Figure 2. Epidemiological dynamics of a vector-borne disease in a seasonal environment.

We consider here that the influx of mosquitoes, θ(t), is a periodic square wave (see equation (5) in the main text). The parameter T measures the duration of the period and the parameter τ measures seasonality: the fraction of time where the environment is not suitable for vector reproduction.The epidemiologic dynamics converges to a periodic equilibrium characterised by fluctuations of the uninfected and infected vector the densities: V(t) and V_I(t) (black and red dashed lines, respectively). We also plot the dynamics of the density of infected hosts: I(t)/10 (red line). Parameter values: , , , . See default values in the Text S1 for other parameters.