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Bosch J, Thumsová B, Puschendorf R, Bielby J. Drivers of Batrachochytrium dendrobatidis infection load, with evidence of infection tolerance in adult male toads (Bufo spinosus). Oecologia 2023; 202:165-174. [PMID: 37147397 DOI: 10.1007/s00442-023-05380-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023]
Abstract
Chytridiomycosis is affecting hundreds of amphibian species worldwide, but while in tropical areas, adult individuals have been the focus of most investigations, the exact role played by infection intensity of breeding adults is not well understood in temperate areas. We conducted mark-recapture-capture surveys during spiny common toad breeding seasons from 2006 to 2018 at the site of the first recorded outbreak of chytridiomycosis in Europe, the Peñalara Massif (Sierra de Guadarrama National Park, central Spain), and collected infection samples and several variables related to the reproductive effort of male individuals. We used general linear mixed models to evaluate the contribution of study variables on the infection loads of adult male toads exhibited at their capturing date. We also analysed the differences on several male characteristics between the pond with the largest breeding population against the rest of the ponds. We found that the duration of time spent in the waterbody and the condition of the host predicted infection loads. Animals of good physical condition, that spent longer in water, have higher infection levels than individuals with the opposite set of traits. The pond supporting the largest breeding population housed smaller male toads and in poorer condition. Our results are consistent with a shift in reproductive strategy in response to infection and potentially a strategy of tolerance, rather than resistance to infection. These findings have applications for disease mitigation and theoretical implications related to the trade-offs made and the evolution of traits in response to the disease.
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Affiliation(s)
- Jaime Bosch
- Biodiversity Research Institute (IMIB), CSIC-University of Oviedo-Principality of Asturias, Mieres, Spain.
- Centro de Investigación, Seguimiento y Evaluación, Parque Nacional de la Sierra de Guadarrama, Rascafría, Spain.
| | - Barbora Thumsová
- Asociación Herpetológica Española (AHE), Madrid, Spain
- Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
| | - Robert Puschendorf
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | - Jon Bielby
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
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2
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Shanebeck KM, Besson AA, Lagrue C, Green SJ. The energetic costs of sub-lethal helminth parasites in mammals: a meta-analysis. Biol Rev Camb Philos Soc 2022; 97:1886-1907. [PMID: 35678252 DOI: 10.1111/brv.12867] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 01/07/2023]
Abstract
Parasites, by definition, have a negative effect on their host. However, in wild mammal health and conservation research, sub-lethal infections are commonly assumed to have negligible health effects unless parasites are present in overwhelming numbers. Here, we propose a definition for host health in mammals that includes sub-lethal effects of parasites on the host's capacity to adapt to the environment and maintain homeostasis. We synthesized the growing number of studies on helminth parasites in mammals to assess evidence for the relative magnitude of sub-lethal effects of infection across mammal taxa based on this expanded definition. Specifically, we develop and apply a framework for organizing disparate metrics of parasite effects on host health and body condition according to their impact on an animal's energetic condition, defined as the energetic burden of pathogens on host physiological and behavioural functions that relate directly to fitness. Applying this framework within a global meta-analysis of helminth parasites in wild, laboratory and domestic mammal hosts produced 142 peer-reviewed studies documenting 599 infection-condition effects. Analysing these data within a multiple working hypotheses framework allowed us to evaluate the relative weighted contribution of methodological (study design, sampling protocol, parasite quantification methods) and biological (phylogenetic relationships and host/parasite life history) moderators to variation in the magnitude of health effects. We found consistently strong negative effects of infection on host energetic condition across taxonomic groups, with unusually low heterogeneity in effect sizes when compared with other ecological meta-analyses. Observed effect size was significantly lower within cross-sectional studies (i.e. observational studies that investigated a sub-set of a population at a single point in time), the most prevalent methodology. Furthermore, opportunistic sampling led to a weaker negative effect compared to proactive sampling. In the model of host taxonomic group, the effect of infection on energetic condition in carnivores was not significant. However, when sampling method was included, it explained substantial inter-study variance; proactive sampling showing a strongly significant negative effect while opportunistic sampling detected only a weak, non-significant effect. This may partly underlie previous assumptions that sub-lethal parasites do not have significant effects on host health. We recommend future studies adopt energetic condition as the framework for assessing parasite effects on wildlife health and provide guidelines for the selection of research protocols, health proxies, and relating infection to fitness.
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Affiliation(s)
- Kyle M Shanebeck
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada
| | - Anne A Besson
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin, 9016, New Zealand
| | - Clement Lagrue
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada.,Department of Zoology, University of Otago, 340 Great King Street, Dunedin, 9016, New Zealand.,Department of Conservation, 265 Princes Street, Dunedin, 9016, New Zealand
| | - Stephanie J Green
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada
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Sorci G, Léchenault-Bergerot C, Faivre B. Age reduces resistance and tolerance in malaria-infected mice. INFECTION GENETICS AND EVOLUTION 2020; 88:104698. [PMID: 33370596 DOI: 10.1016/j.meegid.2020.104698] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/30/2022]
Abstract
Once infected, hosts can rely on two strategies to cope with parasites: fight them (resist the infection) or minimize the damage they induce (tolerate the infection). While there is evidence that aging reduces resistance, how tolerance varies as hosts become old has been barely studied. Here, we used a rodent malaria parasite (Plasmodium yoelii) to investigate whether 2- and 12-month old house mice differ in their capacity to resist and tolerate the infection. We found that 12-month old mice harbored higher parasitemia, showing that age reduces resistance to malaria. Infection-induced deterioration of host health was assessed using red blood cell and body mass loss. Using both traits, the rate of decline in host health, as parasitemia increased, was more pronounced in 12- than in 2-month old mice, showing that age is also associated with impaired tolerance to malaria. Overall, resistance and tolerance positively covaried; however, this was only due to the age effect, since, within age classes, the two traits were not correlated. These results show that senescing individuals might be both more susceptible to infectious diseases and less able to cope with the damage that infection induces.
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Affiliation(s)
- Gabriele Sorci
- Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France.
| | | | - Bruno Faivre
- Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France
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Knap PW, Doeschl-Wilson A. Why breed disease-resilient livestock, and how? Genet Sel Evol 2020; 52:60. [PMID: 33054713 PMCID: PMC7557066 DOI: 10.1186/s12711-020-00580-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 10/01/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Fighting and controlling epidemic and endemic diseases represents a considerable cost to livestock production. Much research is dedicated to breeding disease resilient livestock, but this is not yet a common objective in practical breeding programs. In this paper, we investigate how future breeding programs may benefit from recent research on disease resilience. MAIN BODY We define disease resilience in terms of its component traits resistance (R: the ability of a host animal to limit within-host pathogen load (PL)) and tolerance (T: the ability of an infected host to limit the damage caused by a given PL), and model the host's production performance as a reaction norm on PL, depending on R and T. Based on this, we derive equations for the economic values of resilience and its component traits. A case study on porcine respiratory and reproductive syndrome (PRRS) in pigs illustrates that the economic value of increasing production in infectious conditions through selection for R and T can be more than three times higher than by selection for production in disease-free conditions. Although this reaction norm model of resilience is helpful for quantifying its relationship to its component traits, its parameters are difficult and expensive to quantify. We consider the consequences of ignoring R and T in breeding programs that measure resilience as production in infectious conditions with unknown PL-particularly, the risk that the genetic correlation between R and T is unfavourable (antagonistic) and that a trade-off between them neutralizes the resilience improvement. We describe four approaches to avoid such antagonisms: (1) by producing sufficient PL records to estimate this correlation and check for antagonisms-if found, continue routine PL recording, and if not found, shift to cheaper proxies for PL; (2) by selection on quantitative trait loci (QTL) known to influence both R and T in favourable ways; (3) by rapidly modifying towards near-complete resistance or tolerance, (4) by re-defining resilience as the animal's capacity to resist (or recover from) the perturbation caused by an infection, measured as temporal deviations of production traits in within-host longitudinal data series. CONCLUSIONS All four alternatives offer promising options for genetic improvement of disease resilience, and most rely on technological and methodological developments and innovation in automated data generation.
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Affiliation(s)
| | - Andrea Doeschl-Wilson
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush Estate, Edinburgh, EH25 9RG Scotland, UK
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Gomez SR, Morgans S, Kristan DM. Rapamycin exposure to host and to adult worms affects life history traits of Heligmosomoides bakeri. Exp Parasitol 2019; 204:107720. [PMID: 31279929 DOI: 10.1016/j.exppara.2019.107720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/26/2019] [Accepted: 07/03/2019] [Indexed: 01/24/2023]
Abstract
Parasite life history can be affected by conditions of the host and of the external environment. Rapamycin, a known immunosuppressant of mammals, was fed to laboratory mice that were then infected with the Trichostrongylid nematode Heligmosomoides bakeri to determine if host rapamycin exposure would affect parasite survival, growth, and reproduction. In addition, adult worms from control fed mice were directly exposed to rapamycin to assess if rapamycin would affect worm viability and ex vivo reproduction. We found that host ingestion of rapamycin did not affect H. bakeri survival or growth for male or female worms, but female worms had increased reproduction both in vivo and when removed from the host and cultured ex vivo. After direct rapamycin exposure, motility of female worms was greater at low levels of rapamycin compared to high levels of rapamycin or high levels of DMSO (the vehicle used to solubilize rapamycin) in control media, but was similar to females in low levels of DMSO in control media. Male motility was not affected by the presence of rapamycin or DMSO in the media. Ex vivo egg deposition was higher when exposed to rapamycin than when cultured in control media that contained DMSO, regardless of DMSO dose. Overall, we conclude that host ingestion of rapamycin or direct exposure to rapamycin was generally favorable or neutral for parasite life history traits.
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Affiliation(s)
- Sarah R Gomez
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Scott Morgans
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Deborah M Kristan
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA.
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Schoenle LA, Schoepf I, Weinstein NM, Moore IT, Bonier F. Higher plasma corticosterone is associated with reduced costs of infection in red-winged blackbirds. Gen Comp Endocrinol 2018; 256:89-98. [PMID: 28697920 DOI: 10.1016/j.ygcen.2017.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/06/2017] [Accepted: 07/06/2017] [Indexed: 12/24/2022]
Abstract
Glucocorticoid hormones allow individuals to rapidly adjust their physiology and behavior to meet the challenges of a variable environment. An individual's baseline concentration of glucocorticoids can reflect shifts in life history stage and resource demands while mediating a suite of physiological and behavioral changes that include immune modulation and resource allocation. Thus, glucocorticoids could facilitate a response to parasites that is optimized for an individual's specific challenges and life history stage. We investigated the relationship between endogenous circulating glucocorticoids and measures of resistance and tolerance to Haemosporidian parasites (including those that cause avian malaria) in red-winged blackbirds (Agelaius phoeniceus). We found that higher endogenous concentrations of circulating glucocorticoids were associated with reduced costs of parasite infection, which is indicative of higher tolerance, but were unrelated to parasite burden in free ranging, breeding male birds. Post-breeding, both males and females with higher glucocorticoid concentrations had higher measures of tolerance to Haemosporidian infection. Our findings suggest a potentially adaptive role for glucocorticoids in shifting the response to parasites to align with an individual's current physiological state and the challenges they face.
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Affiliation(s)
- Laura A Schoenle
- Department of Biological Sciences, Virginia Tech, 1405 Perry St., Blacksburg, VA 24061, United States.
| | - Ivana Schoepf
- Department of Biological Sciences, Virginia Tech, 1405 Perry St., Blacksburg, VA 24061, United States; Biology Department, Queen's University, Biosciences Complex 3523, Kingston ON K7L 3N6, Canada.
| | - Nicole M Weinstein
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3900 Spruce St., Philadelphia, PA 19104, United States.
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, 1405 Perry St., Blacksburg, VA 24061, United States.
| | - Frances Bonier
- Department of Biological Sciences, Virginia Tech, 1405 Perry St., Blacksburg, VA 24061, United States; Biology Department, Queen's University, Biosciences Complex 3523, Kingston ON K7L 3N6, Canada.
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Budischak SA, Hansen CB, Caudron Q, Garnier R, Kartzinel TR, Pelczer I, Cressler CE, van Leeuwen A, Graham AL. Feeding Immunity: Physiological and Behavioral Responses to Infection and Resource Limitation. Front Immunol 2018; 8:1914. [PMID: 29358937 PMCID: PMC5766659 DOI: 10.3389/fimmu.2017.01914] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/14/2017] [Indexed: 01/17/2023] Open
Abstract
Resources are a core currency of species interactions and ecology in general (e.g., think of food webs or competition). Within parasite-infected hosts, resources are divided among the competing demands of host immunity and growth as well as parasite reproduction and growth. Effects of resources on immune responses are increasingly understood at the cellular level (e.g., metabolic predictors of effector function), but there has been limited consideration of how these effects scale up to affect individual energetic regimes (e.g., allocation trade-offs), susceptibility to infection, and feeding behavior (e.g., responses to local resource quality and quantity). We experimentally rewilded laboratory mice (strain C57BL/6) in semi-natural enclosures to investigate the effects of dietary protein and gastrointestinal nematode (Trichuris muris) infection on individual-level immunity, activity, and behavior. The scale and realism of this field experiment, as well as the multiple physiological assays developed for laboratory mice, enabled us to detect costs, trade-offs, and potential compensatory mechanisms that mice employ to battle infection under different resource conditions. We found that mice on a low-protein diet spent more time feeding, which led to higher body fat stores (i.e., concentration of a satiety hormone, leptin) and altered metabolite profiles, but which did not fully compensate for the effects of poor nutrition on albumin or immune defenses. Specifically, immune defenses measured as interleukin 13 (IL13) (a primary cytokine coordinating defense against T. muris) and as T. muris-specific IgG1 titers were lower in mice on the low-protein diet. However, these reduced defenses did not result in higher worm counts in mice with poorer diets. The lab mice, living outside for the first time in thousands of generations, also consumed at least 26 wild plant species occurring in the enclosures, and DNA metabarcoding revealed that the consumption of different wild foods may be associated with differences in leptin concentrations. When individual foraging behavior was accounted for, worm infection significantly reduced rates of host weight gain. Housing laboratory mice in outdoor enclosures provided new insights into the resource costs of immune defense to helminth infection and how hosts modify their behavior to compensate for those costs.
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Affiliation(s)
- Sarah A. Budischak
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
| | - Christina B. Hansen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
| | - Quentin Caudron
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
| | - Romain Garnier
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Tyler R. Kartzinel
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, United States
| | - István Pelczer
- Department of Chemistry, Princeton University, Princeton, NJ, United States
| | - Clayton E. Cressler
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | - Anieke van Leeuwen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, Texel, Netherlands
| | - Andrea L. Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
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8
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Garnier R, Cheung CK, Watt KA, Pilkington JG, Pemberton JM, Graham AL. Joint associations of blood plasma proteins with overwinter survival of a large mammal. Ecol Lett 2017; 20:175-183. [DOI: 10.1111/ele.12719] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/31/2016] [Accepted: 11/17/2016] [Indexed: 02/02/2023]
Affiliation(s)
- Romain Garnier
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
| | - Christopher K. Cheung
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
| | - Kathryn A. Watt
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Jill G. Pilkington
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Andrea L. Graham
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
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Lough G, Kyriazakis I, Bergmann S, Lengeling A, Doeschl-Wilson AB. Health trajectories reveal the dynamic contributions of host genetic resistance and tolerance to infection outcome. Proc Biol Sci 2016; 282:rspb.2015.2151. [PMID: 26582028 PMCID: PMC4685823 DOI: 10.1098/rspb.2015.2151] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Resistance and tolerance are two alternative strategies hosts can adopt to survive infections. Both strategies may be genetically controlled. To date, the relative contribution of resistance and tolerance to infection outcome is poorly understood. Here, we use a bioluminescent Listeria monocytogenes (Lm) infection challenge model to study the genetic determination and dynamic contributions of host resistance and tolerance to listeriosis in four genetically diverse mouse strains. Using conventional statistical analyses, we detect significant genetic variation in both resistance and tolerance, but cannot capture the time-dependent relative importance of either host strategy. We overcome these limitations through the development of novel statistical tools to analyse individual infection trajectories portraying simultaneous changes in infection severity and health. Based on these tools, early expression of resistance followed by expression of tolerance emerge as important hallmarks for surviving Lm infections. Our trajectory analysis further reveals that survivors and non-survivors follow distinct infection paths (which are also genetically determined) and provides new survival thresholds as objective endpoints in infection experiments. Future studies may use trajectories as novel traits for mapping and identifying genes that control infection dynamics and outcome. A Matlab script for user-friendly trajectory analysis is provided.
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Affiliation(s)
- Graham Lough
- Genetics and Genomics Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, UK
| | - Ilias Kyriazakis
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, UK
| | - Silke Bergmann
- Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Andreas Lengeling
- Infection and Immunity Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, UK
| | - Andrea B Doeschl-Wilson
- Genetics and Genomics Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, UK
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