Analysis of Sub-Models for the Basic Transmission Dynamics of Zika Virus Infection

In this paper, an age-structured model for the transmission dynamics of Zika virus infection that included the effects of vertical transmission in Aedes vectors, and sexual transmission in humans was formulated and analysed. The model was shown to have a unique, positive and bounded solution in a certain uniformly bounded invariant set. The model was validated using the 2016 outbreak data for Colombia using stratified proportionate random sampling to distribute infections according to the age classification in the model. Due to the complex nature of the model, three independent sub-models were extracted and studied individually. In each case, we computed the disease-free equilibrium (DFE) and the basic reproduction number of the sub-models. The reproduction numbers were found to exist if a certain threshold value which corresponds to the vertical reproduction number in the Aedes vectors progeny is less than one. The DFEs of the sub-models were shown to be globally asymptotically stable if their associated reproduction number is less than one. Global sensitivity analysis using PRCC method revealed that vector biting and mortality rates, vector-human ratio parameter and sexual transmission rates are the most sensitive parameters that should be targeted for comprehensive intervention and disease management.