@article{e8c7ae8d7e084e788a34205588ae3390,
title = "Incomplete host immunity favors the evolution of virulence in an emergent pathogen",
abstract = "Immune memory evolved to protect hosts from reinfection, but incomplete responses that allow future reinfection may inadvertently select for more-harmful pathogens. We present empirical and modeling evidence that incomplete immunity promotes the evolution of higher virulence in a natural host-pathogen system. We performed sequential infections of house finches with Mycoplasma gallisepticum strains of various levels of virulence. Virulent bacterial strains generated stronger host protection against reinfection than less virulent strains and thus excluded less virulent strains from infecting previously exposed hosts. In a two-strain model, the resulting fitness advantage selected for an almost twofold increase in pathogen virulence. Thus, the same immune systems that protect hosts from infection can concomitantly drive the evolution of more-harmful pathogens in nature.",
author = "Fleming-Davies, {Arietta E.} and Williams, {Paul D.} and Dhondt, {Andr{\'e} A.} and Dobson, {Andrew P.} and Hochachka, {Wesley M.} and Leon, {Ariel E.} and Ley, {David H.} and Osnas, {Erik E.} and Hawley, {Dana M.}",
note = "Funding Information: This work is dedicated to the memory of Paul Williams, who inspired us all with his insights and dedication. We thank L. Kirkpatrick, J. Adelman, S. Moyers, and numerous undergraduates for technical assistance. D. J. P{\'a}ez and three anonymous reviewers provided helpful comments on the manuscript. This work was funded through NIH grant 5R01GM105245 to D.M.H. under the NIH-NSF-USDA Ecology and Evolution of Infectious Diseases program. Birds were captured under permits from the Virginia Department of Game and Inland Fisheries (044569) and the U.S. Fish and Wildlife Service (MB158404-1). All data and code to understand and assess the conclusions of this research are included in the main text or are available via Dryad Digital Repository (doi:10.5061/dryad.435h5). Publisher Copyright: {\textcopyright} 2018 The Authors, some rights reserved.",
year = "2018",
month = mar,
day = "2",
doi = "10.1126/science.aao2140",
language = "English (US)",
volume = "359",
pages = "1030--1033",
journal = "Science",
issn = "0036-8075",
publisher = "American Association for the Advancement of Science",
number = "6379",
}