Mathematical modeling and numerical simulation are valuable tools for getting theoretical insights into dynamic processes such as, for example, within-host virus dynamics or disease transmission between individuals. In this work, we propose a new time discretization, a so-called non-standard finite-difference-method, for numerical simulation of the classical target cell limited dynamical within-host HIV-model. In our case, we use a non-local approximation of our right-hand-side function of our dynamical system. This means that this right-hand-side function is approximated by current and previous time steps of our non-equidistant time grid. In contrast to classical explicit time stepping schemes such as Runge-Kutta methods which are often applied in these simulations, the main advantages of our novel time discretization method are preservation of non-negativity, often occurring in biological or physical processes, and convergence towards the correct equilibrium point, independently of the time step size. Additionally, we prove boundedness of our time-discrete solution components which underline biological plausibility of the time-continuous model, and linear convergence towards the time-continuous problem solution. We also construct higher-order non-standard finite-difference-methods from our first-order suggested model by modifying ideas from Richardson's extrapolation. This extrapolation idea improves accuracy of our time-discrete solutions. We finally underline our theoretical findings by numerical experiments.
Citation: Benjamin Wacker, Jan Christian Schlüter. Analysis of a non-standard finite-difference-method for the classical target cell limited dynamical within-host HIV-model - Numerics and applications[J]. Mathematical Biosciences and Engineering, 2025, 22(9): 2360-2390. doi: 10.3934/mbe.2025086
Mathematical modeling and numerical simulation are valuable tools for getting theoretical insights into dynamic processes such as, for example, within-host virus dynamics or disease transmission between individuals. In this work, we propose a new time discretization, a so-called non-standard finite-difference-method, for numerical simulation of the classical target cell limited dynamical within-host HIV-model. In our case, we use a non-local approximation of our right-hand-side function of our dynamical system. This means that this right-hand-side function is approximated by current and previous time steps of our non-equidistant time grid. In contrast to classical explicit time stepping schemes such as Runge-Kutta methods which are often applied in these simulations, the main advantages of our novel time discretization method are preservation of non-negativity, often occurring in biological or physical processes, and convergence towards the correct equilibrium point, independently of the time step size. Additionally, we prove boundedness of our time-discrete solution components which underline biological plausibility of the time-continuous model, and linear convergence towards the time-continuous problem solution. We also construct higher-order non-standard finite-difference-methods from our first-order suggested model by modifying ideas from Richardson's extrapolation. This extrapolation idea improves accuracy of our time-discrete solutions. We finally underline our theoretical findings by numerical experiments.
| [1] | J. D. Murray, Mathematical Biology I: An Introduction, $3^{rd}$ edition, Springer-Verlag, New York, 2002. https://doi.org/10.1007/b98868 |
| [2] |
H. A. Ashi, D. M. Alahmadi, A mathematical model of brain tumor, Math. Method. Appl. Sci., 46 (2023), 10137–10150. https://doi.org/10.1002/mma.9107 doi: 10.1002/mma.9107
|
| [3] |
V. Srivastava, E. M. Takyi, R. D. Parshad, The effect of "fear" on two species competition, Math. Biosci. Eng., 20 (2023), 8814–8855. https://doi.org/10.3934/mbe.2023388 doi: 10.3934/mbe.2023388
|
| [4] |
B. Wacker, J. C. Schlüter, Qualitative analysis of two systems of non-linear first-order ordinary differential equations for biological systems, Math. Meth. Appl. Sci., 45 (2022), 4597–4624. https://doi.org/10.1002/mma.8056 doi: 10.1002/mma.8056
|
| [5] |
O. K. Wanassi, D. F. M. Torres, Modeling blood alcohol concentration using fractional differential equations based on $\Psi$-Caputo derivative, Math. Meth. Appl. Sci., 47 (2024), 7793–7803. https://doi.org/10.1002/mma.10002 doi: 10.1002/mma.10002
|
| [6] | M. Feinberg, Foundations of Chemical Reaction Network Theory, $1^{st}$ edition, Springer-Verlag, Cham, 2019. https://doi.org/10.1007/978-3-030-03858-8 |
| [7] |
L. Formaggia, A. Scotti, Positivity and Conservation Properties of some Integration Schemes for Mass Action Kinetics, SIAM J. Numer. Anal., 49 (2011), 1267–1288. https://doi.org/10.1137/100789592 doi: 10.1137/100789592
|
| [8] |
M. Mincheva, D. Siegel, Nonnegativity and positiveness of solutions to mass action reaction-diffusion systems, J. Math. Chem., 42 (2007), 1135–1145. https://doi.org/10.1007/s10910-007-9292-0 doi: 10.1007/s10910-007-9292-0
|
| [9] |
M. Bohner, S. Streipert, D. F. M. Torres, Exact solution to a dynamic SIR model, Nonlinear Anal. Hybrid Syst., 32 (2019), 228–238. https://doi.org/10.1016/j.nahs.2018.12.005 doi: 10.1016/j.nahs.2018.12.005
|
| [10] |
F. Brauer, Discrete epidemic models, Math. Biosci. Eng., 7 (2010), 1–15. https://doi.org/10.3934/mbe.2010.7.1 doi: 10.3934/mbe.2010.7.1
|
| [11] | M. Martcheva, An Introduction to Mathematical Epidemiology, $1^{st}$ edition, Springer-Verlag, New York, 2015. https://doi.org/10.1007/978-1-4899-7612-3 |
| [12] |
T. Cuchta, S. Streipert, Dynamic gompertz model, Appl. Math. Inf. Sci., 14 (2020), 9–17. https://doi.org/10.18576/amis/140102 doi: 10.18576/amis/140102
|
| [13] |
M. T. Hoang, J. C. Valverde, A generalized model for the population dynamics of a two stage species with recruitment and capture using a nonstandard finite difference scheme, Comput. Appl. Math., 43 (2024), 54. https://doi.org/10.1007/s40314-023-02539-9 doi: 10.1007/s40314-023-02539-9
|
| [14] |
S. H. Streipert, G. S. K. Wolkowicz, Derivation and dynamics of discrete population models with distributed delay in reproduction, Math. Biosci., 376 (2024), 109279. https://doi.org/10.1016/j.mbs.2024.109279 doi: 10.1016/j.mbs.2024.109279
|
| [15] |
S. Alizon, C. Magnus, Modelling the Course of an HIV Infection: Insights from Ecology and Evolution, Viruses, 4 (2012), 1984–2013. https://doi.org/10.3390/v4101984 doi: 10.3390/v4101984
|
| [16] |
I. D'Orso, C. V. Forst, Mathematical Models of HIV-1 Dynamics, Transcription, and Latency, Viruses, 15 (2023), 2119. https://doi.org/10.3390/v15102119 doi: 10.3390/v15102119
|
| [17] | D. E. Kirschner, Using Mathematics to Understand HIV Immune Dynamics, Notices Amer. Math. Soc., 43 (1996), 191–202. Available from: https://www.ams.org/journals/notices/199602/kirschner.pdf |
| [18] |
A. S. Perelson, D. E. Kirschner, R. De Boer, Dynamics of HIV infection of $ {\rm{CD4}}^{+}$ T cells, Math. Biosci., 114 (1993), 81–125. https://doi.org/10.1016/0025-5564(93)90043-A doi: 10.1016/0025-5564(93)90043-A
|
| [19] |
A. S. Perelson, A. U. Neumann, M. Markowitz, J. M. Leonard, D. D. Ho, HIV-1 Dynamics in Vivo: Virion Clearance Rate, Infected Cell Life-Span, and Viral Generation Time, Science, 271 (1996), 1582–1586. https://doi.org/10.1126/science.271.5255.1582 doi: 10.1126/science.271.5255.1582
|
| [20] |
A. S. Perelson, Modelling viral and immune system dynamics, Nat. Rev. Immunol., 2 (2002), 28–36. https://doi.org/10.1038/nri700 doi: 10.1038/nri700
|
| [21] |
B. Wacker, Revisiting the classical target cell limited dynamical within-host HIV model - Basic mathematical properties and stability analysis, Math. Biosci. Eng., 21 (2024), 7805–7829. https://doi.org/10.3934/mbe.2024343 doi: 10.3934/mbe.2024343
|
| [22] |
M. A. Stafford, L. Corey, Y. Cao, E. S. Daar, D. D. Ho, A. S. Perelson, Modeling plasma virus concentration during primary HIV infection, J. Theor. Biol., 203 (2000), 285–301. https://doi.org/10.1006/jtbi.2000.1076 doi: 10.1006/jtbi.2000.1076
|
| [23] |
C. Clarke, S. Pankavich, Three-stage modeling of HIV infection and implications for antiretroviral therapy, J. Math. Biol., 88 (2024), 34. https://doi.org/10.1007/s00285-024-02056-1 doi: 10.1007/s00285-024-02056-1
|
| [24] |
X. Liu, S. Ahmad, M. ur Rahman, Y. Nadeem, A. Akgül, Analysis of a TB and HIV co-infection model under Mittag-Leffler fractal-fractional derivative, Phys. Scr., 97 (2022), 054011. https://doi.org/10.1088/1402-4896/ac645e doi: 10.1088/1402-4896/ac645e
|
| [25] |
M. ur Rahman, Y. Karaca, R. P. Agarwal, S. A. David, Mathematical modelling with computational fractional order for the unfolding dynamics of the communicable diseases, Appl. Math. Sci. Eng., 32 (2024), 2300330. https://doi.org/10.1080/27690911.2023.2300330 doi: 10.1080/27690911.2023.2300330
|
| [26] |
A. Saleem, M. ur Rahman, S. Boulaaras, R. Guefaifia, D. Baleanu, Exploring the dynamics of HIV and HCV co-infection through piecewise modified Mittag-Leffler fractional derivatives, Appl. Math. Sci. Eng., 33 (2025), 2478038. https://doi.org/10.1080/27690911.2025.2478038 doi: 10.1080/27690911.2025.2478038
|
| [27] |
B. Wacker, J. C. Schlüter, Time-continuous and time-discrete SIR models revisited: Theory and applications, Adv. Differ. Equ., 2020 (2020), 556. https://doi.org/10.1186/s13662-020-02995-1 doi: 10.1186/s13662-020-02995-1
|
| [28] | E. Hairer, G. Wanner, S. P. Nørsett, Solving Ordinary Differential Equations I - Nonstiff problems, $1^{st}$ edition, Springer-Verlag, Berlin, 1993. https://doi.org/10.1007/978-3-540-78862-1 |
| [29] | E. Hairer, G. Wanner, Solving Ordinary Differential Equations II - Stiff and Differential-Algebraic Problems, $1^{st}$ edition, Springer-Verlag, Berlin, 1996. https://doi.org/10.1007/978-3-642-05221-7 |
| [30] |
H. Ranocha, M. Sayyari, L. Dalcin, M. Parsani, D. I. Ketcheson, Relaxation Runge-Kutta methods: Fully discrete explicit entropy-stable schemes for the compressible Euler and Navier-stokes equations, SIAM J. Sci. Comput., 42 (2020), A612–A638. https://doi.org/10.1137/19M1263480 doi: 10.1137/19M1263480
|
| [31] |
B. Wacker, J. C. Schlüter, A non-standard finite-difference-method for a non-autonomous epidemiological model: analysis, parameter identification and applications, Math. Biosci. Eng., 20 (2023), 12923–12954. https://doi.org/10.3934/mbe.2023577 doi: 10.3934/mbe.2023577
|
| [32] |
B. Wacker, Framework for solving dynamics of $ {\rm{Ca}}^{2+}$ ion concentrations in liver cells numerically: Analysis of a non-negativity-preserving non-standard finite-difference method, Math. Meth. Appl. Sci., 46 (2023), 16625–16643. https://doi.org/10.1002/mma.9464 doi: 10.1002/mma.9464
|
| [33] | R. E. Mickens, Nonstandard Finite Difference Models of Differential Equations, $1^{st}$ edition, World Scientific, Singapore, 1993. https://doi.org/10.1142/2081 |
| [34] |
R. E. Mickens, Calculation of denominator functions for nonstandard finite difference schemes for differential equations satisfying a positivity condition, Numer. Meth. Part. Differ. Equ., 23 (2007), 672–691. https://doi.org/10.1002/num.20198 doi: 10.1002/num.20198
|
| [35] |
J. Martín-Vaquero, A. Martín del Rey, A. H. Encinas, J. D. Hernández Guillén, A. Queiruga-Dios, G. Rodríguez Sánchez, Higher-order nonstandard finite difference schemes for a MSEIR model for a malware propagation, J. Comput. Appl. Math., 317 (2017), 146–156. https://doi.org/10.1016/j.cam.2016.11.044 doi: 10.1016/j.cam.2016.11.044
|
| [36] |
L. F. Richardson, The approximate arithmetical solution by finite differences of physical problems including differential equations, with an application to the stresses in a masonry dam, Phil. Trans. R. Soc. A, 210 (1911), 307–357. https://doi.org/10.1098/rsta.1911.0009 doi: 10.1098/rsta.1911.0009
|
| [37] |
A. Korobeinikov, Global properties of basic virus dynamics models, Bull. Math. Biol., 66 (2004), 879–883. https://doi.org/10.1016/j.bulm.2004.02.001 doi: 10.1016/j.bulm.2004.02.001
|
| [38] |
J. Yang, X. Wang, F. Zhang, A Differential Equation Model of HIV Infection of $ {\rm{CD4}}^{+}$ T-Cells with Delay, Discrete Dyn. Nat. Soc., 2008 (2008), 903678. https://doi.org/10.1155/2008/903678 doi: 10.1155/2008/903678
|
| [39] |
E. B. S. Marinho, F. S. Bacelar, R. F. S. Andrade, A model of partial differential equations for HIV propagation in lymph nodes, Physica A Stat. Mech. Appl., 391 (2012), 132–141. https://doi.org/10.1016/j.physa.2011.08.023 doi: 10.1016/j.physa.2011.08.023
|
| [40] | A. Ern, J. L. Guermond, Theory and Practice of Finite Element Methods, $1^{st}$ edition, Springer-Verlag, New York, 2004. https://doi.org/10.1007/978-1-4757-4355-5 |
| [41] |
M. T. Hoang, M. Ehrhardt, A dynamically consistent nonstandard finite difference scheme for a generalized SEIR epidemic model, J. Differ. Equ. Appl., 30 (2024), 409–434. https://doi.org/10.1080/10236198.2023.2291151 doi: 10.1080/10236198.2023.2291151
|
| [42] |
M. T. Hoang, M. Ehrhardt, A second-order nonstandard finite difference method for a general Rosenzweig-MacArthur predator-prey model, J. Comput. Appl. Math., 444 (2024), 115752. https://doi.org/10.1016/j.cam.2024.115752 doi: 10.1016/j.cam.2024.115752
|
| [43] |
B. Wacker, J. C. Schlüter, An age- and sex-structured SIR model: Theory and an explicit-implicit numerical solution algorithm, Math. Biosci. Eng., 17 (2020), 5752–5801. https://doi.org/10.3934/mbe.2020309 doi: 10.3934/mbe.2020309
|