Backward Bifurcation Analysis of a Dengue-Chikungunya Model

Abstract

A new deterministic model for the transmission dynamics of Dengue
and its co-endemicity with Chikungunya virus is designed and
theoretically used to assess the misdiagnoses due to the co-endemicity
of the two viruses in the human population. The phenomenon of
backward bifurcation is characterized by the co-existence of a stable
disease-free equilibrium (DFE) and a stable endemic equilibrium
point (EEP). When the associated reproduction number of the model
is less than unity in a population where there is co-endemicity of
Dengue and Chikungunya, the classical requirement of having the
reproduction number less than unity, while necessary is no longer
sufficient for the effective control. The model shows that backward
bifurcation does not occur if and only if the disease induced death for
humans for both Dengue and Chikungunya are absent.