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Coinfection and the Evolution of Resistance: A Mathematical Analysis

This thesis investigates the effect of coinfection on the emergence of resistant pathogens.
Firstly, a multiple infection model with treatment is derived and the conditions for invasion are established.
The invasion condition is then related to an equivalent and easier to obtain condition, R0,
by applying the Next-Generation Theorem. Due to its biological interpretation,
a heuristic derivation of R0 as the invasion condition is also given.
Then assuming that resistance comes at a cost to the pathogen, and using a very simple within-host model, we establish under which specific
set of biological assumptions we should expect coinfection to increase or decrease R0.
Specifically, we obtain that in the no cost of resistance case, reduced transmission case, and increased
mortality case, that coinfection will increase the R0 value and that in the reduced growth
and poor competitor case that the effect is indeterminate. We also introduced a method for
approximating the intrinsic growth rate when the coinfection efficiency is assumed to be small.
Using this method, we show that we obtain the same trend for the cost of resistance cases
when comparing our estimate for the intrinsic growth rate for the coinfection case versus
the intrinsic growth rate for the single infection case. We also use this approximation to
estimate the percentage of resistance as a function of time. Finally, we analyze how both
the intrinsic growth rate and R0 respond to a changing treatment rate, compared
to the intrinsic growth rate and R0 value in the single infection case. We found that
the change in R0 and the intrinsic growth rate can be greater or smaller than the change
in R0 or the intrinsic growth rate for the single infection case. / Thesis (Master, Mathematics & Statistics) -- Queen's University, 2011-05-05 16:36:40.865

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6504
Date06 May 2011
CreatorsHANSEN, Johanna
ContributorsQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish, English
Detected LanguageEnglish
TypeThesis
RightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
RelationCanadian theses

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