1
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Abstract
Plant diseases are strongly influenced by host biodiversity, spatial structure, and abiotic conditions. All of these are undergoing rapid change, as the climate is warming, habitats are being lost, and nitrogen deposition is changing nutrient dynamics of ecosystems with ensuing consequences for biodiversity. Here, I review examples of plant-pathogen associations to demonstrate how our ability to understand, model and predict disease dynamics is becoming increasingly difficult, as both plant and pathogen populations and communities are undergoing extensive change. The extent of this change is influenced via both direct and combined effects of global change drivers, and especially the latter are still poorly understood. Change at one trophic level is expected to drive change also at the other, and hence feedback loops between plants and their pathogens are expected to drive changes in disease risk both through ecological as well as evolutionary mechanisms. Many of the examples discussed here demonstrate an increase in disease risk as a result of ongoing change, suggesting that unless we successfully mitigate global environmental change, plant disease is going to become an increasingly heavy burden on our societies with far-reaching consequences for food security and functioning of ecosystems.
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Affiliation(s)
- Anna-Liisa Laine
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, 8057 Zürich, Switzerland; Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, PO BOX 65 00014, University of Helsinki, Helsinki, Finland.
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2
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Divergence in host–parasite interactions during the cane toad's invasion of Australia. Ecol Evol 2022. [DOI: 10.1002/ece3.9220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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3
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Pigeault R, Chevalier M, Cozzarolo CS, Baur M, Arlettaz M, Cibois A, Keiser A, Guisan A, Christe P, Glaizot O. Determinants of haemosporidian single- and co-infection risks in western palearctic birds. Int J Parasitol 2022; 52:617-627. [PMID: 35760376 DOI: 10.1016/j.ijpara.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022]
Abstract
Understanding the drivers of infection risk helps us to detect the most at-risk species in a community and identify species whose intrinsic characteristics could act as potential reservoirs of pathogens. This knowledge is crucial if we are to predict the emergence and evolution of infectious diseases. To date, most studies have only focused on infections caused by a single parasite, leaving out co-infections. Yet, co-infections are of paramount importance in understanding the ecology and evolution of host-parasite interactions due to the wide range of effects they can have on host fitness and on the evolutionary trajectories of parasites. Here, we used a multinomial Bayesian phylogenetic modelling framework to explore the extent to which bird ecology and phylogeny impact the probability of being infected by one genus (hereafter single infection) or by multiple genera (hereafter co-infection) of haemosporidian parasites. We show that while nesting and migration behaviors influenced both the probability of being single- and co-infected, species position along the slow-fast life-history continuum and geographic range size were only pertinent in explaining variation in co-infection risk. We also found evidence for a phylogenetic conservatism regarding both single- and co-infections, indicating that phylogenetically related bird species tend to have similar infection patterns. This phylogenetic signal was four times stronger for co-infections than for single infections, suggesting that co-infections may act as a stronger selective pressure than single infections. Overall, our study underscores the combined influence of hosts' evolutionary history and attributes in determining infection risk in avian host communities. These results also suggest that co-infection risk might be under stronger deterministic control than single infection risk, potentially paving the way toward a better understanding of the emergence and evolution of infectious diseases.
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Affiliation(s)
- Romain Pigeault
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland; Laboratoire EBI, Equipe EES, UMR CNRS 7267, 86000 Poitiers, France.
| | - Mathieu Chevalier
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland; Ifremer, Centre de Bretagne, DYNECO-LEBCO, CS 10070, 29280 Plouzané, France
| | - Camille-Sophie Cozzarolo
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland; Biogéosciences, UMR 6282 CNRS, université Bourgogne Franche-Comté, 6 boulevard Gabriel, 21000 Dijon, France
| | - Molly Baur
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland
| | | | - Alice Cibois
- Natural History Museum of Geneva, C.P. 6434, CH-1211 Genève 6, Switzerland
| | - André Keiser
- Musée cantonal de zoologie, CH-1014 Lausanne, Switzerland
| | - Antoine Guisan
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland
| | - Philippe Christe
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland
| | - Olivier Glaizot
- Department of Ecology and Evolution, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, CH-1014 Lausanne, Switzerland
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4
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Taborsky B, Kuijper B, Fawcett TW, English S, Leimar O, McNamara JM, Ruuskanen S. An evolutionary perspective on stress responses, damage and repair. Horm Behav 2022; 142:105180. [PMID: 35569424 DOI: 10.1016/j.yhbeh.2022.105180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/16/2022] [Accepted: 04/21/2022] [Indexed: 11/28/2022]
Abstract
Variation in stress responses has been investigated in relation to environmental factors, species ecology, life history and fitness. Moreover, mechanistic studies have unravelled molecular mechanisms of how acute and chronic stress responses cause physiological impacts ('damage'), and how this damage can be repaired. However, it is not yet understood how the fitness effects of damage and repair influence stress response evolution. Here we study the evolution of hormone levels as a function of stressor occurrence, damage and the efficiency of repair. We hypothesise that the evolution of stress responses depends on the fitness consequences of damage and the ability to repair that damage. To obtain some general insights, we model a simplified scenario in which an organism repeatedly encounters a stressor with a certain frequency and predictability (temporal autocorrelation). The organism can defend itself by mounting a stress response (elevated hormone level), but this causes damage that takes time to repair. We identify optimal strategies in this scenario and then investigate how those strategies respond to acute and chronic exposures to the stressor. We find that for higher repair rates, baseline and peak hormone levels are higher. This typically means that the organism experiences higher levels of damage, which it can afford because that damage is repaired more quickly, but for very high repair rates the damage does not build up. With increasing predictability of the stressor, stress responses are sustained for longer, because the animal expects the stressor to persist, and thus damage builds up. This can result in very high (and potentially fatal) levels of damage when organisms are exposed to chronic stressors to which they are not evolutionarily adapted. Overall, our results highlight that at least three factors need to be considered jointly to advance our understanding of how stress physiology has evolved: (i) temporal dynamics of stressor occurrence; (ii) relative mortality risk imposed by the stressor itself versus damage caused by the stress response; and (iii) the efficiency of repair mechanisms.
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Affiliation(s)
- Barbara Taborsky
- Behavioural Ecology Division, Institute of Ecology and Evolution, University of Bern, Switzerland.
| | - Bram Kuijper
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, UK; Institute for Data Science and Artificial Intelligence, University of Exeter, UK
| | - Tim W Fawcett
- Centre for Research in Animal Behaviour (CRAB), University of Exeter, UK
| | - Sinead English
- School of Biological Sciences, University of Bristol, UK
| | - Olof Leimar
- Department of Zoology, Stockholm University, Sweden
| | | | - Suvi Ruuskanen
- Department of Biological and Environmental Science, University of Jyväskylä, Finland
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5
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Ortega N, Roznik EA, Surbaugh KL, Cano N, Price W, Campbell T, Rohr JR. Parasite spillover to native hosts from more tolerant, supershedding invasive hosts: Implications for management. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.13906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole Ortega
- Department of Biology University of Tampa Tampa FL USA
| | - Elizabeth A. Roznik
- North Carolina Zoo Asheboro NC USA
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Kerri L. Surbaugh
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Natalia Cano
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Wayne Price
- Department of Biology University of Tampa Tampa FL USA
| | - Todd Campbell
- Department of Biology University of Tampa Tampa FL USA
| | - Jason R. Rohr
- Department of Biological Sciences University of Notre DameNotre Dame IN USA
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6
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Rohr JR. The Atrazine Saga and its Importance to the Future of Toxicology, Science, and Environmental and Human Health. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:1544-1558. [PMID: 33999476 DOI: 10.1002/etc.5037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/12/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
The herbicide atrazine is one of the most commonly used, well studied, and controversial pesticides on the planet. Much of the controversy involves the effects of atrazine on wildlife, particularly amphibians, and the ethically questionable decision making of members of industry, government, the legal system, and institutions of higher education, in most cases in an effort to "bend science," defined as manipulating research to advance economic, political, or ideological ends. In this Critical Perspective I provide a timeline of the most salient events in the history of the atrazine saga, which includes a multimillion-dollar smear campaign, lawsuits, investigative reporting, accusation of impropriety against the US Environmental Protection Agency, and a multibillion-dollar transaction. I argue that the atrazine controversy must be more than just a true story of cover-ups, bias, and vengeance. It must be used as an example of how manufacturing uncertainty and bending science can be exploited to delay undesired regulatory decisions and how greed and conflicts of interest-situations where personal or organizational considerations have compromised or biased professional judgment and objectivity-can affect environmental and public health and erode trust in the discipline of toxicology, science in general, and the honorable functioning of societies. Most importantly, I offer several recommendations that should help to 1) prevent the history of atrazine from repeating itself, 2) enhance the credibility and integrity of science, and 3) enrich human and environmental health. Environ Toxicol Chem 2021;40:1544-1558. © 2021 SETAC.
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Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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7
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Kim D, Shaw AK. Migration and tolerance shape host behaviour and response to parasite infection. J Anim Ecol 2021; 90:2315-2324. [PMID: 34014562 DOI: 10.1111/1365-2656.13539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/03/2021] [Indexed: 11/26/2022]
Abstract
Numerous theoretical models have demonstrated that migration, a seasonal animal movement behaviour, can minimize the risks and costs of parasite infection. Past work on migration-infection interactions assumes migration is the only strategy available to organisms for dealing with the parasite infection, that is they migrate to a different environment to recover or escape from infection. Thus, migration is similar to the non-spatial strategy of resistance, where hosts prevent infection or kill parasites once infected. However, an alternative defence strategy is to tolerate the infection and experience a lower cost to the infection. To our knowledge, no studies have examined how migration can change based on combining two host strategies (migration and tolerance) for dealing with parasites. In this paper, we aim to understand how both parasite transmission and infection tolerance can influence the host's migratory behaviour. We constructed a model that incorporates two host strategies (migration and tolerance) to understand whether allowing for tolerance affects the proportion of the population that migrates at equilibrium in response to infection. We show that the benefits of tolerance can either decrease or increase the host's migration. Also, if the benefit of migration is great, then individuals are more likely to migrate regardless of the presence of tolerance. Finally, we find that the transmission rate of parasite infection can either decrease or increase the tolerant host's migration, depending on the cost of migration. These findings highlight that adopting two defence strategies is not always beneficial to the hosts. Instead, a single strategy is often better, depending on the costs and benefits of the strategies and infection pressures. Our work further suggests that multiple host-defence strategies as a potential explanation for the evolution of migration to minimize the parasite infection. Moreover, migration can also affect the ecological and evolutionary dynamics of parasite-host interactions.
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Affiliation(s)
- Dongmin Kim
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | - Allison K Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
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8
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Gavel MJ, Young SD, Blais N, Forbes MR, Robinson SA. Trematodes coupled with neonicotinoids: effects on blood cell profiles of a model amphibian. Parasitol Res 2021; 120:2135-2148. [PMID: 33991246 DOI: 10.1007/s00436-021-07176-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 04/27/2021] [Indexed: 11/30/2022]
Abstract
Habitat loss, climate change, environmental contaminants, and parasites and pathogens are among the main factors thought to act singly or together in causing amphibian declines. We tested for combined effects of neonicotinoid pesticides and parasites (versus parasites-only) on mortality, growth, and white blood cell profiles of a model amphibian: the northern leopard frog (Rana pipiens). We first exposed infectious stages of frog trematodes (cercariae of Echinostoma spp.) to low and high concentrations of thiamethoxam or clothianidin versus water-only controls. There were no differences in survival of trematode cercariae between treatments. For the main experiment, we exposed tadpoles to clean water versus high concentrations of clothianidin or thiamethoxam for 2 weeks and added trematode cercariae to all tanks after 1 week. Exposure of tadpoles and parasites to high concentrations of thiamethoxam or clothianidin did not affect parasite infection success. Tadpole survival was not different between treatments before or after parasite addition and there were no significant differences in tadpole snout-to-vent lengths or developmental stages between treatments. Tadpoles exposed to thiamethoxam + parasites had smaller widths than parasite-only tadpoles, whereas tadpoles exposed to clothianidin + parasites had higher eosinophil to leukocyte ratios compared to parasite-only tadpoles. Tadpoles of both neonicotinoid + parasite treatments had significantly lower monocyte to leukocyte ratios relative to parasite-only tadpoles. High concentrations of neonicotinoid combined with parasites appear to influence tadpole immune function important for further defense against parasites and pathogens. This work highlights the need for more holistic approaches to ecotoxicity studies, using multiple stressors.
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Affiliation(s)
- M J Gavel
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - S D Young
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, National Wildlife Research Centre, Environment and Climate Change Canada, 1125 Colonel By Drive, Ottawa, Ontario, K1A 0H3, Canada
| | - N Blais
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - M R Forbes
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Stacey A Robinson
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, National Wildlife Research Centre, Environment and Climate Change Canada, 1125 Colonel By Drive, Ottawa, Ontario, K1A 0H3, Canada.
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9
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Halliday FW, Jalo M, Laine AL. The effect of host community functional traits on plant disease risk varies along an elevational gradient. eLife 2021; 10:67340. [PMID: 33983120 PMCID: PMC8208817 DOI: 10.7554/elife.67340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/10/2021] [Indexed: 01/17/2023] Open
Abstract
Quantifying the relative impact of environmental conditions and host community structure on disease is one of the greatest challenges of the 21st century, as both climate and biodiversity are changing at unprecedented rates. Both increasing temperature and shifting host communities toward more fast-paced life-history strategies are predicted to increase disease, yet their independent and interactive effects on disease in natural communities remain unknown. Here, we address this challenge by surveying foliar disease symptoms in 220, 0.5 m-diameter herbaceous plant communities along a 1100-m elevational gradient. We find that increasing temperature associated with lower elevation can increase disease by (1) relaxing constraints on parasite growth and reproduction, (2) determining which host species are present in a given location, and (3) strengthening the positive effect of host community pace-of-life on disease. These results provide the first field evidence, under natural conditions, that environmental gradients can alter how host community structure affects disease. Climate change is causing shifts in the ecology and biodiversity of different world regions at unprecedented rates. Global warming is also linked with changes in the risk for certain infectious diseases in humans, but also in animals and plants. There are several possible mechanisms for this. For one thing, changing weather patterns may affect how pathogens grow and reproduce. For another, the distribution ranges of animal and plant hosts of certain disease-causing pathogens are changing because of global warming. This means that the distributions of pathogens are also changing, and so is the severity of the diseases that they cause. Increasing temperatures may also influence the physiological traits that make host species suitable for pathogens. This is because the traits that allow species to survive or adapt to changes in their environment may also make them better at hosting and transmitting the pathogens that cause disease. For example, in plant communities, rising temperatures could favor species with faster growth rates, quicker reproduction and high dispersal, and these traits are often associated with more efficient spread of disease. Despite a lot of research into the effects of climate, it remains unclear how temperature, pathogen growth and reproduction, and host species’ traits and distributions combine and interact to alter infectious disease risk, especially in wild plant communities. To investigate this, Halliday, Jalo and Laine studied an area in southeast Switzerland where natural temperature and biodiversity change gradually through the region. The aim was to explore how relationships between plant biodiversity, pathogens and disease risk change with temperature, and to understand whether environmental or biological factors influence infectious disease risk more. Halliday, Jalo and Laine measured the levels of fungal diseases found in the leaves of plant communities spanning 1,100 meters of elevation, showing that higher temperatures increase disease risk both directly and indirectly. Directly, higher temperatures increased pathogen growth and reproduction, and indirectly, they influenced which plants were present and therefore able to act as disease hosts. The results also indicated that temperature can affect how the traits of plants drive the transmission rates of fungal pathogens. Important predictors of disease risk were traits relating to the growth rate of host plants, which tended to increase in areas with low elevation where the surface of the soil was warm. This study represents the first analysis, in wild plants, of how changing temperatures, the traits of shifting host species, and resident parasite populations interact to impact infectious disease risk. The insights Halliday, Jalo and Laine provided could aid in predicting how global climate change will influence infectious disease risk.
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Affiliation(s)
- Fletcher W Halliday
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zurich, Switzerland
| | - Mikko Jalo
- Faculty of Biological and Environmental sciences, University of Helsinki, Helsinki, Finland
| | - Anna-Liisa Laine
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zurich, Switzerland.,Faculty of Biological and Environmental sciences, University of Helsinki, Helsinki, Finland
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10
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Dallas TA, Becker DJ. Taxonomic resolution affects host-parasite association model performance. Parasitology 2021; 148:584-590. [PMID: 33342442 PMCID: PMC10950372 DOI: 10.1017/s0031182020002371] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 11/07/2022]
Abstract
Identifying the factors that structure host–parasite interactions is fundamental to understand the drivers of species distributions and to predict novel cross-species transmission events. More phylogenetically related host species tend to have more similar parasite associations, but parasite specificity may vary as a function of transmission mode, parasite taxonomy or life history. Accordingly, analyses that attempt to infer host−parasite associations using combined data on different parasite groups may perform quite differently relative to analyses on each parasite subset. In essence, are more data always better when predicting host−parasite associations, or does parasite taxonomic resolution matter? Here, we explore how taxonomic resolution affects predictive models of host−parasite associations using the London Natural History Museum's database of host–helminth interactions. Using boosted regression trees, we demonstrate that taxon-specific models (i.e. of Acanthocephalans, Nematodes and Platyhelminthes) consistently outperform full models in predicting mammal-helminth associations. At finer spatial resolutions, full and taxon-specific model performance does not vary, suggesting tradeoffs between phylogenetic and spatial scales of analysis. Although all models identify similar host and parasite covariates as important to such patterns, our results emphasize the importance of phylogenetic scale in the study of host–parasite interactions and suggest that using taxonomic subsets of data may improve predictions of parasite distributions and cross-species transmission. Predictive models of host–pathogen interactions should thus attempt to encompass the spatial resolution and phylogenetic scale desired for inference and prediction and potentially use model averaging or ensemble models to combine predictions from separately trained models.
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Affiliation(s)
- Tad A. Dallas
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA70802, USA
| | - Daniel J. Becker
- Department of Biology, University of Oklahoma, Norman, OK73019, USA
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11
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Brown CR, Hannebaum SL, O’Brien VA, Page CE, Rannala B, Roche EA, Wagnon GS, Knutie SA, Moore AT, Brown MB. The cost of ectoparasitism in Cliff Swallows declines over 35 years. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1446] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Charles R. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Stacey L. Hannebaum
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Valerie A. O’Brien
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Catherine E. Page
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Bruce Rannala
- Department of Evolution and Ecology University of California Davis California 95616 USA
| | - Erin A. Roche
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Gigi S. Wagnon
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut 75 N. Eagleville Rd. Storrs Connecticut 06269 USA
| | - Amy T. Moore
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Mary B. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
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12
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Valenzuela-Sánchez A, Wilber MQ, Canessa S, Bacigalupe LD, Muths E, Schmidt BR, Cunningham AA, Ozgul A, Johnson PTJ, Cayuela H. Why disease ecology needs life-history theory: a host perspective. Ecol Lett 2021; 24:876-890. [PMID: 33492776 DOI: 10.1111/ele.13681] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/16/2022]
Abstract
When facing an emerging infectious disease of conservation concern, we often have little information on the nature of the host-parasite interaction to inform management decisions. However, it is becoming increasingly clear that the life-history strategies of host species can be predictive of individual- and population-level responses to infectious disease, even without detailed knowledge on the specifics of the host-parasite interaction. Here, we argue that a deeper integration of life-history theory into disease ecology is timely and necessary to improve our capacity to understand, predict and mitigate the impact of endemic and emerging infectious diseases in wild populations. Using wild vertebrates as an example, we show that host life-history characteristics influence host responses to parasitism at different levels of organisation, from individuals to communities. We also highlight knowledge gaps and future directions for the study of life-history and host responses to parasitism. We conclude by illustrating how this theoretical insight can inform the monitoring and control of infectious diseases in wildlife.
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Affiliation(s)
- Andrés Valenzuela-Sánchez
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.,ONG Ranita de Darwin, Valdivia and Santiago, Chile.,Centro de Investigación para la Sustentabilidad, Universidad Andrés Bello, Santiago, Chile
| | - Mark Q Wilber
- Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.,Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Stefano Canessa
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Erin Muths
- U.S. Geological Survey, 2150 Centre Avenue Bldg C, Fort Collins, Colorado, 80526, USA
| | - Benedikt R Schmidt
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.,Info Fauna Karch, UniMail, Bâtiment G, Bellevaux 51, 2000, Neuchâtel, Switzerland
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Arpat Ozgul
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA
| | - Hugo Cayuela
- IBIS, Department of Biology, University Laval, Pavillon Charles-Eugène-Marchand, Avenue de la Médecine, Quebec City, Canada.,Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
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13
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Wilber MQ, Briggs CJ, Johnson PTJ. Disease's hidden death toll: Using parasite aggregation patterns to quantify landscape-level host mortality in a wildlife system. J Anim Ecol 2020; 89:2876-2887. [PMID: 32935347 PMCID: PMC9009358 DOI: 10.1111/1365-2656.13343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/06/2020] [Indexed: 12/31/2022]
Abstract
World-wide, infectious diseases represent a major source of mortality in humans and livestock. For wildlife populations, disease-induced mortality is likely even greater, but remains notoriously difficult to estimate-especially for endemic infections. Approaches for quantifying wildlife mortality due to endemic infections have historically been limited by an inability to directly observe wildlife mortality in nature. Here we address a question that can rarely be answered for endemic pathogens of wildlife: what are the population- and landscape-level effects of infection on host mortality? We combined laboratory experiments, extensive field data and novel mathematical models to indirectly estimate the magnitude of mortality induced by an endemic, virulent trematode parasite (Ribeiroia ondatrae) on hundreds of amphibian populations spanning four native species. We developed a flexible statistical model that uses patterns of aggregation in parasite abundance to infer host mortality. Our model improves on previous approaches for inferring host mortality from parasite abundance data by (i) relaxing restrictive assumptions on the timing of host mortality and sampling, (ii) placing all mortality inference within a Bayesian framework to better quantify uncertainty and (iii) accommodating data from laboratory experiments and field sampling to allow for estimates and comparisons of mortality within and among host populations. Applying our approach to 301 amphibian populations, we found that trematode infection was associated with an average of between 13% and 40% population-level mortality. For three of the four amphibian species, our models predicted that some populations experienced >90% mortality due to infection, leading to mortality of thousands of amphibian larvae within a pond. At the landscape scale, the total number of amphibians predicted to succumb to infection was driven by a few high mortality sites, with fewer than 20% of sites contributing to greater than 80% of amphibian mortality on the landscape. The mortality estimates in this study provide a rare glimpse into the magnitude of effects that endemic parasites can have on wildlife populations and our theoretical framework for indirectly inferring parasite-induced mortality can be applied to other host-parasite systems to help reveal the hidden death toll of pathogens on wildlife hosts.
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Affiliation(s)
- Mark Q. Wilber
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Cheryl J. Briggs
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106
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14
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Abstract
Climate change is expected to have complex effects on infectious diseases, causing some to increase, others to decrease, and many to shift their distributions. There have been several important advances in understanding the role of climate and climate change on wildlife and human infectious disease dynamics over the past several years. This essay examines 3 major areas of advancement, which include improvements to mechanistic disease models, investigations into the importance of climate variability to disease dynamics, and understanding the consequences of thermal mismatches between host and parasites. Applying the new information derived from these advances to climate-disease models and addressing the pressing knowledge gaps that we identify should improve the capacity to predict how climate change will affect disease risk for both wildlife and humans.
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Affiliation(s)
- Jason R. Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
| | - Jeremy M. Cohen
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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15
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Buss N, Nelson KN, Hua J, Relyea RA. Effects of different roadway deicing salts on host-parasite interactions: The importance of salt type. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115244. [PMID: 32688196 DOI: 10.1016/j.envpol.2020.115244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 05/27/2023]
Abstract
The application of roadway deicing salts is increasing the salinity of freshwater systems. Increased salinization from salts, such as NaCl, CaCl2 and MgCl2, can have direct, negative impacts on freshwater organisms at concentrations found in nature. Yet, our understanding of how these salts can indirectly impact freshwater organisms by altering important ecological interactions, such as those between hosts and their parasites, is limited. Using a larval amphibian and infectious free-living helminth (i.e. trematode) model, we examined whether exposure to environmentally relevant concentrations of NaCl, CaCl2 and MgCl2 1) influence trematode mortality; 2) alter amphibian-trematode interactions; and 3) alter larval amphibian activity (a behavior associated with parasite avoidance). We found that exposure to CaCl2 greatly reduced trematode survival across all Cl- concentrations (230, 500, 860 and 1000 mg Cl- L-1) while NaCl and MgCl2 had no effect. When both host and parasites were exposed to the salts, exposure to NaCl, but not MgCl2 or CaCl2, increased infection. The lack of effect of CaCl2 on infection was likely driven by CaCl2 reducing trematode survival. Exposure to NaCl increased infection at 500 mg Cl- L-1, but not 230 or 860 mg Cl- L-1. Increased infection was not due to salt exposure altering tadpole behavior. Our results suggest that NaCl can negatively impact amphibian populations indirectly by increasing trematode infections in tadpole hosts.
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Affiliation(s)
- Nicholas Buss
- Biological Sciences Department, Binghamton University (SUNY), Binghamton, NY, 13902, USA.
| | - Kiersten N Nelson
- Department of Biological Sciences, Rensselaer Polytechnic Institute, 110 8th St., Troy, NY, 12180, USA
| | - Jessica Hua
- Biological Sciences Department, Binghamton University (SUNY), Binghamton, NY, 13902, USA
| | - Rick A Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Institute, 110 8th St., Troy, NY, 12180, USA
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16
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Halliday FW, Rohr JR, Laine AL. Biodiversity loss underlies the dilution effect of biodiversity. Ecol Lett 2020; 23:1611-1622. [PMID: 32808427 PMCID: PMC7693066 DOI: 10.1111/ele.13590] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/14/2020] [Accepted: 07/16/2020] [Indexed: 01/16/2023]
Abstract
The dilution effect predicts increasing biodiversity to reduce the risk of infection, but the generality of this effect remains unresolved. Because biodiversity loss generates predictable changes in host community competence, we hypothesised that biodiversity loss might drive the dilution effect. We tested this hypothesis by reanalysing four previously published meta‐analyses that came to contradictory conclusions regarding generality of the dilution effect. In the context of biodiversity loss, our analyses revealed a unifying pattern: dilution effects were inconsistently observed for natural biodiversity gradients, but were commonly observed for biodiversity gradients generated by disturbances causing losses of biodiversity. Incorporating biodiversity loss into tests of generality of the dilution effect further indicated that scale‐dependency may strengthen the dilution effect only when biodiversity gradients are driven by biodiversity loss. Together, these results help to resolve one of the most contentious issues in disease ecology: the generality of the dilution effect.
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Affiliation(s)
- Fletcher W Halliday
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
| | - Jason R Rohr
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Anna-Liisa Laine
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland.,Organismal & Evolutionary Biology Research Program, University of Helsinki, PO Box 65, Helsinki, FI-00014, Finland
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17
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Klemme I, Hyvärinen P, Karvonen A. Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish populations. Proc Biol Sci 2020; 287:20200388. [PMID: 32315591 PMCID: PMC7211438 DOI: 10.1098/rspb.2020.0388] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 03/27/2020] [Indexed: 01/14/2023] Open
Abstract
Genetic variation in defence against parasite infections is fundamental for host-parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host-parasite system. Replicated populations of Atlantic salmon (Salmo salar) and sea trout (an anadromous form of brown trout, Salmo trutta) were raised under common garden conditions and infected with the eye fluke Diplostomum pseudospathaceum. We demonstrate significant genetic variation in the defence traits across host populations and negative associations between the traits, with the most resistant populations showing the weakest avoidance and the lowest infection tolerance. These results are suggestive of trade-offs between different components of defence and possibly underlie the genetic variation in defence traits observed in the wild. Because the three defence mechanisms affect host-parasite evolution in profoundly different ways, we emphasize the importance of studying these traits in concert.
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Affiliation(s)
- Ines Klemme
- Department of Biological and Environmental Science, University of Jyvaskyla, PO Box 35, 40014 Jyvaskyla, Finland
| | - Pekka Hyvärinen
- Natural Resources Institute Finland (LUKE), Aquatic Population Dynamics, Manamansalontie 90, 88300 Paltamo, Finland
| | - Anssi Karvonen
- Department of Biological and Environmental Science, University of Jyvaskyla, PO Box 35, 40014 Jyvaskyla, Finland
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18
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Rohr JR, Civitello DJ, Halliday FW, Hudson PJ, Lafferty KD, Wood CL, Mordecai EA. Towards common ground in the biodiversity-disease debate. Nat Ecol Evol 2019; 4:24-33. [PMID: 31819238 PMCID: PMC7224049 DOI: 10.1038/s41559-019-1060-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/13/2019] [Indexed: 01/16/2023]
Abstract
The disease ecology community has struggled to come to consensus on whether biodiversity reduces or increases infectious disease risk, a question that directly affects policy decisions for biodiversity conservation and public health. Here, we summarize the primary points of contention regarding biodiversity–disease relationships and suggest that vector-borne, generalist wildlife and zoonotic pathogens are the types of parasites most likely to be affected by changes to biodiversity. One synthesis on this topic revealed a positive correlation between biodiversity and human disease burden across countries, but as biodiversity changed over time within these countries, this correlation became weaker and more variable. Another synthesis—a meta-analysis of generally smaller-scale experimental and field studies—revealed a negative correlation between biodiversity and infectious diseases (a dilution effect) in various host taxa. These results raise the question of whether biodiversity–disease relationships are more negative at smaller spatial scales. If so, biodiversity conservation at the appropriate scales might prevent wildlife and zoonotic diseases from increasing in prevalence or becoming problematic (general proactive approaches). Further, protecting natural areas from human incursion should reduce zoonotic disease spillover. By contrast, for some infectious diseases, managing particular species or habitats and targeted biomedical approaches (targeted reactive approaches) might outperform biodiversity conservation as a tool for disease control. Importantly, biodiversity conservation and management need to be considered alongside other disease management options. These suggested guiding principles should provide common ground that can enhance scientific and policy clarity for those interested in simultaneously improving wildlife and human health. There has been intense debate as to whether biodiversity increases or reduces the risk of infectious disease. This Review is the result of researchers from both sides of the debate attempting to reach a consensus.
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Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA.
| | | | - Fletcher W Halliday
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Peter J Hudson
- Center for Infectious Disease Dynamics, Biology Department, The Pennsylvania State University, University Park, PA, USA
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey, c/o Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
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19
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Strauss AT, Hite JL, Civitello DJ, Shocket MS, Cáceres CE, Hall SR. Genotypic variation in parasite avoidance behaviour and other mechanistic, nonlinear components of transmission. Proc Biol Sci 2019; 286:20192164. [PMID: 31744438 DOI: 10.1098/rspb.2019.2164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Traditional epidemiological models assume that transmission increases proportionally to the density of parasites. However, empirical data frequently contradict this assumption. General yet mechanistic models can explain why transmission depends nonlinearly on parasite density and thereby identify potential defensive strategies of hosts. For example, hosts could decrease their exposure rates at higher parasite densities (via behavioural avoidance) or decrease their per-parasite susceptibility when encountering more parasites (e.g. via stronger immune responses). To illustrate, we fitted mechanistic transmission models to 19 genotypes of Daphnia dentifera hosts over gradients of the trophically acquired parasite, Metschnikowia bicuspidata. Exposure rate (foraging, F) frequently decreased with parasite density (Z), and per-parasite susceptibility (U) frequently decreased with parasite encounters (F × Z). Consequently, infection rates (F × U × Z) often peaked at intermediate parasite densities. Moreover, host genotypes varied substantially in these responses. Exposure rates remained constant for some genotypes but decreased sensitively with parasite density for others (up to 78%). Furthermore, genotypes with more sensitive foraging/exposure also foraged faster in the absence of parasites (suggesting 'fast and sensitive' versus 'slow and steady' strategies). These relationships suggest that high densities of parasites can inhibit transmission by decreasing exposure rates and/or per-parasite susceptibility, and identify several intriguing axes for the evolution of host defence.
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Affiliation(s)
| | - Jessica L Hite
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
| | | | - Marta S Shocket
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
| | - Carla E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Spencer R Hall
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
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20
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Cohen JM, McMahon TA, Ramsay C, Roznik EA, Sauer EL, Bessler S, Civitello DJ, Delius BK, Halstead N, Knutie SA, Nguyen KH, Ortega N, Sears B, Venesky MD, Young S, Rohr JR. Impacts of thermal mismatches on chytrid fungus
Batrachochytrium dendrobatidis
prevalence are moderated by life stage, body size, elevation and latitude. Ecol Lett 2019; 22:817-825. [DOI: 10.1111/ele.13239] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/04/2018] [Accepted: 12/05/2018] [Indexed: 01/11/2023]
Affiliation(s)
- Jeremy M. Cohen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Chloe Ramsay
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Erin L. Sauer
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Scott Bessler
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Bryan K. Delius
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut Storrs CT USA
| | - Karena H. Nguyen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Nicole Ortega
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Brittany Sears
- Department of Biological Sciences University of South Florida St. Petersburg St. Petersburg FL USA
| | | | - Suzanne Young
- Ecole polytechnique fédérale de Lausanne (EPFL) Lausanne Switzerland
| | - Jason R. Rohr
- Department of Integrative Biology University of South Florida Tampa FL USA
- Department of Biological Sciences University of Notre Dame Notre Dame IN USA
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21
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McNew SM, Knutie SA, Goodman GB, Theodosopoulos A, Saulsberry A, Yépez R. J, Bush SE, Clayton DH. Annual environmental variation influences host tolerance to parasites. Proc Biol Sci 2019; 286:20190049. [PMID: 30963843 PMCID: PMC6408884 DOI: 10.1098/rspb.2019.0049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/06/2019] [Indexed: 12/16/2022] Open
Abstract
When confronted with a parasite or pathogen, hosts can defend themselves by resisting or tolerating the attack. While resistance can be diminished when resources are limited, it is unclear how robust tolerance is to changes in environmental conditions. Here, we investigate the sensitivity of tolerance in a single host population living in a highly variable environment. We manipulated the abundance of an invasive parasitic fly, Philornis downsi, in nests of Galápagos mockingbirds ( Mimus parvulus) over four field seasons and measured host fitness in response to parasitism. Mockingbird tolerance to P. downsi varied significantly among years and decreased when rainfall was limited. Video observations indicate that parental provisioning of nestlings appears key to tolerance: in drought years, mockingbirds likely do not have sufficient resources to compensate for the effects of P. downsi. These results indicate that host tolerance is a labile trait and suggest that environmental variation plays a major role in mediating the consequences of host-parasite interactions.
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Affiliation(s)
- Sabrina M. McNew
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Sarah A. Knutie
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Graham B. Goodman
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | | | - Ashley Saulsberry
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Janai Yépez R.
- Charles Darwin Research Station, Santa Cruz Island, Galápagos, Ecuador
| | - Sarah E. Bush
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Dale H. Clayton
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
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22
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Civitello DJ, Allman BE, Morozumi C, Rohr JR. Assessing the direct and indirect effects of food provisioning and nutrient enrichment on wildlife infectious disease dynamics. Philos Trans R Soc Lond B Biol Sci 2019. [PMID: 29531153 DOI: 10.1098/rstb.2017.0101] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Anthropogenic resource supplementation can shape wildlife disease directly by altering the traits and densities of hosts and parasites or indirectly by stimulating prey, competitor or predator species. We first assess the direct epidemiological consequences of supplementation, highlighting the similarities and differences between food provisioning and two widespread forms of nutrient input: agricultural fertilization and aquatic nutrient enrichment. We then review an aquatic disease system and a general model to assess whether predator and competitor species can enhance or overturn the direct effects of enrichment. All forms of supplementation can directly affect epidemics by increasing host population size or altering parasite production within hosts, but food provisioning is most likely to aggregate hosts and increase parasite transmission. However, if predators or competitors increase in response to supplementation, they could alter resource-fuelled outbreaks in focal hosts. We recommend identifying the traits of hosts, parasites or interacting species that best predict epidemiological responses to supplementation and evaluating the relative importance of these direct and indirect mechanisms. Theory and experiments should examine the timing of behavioural, physiological and demographic changes for realistic, variable scenarios of supplementation. A more integrative view of resource supplementation and wildlife disease could yield broadly applicable disease management strategies.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'.
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Affiliation(s)
- David J Civitello
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA .,Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Brent E Allman
- Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Connor Morozumi
- Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
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23
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Bailey C, Strepparava N, Wahli T, Segner H. Exploring the immune response, tolerance and resistance in proliferative kidney disease of salmonids. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 90:165-175. [PMID: 30248359 DOI: 10.1016/j.dci.2018.09.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/20/2018] [Accepted: 09/20/2018] [Indexed: 05/24/2023]
Abstract
Proliferative kidney disease (PKD) of salmonids is a disease of economic and environmental concern caused by the myxozoan parasite Tetracapsuloides bryosalmonae. Finer details of the immune repertoire during T. bryosalmonae infection have been elucidated in rainbow trout (Oncorhynchus mykiss). In contrast, there remain many unanswered questions regarding the immune response of the wild fish host in Europe, the brown trout (Salmo trutta) to this parasite. The first aim of this study is to examine the brown trout immune response to T. bryosalmonae and compare it with the published information on rainbow trout as two species that have undergone a different coevolution with the parasite. According to ecoimmunology terminology, infected organisms may manage infection by reducing the damage caused by parasites (tolerance) or by limiting parasite burden (resistance). The second aim of this study is to investigate tolerance/resistance patterns of these species during PKD infection. Our results suggest subtle differences in sequential aspects of the immune response and of immune genes that correlate with parasite intensity for the brown trout, in contrast to rainbow trout, in terms of the B cell response and Th-like interplay that may be linked to PKD pathogenesis. These differences in the immune response also correlate with species-specific differences in tolerance/resistance patterns, in that brown trout had increased tolerance but rainbow trout had greater resistance to infection. The variance in tolerance/resistance investment resulted in a different evolutionary outcome for each host-parasite interaction. A greater exploration of these concepts and an association of immune mechanisms could open an additional gateway for interpreting fish host-parasite interactions.
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Affiliation(s)
- Christyn Bailey
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012, Bern, Switzerland.
| | - Nicole Strepparava
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012, Bern, Switzerland
| | - Thomas Wahli
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012, Bern, Switzerland
| | - Helmut Segner
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012, Bern, Switzerland
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24
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Yamamichi M, Klauschies T, Miner BE, Velzen E. Modelling inducible defences in predator–prey interactions: assumptions and dynamical consequences of three distinct approaches. Ecol Lett 2018; 22:390-404. [DOI: 10.1111/ele.13183] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/29/2018] [Accepted: 10/16/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Masato Yamamichi
- Department of General Systems Studies University of Tokyo 3‐8‐1 Komaba Meguro Tokyo153‐8902 Japan
| | - Toni Klauschies
- Department of Ecology and Ecosystem Modelling Institute of Biochemistry and Biology University of Potsdam Am Neuen Palais 10 Potsdam 14469 Germany
| | - Brooks E. Miner
- Department of Biology Ithaca College 953 Danby Rd. Ithaca NY14850 USA
| | - Ellen Velzen
- Department of Ecology and Ecosystem Modelling Institute of Biochemistry and Biology University of Potsdam Am Neuen Palais 10 Potsdam 14469 Germany
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25
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26
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Keiser CN, Rudolf VHW, Sartain E, Every ER, Saltz JB. Social context alters host behavior and infection risk. Behav Ecol 2018. [DOI: 10.1093/beheco/ary060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Carl N Keiser
- Rice University Academy of Fellows, Rice University, Houston, TX, USA
- Department of BioSciences, Rice University, Houston, TX, USA
| | | | | | - Emma R Every
- Department of BioSciences, Rice University, Houston, TX, USA
| | - Julia B Saltz
- Department of BioSciences, Rice University, Houston, TX, USA
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27
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Proximity to parasites reduces host fitness independent of infection in a Drosophila-Macrocheles system. Parasitology 2018. [PMID: 29530103 DOI: 10.1017/s0031182018000379] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Parasites are known to have direct negative effects on host fitness; however, the indirect effects of parasitism on host fitness sans infection are less well understood. Hosts undergo behavioural and physiological changes when in proximity to parasites. Yet, there is little experimental evidence showing that these changes lead to long-term decreases in host fitness. We aimed to determine if parasite exposure affects host fitness independent of contact, because current approaches to parasite ecology may underestimate the effect of parasites on host populations. We assayed the longevity and reproductive output of Drosophila nigrospiracula exposed or not exposed to ectoparasitic Macrocheles subbadius. In order to preclude contact and infection, mites and flies were permanently separated with a mesh screen. Exposed flies had shorter lives and lower fecundity relative to unexposed flies. Recent work in parasite ecology has argued that parasite-host systems show similar processes as predator-prey systems. Our findings mirror the non-consumptive effects observed in predator-prey systems, in which prey species suffer reduced fitness even if they never come into direct contact with predators. Our results support the perspective that there are analogous effects in parasite-host systems, and suggest new directions for research in both parasite ecology and the ecology of fear.
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28
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Bui S, Dalvin S, Dempster T, Skulstad OF, Edvardsen RB, Wargelius A, Oppedal F. Susceptibility, behaviour, and retention of the parasitic salmon louse (Lepeophtheirus salmonis) differ with Atlantic salmon population origin. JOURNAL OF FISH DISEASES 2018; 41:431-442. [PMID: 28921589 DOI: 10.1111/jfd.12707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 07/18/2017] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
Atlantic salmon populations across the world have diverse ecological and evolutionary histories, from wild anadromous or landlocked, to domestication and genetic modification. The natural host behaviours confer protection from infestation by ectoparasitic salmon lice Lepeophtheirus salmonis, yet whether genetic origin results in different behaviours and thus susceptibility to infestation is unknown. In common garden experiments, we tested antiparasite behaviours, susceptibility and retention of salmon lice in wild anadromous, wild landlocked, domesticated and genetically modified domesticated strains. Within domesticated strains, we tested two infestation histories (previously infested and naïve) and a new phenotype (albino colouring). Farmed stocks initially acquired 24%-44% higher levels of parasite density than the wild and landlocked strains. Burst swimming and displacement behaviours were higher in the domesticated groups, and jumping was more prevalent in the domesticated strains. At 34 days post-infestation, domesticated strains and the wild anadromous strain did not differ significantly from each other; however, landlocked salmon had increased infestation levels considerably. Domesticated strains lost ~20% (±9.9%-16.5%; 95% CI) of their initial parasite load, while parasite load increased by 5.5% (±30.1%) for wild salmon and 20.1% (±28.5%) in landlocked salmon. This study provides early evidence for diverged host-parasite interactions associated with domestication in this system.
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Affiliation(s)
- S Bui
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, University of Melbourne, Parkville, Vic, Australia
- Institute of Marine Research, Bergen, Norway
| | - S Dalvin
- Institute of Marine Research, Bergen, Norway
| | - T Dempster
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, University of Melbourne, Parkville, Vic, Australia
- Institute of Marine Research, Bergen, Norway
| | | | | | - A Wargelius
- Institute of Marine Research, Bergen, Norway
| | - F Oppedal
- Institute of Marine Research, Bergen, Norway
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29
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Manzoli DE, Saravia-Pietropaolo MJ, Antoniazzi LR, Barengo E, Arce SI, Quiroga MA, Beldomenico PM. Contrasting consequences of different defence strategies in a natural multihost-parasite system. Int J Parasitol 2018; 48:445-455. [PMID: 29391194 DOI: 10.1016/j.ijpara.2017.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/01/2017] [Accepted: 11/07/2017] [Indexed: 12/11/2022]
Abstract
Hosts counteract infections using two distinct defence strategies, resistance (reduction in pathogen fitness) and tolerance (limitation of infection damage). These strategies have been minimally investigated in multi-host systems, where they may vary across host species, entailing consequences both for hosts (virulence) and parasites (transmission). Comprehending the interplay among resistance, tolerance, virulence and parasite success is highly relevant for our understanding of the ecology and evolution of infectious and parasitic diseases. Our work investigated the interaction between an insect parasite and its most common bird host species, focusing on two relevant questions: (i) are defence strategies different between main and alternative hosts and, (ii) what are the consequences (virulence and parasite success) of different defence strategies? We conducted a matched field experiment and longitudinal studies at the host and the parasite levels under natural conditions, using a system comprising Philornis torquans flies and three bird hosts - the main host and two of the most frequently used alternative hosts. We found that main and alternative hosts have contrasting defence strategies, which gave rise in turn to contrasting virulence and parasite success. In the main bird host, minor loss of fitness, no detectable immune response, and high parasite success suggest a strategy of high tolerance and negligible resistance. Alternative hosts, on the contrary, resisted by mounting inflammatory responses, although with very different efficiency, which resulted in highly dissimilar parasite success and virulence. These results show clearly distinct defence strategies between main and alternative hosts in a natural multi-host system. They also highlight the importance of defence strategies in determining virulence and infection dynamics, and hint that defence efficiency is a crucial intervening element in these processes.
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Affiliation(s)
- Darío E Manzoli
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Argentina
| | - María J Saravia-Pietropaolo
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - Leandro R Antoniazzi
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - Emilce Barengo
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - Sofía I Arce
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - Martín A Quiroga
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - Pablo M Beldomenico
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Argentina.
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30
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Affiliation(s)
- Jesús M Avilés
- Department of Functional and Evolutionary Ecology, EEZA-CSIC, Carretera de Sacramento S/N, Almería, Spain
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31
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Bui S, Oppedal F, Samsing F, Dempster T. Behaviour in Atlantic salmon confers protection against an ectoparasite. J Zool (1987) 2017. [DOI: 10.1111/jzo.12498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S. Bui
- Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT) School of BioSciences University of Melbourne Melbourne Vic Australia
- Institute of Marine Research Matredal Norway
| | - F. Oppedal
- Institute of Marine Research Matredal Norway
| | - F. Samsing
- Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT) School of BioSciences University of Melbourne Melbourne Vic Australia
| | - T. Dempster
- Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT) School of BioSciences University of Melbourne Melbourne Vic Australia
- Institute of Marine Research Matredal Norway
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32
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Zanet S, Miglio G, Ferrari C, Bassano B, Ferroglio E, von Hardenberg A. Higher risk of gastrointestinal parasite infection at lower elevation suggests possible constraints in the distributional niche of Alpine marmots. PLoS One 2017; 12:e0182477. [PMID: 28763517 PMCID: PMC5538747 DOI: 10.1371/journal.pone.0182477] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 07/19/2017] [Indexed: 11/19/2022] Open
Abstract
Alpine marmots Marmota marmota occupy a narrow altitudinal niche within high elevation alpine environments. For animals living at such high elevations where resources are limited, parasitism represents a potential major cost in life history. Using occupancy models, we tested if marmots living at higher elevation have a reduced risk of being infected with gastro-intestinal helminths, possibly compensating the lower availability of resources (shorter feeding season, longer snow cover and lower temperature) than marmots inhabiting lower elevations. Detection probability of eggs and oncospheres of two gastro-intestinal helminthic parasites, Ascaris laevis and Ctenotaenia marmotae, sampled in marmot feces, was used as a proxy of parasite abundance. As predicted, the models showed a negative relationship between elevation and parasite detectability (i.e. abundance) for both species, while there appeared to be a negative effect of solar radiance only for C. marmotae. Site-occupancy models are used here for the first time to model the constrains of gastrointestinal parasitism on a wild species and the relationship existing between endoparasites and environmental factors in a population of free-living animals. The results of this study suggest the future use of site-occupancy models as a viable tool to account for parasite imperfect detection in eco-parasitological studies, and give useful insights to further investigate the hypothesis of the contribution of parasite infection in constraining the altitudinal niche of Alpine marmots.
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Affiliation(s)
- Stefania Zanet
- Department of Veterinary Sciences, University of Turin, Grugliasco (To), Italy
- * E-mail:
| | - Giacomo Miglio
- Department of Veterinary Sciences, University of Turin, Grugliasco (To), Italy
| | - Caterina Ferrari
- Alpine Wildlife Research Centre, Gran Paradiso National Park, Valsavarenche (Aosta), Italy
| | - Bruno Bassano
- Alpine Wildlife Research Centre, Gran Paradiso National Park, Valsavarenche (Aosta), Italy
| | - Ezio Ferroglio
- Department of Veterinary Sciences, University of Turin, Grugliasco (To), Italy
| | - Achaz von Hardenberg
- Alpine Wildlife Research Centre, Gran Paradiso National Park, Valsavarenche (Aosta), Italy
- Conservation Biology Research Group, Department of Biological Sciences, University of Chester, Chester, United Kingdom
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33
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Adelman JS, Hawley DM. Tolerance of infection: A role for animal behavior, potential immune mechanisms, and consequences for parasite transmission. Horm Behav 2017; 88:79-86. [PMID: 27984034 DOI: 10.1016/j.yhbeh.2016.10.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/24/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
Infected organisms can resist or tolerate infection, with tolerance of infection defined as minimizing per-parasite reductions in fitness. Although tolerance is well studied in plants, researchers have only begun to probe the mechanisms and transmission consequences of tolerance in animals. Here we suggest that research on tolerance in animals would benefit from explicitly incorporating behavior as a component of tolerance, given the importance of behavior for host fitness and parasite transmission. We propose two distinct manifestations of tolerance in animals: tissue-specific tolerance, which minimizes fitness losses due to tissue damage during infection, and behavioral tolerance, which minimizes fitness losses by maintaining normal, fitness-enhancing behaviors during infection. Here we briefly review one set of potential immune mechanisms underlying both responses in vertebrate animals: inflammation and its associated signaling molecules. Inflammatory responses, including broadly effective resistance mechanisms like the production of reactive oxygen species, can incur severe costs in terms of damage to a host's own tissues, thereby reducing tissue-specific tolerance. In addition, signaling molecules involved in these responses facilitate stereotypical behavioral changes during infection, which include lethargy and anorexia, reducing normal behaviors and behavioral tolerance. We consider how tissue-specific and behavioral tolerance may vary independently or in conjunction and outline potential consequences of such covariation for the transmission of infectious diseases. We put forward the distinction between tissue-specific and behavioral tolerance not as a definitive framework, but to help stimulate and broaden future research by considering animal behavior as intimately linked to the mechanisms and consequences of tolerance in animals.
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Affiliation(s)
- James S Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Dr., Ames, IA 50011, United States.
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, 1405 Perry St. Blacksburg, VA 24061, United States.
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34
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Host resistance and tolerance of parasitic gut worms depend on resource availability. Oecologia 2017; 183:1031-1040. [PMID: 28138818 DOI: 10.1007/s00442-017-3822-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 01/13/2017] [Indexed: 01/29/2023]
Abstract
Resource availability can significantly alter host-parasite dynamics. Abundant food can provide more resources for hosts to resist infections, but also increase host tolerance of infections by reducing competition between hosts and parasites for food. Whether abundant food favors host resistance or tolerance (or both) might depend on the type of resource that the parasite exploits (e.g., host tissue vs. food), which can vary based on the stage of infection. In our study, we evaluated how low and high resource diets affect Cuban tree frog (Osteopilus septentrionalis) resistance and tolerance of a skin-penetrating, gut nematode Aplectana sp. at each stage of the infection. Compared to a low resource diet, a high resource diet enhanced frog resistance to worm penetration and tolerance while worms traveled to the gut. In contrast, a low resource diet increased resistance to establishment of the infection. After the infection established and worms could access food resources in the gut, a high resource diet enhanced host tolerance of parasites. On a high resource diet, parasitized frogs consumed significantly more food than non-parasitized frogs; when food was then restricted, mass of non-parasitized frogs did not change, whereas mass of parasitized frogs decreased significantly. Thus, a high resource diet increased frog tolerance of established worms because frogs could fully compensate for energy lost to the parasites. Our study shows that host-parasite dynamics are influenced by the effect of resource availability on host resistance and tolerance, which depends on when parasites have access to food and the stage of infection.
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35
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Klemme I, Karvonen A. Vertebrate defense against parasites: Interactions between avoidance, resistance, and tolerance. Ecol Evol 2016; 7:561-571. [PMID: 28116053 PMCID: PMC5243791 DOI: 10.1002/ece3.2645] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/08/2016] [Accepted: 11/13/2016] [Indexed: 12/03/2022] Open
Abstract
Hosts can utilize different types of defense against the effects of parasitism, including avoidance, resistance, and tolerance. Typically, there is tremendous heterogeneity among hosts in these defense mechanisms that may be rooted in the costs associated with defense and lead to trade‐offs with other life‐history traits. Trade‐offs may also exist between the defense mechanisms, but the relationships between avoidance, resistance, and tolerance have rarely been studied. Here, we assessed these three defense traits under common garden conditions in a natural host–parasite system, the trematode eye‐fluke Diplostomum pseudospathaceum and its second intermediate fish host. We looked at host individuals originating from four genetically distinct populations of two closely related salmonid species (Atlantic salmon, Salmo salar and sea trout, Salmo trutta trutta) to estimate the magnitude of variation in these defense traits and the relationships among them. We show species‐specific variation in resistance and tolerance and population‐specific variation in resistance. Further, we demonstrate evidence for a trade‐off between resistance and tolerance. Our results suggest that the variation in host defense can at least partly result from a compromise between different interacting defense traits, the relative importance of which is likely to be shaped by environmental components. Overall, this study emphasizes the importance of considering different components of the host defense system when making predictions on the outcome of host–parasite interactions.
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Affiliation(s)
- Ines Klemme
- Department of Biological and Environmental Science University of Jyvaskyla Jyvaskyla Finland
| | - Anssi Karvonen
- Department of Biological and Environmental Science University of Jyvaskyla Jyvaskyla Finland
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36
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Effects of parasite pressure on parasite mortality and reproductive output in a rodent-flea system: inferring host defense trade-offs. Parasitol Res 2016; 115:3337-44. [DOI: 10.1007/s00436-016-5093-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/25/2016] [Indexed: 10/21/2022]
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37
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Interspecific variation in larval anuran anti-parasite behavior: a test of the adaptive plasticity hypothesis. Evol Ecol 2016. [DOI: 10.1007/s10682-016-9831-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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Jayawardena UA, Rohr JR, Navaratne AN, Amerasinghe PH, Rajakaruna RS. Combined Effects of Pesticides and Trematode Infections on Hourglass Tree Frog Polypedates cruciger. ECOHEALTH 2016; 13:111-22. [PMID: 26911919 PMCID: PMC4852980 DOI: 10.1007/s10393-016-1103-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/18/2015] [Accepted: 01/27/2016] [Indexed: 05/23/2023]
Abstract
The impact of widespread and common environmental factors, such as chemical contaminants, on infectious disease risk in amphibians is particularly important because both chemical contaminants and infectious disease have been implicated in worldwide amphibian declines. Here we report on the lone and combined effects of exposure to parasitic cercariae (larval stage) of the digenetic trematode, Acanthostomum burminis, and four commonly used pesticides (insecticides: chlorpyrifos, dimethoate; herbicides: glyphosate, propanil) at ecologically relevant concentrations on the survival, growth, and development of the common hourglass tree frog, Polypedates cruciger Blyth 1852. There was no evidence of any pesticide-induced mortality on cercariae because all the cercariae successfully penetrated each tadpole host regardless of pesticide treatment. In isolation, both cercarial and pesticide exposure significantly decreased frog survival, development, and growth, and increased developmental malformations, such as scoliosis, kyphosis, and also edema and skin ulcers. The combination of cercariae and pesticides generally posed greater risk to frogs than either factor alone by decreasing survival or growth or increasing time to metamorphosis or malformations. The exception was that lone exposure to chlorpyrifos had higher mortality without than with cercariae. Consistent with mathematical models that suggest that stress should increase the impact of generalist parasites, the weight of the evidence from the field and laboratory suggests that ecologically relevant concentrations of agrochemicals generally increase the threat that trematodes pose to amphibians, highlighting the importance of elucidating interactions between anthropogenic activities and infectious disease in taxa of conservation concern.
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Affiliation(s)
- Uthpala A Jayawardena
- Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Sri Lanka
- Department of Zoology, University of Peradeniya, Peradeniya, Sri Lanka
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA
| | | | | | - Rupika S Rajakaruna
- Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Sri Lanka.
- Department of Zoology, University of Peradeniya, Peradeniya, Sri Lanka.
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39
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Woodhams DC, Bell SC, Bigler L, Caprioli RM, Chaurand P, Lam BA, Reinert LK, Stalder U, Vazquez VM, Schliep K, Hertz A, Rollins-Smith LA. Life history linked to immune investment in developing amphibians. CONSERVATION PHYSIOLOGY 2016; 4:cow025. [PMID: 27928507 PMCID: PMC5001151 DOI: 10.1093/conphys/cow025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/09/2016] [Accepted: 05/14/2016] [Indexed: 05/03/2023]
Abstract
The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development.
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Affiliation(s)
- Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
- Corresponding author: Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. Tel: +1 617 287 6679.
| | - Sara C Bell
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia
| | - Laurent Bigler
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Richard M Caprioli
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University, Nashville, TN 37232-8575, USA
| | - Pierre Chaurand
- Department of Chemistry, Université de Montréal, Montreal, QC, Canada H3T 1J4
| | - Brianna A Lam
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, USA
| | - Laura K Reinert
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
| | - Urs Stalder
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | | | - Klaus Schliep
- Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
| | - Andreas Hertz
- Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
| | - Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
- Department of Biological Science, Vanderbilt University, Nashville, TN 37235-1634, USA
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
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40
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Predator diversity, intraguild predation, and indirect effects drive parasite transmission. Proc Natl Acad Sci U S A 2015; 112:3008-13. [PMID: 25713379 DOI: 10.1073/pnas.1415971112] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Humans are altering biodiversity globally and infectious diseases are on the rise; thus, there is interest in understanding how changes to biodiversity affect disease. Here, we explore how predator diversity shapes parasite transmission. In a mesocosm experiment that manipulated predator (larval dragonflies and damselflies) density and diversity, non-intraguild (non-IG) predators that only consume free-living cercariae (parasitic trematodes) reduced metacercarial infections in tadpoles, whereas intraguild (IG) predators that consume both parasites and tadpole hosts did not. This likely occurred because IG predators reduced tadpole densities and anticercarial behaviors, increasing per capita exposure rates of the surviving tadpoles (i.e., via density- and trait-mediated effects) despite the consumption of parasites. A mathematical model demonstrated that non-IG predators reduce macroparasite infections, but IG predation weakens this "dilution effect" and can even amplify parasite burdens. Consistent with the experiment and model, a wetland survey revealed that the diversity of IG predators was unrelated to metacercarial burdens in amphibians, but the diversity of non-IG predators was negatively correlated with infections. These results are strikingly similar to generalities that have emerged from the predator diversity-pest biocontrol literature, suggesting that there may be general mechanisms for pest control and that biocontrol research might inform disease management and vice versa. In summary, we identified a general trait of predators--where they fall on an IG predation continuum--that predicts their ability to reduce infections and possibly pests in general. Consequently, managing assemblages of predators represents an underused tool for the management of human and wildlife diseases and pest populations.
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41
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Sears BF, Snyder PW, Rohr JR. Host life history and host-parasite syntopy predict behavioural resistance and tolerance of parasites. J Anim Ecol 2015; 84:625-636. [PMID: 25583069 DOI: 10.1111/1365-2656.12333] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 12/07/2014] [Indexed: 11/27/2022]
Abstract
There is growing interest in the role that life-history traits of hosts, such as their 'pace-of-life', play in the evolution of resistance and tolerance to parasites. Theory suggests that, relative to host species that have high syntopy (local spatial and temporal overlap) with parasites, host species with low syntopy should have lower selection pressures for more constitutive (always present) and costly defences, such as tolerance, and greater reliance on more inducible and cheaper defences, such as behaviour. Consequently, we postulated that the degree of host-parasite syntopy, which is negatively correlated with host pace-of-life (an axis reflecting the developmental rate of tadpoles and the inverse of their size at metamorphosis) in our tadpole-parasitic cercarial (trematode) system, would be a negative and positive predictor of behavioural resistance and tolerance, respectively. To test these hypotheses, we exposed seven tadpole species to a range of parasite (cercarial) doses crossed with anaesthesia treatments that controlled for anti-parasite behaviour. We quantified host behaviour, successful and unsuccessful infections, and each species' reaction norm for behavioural resistance and tolerance, defined as the slope between cercarial exposure (or attempted infections) and anti-cercarial behaviours and mass change, respectively. Hence, tolerance is capturing any cost of parasite exposure. As hypothesized, tadpole pace-of-life was a significant positive predictor of behavioural resistance and negative predictor of tolerance, a result that is consistent with a trade-off between behavioural resistance and tolerance across species that warrants further investigation. Moreover, these results were robust to considerations of phylogeny, all possible re-orderings of the three fastest or slowest paced species, and various measurements of tolerance. These results suggest that host pace-of-life and host-parasite syntopy are powerful drivers of both the strength and type of host defence strategies against parasites. Future research should evaluate how often and how strongly host pace-of-life and host-parasite syntopy are correlated and which is the better predictor of the strength and type of host investments in anti-parasite defences.
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Affiliation(s)
- Brittany F Sears
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | | | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
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