Dynamical Insights into the Current Control Strategies for Chikungunya

This paper addresses the challenge that, under China’s current mosquito-control policy for chikungunya—$\mathit{\text{clearing}}\mathit{\text{stagnant}}\mathit{\text{water,}}\mathit{\text{killing}}\mathit{\text{adult}}\mathit{\text{mosquitoes,}}\mathit{\text{and}}\mathit{\text{preventing}}\mathit{\text{bites}}$—epidemics can still recur and continue to rise. By constructing a vector–host dynamical model that incorporates asymptomatic infections and a screening rate, we derive approximate analytical expressions for the epidemic peak value and peak time, and reveal the intrinsic link between short-term transients and long-term outcomes. Simulations across three scenarios—human-seeded, mosquito-seeded, and joint human–mosquito-seeded—show that (i) even when the vector population is effectively suppressed, asymptomatic carriers can still sustain transmission; (ii) the effect of the screening rate on the peak time is non-monotonic, and there exists a critical threshold that maximizes the delay of the epidemic; and (iii) moderate screening can both suppress the first wave and avoid leaving an excessively large susceptible pool that would amplify subsequent waves. Accordingly, we upgrade the original policy to a $\mathit{\text{Twelve-character}}$ strategy for prevention, mitigation, and control—$\mathit{\text{clearing}}\mathit{\text{stagnant}}\mathit{\text{water,}}\mathit{\text{killing}}\mathit{\text{adult}}\mathit{\text{mosquitoes,}}\mathit{\text{preventing}}\mathit{\text{bites,}}\mathit{\text{and}}\mathit{\text{screening}}\mathit{\text{cases}}\mathit{\text{early}}$—providing theoretical support for chikungunya and other mosquito-borne diseases.