title: Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens.
abstract: Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management.
authors.affiliation: Cary Institute of Ecosystem Studies, Millbrook, New York, United States of America.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Ostfeld
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Taal
authors.initials: T
authors.lastname: Levi
authors.affiliation: Departments of Biomedical Sciences and Zoology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Jolles
authors.affiliation: Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Lynn B
authors.initials: LB
authors.lastname: Martin
authors.affiliation: EcoHealth Alliance, New York, New York, United States of America.
authors.forename: Parviez R
authors.initials: PR
authors.lastname: Hosseini
authors.affiliation: Biology Program, Bard College, Annandale-on-Hudson, New York, United States of America.
authors.forename: Felicia
authors.initials: F
authors.lastname: Keesing
mesh_terms: D041081:Anaplasma phagocytophilum / Q000472:pathogenicity; D000818:Animals; D041001:Babesia microti / Q000472:pathogenicity; D001404:Babesiosis / Q000469:parasitology / Q000635:transmission; D049628:Body Size; D025065:Borrelia burgdorferi / Q000472:pathogenicity; D004197:Disease Reservoirs / Q000382:microbiology / Q000469:parasitology; D016873:Ehrlichiosis / Q000382:microbiology / Q000635:transmission; D006801:Humans; D018884:Ixodes / Q000382:microbiology* / Q000469:parasitology*; D008193:Lyme Disease / Q000382:microbiology / Q000635:transmission; D009656:North America; D011156:Population Density; D017282:Tick-Borne Diseases / Q000382:microbiology / Q000469:parasitology / Q000635:transmission*; D015047:Zoonoses / Q000382:microbiology / Q000469:parasitology / Q000635:transmission*