Stochastic dynamics of Chikungunya virus infection model incorporating general incidence rate and immune responses.

This study investigates a stochastic model of Chikungunya virus (CHIKV) infection that incorporates a general incidence rate along with B-cell and CTL immune responses. Stochasticity is modeled through a log-normal Ornstein-Uhlenbeck process. We first establish the existence of a unique and globally positive solution. Then, the solution's dynamic behavior around the two steady states is examined, and it is shown that the stochastic model's dynamics at the steady state generalizes the global asymptotic stability of the deterministic model. We prove the existence of the stationary distribution by constructing suitable Lyapunov functions when the stochastic reproduction number is greater than one. The probability density function near the quasi-steady state is subsequently derived. Sufficient conditions for CHIKV extinction are provided by spectral radius analysis. Furthermore, we conduct uncertainty and sensitivity analyses to investigate the effects of key parameters on each population and the value of the stochastic reproduction number. Finally, numerical simulations are carried out to explore the impact of noise intensity and the average incidence rate on the dynamic behavior of the model.