Modeling Co-infection of Bovine Brucellosis and Tuberculosis

Bovine tuberculosis and bovine brucellosis continue to cause serious economic and public health burden in low-income countries, especially in many regions of sub-Saharan Africa where the diseases are co-endemic. The economic burden of the two infections in low-income countries trigger important questions about the optimal intervention strategies in co-endemic regions. Hence, the need for comprehensive modelling studies to address such questions is therefore essential, yet only a limited of such studies exist to date despite the power of models to predict the future and, most importantly, to quantify the uncertainty in these predictions. Here, we develop a brucellosistuberculosis co-infection modelling framework that incorporates all relevant biological factors and culling of infectious animals-as the sole intervention strategy. We performed an optimal control study to assess the impact of culling infectious animals on controlling the prevalence of the two infections. Two objective functions have been considered, a linear and a quadratic. Existence and the characterization of the optimal control has been determined. Numerical results are carried out to illustrate the main findings. Our findings highlight the importance of optimal culling on controlling the spread of two infections.