MATHEMATHEMATICAL ASSESSMENT OF WITHIN-HOST CHIKUNGUNYA VIRUS WITH NON-PRODUCTIVE AND PRODUCTIVELY INFECTED CELLS

ASSESSMENT OF WITHIN-HOST CHIKUNGUNYA VIRUS

Abstract

A deterministic within-host model is developed to study the intracellular dynamics of chikungunya virus (CHIKV) infection by separating infected cells into two stages: a non-productive (eclipse) phase and a productively infected phase. The framework tracks susceptible target cells, non-productive infected cells, productively infected cells, and free virus particles, thereby representing the major steps of viral replication. Basic analytical properties, including positivity and boundedness of solutions, are established to guarantee biological plausibility. Using the next-generation matrix method, a within-host reproduction number is derived and shown to determine whether infection is cleared or persists. In particular, the CHIKV-free equilibrium is proven to be locally and globally asymptotically stable when the reproduction number is below one, whereas a unique endemic equilibrium arises when it exceeds one. A forward bifurcation analysis indicates a continuous shift from clearance to persistence at the threshold. Sensitivity analysis results show that viral production, intracellular transition to productive infection, and viral clearance exert the strongest influence on infection outcomes. Numerical simulations reinforce the theoretical findings and demonstrate how viral load profiles change with parameter values. Overall, the model offers a compact mechanistic basis for interpreting CHIKV within-host kinetics and for identifying intracellular processes that may be targeted for control.