Trait-based variation in host contribution to pathogen transmission Public Deposited

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  • March 19, 2019
Creator
  • Welsh, Miranda
    • Affiliation: College of Arts and Sciences, Curriculum in Environment and Ecology
Abstract
  • Host competence defines a host’s potential to transmit disease, and, from the perspective of a pathogen, a good host is a competent one. Highly competent hosts boost transmission, increase the size of epidemics, and promote emergence in new host populations. From a host’s perspective, competent hosts increase disease risk, and control efforts are more successful when competent hosts can be rapidly identified and targeted. Competence varies widely both within and among host species, and this variation is generally quantified observationally, on a case-by-case basis. While locally effective, this approach limits our ability to successfully control pathogens that emerge in new hosts or novel conditions. To this end, I tested whether the functional traits of hosts can predict host competence. These traits include host physiological, morphological, and life-history characteristics. I focused on functional traits for two reasons: 1) several functional traits have demonstrated effects on host-pathogen or host-vector interactions, and 2) functional traits have provided a useful framework for developing general, predictive models of ecological processes in both simple and complex systems (e.g., competition, community assembly). In developing and testing trait-based models of host competence, my overarching goal was to contribute to a mechanistic understanding of disease processes and to promote synthesis across models of disease and community dynamics. Across 23 hosts of a generalist, vector-borne pathogen, hosts functional traits covaried along a single, general axis of ecological strategy. This axis ran from traits associated with slow growth and resource conservation to traits associated with fast growth and resource acquisition. As hosts became more fast-growing along this axis, they became more likely to acquire and transmit pathogen infection, but they were also more impacted by infection. This suggests that fast-growing hosts contribute disproportionately to transmission, but slow-growing hosts may encourage pathogen persistence. Trait-based models of competence could become less accurate in two cases: 1) when applied at the individual instead of the species level, and 2) when hosts were exposed to novel environments. Combined, my results demonstrate the potential for trait-based approaches to improve forecasts of pathogen transmission and emergence, and also illustrate two important caveats to their application.
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  • In Copyright
Advisor
  • Mitchell, Charles
  • Hoffmann, William
  • Umbanhowar, James
  • Bruno, John
  • Moody, Aaron
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2016
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