Many infectious pathogens, and in particular viruses, have an
extremely high rate of mutation. This can lead to rapid evolution
driven by selection pressures operating at both the within- and
between-host levels, as strains compete for resources within their
chosen host while also competing to effectively transmit to new
hosts. In the case of chronic viral infections, such as the human
immunodeficiency virus (HIV) or hepatitis C, substantial viral
evolution may take place within a single infected host. The fitness
of a pathogen has been studied at the between-host level and at the
within-host level, but linking the two levels of selection pressure
is a difficult problem that has yet to be studied satisfactorily.
We modify a simple model describing the within host dynamics of HIV
infection by including multiple pathogen strains with different
properties and allowing these strains to mutate. Within the host we
observe different strategies for pathogen success during different
stages of infection, which often leads to different strains
predominating within the host over the course of infection. We then
embed our within-host model into a Monte Carlo simulation that
models the interactions between infected individuals. This approach
allows us to combine selective pressure at the within-host level
with pressures at the between-host level and helps us to predict
which strains are most likely to be present within the population.
We show that under our model assumptions the co-existence of
multiple strains is possible and we explore the factors leading to
the success of a pathogen.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU./57 |
| Date | 11 1900 |
| Creators | Ball, Colleen |
| Publisher | University of British Columbia |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | 1248552 bytes, application/pdf |
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