{"title":"Stability of an HTLV-HIV coinfection model with multiple delays and CTL-mediated immunity.","authors":"N H AlShamrani","doi":"10.1186/s13662-021-03416-7","DOIUrl":"https://doi.org/10.1186/s13662-021-03416-7","url":null,"abstract":"<p><p>In the literature, several mathematical models have been formulated and developed to describe the within-host dynamics of either human immunodeficiency virus (HIV) or human T-lymphotropic virus type I (HTLV-I) monoinfections. In this paper, we formulate and analyze a novel within-host dynamics model of HTLV-HIV coinfection taking into consideration the response of cytotoxic T lymphocytes (CTLs). The uninfected <math><mi>CD</mi> <msup><mn>4</mn> <mo>+</mo></msup> <mi>T</mi></math> cells can be infected via HIV by two mechanisms, free-to-cell and infected-to-cell. On the other hand, the HTLV-I has two modes for transmission, (i) horizontal, via direct infected-to-cell touch, and (ii) vertical, by mitotic division of active HTLV-infected cells. It is well known that the intracellular time delays play an important role in within-host virus dynamics. In this work, we consider six types of distributed-time delays. We investigate the fundamental properties of solutions. Then, we calculate the steady states of the model in terms of threshold parameters. Moreover, we study the global stability of the steady states by using the Lyapunov method. We conduct numerical simulations to illustrate and support our theoretical results. In addition, we discuss the effect of multiple time delays on stability of the steady states of the system.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2021 1","pages":"270"},"PeriodicalIF":4.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-021-03416-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38953292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mostafa Bachar, Mohamed A Khamsi, Messaoud Bounkhel
{"title":"A mathematical model for the spread of COVID-19 and control mechanisms in Saudi Arabia.","authors":"Mostafa Bachar, Mohamed A Khamsi, Messaoud Bounkhel","doi":"10.1186/s13662-021-03410-z","DOIUrl":"https://doi.org/10.1186/s13662-021-03410-z","url":null,"abstract":"<p><p>In this work, we develop and analyze a nonautonomous mathematical model for the spread of the new corona-virus disease (<i>COVID-19</i>) in Saudi Arabia. The model includes eight time-dependent compartments: the dynamics of low-risk <math><msub><mi>S</mi> <mi>L</mi></msub> </math> and high-risk <math><msub><mi>S</mi> <mi>M</mi></msub> </math> susceptible individuals; the compartment of exposed individuals <i>E</i>; the compartment of infected individuals (divided into two compartments, namely those of infected undiagnosed individuals <math><msub><mi>I</mi> <mi>U</mi></msub> </math> and the one consisting of infected diagnosed individuals <math><msub><mi>I</mi> <mi>D</mi></msub> </math> ); the compartment of recovered undiagnosed individuals <math><msub><mi>R</mi> <mi>U</mi></msub> </math> , that of recovered diagnosed <math><msub><mi>R</mi> <mi>D</mi></msub> </math> individuals, and the compartment of extinct <i>Ex</i> individuals. We investigate the persistence and the local stability including the reproduction number of the model, taking into account the control measures imposed by the authorities. We perform a parameter estimation over a short period of the total duration of the pandemic based on the <i>COVID-19</i> epidemiological data, including the number of infected, recovered, and extinct individuals, in different time episodes of the <i>COVID-19</i> spread.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2021 1","pages":"253"},"PeriodicalIF":4.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-021-03410-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38996186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global dynamics of a novel deterministic and stochastic SIR epidemic model with vertical transmission and media coverage.","authors":"Xiaodong Wang, Chunxia Wang, Kai Wang","doi":"10.1186/s13662-020-03145-3","DOIUrl":"https://doi.org/10.1186/s13662-020-03145-3","url":null,"abstract":"<p><p>In this paper, we study a novel deterministic and stochastic SIR epidemic model with vertical transmission and media coverage. For the deterministic model, we give the basic reproduction number <math><msub><mi>R</mi> <mn>0</mn></msub> </math> which determines the extinction or prevalence of the disease. In addition, for the stochastic model, we prove existence and uniqueness of the positive solution, and extinction and persistence in mean. Furthermore, we give numerical simulations to verify our results.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"685"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-020-03145-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38352119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A numerical solution by alternative Legendre polynomials on a model for novel coronavirus (COVID-19).","authors":"Elham Hashemizadeh, Mohammad Ali Ebadi","doi":"10.1186/s13662-020-02984-4","DOIUrl":"https://doi.org/10.1186/s13662-020-02984-4","url":null,"abstract":"<p><p>Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus. This paper provides a numerical solution for the mathematical model of the novel coronavirus by the application of alternative Legendre polynomials to find the transmissibility of COVID-19. The mathematical model of the present problem is a system of differential equations. The goal is to convert this system to an algebraic system by use of the useful property of alternative Legendre polynomials and collocation method that can be solved easily. We compare the results of this method with those of the Runge-Kutta method to show the efficiency of the proposed method.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"527"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-020-02984-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38553429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shahram Rezapour, Hakimeh Mohammadi, Mohammad Esmael Samei
{"title":"SEIR epidemic model for COVID-19 transmission by Caputo derivative of fractional order.","authors":"Shahram Rezapour, Hakimeh Mohammadi, Mohammad Esmael Samei","doi":"10.1186/s13662-020-02952-y","DOIUrl":"10.1186/s13662-020-02952-y","url":null,"abstract":"<p><p>We provide a SEIR epidemic model for the spread of COVID-19 using the Caputo fractional derivative. The feasibility region of the system and equilibrium points are calculated and the stability of the equilibrium points is investigated. We prove the existence of a unique solution for the model by using fixed point theory. Using the fractional Euler method, we get an approximate solution to the model. To predict the transmission of COVID-19 in Iran and in the world, we provide a numerical simulation based on real data.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"490"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-020-02952-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38398611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A fractional system of delay differential equation with nonsingular kernels in modeling hand-foot-mouth disease.","authors":"Behzad Ghanbari","doi":"10.1186/s13662-020-02993-3","DOIUrl":"10.1186/s13662-020-02993-3","url":null,"abstract":"<p><p>In this article, we examine a computational model to explore the prevalence of a viral infectious disease, namely hand-foot-mouth disease, which is more common in infants and children. The structure of this model consists of six sub-populations along with two delay parameters. Besides, by taking advantage of the Atangana-Baleanu fractional derivative, the ability of the model to justify different situations for the system has been improved. Discussions about the existence of the solution and its uniqueness are also included in the article. Subsequently, an effective numerical scheme has been employed to obtain several meaningful approximate solutions in various scenarios imposed on the problem. The sensitivity analysis of some existing parameters in the model has also been investigated through several numerical simulations. One of the advantages of the fractional derivative used in the model is the use of the concept of memory in maintaining the substantial properties of the understudied phenomena from the origin of time to the desired time. It seems that the tools used in this model are very powerful and can effectively simulate the expected theoretical conditions in the problem, and can also be recommended in modeling other computational models in infectious diseases.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"536"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523494/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38553430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A stochastic SIR epidemic model with Lévy jump and media coverage.","authors":"Yingfen Liu, Yan Zhang, Qingyun Wang","doi":"10.1186/s13662-020-2521-6","DOIUrl":"https://doi.org/10.1186/s13662-020-2521-6","url":null,"abstract":"<p><p>A stochastic susceptible-infectious-recovered epidemic model with temporary immunity and media coverage is proposed. The effects of Lévy jumps on the dynamics of the model are considered. A unique global positive solution for the epidemic model is obtained. Sufficient conditions are derived to guarantee that the epidemic disease is extinct and persistent in the mean. The threshold behavior is discussed. Numerical simulations are given to verify our theoretical results.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"70"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-020-2521-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37957997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bifurcation analysis of a SEIR epidemic system with governmental action and individual reaction.","authors":"Abdelhamid Ajbar, Rubayyi T Alqahtani","doi":"10.1186/s13662-020-02997-z","DOIUrl":"https://doi.org/10.1186/s13662-020-02997-z","url":null,"abstract":"<p><p>In this paper, the dynamical behavior of a SEIR epidemic system that takes into account governmental action and individual reaction is investigated. The transmission rate takes into account the impact of governmental action modeled as a step function while the decreasing contacts among individuals responding to the severity of the pandemic is modeled as a decreasing exponential function. We show that the proposed model is capable of predicting Hopf bifurcation points for a wide range of physically realistic parameters for the COVID-19 disease. In this regard, the model predicts periodic behavior that emanates from one Hopf point. The model also predicts stable oscillations connecting two Hopf points. The effect of the different model parameters on the existence of such periodic behavior is numerically investigated. Useful diagrams are constructed that delineate the range of periodic behavior predicted by the model.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"541"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13662-020-02997-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38554653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stochastic SIRC epidemic model with time-delay for COVID-19.","authors":"F A Rihan, H J Alsakaji, C Rajivganthi","doi":"10.1186/s13662-020-02964-8","DOIUrl":"10.1186/s13662-020-02964-8","url":null,"abstract":"<p><p>Environmental factors, such as humidity, precipitation, and temperature, have significant impacts on the spread of the new strain coronavirus COVID-19 to humans. In this paper, we use a stochastic epidemic SIRC model, with cross-immune class and time-delay in transmission terms, for the spread of COVID-19. We analyze the model and prove the existence and uniqueness of positive global solution. We deduce the basic reproduction number <math><msubsup><mi>R</mi> <mn>0</mn> <mi>s</mi></msubsup> </math> for the stochastic model which is smaller than <math><msub><mi>R</mi> <mn>0</mn></msub> </math> of the corresponding deterministic model. Sufficient conditions that guarantee the existence of a unique ergodic stationary distribution, using the stochastic Lyapunov function, and conditions for the extinction of the disease are obtained. Our findings show that white noise plays an important part in controlling the spread of the disease; When the white noise is relatively large, the infectious diseases will become extinct; Re-infection and periodic outbreaks can occur due to the existence of feedback time-delay (or memory) in the transmission terms.</p>","PeriodicalId":53311,"journal":{"name":"Advances in Difference Equations","volume":"2020 1","pages":"502"},"PeriodicalIF":4.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7499021/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38411033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}