Browsing by Author "Njankou, Sylvie Diane Djiomba"

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    Modelling the potential role of control strategies on Ebola virus disease dynamics
    (Stellenbosch : Stellenbosch University, 2015-12) Njankou, Sylvie Diane Djiomba; Nyabadza, Farai; Stellenbosch University. Faculty of Science. Department Mathematical Sciences (Mathematics)
    ENGLISH ABSTRACT : The most deadly Ebola disease epidemic ever was still ongoing as of June 2015 in West Africa. It started in Guinea, where the first cases were recorded in March 2014. Control strategies, aiming at stopping the transmission chain of Ebola disease were publicised through national and international media and were successful in Liberia. Using two different approaches, the dynamics of Ebola disease is described in this thesis. First, a six compartments mathematical model is formulated to investigate the role of media campaigns on Ebola transmission. The model includes tweets or messages sent by individuals with different disease status through the media. The media campaigns reproduction number 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 together with the existence and local stability of the endemic equilibrium. We concluded through numerical simulations, that messages sent through media have a time limited beneficial effect on the reduction of Ebola cases and media campaigns must be spaced out in order to be more efficacious. Second, we use a seven compartments model to describe the evolution of the disease in the population when educational campaigns, active case-finding and pharmaceutical interventions are implemented as controls against the disease. We prove the existence of an optimal control set and analyse the necessary and sufficient conditions, optimality and transversality conditions. Using data from affected countries, we conclude using numerical analysis that containing an Ebola outbreak needs early and long term implementation of the joint control strategies.
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    Modelling the potential role of media campaigns in ebola transmission dynamics
    (Hindawi Publishing Corporation, 2017) Njankou, Sylvie Diane Djiomba; Nyabadza, Farai
    A six-compartment mathematical model is formulated to investigate the role of media campaigns in Ebola transmission dynamics. The model includes tweets or messages sent by individuals in different compartments. The media campaigns reproduction number is computed and used to discuss the stability of the disease states. The presence of a backward bifurcation as well as a forward bifurcation is shown together with the existence and local stability of the endemic equilibrium. Results show that messages sent through media have a more significant beneficial effect on the reduction of Ebola cases if they are more effective and spaced out.