Modeling and control of Chikungunya with chronic infection.

Recognized globally as a major public health concern in the tropics and subtropics, Chikungunya fever also poses a potential epidemic risk in areas of China such as Guangdong Province, where suitable mosquito vector habitats exist. Based on a Chikungunya fever outbreak in Shunde District, Foshan City, this study develops a dynamical model incorporating a chronic infection stage. We derive R 0 and perform a thorough stability analysis of all equilibria. Using daily reported case data from Shunde District, model fitting yields estimates for three key transmission parameters (β, ρ 1, ρ 2), the total mosquito population (T v ), and the initial number of infected mosquitoes (I v (0)). Sensitivity analysis identifies that the primary positive and negative parameters on disease transmission are mosquito biting rate (β) and mosquito mortality rate (ϵ v ), respectively. Accordingly, five types of intervention measures are designed: personal protection, screening and detection, treatment of acute patients, management of chronic cases, and mosquito vector control measures. Based on these findings, we formulate a control framework to optimize intervention strategies. Numerical simulations not only validate the global asymptotic stability of the disease-free equilibrium when R 0 < 1 and that of the endemic equilibrium when R 0 > 1, but also assess the effectiveness of different control strategies. Strategy A, which emphasizes personal protection, emerges as the most economically efficient option in the cost-effectiveness analysis. It not only effectively interrupts virus transmission but also optimally reduces the burden of chronic cases, thereby offering a scientifically sound and economically feasible approach for public health resource allocation.