Modeling Transmission Dynamics ofStreptococcus suiswith Stage Structure and Sensitivity Analysis

Streptococcosis is one of the major infectious and contagious bacterial diseases for swine farm in southern China. The influence of various control measures on the outbreaks and transmission of S. suis is not currently known. In this study, in order to explore effective control and prevention measures we studied a deterministic dynamic model with stage structure for S. suis. The basic reproduction number ℛ0 is identified and global dynamics are completely determined by ℛ0. It shows that if ℛ0<1, the disease-free equilibrium is globally stable and the disease dies out, whereas if ℛ0>1, there is a unique endemic equilibrium which is globally stable and thus the disease persists in the population. The model simulations well agree with new clinical cases and the basic reproduction number of this model is about 1.1333. Some sensitivity analyses of ℛ0 in terms of the model parameters are given. Our study demonstrates that combination of vaccination and disinfection of the environment are the useful control strategy for S. suis