Global Dynamics of a Multiscale Immuno-Cholera Transmission Model With Bacterial Hyperinfectivity on Complex Networks

Abstract

The spread of cholera at the population level depends on the immunological characteristics of pathogens at the individual level. In addition, contact heterogeneity among individuals plays a significant role in cholera transmission. In this paper, we construct a multiscale coupled immuno-cholera model considering waning vaccine-induced immunity and hyperinfectious vibrios and utilize a nested approach to bridge within-host vibrio evolution and between-host cholera transmission on complex networks. The basic reproduction numbers $R_0^W$ and $R_0^B$ for the within- and between-host models are derived, respectively, and $R_0^B$ is validated to serve as a sharp threshold between extinction and persistence of cholera. Specifically, the global asymptotic stability of each feasible equilibrium for the between-host system is established by formulating appropriate Lyapunov functionals. Numerical simulations are performed to assess the influences of within-host vibrio dynamics and network topology on between-host cholera transmission dynamics. The results show that the equilibrium level of total infected individuals is a nonmonotonic function of vibrio growth rate, implying that hampering within-host vibrio growth by drug treatment during the outbreak could alter the long-term outcomes of cholera. Furthermore, the heterogeneity of network degree distributions increases the risk of cholera outbreaks, suggesting that isolation and supervision for infected individuals with high degrees are effective measures to prevent and control cholera transmission.