone.

关键词： Ebola virus disease endemic equilibrium basic reproduction number hos-pitalization infectiousness optimal control transmission dynamics time series datafitting.

Mathematical modeling for Delta and Omicron variant of SARS-CoV-2 transmission dynamics in Greece

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Infectious Disease Modelling 2023年第3期8卷 794-805页

作者： Sofia Liossi E.Tsiambas S.Maipas E.Papageorgiou A.Lazaris N.Kavantzas 1st Department of Pathology School of MedicineNational and Kapodistrian University of AthensAthens General Hospital“Laikon”AthensGreece Department of Cytopathology 417 Army Equity Fund Hospital(NIMTS)AthensGreece Master Program“Environment and Health.Management of Environmental Health Effects” School of MedicineNational and Kapodistrian University of AthensAthensGreece Department of Biomedical Sciences School of Health&Welfare SciencesUniversity of West AtticaEgaleoGreece

A compartmental,epidemiological,mathematical model was developed in order to analyze the transmission dynamics of Delta and Omicron variant,of SARS-CoV-2,in *** model was parameterized twice during the 4th and 5th wave of the *** 4th wave refers to the period during which the Delta variant was dominant(approximately July to December of 2021)and the 5th wave to the period during which the Omicron variant was dominant(approximately January to May of 2022),in accordance with the official data from the National Public Health Organization(NPHO).Fitting methods were applied to evaluate important parameters in connection with the transmission of the variants,as well as the social behavior of population during these periods of *** models revealed higher numbers of contagiousness and cases of asymptomatic disease during the Omicron variant period,but a decreased rate of hospitalization compared to the Delta ***,parameters related to the behavior of the population in Greece were also *** specifically,the use of protective masks and the abidance of social distancing *** revealed that over 5,000 deaths could have been avoided,if mask usage and social distancing were 20%more efficient,during the short period of the Delta and Omicron ***,the spread of the variants was assessed using viral load *** data were recorded from PCR tests at 417 Army Equity Fund Hospital(NIMTS),in Athens and the Ct values from 746 patients with COVID-19 were processed,to explain transmission phenomena and disease severity in *** period when the Delta variant prevailed in the country,the average Ct value was calculated as 25.19(range:12.32e39.29),whereas during the period when the Omicron variant prevailed,the average Ct value was calculated as 28(range:14.41e39.36).In conclusion,our experimental study showed that the higher viral load,which is related to the Delta variant,may interpret the severity of the

关键词： Delta variant Omicron variant Mathematical modeling transmission dynamics Ct value Data fitting

Infer HIV transmission dynamics from gene sequences among young men who have sex with men in China

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Infectious Disease Modelling 2021年第1期6卷 832-838页

作者： Xin Jin Jinjin Cheng Jie Lou Department of Mathematics Shanghai University99 Shangda RoadShanghai200444PR China

To investigate the transmission dynamics and temporal and spatial migration characteristics of HIV spread among men who have sex with men(MSM)in China,a total of 1012 HIV-1 partial pol sequences,including five subtypes,were *** analysis were applied for each subtype to infer its dynamic characters including the effective reproductive number(R_(e))and migration *** mean curve of each R_(e) was almost always greater than 1(even the 95%highest posterior density(HPD)lower value)along with time,which supports the necessity for a comprehensive study about risk behaviors among young MSM group in *** also should reappraise the free treatment strategy,especially the therapeutic effect during the free treatment policy.

关键词： HIV Gene sequence transmission dynamics Bayesian analysis Effective reproductive number

Cascading Failure Propagation Simulation in Integrated Electricity and Natural Gas Systems

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Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 961-970页

作者： Zhejing Bao Qihong Zhang Lei Wu Dawei Chen College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Department of Electrical and Computer Engineering Stevens Institute of TechnologyHobokenNJ 07901USA

The sharp increase in the total installed capacity of natural gas generators has intensified the dynamic interaction between the electricity and natural gas systems,which could induce cascading failure propagation across the two systems that deserves intensive *** the distinct time response behaviors of the two systems,this paper discusses an integrated simulation approach to simulate the cascading failure propagation process of integrated electricity and natural gas systems(IEGSs).On one hand,considering instantaneous re-distribution of power flows after the occurrence of disturbance or failure,the steady-state AC power flow model is *** the other hand,gas transmission dynamics are represented by dynamic model to capture the details of its transition *** interactions between the two systems,intensified by energy coupling components(such as gas-fired generator and electricity-driven gas compressor)as well as the switching among the operation modes of compressors during the cascading failure propagation process,are *** IEGS composed of the IEEE 30-bus electricity system and a 14-node 15-pipeline gas system is established to illustrate the effectiveness of the proposed simulation approach,in which two energy sub-systems are coupled by compressor and gas-fired *** results clearly demonstrate that heterogeneous interactions between electricity and gas systems would trigger the cascading failure propagation between the two coupling systems.

关键词： Cascading failure propagation integrated electricity and natural gas system(IEGS) gas compressor transmission dynamics

EpiMix:A novel method to estimate effective reproduction number

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Infectious Disease Modelling 2023年第3期8卷 704-716页

作者： Shihui Jin Borame Lee Dickens Jue Tao Lim Alex R.Cook Saw Swee Hock School of Public Health National University of Singapore and National University Health SystemSingapore Lee Kong Chian School of Medicine Nanyang Technological UniversitySingapore Department of Statistics and Data Science National University of SingaporeSingapore

transmission potential of a pathogen,often quantified by the time-varying reproduction number R t,provides the current pace of infection for a disease and indicates whether an emerging epidemic is under *** this study,we proposed a novel method,EpiMix,for R t estimation,wherein we incorporated the impacts of exogenous factors and random effects under a Bayesian regression *** Integrated Nested Laplace Approx-imation,EpiMix is able to efficiently generate reliable,deterministic R t *** the simulations and case studies performed,we further demonstrated the method's robust-ness in low-incidence scenarios,together with other merits,including its flexibility in selecting variables and tolerance of varying reporting *** these make EpiMix a potentially useful tool for real-time R t estimation provided that the serial interval distri-bution,time series of case counts and external influencing factors are available.

关键词： Epidemics INLA Regression Reproduction number SARS-CoV-2 transmission dynamics

COVID-19 transmission driven by age-group mathematical model in Shijiazhuang City of China

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Infectious Disease Modelling 2023年第4期8卷 1050-1062页

作者： Fengying Wei Ruiyang Zhou Zhen Jin Senzhong Huang Zhihang Peng Jinjie Wang Ximing Xu Xinyan Zhang Jun Xu Yao Bai Xiaoli Wang Bulai Lu Zhaojun Wang Jianguo Xu School of Mathematics and Statistics Fuzhou UniversityFuzhou350116FujianChina Center for Applied Mathematics of Fujian Province Fuzhou UniversityFuzhou350116FujianChina Key Laboratory of Operations Research and Control of Universities in Fujian Fuzhou UniversityFuzhou350116FujianChina Complex Systems Research Center Shanxi UniversityTaiyuan030006ShanxiChina School of Statistics and Data Science ZhiYing Research Center for Health DataNankai University300071TianjinChina Department of Biostatistics School of Public HealthNanjing Medical UniversityNanjing211166JiangsuChina Nankai Institute of Economics Binhai Development InstituteNankai UniversityTianjin300071China Children's Hospital of Chongqing Medical University Chongqing400010China Jinzhou Center for Disease Control and Prevention Jinzhou121000LiaoningChina School of Statistics and Data Science Nankai UniversityTianjin300071China Xi'an Center for Disease Control and Prevention Xi'an710061ShaanxiChina Beijing Center for Disease Control and Prevention Beijing100013China Suzhou Center for Disease Control and Prevention Suzhou215004JiangsuChina State Key Laboratory of Communicable Disease Prevention and Control National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing102206China Institute of Public Health Nankai UniversityTianjin300071China

Background:A COVID-19 outbreak in the rural areas of Shijiazhuang City was attributed to the complex interactions among vaccination,host,and non-pharmaceutical interventions(NPIs).Herein,we investigated the epidemiological characteristics of all reported symptomatic cases by picking Shijiazhuang City,Hebei Province in Northern China as research *** addition,we established an age-group mathematical model to perform the optimal fitting and to investigate the dynamical profiles under three ***:All reported symptomatic cases of Shijiazhuang epidemic(January 2-February 3,2021)were investigated in our *** cases were classified by gender,age group and location,the distributions were analyzed by epidemiological ***,the reported data from Health Commission of Hebei Province was also analyzed by using an age-group mathematical model by two phases and three ***:Shijiazhuang epidemic caused by SARS-CoV-2 wild strain was recorded with the peak 84 cases out of 868 reported symptomatic cases on January 11,2021,which was implemented with strong NPIs by local government and referred as baseline situation in this *** research results showed that R0 under baseline situation ranged from 4.47 to 7.72,and Rt of Gaocheng Distinct took 3.72 with 95%confidence interval from 3.23 to 4.35 on January 9,the declining tendencies of Rt under baseline situation were kept till February 3,the value of Rt reached below 1 on January 19 and remained low value up to February 3 for Gaocheng District and Shijiazhuang City during Shijiazhuang *** indicated Shijiazhuang epidemic was under control on January ***,if the strong NPIs were kept,but remote isolation operated on January 11 was not implemented as of February 9,then the scale of Shijiazhuang epidemic reached 9,482 cases from age group who were 60 years old and over out of 31,017 symptomatic *** investigation also revealed that Shijiazhuang epidemic reache

关键词： COVID-19 Wild strain Non-pharmaceutical interventions Shijiazhuang epidemic transmission dynamics

Dynamic evolution of an SVEIR model with variants and non-pharmaceutical interventions for controlling COVID-19

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Journal of Biosafety and Biosecurity 2024年第2期6卷 67-75页

作者： Ruiyang Zhou Shaojian Cai Guangmin Chen Senzhong Huang Zhen Jin Zhihang Peng Weichuan Lin Fengying Wei Kuicheng Zheng School of Mathematics and Statistics Fuzhou UniversityFuzhou 350116FujianChina Fujian Provincial Center for Disease Control and Prevention Fuzhou 350012FujianChina School of Statistics and Data Science ZhiYing Research Center for Health DataNankai UniversityTianjin 300071China Complex Systems Research Center Shanxi UniversityTaiyuan 030006ShanxiChina Department of Biostatistics School of Public HealthNanjing Medical UniversityNanjing 211166JiangsuChina School of Mathematics and Statistics Fujian Normal UniversityFuzhou 350007FujianChina Center for Applied Mathematics of Fujian Province Fuzhou UniversityFuzhou 350116FujianChina Key Laboratory of Operations Research and Control of Universities in Fujian Fuzhou UniversityFuzhou 350116FujianChina Fujian Provincial Key Laboratory of Zoonosis Research Fuzhou 350001FujianChina Teaching Base of the School of Public Health of Fujian Medical University Fuzhou 350001FujianChina

The epidemiological characteristics and distributions of two epidemics in Fujian Province of Southeast China were attributed to the complex interactions among variant,host,and non-pharmaceutical interventions(NPIs).All reported cases in the Putian epidemic(September 8–October 2,2021,Delta variant B.1.617.2)and Fuzhou epidemic(October 22–November 18,2022,Omicron variant BA.5.2)were classified by sex,age group,occupation,and location in this *** surveillance data from the Fujian Provincial Center for Disease Control and Prevention,we established a virus-oriented SVEIR(Susceptible–Vaccinated–Exposed–Infected–Recovered)model to investigate the dynamic evolution features of these two variants and the effects of *** optimal simulations were carried out with variants and scenario *** scenario investigations showed that NPIs significantly reduced the transmission risk and infection scales of COVID-19,and that the Omicron variant was more infectious than the Delta ***,the dynamic investigations revealed the increasing tendencies from Delta to Omicron,such as the basic reproduction number,infection rate,percentage of high-risk cases,and the growth *** tendencies were also identified,such as the average recovery period,the awareness delay,and the percentage of symptomatic *** study highlighted that NPIs played critical roles in successfully containing the two *** interventions are strongly recommended to public health policymakers.

关键词： COVID-19 SVEIR model transmission dynamics Non-pharmaceutical interventions Delta variant Omicron variant