Current Projects
Evolution, mechanisms, and consequences of disease tolerance
Once infected, a host can attempt to kill the infecting pathogen (resistance) and/or minimize per-pathogen reductions in fitness (tolerance). Although inflammatory responses like fever, free-radical production, and localized swelling can help clear a variety of parasites (i.e., increase resistance), these responses have a high potential to damage a host's own tissues (i.e., decrease tolerance). In collaboration with Dana Hawley at Virginia Tech, Rami Dalloul at UGA, and Michal Vinkler at Charles University, Ambi Henschen is investigating the mechanistic and evolutionary relationships among inflammatory responses, tolerance, and pathogen transmission in house finches infected with Mycoplasma gallisepticum, a bacterial pathogen that first jumped from poultry into wild songbirds in the 1990s.
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We're finding that populations with a longer history of MG endemism show more tolerance and fewer differentially expressed genes during infection, including many involved in inflammation.
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In addition, we've started looking at the consequences of tolerance on transmission, especially breaking tolerance into tissue-specific (physiological) and behavioral components (see Rachel Ruden's recent paper, below).
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Finally, Frank Tillman has started asking about how behavioral tolerance varies across populations and how it interacts with optimal foraging.
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These projects are funded in part by a grant from the National Science Foundation (IOS-1950307).
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Related publications
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Ecological and evolutionary causes and consequences of heterogeneity in susceptibility induced by prior exposure (in house finches)
This new project asks how variation in susceptibility to an infectious disease both arises and shapes the potential coevolution of pathogens. Rather than just differences in average susceptibility, this heterogeneity can have major, though less-understood, impacts on infectious disease dynamics. To uncover those, we'll perform empirical tests in the house finch - Mycoplasma system, blending these with statistical and theoretical models and sequencing of the pathogen conducted by our colleagues, Dana Hawley (PI, Virginia Tech), Lauren Childs (VT), Arietta Fleming-Davies (U. San Diego), Steven Geary (UConn), Kate Langwig (VT), and Edan Tulman (UConn). This project is funded by the multi-agency Ecology and Evolution of Infectious Diseases program (NIH NIGMS 1R01GM144972-01).
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Related publications
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Can animal behavior and community science improve surveillance for bighorn sheep respiratory disease?
In a twist on our typical bird theme, we've branched out into mammals! Sidney Brenkus is heading up this project, which focuses on several herds of bighorn sheep in Montana and the respiratory disease that causes periodic epizootics that dramatically reduce lamb survival. She's asking whether behavior provides a cheap and reliable means to detect the presence of this disease within a population and how to train community scientists (members of the general public) to collect behavioral data for wildlife managers. Collaborators include Bob Klaver with the USGS and Iowa State University, Cassandra Nuñez here at Memphis, and MT Fish Wildlife and Parks. This project is funded by a US DOI/BLM Intra Agency Agreement.
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Related publications
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