Infected Equilibrium Research Articles

Global stability of a virus dynamics model with cure rate and absorption

Abstract In this paper, we investigate a mathematical model which takes account the cure of infected cells and the loss of viral particles due to the absorption into uninfected cells. The global stability of the model is determined by using the direct Lyapunov method for disease-free equilibrium, and the geometrical approach for chronic infection equilibrium.

Global stability of nonresident computer virus models

In this paper, applying Lyapunov functional techniques to nonresident computer virus models, we establish global dynamics of the model whose threshold parameter is the basic reproduction number R0 such that the virus‐free equilibrium is globally asymptotically stable when R0 ≤ 1, and the infected equilibrium is globally asymptotically stable when R0 > 1 under the same restricted condition on a parameter, which appeared in the literature on delayed susceptible‐infected‐recovered‐susceptible (SIRS) epidemic models. We use new techniques on permanence and global stability of this model for R0 > 1. Copyright © 2014 John Wiley & Sons, Ltd.

Analysis of a CD4$^+$ T cell viral infection model with a class of saturated infection rate

This paper formulates and analyzes an HIV-1 infection model with saturated infection rate. We first discuss the boundedness of the solution and the existence of the equilibrium. The local stability of the virus-free equilibrium and infected equilibrium is established by analyzing the roots of the characteristic equations. Furthermore, we study the global stability of the virus-free equilibrium and infected equilibrium by using suitable Lyapunov function and LaSalle's invariance principle, and obtain sufficient conditions for the global stability of the infected equilibrium. Finally, numerical simulations are presented to illustrate the main results.

Global Analysis of a Virus Dynamics Model with General Incidence Function and Cure Rate

A virus dynamics model with logistic function, general incidence function, and cure rate is considered. By carrying out mathematical analysis, we show that the infection-free equilibrium is globally asymptotically stable if the basic reproduction numberℛ0≤1. Ifℛ0>1, then the infection equilibrium is globally asymptotically stable under some assumptions. Furthermore, we also obtain the conditions for which the model exists an orbitally asymptotically stable periodic solution. Examples are provided to support our analytical conclusions.

Global Dynamics of an HTLV-1 Model with Cell-to-Cell Infection and Mitosis

A mathematical model of human T-cell lymphotropic virus type 1 in vivo with cell-to-cell infection and mitosis is formulated and studied. The basic reproductive numberR0is derived. It is proved that the dynamics of the model can be determined completely by the magnitude ofR0. The infection-free equilibrium is globally asymptotically stable (unstable) ifR0<1 (R0>1). There exists a chronic infection equilibrium and it is globally asymptotically stable ifR0>1.

Dynamics analysis and simulation of a modified HIV infection model with a saturated infection rate.

This paper studies a modified human immunodeficiency virus (HIV) infection differential equation model with a saturated infection rate. It is proved that if the basic virus reproductive number R 0 of the model is less than one, then the infection-free equilibrium point of the model is globally asymptotically stable; if R 0 of the model is more than one, then the endemic infection equilibrium point of the model is globally asymptotically stable. Based on the clinical data from HIV drug resistance database of Stanford University, using the proposed model simulates the dynamics of the two groups of patients' anti-HIV infection treatment. The numerical simulation results are in agreement with the evolutions of the patients' HIV RNA levels. It can be assumed that if an HIV infected individual's basic virus reproductive number R 0 < 1 then this person will recover automatically; if an antiretroviral therapy makes an HIV infected individual's R 0 < 1, this person will be cured eventually; if an antiretroviral therapy fails to suppress an HIV infected individual's HIV RNA load to be of unpredictable level, the time that the patient's HIV RNA level has achieved the minimum value may be the starting time that drug resistance has appeared.

具有饱和感染率的随机SIR传染病模型的性质分析

建立了一类具有饱和感染率的随机SIR模型，假设易感者、感染者及移出者三群体的自然死亡率和疾病感染率分别受到相互独立的高斯白噪声干扰。首先证明了在一定的条件下，感染者与移出者种群将依指数趋于灭绝。再就是相应确定性系统的地方病平衡点存在时，得到了该随机系统围绕该点具有稳定的分布且该分布是遍历的充分条件。A stochastically mathematical model of a stochastic SIR epidemic model with saturated incidence rates is proposed and analyzed, setting that all the death rate and incident rate are similarly per-turbed by an independent Gaussian white noise. First the paper shows that the infective population and recovered individuals will tend to zero exponentially almost surely under some additional condition. In addition, a sufficient condition for the stationary distribution around the endemic infection equilibrium state of the corresponding deterministic model is derived and the solution is ergodic.

Stability and Hopf Bifurcation of a Computer Virus Model with Infection Delay and Recovery Delay

A computer virus model with infection delay and recovery delay is considered. The sufficient conditions for the global stability of the virus infection equilibrium are established. We show that the time delay can destabilize the virus infection equilibrium and give rise to Hopf bifurcations and stable periodic orbits. By the normal form and center manifold theory, the direction of the Hopf bifurcation and stability of the bifurcating periodic orbits are determined. Numerical simulations are provided to support our theoretical conclusions.

Hopf Bifurcation and Stability of Periodic Solutions for Delay Differential Model of HIV Infection of CD4+T-cells

This paper deals with stability and Hopf bifurcation analyses of a mathematical model of HIV infection ofCD4+T-cells. The model is based on a system of delay differential equations with logistic growth term and antiretroviral treatment with a discrete time delay, which plays a main role in changing the stability of each steady state. By fixing the time delay as a bifurcation parameter, we get a limit cycle bifurcation about the infected steady state. We study the effect of the time delay on the stability of the endemically infected equilibrium. We derive explicit formulae to determine the stability and direction of the limit cycles by using center manifold theory and normal form method. Numerical simulations are presented to illustrate the results.

Stability and Hopf bifurcation for a virus infection model with delayed humoral immunity response

In this paper, we investigate the dynamical behavior of a virus infection model with delayed humoral immunity. By using suitable Lyapunov functional and the LaSalleʼs invariance principle, we establish the global stabilities of the two boundary equilibria. If R0<1, the uninfected equilibrium E0 is globally asymptotically stable; if R1<1<R0, the infected equilibrium without immunity E1 is globally asymptotically stable. When R1>1, we obtain the sufficient conditions to the local stability of the infected equilibrium with immunity E2. The time delay can change the stability of E2 and lead to the existence of Hopf bifurcations. The stabilities of bifurcating periodic solutions is also studied. We check our theorems with numerical simulations in the end.

Dynamical behaviors of a discrete HIV-1 virus model with bilinear infective rate

We establish a discrete virus dynamic model by discretizing a continuous HIV-1 virus model with bilinear infective rate using ‘hybrid’ Euler method. We discuss not only the existence and global stability of the uninfected equilibrium but also the existence and local stability of the infected equilibrium. We prove that there exists a crucial value similar to that of the continuous HIV-1 virus dynamics, which is called the basic reproductive ratio of the virus. If the basic reproductive ratio of the virus is less than one, the uninfected equilibrium is globally asymptotically stable. If the basic reproductive ratio of the virus is larger than one, the infected equilibrium exists and is locally stable. Moreover, we consider the permanence for such a system by constructing a Lyapunov function vn. Copyright © 2013 John Wiley & Sons, Ltd.

Global Dynamics of a HIV Infection Model with Delayed CTL Response and Cure Rate

In this paper, we have considered a viral infection model with delayed CTL response and cure rate. For this model, we have researched the stability of these three equilibriums depend on two threshold parameters and , that is, if , the infected-free equilibrium is locally asymptotically stable; if , the infected equilibrium without CTL response is globally asymptotically stable; and if , the infected equilibrium exists, at he same time, we have found that the time delay can lead to Hopf bifurcations and stable periodic solutions when the is unstable.

Global Stability of a HBV Infection Model with Saturated Infection Rates and Time Delay

This paper investigates the global stability of a viral infection model of HBV infection of hepatocytes with saturated infection rate and intracellular delay. we obtain if the basic reproductive number is less than or equal to one, the infection-free equilibrium is globally asymptotically stable. If its greater than one, we obtain the sufficient conditions for the global stability of the infected equilibrium.

Mathematical analysis of the global dynamics of an eco-epidemiological model with time delay

In this paper, an eco-epidemiological predator–prey model with time delay representing the gestation period of the predator is investigated. In the model, it is assumed that the predator population suffers a transmissible disease by contact. By analyzing corresponding characteristic equations, the local stability of each of feasible equilibria and the existence of Hopf bifurcations at the disease-free equilibrium, the prey–infected predator equilibrium and the endemic-coexistence equilibrium are established. By means of Lyapunov functionals and LaSalle's invariance principle, sufficient conditions are obtained for the global asymptotic stability of the predator-extinction equilibrium, the disease-free equilibrium, the prey–infected predator equilibrium and the endemic-coexistence equilibrium of the model.

Dynamic Model on the Transmission of Malicious Codes in Network

This paper introduces differential susceptible e-epidemic model SSiiIIII (susceptible class-1 for virus (S1) susceptible class-2 for worms (S2) -susceptible class-3 for Trojan horse (S3) – infectious (I) – recovered (R)) for the transmission of malicious codes in a computer network. We derive the formula for reproduction number (R0) to study the spread of malicious codes in computer network. We show that the Infectious free equilibrium is globally asymptotically stable and endemic equilibrium is locally asymptotically sable when reproduction number is less than one. Also an analysis has been made on the effect of antivirus software in the infectious nodes. Numerical methods are employed to solve and simulate the system of equations developed. Index Terms — Computer network; Worms; Virus; Trojan horse; Epidemic Model; Reproduction number; Global stability

Global stability of the virus dynamics model with intracellular delay and Crowley–Martin functional response

In this paper, a virus dynamics model with intracellular delay and Crowley–Martin functional response is discussed. By constructing suitable Lyapunov functions and using LaSalles invariance principle for delay differential equations, we established the global stability of uninfected equilibrium and infected equilibrium; it is proved that if the basic reproductive number is less than or equal to one, the uninfected equilibrium is globally asymptotically stable; if the basic reproductive number is more than one, the infected equilibrium is globally asymptotically stable. We also discuss the effects of intracellular delay on global dynamical properties by comparing the results with the stability conditions for the model without delay. Copyright © 2013 John Wiley &amp; Sons, Ltd.

A Delay Virus Dynamics Model with General Incidence Rate

In this paper, the dynamical behavior of a virus dynamics model with general incidence rate and intracellular delay is studied. Lyapunov functionals are constructed and LaSalle invariance principle for delay differential equation is used to establish the global asymptotic stability of the disease-free equilibrium and the chronic infection equilibrium. The results obtained show that the global dynamics are completely determined by the value of a certain threshold parameter called the basic reproduction number $$R_0$$ and under some assumptions on the general incidence function. Our results extend the known results on delay virus dynamics considered in other papers and suggest useful methods to control virus infection. These results can be applied to a variety of possible incidence functions that could be used in virus dynamics model as well as epidemic models.

Global stability analysis for delayed virus infection model with general incidence rate and humoral immunity

In this paper, we investigate the dynamical behavior of a virus infection model with general incidence rate and humoral immunity. By using suitable Lyapunov functional and the LaSalle's invariance principle, we establish the global stability of the three equilibria. The uninfected equilibrium E0 is globally asymptotically stable if R0≤1, the infected equilibrium without immunity E1 is globally asymptotically stable if R1≤1 and R0>1, the infected equilibrium with humoral immunity E2 is globally asymptotically stable if R1>1. We check our theorems with numerical simulation in the end.

Two-dimensional stability analysis in a HIV model with quadratic logistic growth term

We consider a Human Immunodeficiency Virus (HIV) model with a logistic growth term and continue the analysis of the previous article [6]. We now take the viral diffusion in a two-dimensional environment. The model consists of two ODEs for the concentrations of the target T cells, the infected cells, and a parabolic PDE for the virus particles. We study the stability of the uninfected and infected equilibria, the occurrence of Hopf bifurcation and the stability of the periodic solutions.

Global Stability of HIV-1 Infection Model with Two Time Delays

We investigate global dynamics for a system of delay differential equations which describes a virus-immune interaction in vivo. The model has two time delays describing time needed for infection of cell and CTLs generation. Our model admits three possible equilibria: infection-free equilibrium, CTL-absent infection equilibrium, and CTL-present infection equilibrium. The effect of time delay on stability of the equilibria of the CTL immune response model has been studied.