Modelling yellow fever control in the presence of toxic infections

Abstract

Yellow fever is one of the re-emerging Neglected Tropical Diseases with high socio-economic burden in Africa and Tropical Southern America. In this study, a compartmentalized epidemic model for yellow fever with a toxic infected host population is formulated to explore the dynamics of the disease in a community. The model’s disease-free equilibrium state is shown to admit a local and global asymptotic stability whenever the model’s reproductive number (R₀) is less than one. Furthermore, using the Descartes Rule of Sign Change, the conditions for the existence of a global asymptotic unique endemic equilibrium have been elaborated. The normalized forward sensitivity index formula is used to determine the relative contributions of the model parameters to the endemicity of yellow fever. These results revealed that yellow fever epidemic is highly sensitive to the removal and biting rates of the disease vectors. Numerical simulations were also performed to investigate the impact of different vaccination and vector biting rates.