modelling cholera transmission incorporating media coverage

Abstract

Cholera is a gastrointestinal disease caused by a bacterium called Vibrio cholerae. The spread of the disease depends largely on social and environmental factors such as, eating food or drinking water contaminated with feaces from an infected person. Cholera outbreaks, for instance, in Kenya have led to deaths and hospi- talisation. Since cholera spreads and kills very fast, the effectiveness of control strategies such as vaccination, water chlorination and therapeutic treatment may be enhanced by the use of media alert and awareness campaigns. This aspect has not been considered in existing cholera models. In this study, the impact of media coverage on the spread of cholera was investigated using a mathematical model. The specific objectives of the study were to construct a mathematical model for cholera transmission incorporating media coverage, to analyse the stability of equi- librium points of the model and to evaluate the role of media coverage as a disease control strategy. Positivity and boundedness of solutions was established to ensure that the model was biologically meaningful. The model was thereafter analysed using the stability theory of differential equations. The basic reproduction num- ber R 0 , was derived using the next generation matrix approach. The existence of equilibrium points of the model was determined. The results of stability analysis showed that the disease free equilibrium was both locally and globally asymptoti- cally stable when R 0 < 1 while the endemic equilibrium was locally asymptotically stable when R 0 > 1. Simulation analysis done using existing epidemiological data graphically confirmed the validity of the analytic results. The simulation results also showed that when media coverage was efficient (ρ = 0.9, where 0 < ρ < 1 measures the efficacy of media coverage) the number of cholera infectives decreased faster, while inefficient media reporting (ρ = 0.4) on an outbreak and the preven- tive measures led to increased cases of infection, implying that, media alert and awareness campaigns are vital in controlling the spread of cholera. Based on this study, it is recommended that health practictioners embrace the use of efficacious means of media coverage to publicise awareness campaigns of an outbreak and the preventive measures.