Modelling the potential role of control strategies on Ebola virus disease dynamics

[摘要] ENGLISH ABSTRACT : The most deadly Ebola disease epidemic ever was still ongoing as of June 2015 in WestAfrica. It started in Guinea, where the first cases were recorded in March 2014. Controlstrategies, aiming at stopping the transmission chain of Ebola disease were publicisedthrough national and international media and were successful in Liberia. Using two differentapproaches, the dynamics of Ebola disease is described in this thesis. First, a sixcompartments mathematical model is formulated to investigate the role of media campaignson Ebola transmission. The model includes tweets or messages sent by individualswith different disease status through the media. The media campaigns reproductionnumber is computed and used to investigate the stability of the disease free steady state.The presence of a backward bifurcation as well as a forward bifurcation are shown togetherwith the existence and local stability of the endemic equilibrium. We concludedthrough numerical simulations, that messages sent through media have a time limitedbeneficial effect on the reduction of Ebola cases and media campaigns must be spacedout in order to be more efficacious. Second, we use a seven compartments model todescribe the evolution of the disease in the population when educational campaigns, activecase-finding and pharmaceutical interventions are implemented as controls againstthe disease. We prove the existence of an optimal control set and analyse the necessaryand sufficient conditions, optimality and transversality conditions. Using data from affected countries, we conclude using numerical analysis that containing an Ebola outbreakneeds early and long term implementation of the joint control strategies.

[发布机构] Stellenbosch University