Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Natural Resource Ecology and Management


Wildlife Ecology

First Advisor

James S Adelman


Individual animals vary greatly in their responses to pathogenic challenge. One such response that remains understudied in animals is the ability to minimize the per-pathogen costs of infection on host fitness. Phenotypically, this presents as individuals with milder clinical signs of disease despite substantial pathogen burdens. Hosts that develop milder pathology, a measure of tissue damage, or express milder sickness behaviors are therefore described as being tolerant. Because tolerant hosts survive infection through damage limitation but not necessarily pathogen elimination, they may be more likely to infect others by shedding higher numbers of pathogen over longer windows of time. This suggests that tolerant hosts may also be more competent, with direct implications on infectious disease dynamics. Here, I characterize sources of variation in disease phenotype and its effect on epidemic outcomes, using an ecologically-relevant disease system as a model. Specifically, I use captive studies on house finches experimentally-infected with Mycoplasma gallisepticum to explore potential mechanisms underlying tolerance, the impacts of tolerance on pathogen transmission, and finally, novel ways to measure individual disease outcomes and tolerant phenotypes.


Copyright Owner

Rachel Morgan Ruden



File Format


File Size

90 pages