Modelling of the invasion dynamics of plasmodium falciparum merozoites into red blood cells
Date
2016-03
Authors
Journal Title
Journal ISSN
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Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT :
BACKGROUND The physiological symptoms of P. falciparum infection are associated with a 48 hour
replication cycle whereby parasites (merozoites) invade susceptible red blood cells (RBCs), develop
and multiply within these now infected RBCs and eventually rupture them, releasing 8 to 32 daughter
merozoites which are free to di use through their environment and may subsequently invade other
available RBCs and begin a new replication cycle.
OBJECTIVES: To develop a novel, parameterised mechanistic mathematical model which describes the
dynamics of merozoite invasion during the initial stages of malarial infection. Furthermore, to determine
if the dispersal of daughter merozoites can be modelled by a random walk model and extrapolated to a
di usion process.
APPROACH: Two novel mathematical models were constructed to describe the dynamics of the
aforementioned invasion process { a deterministic model consisting of four coupled ordinary di erential
equations and a stochastic, random walk model. In addition, several forms of the mechanistic model
were built to accommodate multiply-invaded RBCs. These parasitised RBCs are those which have been
invaded by more than one merozoite; a phenomenon largely absent from modelling exercises seen in the
literature. The novelty of the models pertains to the inclusion of a "merozoite-erythrocyte complex" or
MEC. This is an unstable, intermediary species which forms after the initial interaction between a free
merozoite and susceptible RBC but before successful invasion may occur.
CONCLUSION: The most signi cant conclusion gained from this research was that while the mathe-
matical models were constructed in a theoretically sound manner in which all interactions were based
on observable phenomena, the data required to robustly validate these models and acquire accurate
estimates for the parameters was not available.
AFRIKAANSE OPSOMMING : Geen Afrikaanse opsomming geskikbaar nie
AFRIKAANSE OPSOMMING : Geen Afrikaanse opsomming geskikbaar nie
Description
Thesis (MSc)--Stellenbosch University, 2016
Keywords
Malaria -- Infection, Malaria -- Parasitic factors, Plasmodium falciparum -- Infection, Merozoite -- Life cycle, Red blood cells (RBCs) -- Invasion, Epidemiology -- Mathematical modelling, Malaria mosquitoes -- Life cycle