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Hardy BM, Muths E, Funk WC, Bailey LL. Quantifying intraspecific variation in host resistance and tolerance to a lethal pathogen. J Anim Ecol 2024. [PMID: 38773788 DOI: 10.1111/1365-2656.14106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 03/14/2024] [Indexed: 05/24/2024]
Abstract
Testing for intraspecific variation for host tolerance or resistance in wild populations is important for informing conservation decisions about captive breeding, translocation, and disease treatment. Here, we test the importance of tolerance and resistance in multiple populations of boreal toads (Anaxyrus boreas boreas) against Batrachochytrium dendrobatidis (Bd), the amphibian fungal pathogen responsible for the greatest host biodiversity loss due to disease. Boreal toads have severely declined in Colorado (CO) due to Bd, but toad populations challenged with Bd in western Wyoming (WY) appear to be less affected. We used a common garden infection experiment to expose post-metamorphic toads sourced from four populations (2 in CO and 2 in WY) to Bd and monitored changes in mass, pathogen burden and survival for 8 weeks. We used a multi-state modelling approach to estimate weekly survival and transition probabilities between infected and cleared states, reflecting a dynamic infection process that traditional approaches fail to capture. We found that WY boreal toads are more tolerant to Bd infection with higher survival probabilities than those in CO when infected with identical pathogen burdens. WY toads also appeared more resistant to Bd with a higher probability of infection clearance and an average of 5 days longer to reach peak infection burdens. Our results demonstrate strong intraspecific differences in tolerance and resistance that likely contribute to why population declines vary regionally across this species. Our multi-state framework allowed us to gain inference on typically hidden disease processes when testing for host tolerance or resistance. Our findings demonstrate that describing an entire host species as 'tolerant' or 'resistant' (or lack thereof) is unwise without testing for intraspecific variation.
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Affiliation(s)
- Bennett M Hardy
- Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Erin Muths
- United States Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | - W Chris Funk
- Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Larissa L Bailey
- Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
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2
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Gutiérrez-Ramos NA, Acevedo MA. Higher body condition with infection by Haemoproteus parasites in Bananaquits ( Coereba flaveola). PeerJ 2024; 12:e16361. [PMID: 38563018 PMCID: PMC10984167 DOI: 10.7717/peerj.16361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 10/05/2023] [Indexed: 04/04/2024] Open
Abstract
Parasite transmission is a heterogenous process in host-parasite interactions. This heterogeneity is particularly apparent in vector-borne parasite transmission where the vector adds an additional level of complexity. Haemosporidian parasites, a widespread protist, cause a malaria-like disease in birds globally, but we still have much to learn about the consequences of infection to hosts' health. In the Caribbean, where malarial parasites are endemic, studying host-parasites interactions may give us important insights about energetic trade-offs involved in malarial parasites infections in birds. In this study, we tested the consequences of Haemoproteus infection on the Bananaquit, a resident species of Puerto Rico. We also tested for potential sources of individual heterogeneity in the consequences of infection such as host age and sex. To quantify the consequences of infection to hosts' health we compared three complementary body condition indices between infected and uninfected individuals. Our results showed that Bananaquits infected by Haemoproteus had higher body condition than uninfected individuals. This result was consistent among the three body condition indices. Still, we found no clear evidence that this effect was mediated by host age or sex. We discuss a set of non-mutually exclusive hypotheses that may explain this pattern including metabolic syndrome, immunological responses leading to host tolerance or resistance to infection, and potential changes in consumption rates. Overall, our results suggest that other mechanisms, may drive the consequences of avian malarial infection.
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Affiliation(s)
| | - Miguel A. Acevedo
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, United States
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3
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Hawley DM, Pérez-Umphrey AM, Adelman JS, Fleming-Davies AE, Garrett-Larsen J, Geary SJ, Childs LM, Langwig KE. Prior exposure to pathogens augments host heterogeneity in susceptibility and has key epidemiological consequences. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.05.583455. [PMID: 38496428 PMCID: PMC10942282 DOI: 10.1101/2024.03.05.583455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Pathogen epidemics are key threats to human and wildlife health. Across systems, host protection from pathogens following initial exposure is often incomplete, resulting in recurrent epidemics through partially-immune hosts. Variation in population-level protection has important consequences for epidemic dynamics, but whether acquired protection influences host heterogeneity in susceptibility and its epidemiological consequences remains unexplored. We experimentally investigated whether prior exposure (none, low-dose, or high-dose) to a bacterial pathogen alters host heterogeneity in susceptibility among songbirds. Hosts with no prior pathogen exposure had little variation in protection, but heterogeneity in susceptibility was significantly augmented by prior pathogen exposure, with the highest variability detected in hosts given high-dose prior exposure. An epidemiological model parameterized with experimental data found that heterogeneity in susceptibility from prior exposure more than halved epidemic sizes compared with a homogeneous population with identical mean protection. However, because infection-induced mortality was also greatly reduced in hosts with prior pathogen exposure, reductions in epidemic size were smaller than expected in hosts with prior exposure. These results highlight the importance of variable protection from prior exposure and/or vaccination in driving host heterogeneity and epidemiological dynamics.
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Affiliation(s)
- Dana M. Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | | | - James S. Adelman
- Department of Biological Sciences, University of Memphis, Memphis, TN, USA
| | | | | | - Steven J. Geary
- Department of Pathobiology & Veterinary Science, University of Connecticut, Storrs, CT, USA
| | | | - Kate E. Langwig
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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4
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Kuttiyarthu Veetil N, Henschen AE, Hawley DM, Melepat B, Dalloul RA, Beneš V, Adelman JS, Vinkler M. Varying conjunctival immune response adaptations of house finch populations to a rapidly evolving bacterial pathogen. Front Immunol 2024; 15:1250818. [PMID: 38370402 PMCID: PMC10869556 DOI: 10.3389/fimmu.2024.1250818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 01/11/2024] [Indexed: 02/20/2024] Open
Abstract
Pathogen adaptations during host-pathogen co-evolution can cause the host balance between immunity and immunopathology to rapidly shift. However, little is known in natural disease systems about the immunological pathways optimised through the trade-off between immunity and self-damage. The evolutionary interaction between the conjunctival bacterial infection Mycoplasma gallisepticum (MG) and its avian host, the house finch (Haemorhous mexicanus), can provide insights into such adaptations in immune regulation. Here we use experimental infections to reveal immune variation in conjunctival tissue for house finches captured from four distinct populations differing in the length of their co-evolutionary histories with MG and their disease tolerance (defined as disease severity per pathogen load) in controlled infection studies. To differentiate contributions of host versus pathogen evolution, we compared house finch responses to one of two MG isolates: the original VA1994 isolate and a more evolutionarily derived one, VA2013. To identify differential gene expression involved in initiation of the immune response to MG, we performed 3'-end transcriptomic sequencing (QuantSeq) of samples from the infection site, conjunctiva, collected 3-days post-infection. In response to MG, we observed an increase in general pro-inflammatory signalling, as well as T-cell activation and IL17 pathway differentiation, associated with a decrease in the IL12/IL23 pathway signalling. The immune response was stronger in response to the evolutionarily derived MG isolate compared to the original one, consistent with known increases in MG virulence over time. The host populations differed namely in pre-activation immune gene expression, suggesting population-specific adaptations. Compared to other populations, finches from Virginia, which have the longest co-evolutionary history with MG, showed significantly higher expression of anti-inflammatory genes and Th1 mediators. This may explain the evolution of disease tolerance to MG infection in VA birds. We also show a potential modulating role of BCL10, a positive B- and T-cell regulator activating the NFKB signalling. Our results illuminate potential mechanisms of house finch adaptation to MG-induced immunopathology, contributing to understanding of the host evolutionary responses to pathogen-driven shifts in immunity-immunopathology trade-offs.
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Affiliation(s)
| | - Amberleigh E. Henschen
- Department of Biological Sciences, The University of Memphis, Memphis, TN, United States
| | - Dana M. Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Balraj Melepat
- Department of Zoology, Charles University, Faculty of Science, Prague, Czechia
| | - Rami A. Dalloul
- Department of Poultry Science, The University of Georgia, Athens, GA, United States
| | - Vladimír Beneš
- European Molecular Biology Laboratory (EMBL), Genomics Core Facility, Heidelberg, Germany
| | - James S. Adelman
- Department of Biological Sciences, The University of Memphis, Memphis, TN, United States
| | - Michal Vinkler
- Department of Zoology, Charles University, Faculty of Science, Prague, Czechia
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5
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Kuttiyarthu Veetil N, Cedraz de Oliveira H, Gomez-Samblas M, Divín D, Melepat B, Voukali E, Świderská Z, Krajzingrová T, Těšický M, Jung F, Beneš V, Madsen O, Vinkler M. Peripheral inflammation-induced changes in songbird brain gene expression: 3' mRNA transcriptomic approach. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2024; 151:105106. [PMID: 38013114 DOI: 10.1016/j.dci.2023.105106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 11/03/2023] [Accepted: 11/21/2023] [Indexed: 11/29/2023]
Abstract
Species-specific neural inflammation can be induced by profound immune signalling from periphery to brain. Recent advances in transcriptomics offer cost-effective approaches to study this regulation. In a population of captive zebra finch (Taeniopygia guttata), we compare the differential gene expression patterns in lipopolysaccharide (LPS)-triggered peripheral inflammation revealed by RNA-seq and QuantSeq. The RNA-seq approach identified more differentially expressed genes but failed to detect any inflammatory markers. In contrast, QuantSeq results identified specific expression changes in the genes regulating inflammation. Next, we adopted QuantSeq to relate peripheral and brain transcriptomes. We identified subtle changes in the brain gene expression during the peripheral inflammation (e.g. up-regulation in AVD-like and ACOD1 expression) and detected co-structure between the peripheral and brain inflammation. Our results suggest benefits of the 3'end transcriptomics for association studies between peripheral and neural inflammation in genetically heterogeneous models and identify potential targets for the future brain research in birds.
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Affiliation(s)
- Nithya Kuttiyarthu Veetil
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Haniel Cedraz de Oliveira
- Wageningen University and Research, Department of Animal Sciences, Animal Breeding and Genomics, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands; Federal University of Viçosa, Viçosa, MG, 36570-900, Brazil.
| | - Mercedes Gomez-Samblas
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic; Granada University, Science faculty, Department of Parasitology, CP:18071, Granada, Granada, Spain.
| | - Daniel Divín
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Balraj Melepat
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Eleni Voukali
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Zuzana Świderská
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Tereza Krajzingrová
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Martin Těšický
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
| | - Ferris Jung
- EMBL, Genomics Core Facility, Meyerhofstraße 1, 69117, Heidelberg, Germany.
| | - Vladimír Beneš
- EMBL, Genomics Core Facility, Meyerhofstraße 1, 69117, Heidelberg, Germany.
| | - Ole Madsen
- Wageningen University and Research, Department of Animal Sciences, Animal Breeding and Genomics, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands.
| | - Michal Vinkler
- Charles University, Faculty of Science, Department of Zoology, Viničná 7, 128 43, Prague, Czech Republic.
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6
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Sauer EL, Connelly C, Perrine W, Love AC, DuRant SE. Male pathology regardless of behaviour drives transmission in an avian host-pathogen system. J Anim Ecol 2024; 93:36-44. [PMID: 38044497 DOI: 10.1111/1365-2656.14026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 10/04/2023] [Indexed: 12/05/2023]
Abstract
Host sex is an important source of heterogeneity in the severity of epidemics. Pinpointing the mechanisms causing this heterogeneity can be difficult because differences in behaviour among sexes (e.g. greater territorial aggression in males) can bias exposure risk, obfuscating the role of immune function, which can lead to differences in pathology, in driving differential susceptibility between sexes. Thus, sex-biased transmission driven by differences in immune function independent of behaviour is poorly understood, especially in non-mammalian systems. Here we examine the previously unexplored potential for male-biased pathology to affect transmission using an avian host-pathogen system. We employ a sex-dependent multistate transmission model parameterized with isolated, individual-based experimental exposures of domestic canaries and experimental transmission data of house finches. The experiment revealed that male birds have shorter incubation periods, longer recovery periods, higher pathogen burdens and greater disease pathology than females. Our model revealed that male-biased pathology led to epidemic size rapidly increasing with the proportion of male birds, with a nearly 10-fold increase in total epidemic size from an all-female to an all-male simulation. Our results demonstrate that female-biased resistance, independent of male behaviour, can drive sex-dependent transmission in wildlife, indicating that sex-based differences in immune function, not just differences in exposure risk, can shape epidemic dynamics.
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Affiliation(s)
- Erin L Sauer
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Chloe Connelly
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Weston Perrine
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Ashely C Love
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Sarah E DuRant
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
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7
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Prakash A, Monteith KM, Bonnet M, Vale PF. Duox and Jak/Stat signalling influence disease tolerance in Drosophila during Pseudomonas entomophila infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104756. [PMID: 37302730 DOI: 10.1016/j.dci.2023.104756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/18/2023] [Accepted: 06/09/2023] [Indexed: 06/13/2023]
Abstract
Disease tolerance describes an infected host's ability to maintain health independently of the ability to clear microbe loads. The Jak/Stat pathway plays a pivotal role in humoral innate immunity by detecting tissue damage and triggering cellular renewal, making it a candidate tolerance mechanism. Here, we find that in Drosophila melanogaster infected with Pseudomonas entomophila disrupting ROS-producing dual oxidase (duox) or the negative regulator of Jak/Stat Socs36E, render male flies less tolerant. Another negative regulator of Jak/Stat, G9a - which has previously been associated with variable tolerance of viral infections - did not affect the rate of mortality with increasing microbe loads compared to flies with functional G9a, suggesting it does not affect tolerance of bacterial infection as in viral infection. Our findings highlight that ROS production and Jak/Stat signalling influence the ability of flies to tolerate bacterial infection sex-specifically and may therefore contribute to sexually dimorphic infection outcomes in Drosophila.
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Affiliation(s)
- Arun Prakash
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK.
| | - Katy M Monteith
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK
| | - Mickael Bonnet
- UFR De Biologie, Campus Universitaire Des Cezeaux, France
| | - Pedro F Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK.
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8
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Henschen AE, Vinkler M, Langager MM, Rowley AA, Dalloul RA, Hawley DM, Adelman JS. Rapid adaptation to a novel pathogen through disease tolerance in a wild songbird. PLoS Pathog 2023; 19:e1011408. [PMID: 37294834 DOI: 10.1371/journal.ppat.1011408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 05/08/2023] [Indexed: 06/11/2023] Open
Abstract
Animal hosts can adapt to emerging infectious disease through both disease resistance, which decreases pathogen numbers, and disease tolerance, which limits damage during infection without limiting pathogen replication. Both resistance and tolerance mechanisms can drive pathogen transmission dynamics. However, it is not well understood how quickly host tolerance evolves in response to novel pathogens or what physiological mechanisms underlie this defense. Using natural populations of house finches (Haemorhous mexicanus) across the temporal invasion gradient of a recently emerged bacterial pathogen (Mycoplasma gallisepticum), we find rapid evolution of tolerance (<25 years). In particular, populations with a longer history of MG endemism have less pathology but similar pathogen loads compared with populations with a shorter history of MG endemism. Further, gene expression data reveal that more-targeted immune responses early in infection are associated with tolerance. These results suggest an important role for tolerance in host adaptation to emerging infectious diseases, a phenomenon with broad implications for pathogen spread and evolution.
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Affiliation(s)
- Amberleigh E Henschen
- Department of Biological Sciences, University of Memphis; Memphis, Tennessee, United States of America
- Department of Natural Resource Ecology and Management, Iowa State University; Ames, Iowa, United States of America
| | - Michal Vinkler
- Department of Zoology, Charles University; Prague, Czech Republic
| | - Marissa M Langager
- Department of Biological Sciences, Virginia Tech; Blacksburg, Virginia, United States of America
| | - Allison A Rowley
- Department of Biological Sciences, Virginia Tech; Blacksburg, Virginia, United States of America
| | - Rami A Dalloul
- Department of Poultry Science, University of Georgia; Athens, Georgia, United States of America
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech; Blacksburg, Virginia, United States of America
| | - James S Adelman
- Department of Biological Sciences, University of Memphis; Memphis, Tennessee, United States of America
- Department of Natural Resource Ecology and Management, Iowa State University; Ames, Iowa, United States of America
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9
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Vinkler M, Fiddaman SR, Těšický M, O'Connor EA, Savage AE, Lenz TL, Smith AL, Kaufman J, Bolnick DI, Davies CS, Dedić N, Flies AS, Samblás MMG, Henschen AE, Novák K, Palomar G, Raven N, Samaké K, Slade J, Veetil NK, Voukali E, Höglund J, Richardson DS, Westerdahl H. Understanding the evolution of immune genes in jawed vertebrates. J Evol Biol 2023; 36:847-873. [PMID: 37255207 PMCID: PMC10247546 DOI: 10.1111/jeb.14181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 06/01/2023]
Abstract
Driven by co-evolution with pathogens, host immunity continuously adapts to optimize defence against pathogens within a given environment. Recent advances in genetics, genomics and transcriptomics have enabled a more detailed investigation into how immunogenetic variation shapes the diversity of immune responses seen across domestic and wild animal species. However, a deeper understanding of the diverse molecular mechanisms that shape immunity within and among species is still needed to gain insight into-and generate evolutionary hypotheses on-the ultimate drivers of immunological differences. Here, we discuss current advances in our understanding of molecular evolution underpinning jawed vertebrate immunity. First, we introduce the immunome concept, a framework for characterizing genes involved in immune defence from a comparative perspective, then we outline how immune genes of interest can be identified. Second, we focus on how different selection modes are observed acting across groups of immune genes and propose hypotheses to explain these differences. We then provide an overview of the approaches used so far to study the evolutionary heterogeneity of immune genes on macro and microevolutionary scales. Finally, we discuss some of the current evidence as to how specific pathogens affect the evolution of different groups of immune genes. This review results from the collective discussion on the current key challenges in evolutionary immunology conducted at the ESEB 2021 Online Satellite Symposium: Molecular evolution of the vertebrate immune system, from the lab to natural populations.
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Affiliation(s)
- Michal Vinkler
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | | | - Martin Těšický
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | | | - Anna E. Savage
- Department of BiologyUniversity of Central FloridaFloridaOrlandoUSA
| | - Tobias L. Lenz
- Research Unit for Evolutionary ImmunogenomicsDepartment of BiologyUniversity of HamburgHamburgGermany
| | | | - Jim Kaufman
- Institute for Immunology and Infection ResearchUniversity of EdinburghEdinburghUK
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Daniel I. Bolnick
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticutUSA
| | | | - Neira Dedić
- Department of Botany and ZoologyMasaryk UniversityBrnoCzech Republic
| | - Andrew S. Flies
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmaniaAustralia
| | - M. Mercedes Gómez Samblás
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
- Department of ParasitologyUniversity of GranadaGranadaSpain
| | | | - Karel Novák
- Department of Genetics and BreedingInstitute of Animal SciencePragueUhříněvesCzech Republic
| | - Gemma Palomar
- Faculty of BiologyInstitute of Environmental SciencesJagiellonian UniversityKrakówPoland
| | - Nynke Raven
- Department of ScienceEngineering and Build EnvironmentDeakin UniversityVictoriaWaurn PondsAustralia
| | - Kalifa Samaké
- Department of Genetics and MicrobiologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | - Joel Slade
- Department of BiologyCalifornia State UniversityFresnoCaliforniaUSA
| | | | - Eleni Voukali
- Department of ZoologyFaculty of ScienceCharles UniversityPragueCzech Republic
| | - Jacob Höglund
- Department of Ecology and GeneticsUppsala UniversitetUppsalaSweden
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10
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Kutzer MAM, Gupta V, Neophytou K, Doublet V, Monteith KM, Vale PF. Intraspecific genetic variation in host vigour, viral load and disease tolerance during Drosophila C virus infection. Open Biol 2023; 13:230025. [PMID: 36854375 PMCID: PMC9974301 DOI: 10.1098/rsob.230025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Genetic variation for resistance and disease tolerance has been described in a range of species. In Drosophila melanogaster, genetic variation in mortality following systemic Drosophila C virus (DCV) infection is driven by large-effect polymorphisms in the restriction factor pastrel (pst). However, it is unclear if pst contributes to disease tolerance. We investigated systemic DCV challenges spanning nine orders of magnitude, in males and females of 10 Drosophila Genetic Reference Panel lines carrying either a susceptible (S) or resistant (R) pst allele. We find among-line variation in fly survival, viral load and disease tolerance measured both as the ability to maintain survival (mortality tolerance) and reproduction (fecundity tolerance). We further uncover novel effects of pst on host vigour, as flies carrying the R allele exhibited higher survival and fecundity even in the absence of infection. Finally, we found significant genetic variation in the expression of the JAK-STAT ligand upd3 and the epigenetic regulator of JAK-STAT G9a. However, while G9a has been previously shown to mediate tolerance of DCV infection, we found no correlation between the expression of either upd3 or G9a on fly tolerance or resistance. Our work highlights the importance of both resistance and tolerance in viral defence.
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Affiliation(s)
- Megan A. M. Kutzer
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Vanika Gupta
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, UK
| | - Vincent Doublet
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Katy M. Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
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11
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Ruden RM, Adelman JS. Modulating disease phenotype in a songbird: A role for inflammation in disease tolerance? JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:83-91. [PMID: 36127806 DOI: 10.1002/jez.2655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 12/15/2022]
Abstract
Individual animals vary greatly in their responses to infection, either killing off the invading pathogen (resistance) or minimizing the per-pathogen costs of infection on host fitness (tolerance). Though we understand little about the physiological drivers of tolerance in wild animals, phenotypically, it manifests as milder clinical signs of disease. Here, we use a well-described disease system, finch mycoplasmosis, to evaluate the role of inflammation in disease tolerance. House finches (Haemorhous mexicanus) infected with the bacterial pathogen Mycoplasma gallisepticum (MG) develop conjunctival pathology that satisfies the cardinal signs of inflammation. We report on a captive trial performed in 2016 and replicated in 2018 that tested whether chemotherapeutics, specifically nonsteroidal anti-inflammatory drugs (NSAIDs), can reduce lesion severity, thus pushing individuals toward more tolerant phenotypes. Though birds treated with NSAIDs in the first trial developed milder pathology per unit pathogen load, we found no effect of treatment in the second trial, perhaps due to natural variation in baseline tolerance within the source population across years. Second-trial control birds developed markedly milder pathology than first-year controls, suggesting that the effect of trial swamped the effect of treatment in this study. Moving forward, using birds from a population in which the disease is absent or only recently emerged-and so tolerance has not yet been selected for-may better elucidate the role of pro-inflammatory mediators in disease tolerance.
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Affiliation(s)
- Rachel M Ruden
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA.,Iowa Department of Natural Resources, Ames, Iowa, USA
| | - James S Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA.,Department of Biological Sciences, University of Memphis, Memphis, Tennessee, USA
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12
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Prakash A, Monteith KM, Vale PF. Mechanisms of damage prevention, signalling and repair impact disease tolerance. Proc Biol Sci 2022; 289:20220837. [PMID: 35975433 PMCID: PMC9382215 DOI: 10.1098/rspb.2022.0837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The insect gut is frequently exposed to pathogenic threats and must not only clear these potential infections, but also tolerate relatively high microbe loads. In contrast to the mechanisms that eliminate pathogens, we currently know less about the mechanisms of disease tolerance. We investigated how well-described mechanisms that prevent, signal, control or repair damage during infection contribute to the phenotype of disease tolerance. We established enteric infections with the bacterial pathogen Pseudomonas entomophila in transgenic lines of Drosophila melanogaster fruit flies affecting dcy (a major component of the peritrophic matrix), upd3 (a cytokine-like molecule), irc (a negative regulator of reactive oxygen species) and egfr1 (epithelial growth factor receptor). Flies lacking dcy experienced the highest mortality, while loss of function of either irc or upd3 reduced tolerance in both sexes. The disruption of egfr1 resulted in a severe loss in tolerance in male flies but had no substantial effect on the ability of female flies to tolerate P. entomophila infection, despite carrying greater microbe loads than males. Together, our findings provide evidence for the role of damage limitation mechanisms in disease tolerance and highlight how sexual dimorphism in these mechanisms could generate sex differences in infection outcomes.
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Affiliation(s)
- Arun Prakash
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Katy M. Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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Weitzman CL, Belden LK, May M, Langager MM, Dalloul RA, Hawley DM. Antibiotic perturbation of gut bacteria does not significantly alter host responses to ocular disease in a songbird species. PeerJ 2022; 10:e13559. [PMID: 35707121 PMCID: PMC9190666 DOI: 10.7717/peerj.13559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 05/19/2022] [Indexed: 01/17/2023] Open
Abstract
Bacterial communities in and on wild hosts are increasingly appreciated for their importance in host health. Through both direct and indirect interactions, bacteria lining vertebrate gut mucosa provide hosts protection against infectious pathogens, sometimes even in distal body regions through immune regulation. In house finches (Haemorhous mexicanus), the bacterial pathogen Mycoplasma gallisepticum (MG) causes conjunctivitis, with ocular inflammation mediated by pro- and anti-inflammatory cytokines and infection triggering MG-specific antibodies. Here, we tested the role of gut bacteria in host responses to MG by using oral antibiotics to perturb bacteria in the gut of captive house finches prior to experimental inoculation with MG. We found no clear support for an impact of gut bacterial disruption on conjunctival pathology, MG load, or plasma antibody levels. However, there was a non-significant trend for birds with intact gut communities to have greater conjunctival pathology, suggesting a possible impact of gut bacteria on pro-inflammatory cytokine stimulation. Using 16S bacterial rRNA amplicon sequencing, we found dramatic differences in cloacal bacterial community composition between captive, wild-caught house finches in our experiment and free-living finches from the same population, with lower bacterial richness and core communities composed of fewer genera in captive finches. We hypothesize that captivity may have affected the strength of results in this experiment, necessitating further study with this consideration. The abundance of anthropogenic impacts on wildlife and their bacterial communities, alongside the emergence and spread of infectious diseases, highlights the importance of studies addressing the role of commensal bacteria in health and disease, and the consequences of gut bacterial shifts on wild hosts.
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Affiliation(s)
- Chava L. Weitzman
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America,Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Lisa K. Belden
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Meghan May
- Department of Biomedical Sciences, University of New England, Biddeford, ME, United States of America
| | - Marissa M. Langager
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Rami A. Dalloul
- Department of Poultry Science, University of Georgia, Athens, GA, United States of America
| | - Dana M. Hawley
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
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15
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Ruden RM, Adelman JS. Disease tolerance alters host competence in a wild songbird. Biol Lett 2021; 17:20210362. [PMID: 34699737 PMCID: PMC8548076 DOI: 10.1098/rsbl.2021.0362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/04/2021] [Indexed: 11/12/2022] Open
Abstract
Individuals can express a range of disease phenotypes during infection, with important implications for epidemics. Tolerance, in particular, is a host response that minimizes the per-pathogen fitness costs of infection. Because tolerant hosts show milder clinical signs and higher survival, despite similar pathogen burdens, their potential for prolonged pathogen shedding may facilitate the spread of pathogens. To test this, we simulated outbreaks of mycoplasmal conjunctivitis in house finches, asking how the speed of transmission varied with tissue-specific and behavioural components of tolerance, milder conjunctivitis and anorexia for a given pathogen load, respectively. Because tissue-specific tolerance hinders pathogen deposition onto bird feeders, important transmission hubs, we predicted it would slow transmission. Because behavioural tolerance should increase interactions with bird feeders, we predicted it would speed transmission. Our findings supported these predictions, suggesting that variation in tolerance could help identify individuals most likely to transmit pathogens.
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Affiliation(s)
- Rachel M. Ruden
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, USA
- Iowa Department of Natural Resources, Des Moines, IA, USA
| | - James S. Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, USA
- Department of Biological Sciences, University of Memphis, Memphis, TN, USA
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Seal S, Dharmarajan G, Khan I. Evolution of pathogen tolerance and emerging infections: A missing experimental paradigm. eLife 2021; 10:e68874. [PMID: 34544548 PMCID: PMC8455132 DOI: 10.7554/elife.68874] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/23/2021] [Indexed: 12/11/2022] Open
Abstract
Researchers worldwide are repeatedly warning us against future zoonotic diseases resulting from humankind's insurgence into natural ecosystems. The same zoonotic pathogens that cause severe infections in a human host frequently fail to produce any disease outcome in their natural hosts. What precise features of the immune system enable natural reservoirs to carry these pathogens so efficiently? To understand these effects, we highlight the importance of tracing the evolutionary basis of pathogen tolerance in reservoir hosts, while drawing implications from their diverse physiological and life-history traits, and ecological contexts of host-pathogen interactions. Long-term co-evolution might allow reservoir hosts to modulate immunity and evolve tolerance to zoonotic pathogens, increasing their circulation and infectious period. Such processes can also create a genetically diverse pathogen pool by allowing more mutations and genetic exchanges between circulating strains, thereby harboring rare alive-on-arrival variants with extended infectivity to new hosts (i.e., spillover). Finally, we end by underscoring the indispensability of a large multidisciplinary empirical framework to explore the proposed link between evolved tolerance, pathogen prevalence, and spillover in the wild.
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Affiliation(s)
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of GeorgiaAikenUnited States
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USING MULTIVARIATE ANALYSES TO EXPLORE DISEASE PROGRESSION OF FINCH MYCOPLASMOSIS. J Wildl Dis 2021; 57:525-533. [PMID: 33979448 DOI: 10.7589/jwd-d-20-00123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/27/2020] [Indexed: 11/20/2022]
Abstract
Lesion severity scales have been developed for a number of wildlife diseases causing external pathology. Perhaps the best known and most widely used scoring system has been developed for finch mycoplasmosis in which observers measure conjunctival pathology along a four-point scale of increasing severity. We developed novel techniques to characterize variation in host phenotype based on occupancy of multidimensional trait space (disease space). First, we used shape analysis to track distortions of the inner and outer eye rims, defined by 16 anatomical landmarks. Then, we used community analysis to evaluate pathology based on the presence or absence of a unique set of binary descriptors. We applied these techniques to experimental infection data to relate differences in conjunctival pathology to stage of infection. Specifically, by comparing specimens that received the same severity score at different time points in infection, we asked if shape or community analyses could distinguish between individuals in early infection versus those in recovery. We found that individual eyes followed predictable loops through disease space, tracking further from their origin with more severe pathology. Also, certain pathological descriptors were more likely to appear earlier versus later in infection. Our results indicated that leveraging differences in pathology captured in complex trait space could complement severity scores by better resolving the time course of infection from limited data points.
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Love AC, Grisham K, Krall JB, Goodchild CG, DuRant SE. Perception of infection: disease-related social cues influence immunity in songbirds. Biol Lett 2021; 17:20210125. [PMID: 34102069 PMCID: PMC8187024 DOI: 10.1098/rsbl.2021.0125] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/18/2021] [Indexed: 12/13/2022] Open
Abstract
While avoidance of sick conspecifics is common among animals, little is known about how detecting diseased conspecifics influences an organism's physiological state, despite its implications for disease transmission dynamics. The avian pathogen Mycoplasma gallisepticum (MG) causes obvious visual signs of infection in domestic canaries (Serinus canaria domestica), including lethargy and conjunctivitis, making this system a useful tool for investigating how the perception of cues from sick individuals shapes immunity in healthy individuals. We tested whether disease-related social information can stimulate immune responses in canaries housed in visual contact with either healthy or MG-infected conspecifics. We found higher complement activity and higher heterophil counts in healthy birds viewing MG-infected individuals around 6-12 days post-inoculation, which corresponded with the greatest degree of disease pathology in infected stimulus birds. However, we did not detect the effects of disease-related social cues on the expression of two proinflammatory cytokines in the blood. These data indicate that social cues of infection can alter immune responses in healthy individuals and suggest that public information about the disease can shape how individuals respond to infection.
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Affiliation(s)
- Ashley C. Love
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
- Department of Biological Sciences, University of Arkansas, 601 Science and Engineering, Fayetteville, AR 72701, USA
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, CT 06269, USA
| | - Kevin Grisham
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
| | - Jeffrey B. Krall
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
| | - Christopher G. Goodchild
- Department of Biology, University of Central Oklahoma, 100 North University Drive, Edmond, OK 73034, USA
| | - Sarah E. DuRant
- Department of Biological Sciences, University of Arkansas, 601 Science and Engineering, Fayetteville, AR 72701, USA
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Hochachka WM, Dobson AP, Hawley DM, Dhondt AA. Host population dynamics in the face of an evolving pathogen. J Anim Ecol 2021; 90:1480-1491. [PMID: 33821505 DOI: 10.1111/1365-2656.13469] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 02/19/2021] [Indexed: 11/28/2022]
Abstract
Interactions between hosts and pathogens are dynamic at both ecological and evolutionary levels. In the resultant 'eco-evolutionary dynamics' ecological and evolutionary processes affect each other. For example, the house finch Haemorhous mexicanus and its recently emerged pathogen, the bacterium Mycoplasma gallisepticum, form a system in which evidence suggests that changes in bacterial virulence through time enhance levels of host immunity in ways that drive the evolution of virulence in an arms race. We use data from two associated citizen science projects in order to determine whether this arms race has had any detectable effect at the population level in the north-eastern United States. We used data from two citizen science projects, based on observations of birds at bird feeders, which provide information on the long-term changes in sizes of aggregations of house finches (host population density), and the probabilities that these house finches have observable disease (disease prevalence). The initial emergence of M. gallisepticum caused a rapid halving of house finch densities; this was then followed by house finch populations remaining stable or slowly declining. Disease prevalence also decreased sharply after the initial emergence and has remained low, although with fluctuations through time. Surprisingly, while initially higher local disease prevalence was found at sites with higher local densities of finches, this relationship has reversed over time. The ability of a vertebrate host species, with a generation time of at least 1 year, to maintain stable populations in the face of evolved higher virulence of a bacterium, with generation times measurable in minutes, suggests that genetic changes in the host are insufficient to explain the observed population-level patterns. We suggest that acquired immunity plays an important role in the observed interaction between house finches and M. gallisepticum.
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Affiliation(s)
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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20
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Hawley DM, Gibson AK, Townsend AK, Craft ME, Stephenson JF. Bidirectional interactions between host social behaviour and parasites arise through ecological and evolutionary processes. Parasitology 2021; 148:274-288. [PMID: 33092680 PMCID: PMC11010184 DOI: 10.1017/s0031182020002048] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 02/07/2023]
Abstract
An animal's social behaviour both influences and changes in response to its parasites. Here we consider these bidirectional links between host social behaviours and parasite infection, both those that occur from ecological vs evolutionary processes. First, we review how social behaviours of individuals and groups influence ecological patterns of parasite transmission. We then discuss how parasite infection, in turn, can alter host social interactions by changing the behaviour of both infected and uninfected individuals. Together, these ecological feedbacks between social behaviour and parasite infection can result in important epidemiological consequences. Next, we consider the ways in which host social behaviours evolve in response to parasites, highlighting constraints that arise from the need for hosts to maintain benefits of sociality while minimizing fitness costs of parasites. Finally, we consider how host social behaviours shape the population genetic structure of parasites and the evolution of key parasite traits, such as virulence. Overall, these bidirectional relationships between host social behaviours and parasites are an important yet often underappreciated component of population-level disease dynamics and host-parasite coevolution.
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Affiliation(s)
- Dana M. Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA24061, USA
| | - Amanda K. Gibson
- Department of Biology, University of Virginia, Charlottesville, VA22903, USA
| | | | - Meggan E. Craft
- Department of Veterinary Population Medicine and Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN55108, USA
| | - Jessica F. Stephenson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA15260, USA
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21
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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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Luzuriaga-Neira A, Sandmeier FC, Weitzman CL, Tracy CR, Bauschlicher SN, Tillett RL, Alvarez-Ponce D. Mycoplasma agassizii, an opportunistic pathogen of tortoises, shows very little genetic variation across the Mojave and Sonoran Deserts. PLoS One 2021; 16:e0245895. [PMID: 33534823 PMCID: PMC7857612 DOI: 10.1371/journal.pone.0245895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/10/2021] [Indexed: 12/01/2022] Open
Abstract
Mycoplasma agassizii is a common cause of upper respiratory tract disease in Mojave desert tortoises (Gopherus agassizii). So far, only two strains of this bacterium have been sequenced, and very little is known about its patterns of genetic diversity. Understanding genetic variability of this pathogen is essential to implement conservation programs for their threatened, long-lived hosts. We used next generation sequencing to explore the genomic diversity of 86 cultured samples of M. agassizii collected from mostly healthy Mojave and Sonoran desert tortoises in 2011 and 2012. All samples with enough sequencing coverage exhibited a higher similarity to M. agassizii strain PS6T (collected in Las Vegas Valley, Nevada) than to strain 723 (collected in Sanibel Island, Florida). All eight genomes with a sequencing coverage over 2x were subjected to multiple analyses to detect single-nucleotide polymorphisms (SNPs). Strikingly, even though we detected 1373 SNPs between strains PS6T and 723, we did not detect any SNP between PS6T and our eight samples. Our whole genome analyses reveal that M. agassizii strain PS6T may be present across a wide geographic extent in healthy Mojave and Sonoran desert tortoises.
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Affiliation(s)
- Agusto Luzuriaga-Neira
- Department of Biology, University of Nevada Reno, Reno, Nevada, United States of America
| | - Franziska C. Sandmeier
- Biology Department, Colorado State University, Pueblo, Colorado, United States of America
- * E-mail: (FCS); (DAP)
| | - Chava L. Weitzman
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, Virginia, United States of America
| | - C. Richard Tracy
- Department of Biology, University of Nevada Reno, Reno, Nevada, United States of America
| | - Shalyn N. Bauschlicher
- Biology Department, Colorado State University, Pueblo, Colorado, United States of America
| | - Richard L. Tillett
- Nevada Center for Bioinformatics, University of Nevada, Reno, Nevada, United States of America
| | - David Alvarez-Ponce
- Department of Biology, University of Nevada Reno, Reno, Nevada, United States of America
- * E-mail: (FCS); (DAP)
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Sorci G, Léchenault-Bergerot C, Faivre B. Age reduces resistance and tolerance in malaria-infected mice. INFECTION GENETICS AND EVOLUTION 2020; 88:104698. [PMID: 33370596 DOI: 10.1016/j.meegid.2020.104698] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/30/2022]
Abstract
Once infected, hosts can rely on two strategies to cope with parasites: fight them (resist the infection) or minimize the damage they induce (tolerate the infection). While there is evidence that aging reduces resistance, how tolerance varies as hosts become old has been barely studied. Here, we used a rodent malaria parasite (Plasmodium yoelii) to investigate whether 2- and 12-month old house mice differ in their capacity to resist and tolerate the infection. We found that 12-month old mice harbored higher parasitemia, showing that age reduces resistance to malaria. Infection-induced deterioration of host health was assessed using red blood cell and body mass loss. Using both traits, the rate of decline in host health, as parasitemia increased, was more pronounced in 12- than in 2-month old mice, showing that age is also associated with impaired tolerance to malaria. Overall, resistance and tolerance positively covaried; however, this was only due to the age effect, since, within age classes, the two traits were not correlated. These results show that senescing individuals might be both more susceptible to infectious diseases and less able to cope with the damage that infection induces.
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Affiliation(s)
- Gabriele Sorci
- Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France.
| | | | - Bruno Faivre
- Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France
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Gupta P, Vishnudas CK, Robin VV, Dharmarajan G. Host phylogeny matters: Examining sources of variation in infection risk by blood parasites across a tropical montane bird community in India. Parasit Vectors 2020; 13:536. [PMID: 33115505 PMCID: PMC7594458 DOI: 10.1186/s13071-020-04404-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/14/2020] [Indexed: 11/10/2022] Open
Abstract
Background Identifying patterns and drivers of infection risk among host communities is crucial to elucidate disease dynamics and predict infectious disease risk in wildlife populations. Blood parasites of the genera Plasmodium and Haemoproteus are a diverse group of vector-borne protozoan parasites that affect bird populations globally. Despite their widespread distribution and exceptional diversity, factors underlying haemosporidian infection risk in wild bird communities remain poorly understood. While some studies have examined variation in avian haemosporidian risk, researchers have primarily focused on host ecological traits without considering host phylogenetic relationships. In this study, we employ a phylogenetically informed approach to examine the association between host ecological traits and haemosporidian infection risk in endemic bird communities in the Western Ghats Sky Islands. Methods We used parasite sequence data based on partial mitochondrial cytochrome b gene, that was amplified from genomic DNA extracted from 1177 birds (28 species) across the Western Ghats to assess infection of birds with haemosporidian parasites. We employed a Bayesian phylogenetic mixed effect modelling approach to test whether haemosporidian infection risk was affected by seven species-specific and four individual-level ecological predictors. We also examined the effect of host phylogenetic relationships on the observed patterns of variation in haemosporidian infection risk by estimating phylogenetic signal. Results Our study shows that host ecological traits and host phylogeny differentially influence infection risk by Plasmodium (generalist parasite) and Haemoproteus (specialist parasite). For Plasmodium, we found that sociality, sexual dimorphism and foraging strata were important ecological predictors. For Haemoproteus, patterns of infection risk among host species were associated with sociality, species elevation and individual body condition. Interestingly, variance in infection risk explained by host phylogeny was higher for Haemoproteus parasites compared to Plasmodium. Conclusions Our study highlights that while host ecological traits promoting parasite exposure and host susceptibility are important determinants of infection risk, host phylogeny also contributes substantially to predicting patterns of haemosporidian infection risk in multi-host communities. Importantly, infection risk is driven by joint contributions of host ecology and host phylogeny and studying these effects together could increase our ability to better understand the drivers of infection risk and predict future disease threats. Graphical abstract ![]()
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Affiliation(s)
- Pooja Gupta
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA. .,Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA. .,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India.
| | - C K Vishnudas
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - V V Robin
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA.,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India
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25
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Stephenson JF, Stevens M, Troscianko J, Jokela J. The Size, Symmetry, and Color Saturation of a Male Guppy's Ornaments Forecast His Resistance to Parasites. Am Nat 2020; 196:597-608. [PMID: 33064581 DOI: 10.1086/711033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractSexually selected ornaments range from highly dynamic traits to those that are fixed during development and relatively static throughout sexual maturity. Ornaments along this continuum differ in the information they provide about the qualities of potential mates, such as their parasite resistance. Dynamic ornaments enable real-time assessment of the bearer's condition: they can reflect an individual's current infection status, or they can reflect resistance to recent infections. Static ornaments, however, are not affected by recent infection but may instead indicate an individual's genetically determined resistance, even in the absence of infection. Given the typically aggregated distribution of parasites among hosts, infection is unlikely to affect the ornaments of the vast majority of individuals in a population: static ornaments may therefore be the more reliable indicators of parasite resistance. To test this hypothesis, we quantified the ornaments of male guppies (Poecilia reticulata) before experimentally infecting them with Gyrodactylus turnbulli. Males with more left-right symmetrical black coloration and those with larger areas of orange coloration, both static ornaments, were more resistant. However, males with more saturated orange coloration, a dynamic ornament, were less resistant. Female guppies often prefer symmetrical males with larger orange ornaments, suggesting that parasite-mediated natural and sexual selection act in concert on these traits.
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26
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Bale NM, Leon AE, Hawley DM. Differential house finch leukocyte profiles during experimental infection with Mycoplasma gallisepticum isolates of varying virulence. Avian Pathol 2020; 49:342-354. [PMID: 32270701 DOI: 10.1080/03079457.2020.1753652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Leukocyte differentials are a useful tool for assessing systemic immunological changes during pathogen infections, particularly for non-model species. To date, no study has explored how experimental infection with a common bacterial pathogen, Mycoplasma gallisepticum (MG), influences the course and strength of haematological changes in the natural songbird host, house finches. Here we experimentally inoculated house finches with MG isolates known to vary in virulence, and quantified the proportions of circulating leukocytes over the entirety of infection. First, we found significant temporal effects of MG infection on the proportions of most cell types, with strong increases in heterophil and monocyte proportions during infection. Marked decreases in lymphocyte proportions also occurred during infection, though these proportional changes may simply be driven by correlated increases in other leukocytes. Second, we found significant effects of isolate virulence, with the strongest changes in cell proportions occurring in birds inoculated with the higher virulence isolates, and almost no detectable changes relative to sham treatment groups in birds inoculated with the lowest virulence isolate. Finally, we found that variation in infection severity positively predicted the proportion of circulating heterophils and lymphocytes, but the strength of these correlations was dependent on isolate. Taken together, these results indicate strong haematological changes in house finches during MG infection, with markedly different responses to MG isolates of varying virulence. These results are consistent with the possibility that evolved virulence in house finch MG results in higher degrees of immune stimulation and associated immunopathology, with potential direct benefits for MG transmission. RESEARCH HIGHLIGHTS House finches show a marked pro-inflammatory response to M. gallisepticum infection. Virulent pathogen isolates produce stronger finch white blood cell responses. Among birds, stronger white blood cell responses are associated with higher infection severity.
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Affiliation(s)
- Natalie M Bale
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Ariel E Leon
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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27
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Henschen AE, Adelman JS. What Does Tolerance Mean for Animal Disease Dynamics When Pathology Enhances Transmission? Integr Comp Biol 2020; 59:1220-1230. [PMID: 31141137 DOI: 10.1093/icb/icz065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Host competence, or how well an individual transmits pathogens, varies substantially within and among animal populations. As this variation can alter the course of epidemics and epizootics, revealing its underlying causes will help predict and control the spread of disease. One host trait that could drive heterogeneity in competence is host tolerance, which minimizes fitness losses during infection without decreasing pathogen load. In many cases, tolerance should increase competence by extending infectious periods and enabling behaviors that facilitate contact among hosts. However, we argue that the links between tolerance and competence are more varied. Specifically, the different physiological and behavioral mechanisms by which hosts achieve tolerance should have a range of effects on competence, enhancing the ability to transmit pathogens in some circumstances and impeding it in others. Because tissue-based pathology (damage) that reduces host fitness is often critical for pathogen transmission, we focus on two mechanisms that can underlie tolerance at the tissue level: damage-avoidance and damage-repair. As damage-avoidance reduces transmission-enhancing pathology, this mechanism is likely to decrease host competence and pathogen transmission. In contrast, damage-repair does not prevent transmission-relevant pathology from occurring. Rather, damage-repair provides new, healthy tissues that pathogens can exploit, likely extending the infectious period and increasing host competence. We explore these concepts through graphical models and present three disease systems in which damage-avoidance and damage-repair alter host competence in the predicted directions. Finally, we suggest that by incorporating these links, future theoretical studies could provide new insights into infectious disease dynamics and host-pathogen coevolution.
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Affiliation(s)
- Amberleigh E Henschen
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Drive, Ames, IA 50011, USA
| | - James S Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Drive, Ames, IA 50011, USA
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28
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Becker DJ, Nachtmann C, Argibay HD, Botto G, Escalera-Zamudio M, Carrera JE, Tello C, Winiarski E, Greenwood AD, Méndez-Ojeda ML, Loza-Rubio E, Lavergne A, de Thoisy B, Czirják GÁ, Plowright RK, Altizer S, Streicker DG. Leukocyte Profiles Reflect Geographic Range Limits in a Widespread Neotropical Bat. Integr Comp Biol 2020; 59:1176-1189. [PMID: 30873523 PMCID: PMC6907035 DOI: 10.1093/icb/icz007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Quantifying how the environment shapes host immune defense is important for understanding which wild populations may be more susceptible or resistant to pathogens. Spatial variation in parasite risk, food and predator abundance, and abiotic conditions can each affect immunity, and these factors can also manifest at both local and biogeographic scales. Yet identifying predictors and the spatial scale of their effects is limited by the rarity of studies that measure immunity across many populations of broadly distributed species. We analyzed leukocyte profiles from 39 wild populations of the common vampire bat (Desmodus rotundus) across its wide geographic range throughout the Neotropics. White blood cell differentials varied spatially, with proportions of neutrophils and lymphocytes varying up to six-fold across sites. Leukocyte profiles were spatially autocorrelated at small and very large distances, suggesting that local environment and large-scale biogeographic factors influence cellular immunity. Generalized additive models showed that bat populations closer to the northern and southern limits of the species range had more neutrophils, monocytes, and basophils, but fewer lymphocytes and eosinophils, than bats sampled at the core of their distribution. Habitats with access to more livestock also showed similar patterns in leukocyte profiles, but large-scale patterns were partly confounded by time between capture and sampling across sites. Our findings suggest that populations at the edge of their range experience physiologically limiting conditions that predict higher chronic stress and greater investment in cellular innate immunity. High food abundance in livestock-dense habitats may exacerbate such conditions by increasing bat density or diet homogenization, although future spatially and temporally coordinated field studies with common protocols are needed to limit sampling artifacts. Systematically assessing immune function and response over space will elucidate how environmental conditions influence traits relevant to epidemiology and help predict disease risks with anthropogenic disturbance, land conversion, and climate change.
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Affiliation(s)
- Daniel J Becker
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA 30602, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Cecilia Nachtmann
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Hernan D Argibay
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Germán Botto
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59715, USA.,Departamento de Metodos Cuantitativos, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
| | - Marina Escalera-Zamudio
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany.,Department of Zoology, University of Oxford, Oxford OX1 3SY, UK
| | - Jorge E Carrera
- Facultad de Ciencias, Universidad Nacional de Piura, Piura 20009, Peru.,Programa de Conservación de Murciélagos de Perú, Piura Lima-1, Peru
| | - Carlos Tello
- Association for the Conservation and Development of Natural Resources, Lima 15037, Peru.,Yunkawasi, Lima 15049, Peru
| | - Erik Winiarski
- Departamento de Histología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
| | - Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany.,Department of Veterinary Medicine, Freie Universität Berlin, Berlin 14163, Germany
| | - Maria L Méndez-Ojeda
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Veracruzana, Veracruz 91710, Mexico
| | - Elizabeth Loza-Rubio
- Centro Nacional de Investigación Disciplinaria en Microbiología Animal, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Mexico City 05110, Mexico
| | - Anne Lavergne
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana F-97300, France
| | - Benoit de Thoisy
- Laboratoire des Interactions Virus-Hôtes, Institut Pasteur de la Guyane, Cayenne, French Guiana F-97300, France
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin 10315, Germany
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59715, USA
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA 30602, USA
| | - Daniel G Streicker
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.,MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
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29
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Becker DJ, Albery GF, Kessler MK, Lunn TJ, Falvo CA, Czirják GÁ, Martin LB, Plowright RK. Macroimmunology: The drivers and consequences of spatial patterns in wildlife immune defence. J Anim Ecol 2020; 89:972-995. [PMID: 31856309 DOI: 10.1111/1365-2656.13166] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 11/06/2019] [Indexed: 01/26/2023]
Abstract
The prevalence and intensity of parasites in wild hosts varies across space and is a key determinant of infection risk in humans, domestic animals and threatened wildlife. Because the immune system serves as the primary barrier to infection, replication and transmission following exposure, we here consider the environmental drivers of immunity. Spatial variation in parasite pressure, abiotic and biotic conditions, and anthropogenic factors can all shape immunity across spatial scales. Identifying the most important spatial drivers of immunity could help pre-empt infectious disease risks, especially in the context of how large-scale factors such as urbanization affect defence by changing environmental conditions. We provide a synthesis of how to apply macroecological approaches to the study of ecoimmunology (i.e. macroimmunology). We first review spatial factors that could generate spatial variation in defence, highlighting the need for large-scale studies that can differentiate competing environmental predictors of immunity and detailing contexts where this approach might be favoured over small-scale experimental studies. We next conduct a systematic review of the literature to assess the frequency of spatial studies and to classify them according to taxa, immune measures, spatial replication and extent, and statistical methods. We review 210 ecoimmunology studies sampling multiple host populations. We show that whereas spatial approaches are relatively common, spatial replication is generally low and unlikely to provide sufficient environmental variation or power to differentiate competing spatial hypotheses. We also highlight statistical biases in macroimmunology, in that few studies characterize and account for spatial dependence statistically, potentially affecting inferences for the relationships between environmental conditions and immune defence. We use these findings to describe tools from geostatistics and spatial modelling that can improve inference about the associations between environmental and immunological variation. In particular, we emphasize exploratory tools that can guide spatial sampling and highlight the need for greater use of mixed-effects models that account for spatial variability while also allowing researchers to account for both individual- and habitat-level covariates. We finally discuss future research priorities for macroimmunology, including focusing on latitudinal gradients, range expansions and urbanization as being especially amenable to large-scale spatial approaches. Methodologically, we highlight critical opportunities posed by assessing spatial variation in host tolerance, using metagenomics to quantify spatial variation in parasite pressure, coupling large-scale field studies with small-scale field experiments and longitudinal approaches, and applying statistical tools from macroecology and meta-analysis to identify generalizable spatial patterns. Such work will facilitate scaling ecoimmunology from individual- to habitat-level insights about the drivers of immune defence and help predict where environmental change may most alter infectious disease risk.
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Affiliation(s)
- Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| | - Gregory F Albery
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Tamika J Lunn
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Caylee A Falvo
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Lynn B Martin
- Department of Global and Planetary Health, University of South Florida, Tampa, FL, USA
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
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30
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Cooke SJ, Madliger CL, Cramp RL, Beardall J, Burness G, Chown SL, Clark TD, Dantzer B, de la Barrera E, Fangue NA, Franklin CE, Fuller A, Hawkes LA, Hultine KR, Hunt KE, Love OP, MacMillan HA, Mandelman JW, Mark FC, Martin LB, Newman AEM, Nicotra AB, Robinson SA, Ropert-Coudert Y, Rummer JL, Seebacher F, Todgham AE. Reframing conservation physiology to be more inclusive, integrative, relevant and forward-looking: reflections and a horizon scan. CONSERVATION PHYSIOLOGY 2020; 8:coaa016. [PMID: 32274063 PMCID: PMC7125050 DOI: 10.1093/conphys/coaa016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/27/2020] [Accepted: 02/10/2020] [Indexed: 05/21/2023]
Abstract
Applying physiological tools, knowledge and concepts to understand conservation problems (i.e. conservation physiology) has become commonplace and confers an ability to understand mechanistic processes, develop predictive models and identify cause-and-effect relationships. Conservation physiology is making contributions to conservation solutions; the number of 'success stories' is growing, but there remain unexplored opportunities for which conservation physiology shows immense promise and has the potential to contribute to major advances in protecting and restoring biodiversity. Here, we consider how conservation physiology has evolved with a focus on reframing the discipline to be more inclusive and integrative. Using a 'horizon scan', we further explore ways in which conservation physiology can be more relevant to pressing conservation issues of today (e.g. addressing the Sustainable Development Goals; delivering science to support the UN Decade on Ecosystem Restoration), as well as more forward-looking to inform emerging issues and policies for tomorrow. Our horizon scan provides evidence that, as the discipline of conservation physiology continues to mature, it provides a wealth of opportunities to promote integration, inclusivity and forward-thinking goals that contribute to achieving conservation gains. To advance environmental management and ecosystem restoration, we need to ensure that the underlying science (such as that generated by conservation physiology) is relevant with accompanying messaging that is straightforward and accessible to end users.
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Affiliation(s)
- Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada
- Corresponding author: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada.
| | - Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada
| | - Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Gary Burness
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Steven L Chown
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Timothy D Clark
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 14 3216, Australia
| | - Ben Dantzer
- Department of Psychology, Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Erick de la Barrera
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Morelia, Michoacán, 58190, Mexico
| | - Nann A Fangue
- Department of Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, 7 York Rd, Parktown, 2193, South Africa
| | - Lucy A Hawkes
- College of Life and Environmental Sciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter, EX4 4PS, UK
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA 22030, USA
| | - Oliver P Love
- Department of Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada
| | - Heath A MacMillan
- Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S 5B6, Canada
| | - John W Mandelman
- Anderson Cabot Center for Ocean Life, New England Aquarium, 1 Central Wharf, Boston, MA 02110, USA
| | - Felix C Mark
- Department of Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Am Handelshafen 12, 27574 Bremerhaven, Germany
| | - Lynn B Martin
- Global Health and Infectious Disease Research, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Adrienne B Nicotra
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Sharon A Robinson
- School of Earth, Atmospheric and Life Sciences (SEALS) and Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Yan Ropert-Coudert
- Centre d'Etudes Biologiques de Chizé, CNRS UMR 7372 - La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 5811, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, NSW 2006, Australia
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, One Shields Ave. Davis, CA, 95616, USA
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31
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Gu X, Liu S, Guo X, Weng R, Zhong Z. Epidemiological investigation and antimicrobial susceptibility analysis of mycoplasma in patients with genital manifestations. J Clin Lab Anal 2019; 34:e23118. [PMID: 31721313 PMCID: PMC7171337 DOI: 10.1002/jcla.23118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/18/2019] [Accepted: 10/24/2019] [Indexed: 11/25/2022] Open
Abstract
Background The aim of this study was to investigate the infection and antimicrobial resistance of Ureaplasma urealyticum and Mycoplasma hominis in patients with genitourinary symptoms among Hakka population in Meizhou, China. Methods A total of 12 633 females and 3315 males who presented urogenital symptoms and were subjected to mycoplasma tests from 2014 to 2018 were enrolled in this study. The mycoplasma detection and antimicrobial susceptibility were tested using the Mycoplasma ID/AST kit. Results The total incidence of mycoplasma infection, as well as the incidence of U urealyticum in Hakka population was annually increasing from 2014 to 2018. The total incidences and U urealyticum infection were more prevalent in females than males. Higher positive rate of mycoplasmas infection was observed in women aged 16‐20 (50.9%) and men aged 26‐30 (25.4%). The occurrence of antimicrobial resistance of mycoplasma to antibacterial agents remained relatively similar in the past five years. Ureaplasma urealyticum infection, M hominis infection, and co‐infection of resistance to levofloxacin, erythromycin, ciprofloxacin, ofloxacin, roxithromycin, azithromycin, clarithromycin, and sparfloxacin were dramatically higher in females than in males. Conclusion Our findings indicate a high burden of mycoplasmas infection and antimicrobial resistance of mycoplasmas infection among females, and josamycin and minocycline may be recommended as the primary choice in clinical treatment of anti‐mycoplasmas.
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Affiliation(s)
- Xiaodong Gu
- Research Experimental Center, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translational Research of Hakka Population, Meizhou, China.,Guangdong Provincial Engineering and Technological Research Center for Molecular Diagnostics of Cardiovascular Diseases, Meizhou, China
| | - Sudong Liu
- Research Experimental Center, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translational Research of Hakka Population, Meizhou, China.,Guangdong Provincial Engineering and Technological Research Center for Molecular Diagnostics of Cardiovascular Diseases, Meizhou, China
| | - Xuemin Guo
- Research Experimental Center, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translational Research of Hakka Population, Meizhou, China.,Guangdong Provincial Engineering and Technological Research Center for Molecular Diagnostics of Cardiovascular Diseases, Meizhou, China
| | - Ruiqiang Weng
- Research Experimental Center, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translational Research of Hakka Population, Meizhou, China.,Guangdong Provincial Engineering and Technological Research Center for Molecular Diagnostics of Cardiovascular Diseases, Meizhou, China
| | - Zhixiong Zhong
- Research Experimental Center, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translational Research of Hakka Population, Meizhou, China.,Guangdong Provincial Engineering and Technological Research Center for Molecular Diagnostics of Cardiovascular Diseases, Meizhou, China.,Center for Cardiovascular Diseases, Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University, Meizhou, China
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32
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Staley M, Bonneaud C, McGraw KJ, Vleck CM, Hill GE. Detection of Mycoplasma gallisepticum in House Finches ( Haemorhous mexicanus) from Arizona. Avian Dis 2019; 62:14-17. [PMID: 29620468 DOI: 10.1637/11610-021317-reg.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In 1994, an endemic poultry pathogen, Mycoplasma gallisepticum (MG), was identified as the causative agent of a novel disease in house finches ( Haemorhous mexicanus). After an initial outbreak in Maryland, MG spread rapidly throughout eastern North American populations of house finches. Subsequently, MG spread slowly through the northern interior of North America and then into the Pacific Northwest, finally reaching California in 2006. Until 2009, there were no reports of MG in the southwestern United States east of California. In August 2011, after reports of house finches displaying conjunctivitis characteristic of MG infection in Arizona, we trapped house finches at bird feeders in central Arizona (Tempe) and southern Arizona (Tucson and Green Valley) to assay for MG infection. Upon capture, we noted whether birds exhibited conjunctivitis, and we collected choanal swabs to test for the presence of MG DNA using PCR. We detected MG in finches captured from Green Valley (in ∼12% of birds captured), but not in finches from Tucson or Tempe. Based on resampling of house finches at these sites in July 2014, we suggest that central Arizona finches likely remain unexposed to MG. We also suggest that low urban connectivity between arid habitats of southern and central Arizona or a reduction in the prevalence of MG after its initial arrival in Arizona may be limiting the spread of MG from south to north in Arizona. In addition, the observed conjunctivitis-like signs in house finches that were negative for MG by PCR may be caused primarily by avian pox virus.
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Affiliation(s)
- Molly Staley
- A Department of Biological Sciences, Auburn University, Auburn, AL 36849.,B Chicago Zoological Society, Brookfield, IL 60513
| | - Camille Bonneaud
- D Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9EF, United Kingdom
| | - Kevin J McGraw
- E School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - Carol M Vleck
- F Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011
| | - Geoffrey E Hill
- A Department of Biological Sciences, Auburn University, Auburn, AL 36849
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33
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Bonneaud C, Tardy L, Giraudeau M, Hill GE, McGraw KJ, Wilson AJ. Evolution of both host resistance and tolerance to an emerging bacterial pathogen. Evol Lett 2019. [DOI: 10.1002/evl3.133] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Camille Bonneaud
- Centre for Ecology and Conservation; University of Exeter; Penryn Cornwall TR10 9FE United Kingdom
| | - Luc Tardy
- Centre for Ecology and Conservation; University of Exeter; Penryn Cornwall TR10 9FE United Kingdom
| | - Mathieu Giraudeau
- Centre for Ecology and Conservation; University of Exeter; Penryn Cornwall TR10 9FE United Kingdom
- School of Life Sciences; Arizona State University; Tempe Arizona 85287
- Current address: Centre for Ecological and Evolutionary Research on Cancer; UMR CNRS/IRD/UM 5290 MIVEGEC; 34394 Montpellier France
| | - Geoffrey E. Hill
- Department of Biological Sciences; Auburn University; Auburn Alabama 36849
| | - Kevin J. McGraw
- School of Life Sciences; Arizona State University; Tempe Arizona 85287
| | - Alastair J. Wilson
- Centre for Ecology and Conservation; University of Exeter; Penryn Cornwall TR10 9FE United Kingdom
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34
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Stutz WE, Calhoun DM, Johnson PTJ. Resistance and tolerance: A hierarchical framework to compare individual versus family-level host contributions in an experimental amphibian-trematode system. Exp Parasitol 2019; 199:80-91. [PMID: 30862495 DOI: 10.1016/j.exppara.2019.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/22/2019] [Accepted: 03/06/2019] [Indexed: 11/18/2022]
Abstract
Hosts have two general strategies for mitigating the fitness costs of parasite exposure and infection: resistance and tolerance. The resistance-tolerance framework has been well developed in plant systems, but only recently has it been applied to animal-parasite interactions. However, difficulties associated with estimating fitness, controlling parasite exposure, and quantifying parasite burden have limited application of this framework to animal systems. Here, we used an experimental approach to quantify the relative influence of variation among host individuals and genetic families in determining resistance and tolerance within an amphibian-trematode system. Importantly, we used multiple, alternative metrics to assess each strategy, and employed a Bayesian analytical framework to compare among responses while incorporating uncertainty. Relative to unexposed hosts, exposure to the pathogenic trematode (Ribeiroia ondatrae) reduced the survival and growth of California newts (Taricha torosa) (survival: 93% vs. 74%; growth: 0.29 vs. -0.5 vs mm day -1). Similarly, parasite infection success (the inverse of resistance) ranged from 8% to 100%. Yet despite this broad variation in host resistance and tolerance among individual newts, we found no evidence for transmissable, among-family variation in any of the resistance or tolerance metrics. This suggests that opportunities for evolution of these traits is limited, likely requiring significant increases in mutation, gene flow, or environmental heterogeneity. Our study provides a quantitative framework for evaluating the importance of alternative metrics of resistance and tolerance across multiple time points in the study of host-parasite interactions in animal systems.
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Affiliation(s)
- William E Stutz
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Dana M Calhoun
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA.
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
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35
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Burgan SC, Gervasi SS, Johnson LR, Martin LB. How Individual Variation in Host Tolerance Affects Competence to Transmit Parasites. Physiol Biochem Zool 2019; 92:49-57. [PMID: 30481116 DOI: 10.1086/701169] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tolerance, or the maintenance of host health or fitness at a given parasite burden, has often been studied in evolutionary and medical contexts, particularly with respect to effects on the evolution of parasite virulence and individual patient outcomes. These bodies of work have provided insight about tolerance for evolutionary phenomena (e.g., virulence) and individual health (e.g., recovering from an infection). However, due to the specific motivations of that work, few studies have considered the ecological ramifications of variation in tolerance, namely, how variation in forms of tolerance could mediate parasite movement through populations and even community-level disease dynamics. Tolerance is most commonly regarded as the relationship between host fitness and parasite burden. However, few if any studies have actually quantified host fitness, instead utilizing proxies of fitness as the response variables to be regressed against parasite burden. Here, we address how attention to the effects of parasite burden on traits that are relevant to host competence (i.e., the ability to amplify parasites to levels transmissible to other hosts/vectors) will enhance our understanding of disease dynamics in nature. We also provide several forms of guidance for how to overcome the challenges of quantifying tolerance in wild organisms.
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36
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Walker DJ, Zimmer C, Larriva M, Healy SD, Spencer KA. Early-life adversity programs long-term cytokine and microglia expression within the HPA axis in female Japanese quail. J Exp Biol 2019; 222:jeb.187039. [DOI: 10.1242/jeb.187039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 02/21/2019] [Indexed: 12/14/2022]
Abstract
Stress exposure during pre and post-natal development can have persistent and often dysfunctional effects on several physiological systems, including immune function, affecting the ability to combat infection. The neuro-immune response is inextricably linked to the action of the Hypothalamic Pituitary Adrenal (HPA) axis. Cytokines released from neuro-immune cells, including microglia, activate the HPA axis while glucocorticoids in turn regulate cytokine release from microglia. Because of the close links between these two physiological systems, coupled with potential for persistent changes to HPA axis activity following developmental stress, components of the neuro-immune system could be targets for developmental programming. However, little is known of any programming effects of developmental stress on neuro-immune function. We investigated whether developmental stress exposure via elevated pre-natal corticosterone (CORT) or post-natal unpredictable food availability, had long-term effects on pro (IL-1β) and anti-inflammatory (IL-10) cytokine and microglia-dependent gene (CSF1R) expression within HPA axis tissues in a precocial bird, the Japanese quail (Coturnix japonica). Following post-natal stress, we observed increased IL-1β expression in the pituitary gland, reduced IL-10 expression in the amygdala and hypothalamus and reduced CSF1R expression within the hypothalamus and pituitary gland. Post-natal stress disrupted the ratio of IL-1β:IL-10 expression within the hippocampus and hypothalamus. Pre-natal stress only increased IL-1β expression in the pituitary gland. We found no evidence for interactive or cumulative effects across life stages on basal cytokine and glia expression in adulthood. We show that post-natal stress may have a larger impact than elevated pre-natal CORT on basal immunity in HPA axis specific brain regions, with changes in cytokine homeostasis and microglia abundance. These results provide evidence for post-natal programming of a pro-inflammatory neuro-immune phenotype at the expense of reduced microglia, which could have implications for CNS health and subsequent neuro-immune responses.
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Affiliation(s)
- David J. Walker
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
| | - Cédric Zimmer
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14850, USA
| | - Maria Larriva
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
| | - Susan D. Healy
- School of Biology, Harold Mitchell Building, University of St Andrews, KY16 9TH, UK
| | - Karen A. Spencer
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
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Tavalire HF, Beechler BR, Buss PE, Gorsich EE, Hoal EG, le Roex N, Spaan JM, Spaan RS, van Helden PD, Ezenwa VO, Jolles AE. Context-dependent costs and benefits of tuberculosis resistance traits in a wild mammalian host. Ecol Evol 2018; 8:12712-12726. [PMID: 30619576 PMCID: PMC6308860 DOI: 10.1002/ece3.4699] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/02/2018] [Accepted: 10/12/2018] [Indexed: 12/24/2022] Open
Abstract
Disease acts as a powerful driver of evolution in natural host populations, yet individuals in a population often vary in their susceptibility to infection. Energetic trade-offs between immune and reproductive investment lead to the evolution of distinct life history strategies, driven by the relative fitness costs and benefits of resisting infection. However, examples quantifying the cost of resistance outside of the laboratory are rare. Here, we observe two distinct forms of resistance to bovine tuberculosis (bTB), an important zoonotic pathogen, in a free-ranging African buffalo (Syncerus caffer) population. We characterize these phenotypes as "infection resistance," in which hosts delay or prevent infection, and "proliferation resistance," in which the host limits the spread of lesions caused by the pathogen after infection has occurred. We found weak evidence that infection resistance to bTB may be heritable in this buffalo population (h 2 = 0.10) and comes at the cost of reduced body condition and marginally reduced survival once infected, but also associates with an overall higher reproductive rate. Infection-resistant animals thus appear to follow a "fast" pace-of-life syndrome, in that they reproduce more quickly but die upon infection. In contrast, proliferation resistance had no apparent costs and was associated with measures of positive host health-such as having a higher body condition and reproductive rate. This study quantifies striking phenotypic variation in pathogen resistance and provides evidence for a link between life history variation and a disease resistance trait in a wild mammalian host population.
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Affiliation(s)
- Hannah F. Tavalire
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
- The Institute of Ecology and EvolutionUniversity of OregonEugeneOregon
- Present address:
Prevention Science InstituteUniversity of OregonEugeneOregon
- Present address:
Institute of Ecology and EvolutionUniversity of OregonEugeneOregon
| | | | | | - Erin E. Gorsich
- College of Veterinary MedicineOregon State UniversityCorvallisOregon
- Present address:
Erin E. Gorsich, Zeeman Institute: Systems Biology and Infectious Disease Epidemiology Research (SBIDER)University of WarwickCoventryUK
- Present address:
School of Life SciencesUniversity of WarwickCoventryUK
| | - Eileen G. Hoal
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Nikki le Roex
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Johannie M. Spaan
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
| | - Robert S. Spaan
- Department of Fisheries and WildlifeOregon State UniversityCorvallisOregon
| | - Paul D. van Helden
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Vanessa O. Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary MedicineUniversity of GeorgiaAthensGeorgia
| | - Anna E. Jolles
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
- College of Veterinary MedicineOregon State UniversityCorvallisOregon
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Gates DE, Valletta JJ, Bonneaud C, Recker M. Quantitative host resistance drives the evolution of increased virulence in an emerging pathogen. J Evol Biol 2018; 31:1704-1714. [PMID: 30107064 DOI: 10.1111/jeb.13366] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/31/2018] [Accepted: 08/09/2018] [Indexed: 12/01/2022]
Abstract
Emergent infectious diseases can have a devastating impact on host populations. The high selective pressures on both the hosts and the pathogens frequently lead to rapid adaptations not only in pathogen virulence but also host resistance following an initial outbreak. However, it is often unclear whether hosts will evolve to avoid infection-associated fitness costs by preventing the establishment of infection (here referred to as qualitative resistance) or by limiting its deleterious effects through immune functioning (here referred to as quantitative resistance). Equally, the evolutionary repercussions these different resistance mechanisms have for the pathogen are often unknown. Here, we investigate the co-evolutionary dynamics of pathogen virulence and host resistance following the epizootic outbreak of the highly pathogenic bacterium Mycoplasma gallisepticum in North American house finches (Haemorhous mexicanus). Using an evolutionary modelling approach and with a specific emphasis on the evolved resistance trait, we demonstrate that the rapid increase in the frequency of resistant birds following the outbreak is indicative of strong selection pressure to reduce infection-associated mortality. This, in turn, created the ecological conditions that selected for increased bacterial virulence. Our results thus suggest that quantitative host resistance was the key factor underlying the evolutionary interactions in this natural host-pathogen system.
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Affiliation(s)
| | - John Joseph Valletta
- Centre for Mathematics & the Environment, University of Exeter, Penryn, Cornwall, UK
| | | | - Mario Recker
- Centre for Mathematics & the Environment, University of Exeter, Penryn, Cornwall, UK
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Rapid Antagonistic Coevolution in an Emerging Pathogen and Its Vertebrate Host. Curr Biol 2018; 28:2978-2983.e5. [PMID: 30197084 DOI: 10.1016/j.cub.2018.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 04/24/2018] [Accepted: 07/02/2018] [Indexed: 02/02/2023]
Abstract
Host-pathogen coevolution is assumed to play a key role in eco-evolutionary processes, including epidemiological dynamics and the evolution of sexual reproduction [1-4]. Despite this, direct evidence for host-pathogen coevolution is exceptional [5-7], particularly in vertebrate hosts. Indeed, although vertebrate hosts have been shown to evolve in response to pathogens or vice versa [8-12], there is little evidence for the necessary reciprocal changes in the success of both antagonists over time [13]. Here, we generate a time-shift experiment to demonstrate adaptive, reciprocal changes in North American house finches (Haemorhous mexicanus) and their emerging bacterial pathogen, Mycoplasma gallisepticum [14-16]. Our experimental design is made possible by the existence of disease-exposed and unexposed finch populations, which were known to exhibit equivalent responses to experimental inoculation until the recent spread of genetic resistance in the former [14, 17]. Whereas inoculations with pathogen isolates from epidemic outbreak caused comparable sub-lethal eye swelling in hosts from exposed (hereafter adapted) and unexposed (hereafter ancestral) populations, inoculations with isolates sampled after the spread of resistance were threefold more likely to cause lethal symptoms in hosts from ancestral populations. Similarly, the probability that pathogens successfully established an infection in the primary host and, before inducing death, transmitted to an uninfected sentinel was highest when recent isolates were inoculated in hosts from ancestral populations and lowest when early isolates were inoculated in hosts from adapted populations. Our results demonstrate antagonistic host-pathogen coevolution, with hosts and pathogens displaying increased resistance and virulence in response to each other over time.
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Burgan SC, Gervasi SS, Martin LB. Parasite Tolerance and Host Competence in Avian Host Defense to West Nile Virus. ECOHEALTH 2018; 15:360-371. [PMID: 29569179 DOI: 10.1007/s10393-018-1332-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 02/15/2018] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
Competence, or the propensity of a host to transmit parasites, is partly underlain by host strategies to cope with infection (e.g., resistance and tolerance). Resistance represents the ability of hosts to prevent or clear infections, whereas tolerance captures the ability of individuals to cope with a given parasite burden. Here, we investigated (1) whether one easy-to-measure form of tolerance described well the dynamic relationships between host health and parasite burden, and (2) whether individual resistance and tolerance to West Nile virus (WNV) were predictable from single cytokine measures. We exposed house sparrows (HOSP) to WNV and measured subsequent changes in host performance, viral burden, and cytokine expression. We then used two novel approaches (one complex, one simpler) to estimate tolerance within-individual HOSP using four separate host performance traits. We lastly investigated changes in the expression of pro-inflammatory cytokine interferon-γ (IFN-γ) and anti-inflammatory cytokine interleukin-10 (IL-10). Both approaches to estimating tolerance were equivalent among WNV-infected HOSP; thus, an easy-to-measure tolerance estimation may be successfully applied in field studies. Constitutive expression of IFN-γ and IL-10 were predictive of resistance and tolerance to WNV, implicating these cytokines as viable biomarkers of host competence to WNV.
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Affiliation(s)
- Sarah C Burgan
- Department of Integrative Biology, University of South Florida, SCA 130, 12037 USF Beard Drive, Tampa, FL, 33620, USA
| | | | - Lynn B Martin
- Department of Integrative Biology, University of South Florida, SCA 130, 12037 USF Beard Drive, Tampa, FL, 33620, USA.
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Jaeger A, Lebarbenchon C, Bourret V, Bastien M, Lagadec E, Thiebot JB, Boulinier T, Delord K, Barbraud C, Marteau C, Dellagi K, Tortosa P, Weimerskirch H. Avian cholera outbreaks threaten seabird species on Amsterdam Island. PLoS One 2018; 13:e0197291. [PMID: 29847561 PMCID: PMC5976148 DOI: 10.1371/journal.pone.0197291] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 04/29/2018] [Indexed: 11/19/2022] Open
Abstract
Infectious diseases may be particularly critical for the conservation of endangered species. A striking example is the recurrent outbreaks that have been occurring in seabirds on Amsterdam Island for the past 30 years, threatening populations of three Endangered seabird species and of the endemic, Critically Endangered Amsterdam albatross Diomedea amsterdamensis. The bacteria Pasteurella multocida (avian cholera causative agent), and to a lesser extent Erysipelothrix rhusiopathiae (erysipelas causative agent), were both suspected to be responsible for these epidemics. Despite this critical situation, demographic trends were not available for these threatened populations, and the occurrence and characterization of potential causative agents of epizootics remain poorly known. The aims of the current study were to (i) provide an update of population trends for four threatened seabird species monitored on Amsterdam Island, (ii) assess the occurrence of P. multocida, and E. rhusiopathiae in live birds from five species, (iii) search for other infectious agents in these samples and, (iv) isolate and genotype the causative agent(s) of epizooties from dead birds. Our study shows that the demographic situation has worsened substantially in three seabird species during the past decade, with extremely low reproductive success and declining populations for Indian yellow-nosed albatrosses Thalassarche carteri, sooty albatrosses Phoebetria fusca, and northern rockhopper penguins Eudyptes moseleyi. Pasteurella multocida or E. rhusiopathiae were detected by PCR in live birds of all five investigated species, while results were negative for eight additional infectious agents. A single strain of P. multocida was repeatedly cultured from dead birds, while no E. rhusiopathiae could be isolated. These results highlight the significance of P. multocida in this particular eco-epidemiological system as the main agent responsible for epizootics. The study stresses the urgent need to implement mitigation measures to alter the course of avian cholera outbreaks threatening the persistence of seabird populations on Amsterdam Island.
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Affiliation(s)
- Audrey Jaeger
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS 9192, INSERM 1187, IRD 249, GIP CYROI, Saint Denis, La Réunion, France
- Université de la Réunion, UMR ENTROPIE, UR, IRD, CNRS, Saint Denis, La Réunion, France
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
| | - Camille Lebarbenchon
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS 9192, INSERM 1187, IRD 249, GIP CYROI, Saint Denis, La Réunion, France
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
| | - Vincent Bourret
- Centre d’Ecologie Fonctionnelle et Evolutive, CNRS-Université Montpellier UMR 5175, Montpellier, France
| | - Matthieu Bastien
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
- Réserve Naturelle Nationale des Terres Australes Françaises, Terres Australes et Antarctiques Françaises, rue Gabriel Dejean, Saint Pierre, La Réunion, France
| | - Erwan Lagadec
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS 9192, INSERM 1187, IRD 249, GIP CYROI, Saint Denis, La Réunion, France
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
- Réserve Naturelle Nationale des Terres Australes Françaises, Terres Australes et Antarctiques Françaises, rue Gabriel Dejean, Saint Pierre, La Réunion, France
| | - Jean-Baptiste Thiebot
- Réserve Naturelle Nationale des Terres Australes Françaises, Terres Australes et Antarctiques Françaises, rue Gabriel Dejean, Saint Pierre, La Réunion, France
- Centre d’Etudes Biologiques de Chizé, UMR 7372CNRS – Université de La Rochelle, Villiers en Bois, France
| | - Thierry Boulinier
- Centre d’Ecologie Fonctionnelle et Evolutive, CNRS-Université Montpellier UMR 5175, Montpellier, France
| | - Karine Delord
- Centre d’Etudes Biologiques de Chizé, UMR 7372CNRS – Université de La Rochelle, Villiers en Bois, France
| | - Christophe Barbraud
- Centre d’Etudes Biologiques de Chizé, UMR 7372CNRS – Université de La Rochelle, Villiers en Bois, France
| | - Cédric Marteau
- Réserve Naturelle Nationale des Terres Australes Françaises, Terres Australes et Antarctiques Françaises, rue Gabriel Dejean, Saint Pierre, La Réunion, France
| | - Koussay Dellagi
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS 9192, INSERM 1187, IRD 249, GIP CYROI, Saint Denis, La Réunion, France
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
| | - Pablo Tortosa
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS 9192, INSERM 1187, IRD 249, GIP CYROI, Saint Denis, La Réunion, France
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien, GIP CYROI, Sainte Clotilde, La Réunion, France
| | - Henri Weimerskirch
- Centre d’Etudes Biologiques de Chizé, UMR 7372CNRS – Université de La Rochelle, Villiers en Bois, France
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42
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Koch RE, Hill GE. Do carotenoid‐based ornaments entail resource trade‐offs? An evaluation of theory and data. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13122] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rebecca E. Koch
- Department of Biological SciencesAuburn University Auburn Alabama
- School of Biological SciencesMonash University Clayton Vic. Australia
| | - Geoffrey E. Hill
- Department of Biological SciencesAuburn University Auburn Alabama
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43
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Fleming-Davies AE, Williams PD, Dhondt AA, Dobson AP, Hochachka WM, Leon AE, Ley DH, Osnas EE, Hawley DM. Incomplete host immunity favors the evolution of virulence in an emergent pathogen. Science 2018; 359:1030-1033. [PMID: 29496878 PMCID: PMC6317705 DOI: 10.1126/science.aao2140] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/12/2018] [Indexed: 12/21/2022]
Abstract
Immune memory evolved to protect hosts from reinfection, but incomplete responses that allow future reinfection may inadvertently select for more-harmful pathogens. We present empirical and modeling evidence that incomplete immunity promotes the evolution of higher virulence in a natural host-pathogen system. We performed sequential infections of house finches with Mycoplasma gallisepticum strains of various levels of virulence. Virulent bacterial strains generated stronger host protection against reinfection than less virulent strains and thus excluded less virulent strains from infecting previously exposed hosts. In a two-strain model, the resulting fitness advantage selected for an almost twofold increase in pathogen virulence. Thus, the same immune systems that protect hosts from infection can concomitantly drive the evolution of more-harmful pathogens in nature.
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Affiliation(s)
- Arietta E Fleming-Davies
- Department of Biology, University of San Diego, San Diego, CA 92110, USA.
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biology, Radford University, Radford, VA 24141, USA
| | - Paul D Williams
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| | - André A Dhondt
- Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
- Santa Fe Institute, Santa Fe, NM 87501, USA
| | | | - Ariel E Leon
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - David H Ley
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Erik E Osnas
- U.S. Fish and Wildlife Service, Anchorage, AK 99503, USA
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
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44
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Gervasi SS, Burgan SC, Hofmeister E, Unnasch TR, Martin LB. Stress hormones predict a host superspreader phenotype in the West Nile virus system. Proc Biol Sci 2018; 284:rspb.2017.1090. [PMID: 28724737 DOI: 10.1098/rspb.2017.1090] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/14/2017] [Indexed: 12/20/2022] Open
Abstract
Glucocorticoid stress hormones, such as corticosterone (CORT), have profound effects on the behaviour and physiology of organisms, and thus have the potential to alter host competence and the contributions of individuals to population- and community-level pathogen dynamics. For example, CORT could alter the rate of contacts among hosts, pathogens and vectors through its widespread effects on host metabolism and activity levels. CORT could also affect the intensity and duration of pathogen shedding and risk of host mortality during infection. We experimentally manipulated songbird CORT, asking how CORT affected behavioural and physiological responses to a standardized West Nile virus (WNV) challenge. Although all birds became infected after exposure to the virus, only birds with elevated CORT had viral loads at or above the infectious threshold. Moreover, though the rate of mortality was faster in birds with elevated CORT compared with controls, most hosts with elevated CORT survived past the day of peak infectiousness. CORT concentrations just prior to inoculation with WNV and anti-inflammatory cytokine concentrations following viral exposure were predictive of individual duration of infectiousness and the ability to maintain physical performance during infection (i.e. tolerance), revealing putative biomarkers of competence. Collectively, our results suggest that glucocorticoid stress hormones could directly and indirectly mediate the spread of pathogens.
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Affiliation(s)
| | - Sarah C Burgan
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Erik Hofmeister
- USGS National Wildlife Health Center, Madison, WI 53711, USA
| | - Thomas R Unnasch
- Department of Global Health, University of South Florida, Tampa, FL 33620, USA
| | - Lynn B Martin
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
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45
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Vinkler M, Leon AE, Kirkpatrick L, Dalloul RA, Hawley DM. Differing House Finch Cytokine Expression Responses to Original and Evolved Isolates of Mycoplasma gallisepticum. Front Immunol 2018. [PMID: 29403495 DOI: 10.3389/fimmu.2018.00013/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The recent emergence of the poultry bacterial pathogen Mycoplasma gallisepticum (MG) in free-living house finches (Haemorhous mexicanus), which causes mycoplasmal conjunctivitis in this passerine bird species, resulted in a rapid coevolutionary arms-race between MG and its novel avian host. Despite extensive research on the ecological and evolutionary dynamics of this host-pathogen system over the past two decades, the immunological responses of house finches to MG infection remain poorly understood. We developed seven new probe-based one-step quantitative reverse transcription polymerase chain reaction assays to investigate mRNA expression of house finch cytokine genes (IL1B, IL6, IL10, IL18, TGFB2, TNFSF15, and CXCLi2, syn. IL8L). These assays were then used to describe cytokine transcription profiles in a panel of 15 house finch tissues collected at three distinct time points during MG infection. Based on initial screening that indicated strong pro-inflammatory cytokine expression during MG infection at the periorbital sites in particular, we selected two key house finch tissues for further characterization: the nictitating membrane, i.e., the internal eyelid in direct contact with MG, and the Harderian gland, the secondary lymphoid tissue responsible for regulation of periorbital immunity. We characterized cytokine responses in these two tissues for 60 house finches experimentally inoculated either with media alone (sham) or one of two MG isolates: the earliest known pathogen isolate from house finches (VA1994) or an evolutionarily more derived isolate collected in 2006 (NC2006), which is known to be more virulent. We show that the more derived and virulent isolate NC2006, relative to VA1994, triggers stronger local inflammatory cytokine signaling, with peak cytokine expression generally occurring 3-6 days following MG inoculation. We also found that the extent of pro-inflammatory interleukin 1 beta signaling was correlated with conjunctival MG loads and the extent of clinical signs of conjunctivitis, the main pathological effect of MG in house finches. These results suggest that the pathogenicity caused by MG infection in house finches is largely mediated by host pro-inflammatory immune responses, with important implications for the dynamics of host-pathogen coevolution.
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Affiliation(s)
- Michal Vinkler
- Faculty of Science, Department of Zoology, Charles University, Prague, Czechia
| | - Ariel E Leon
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Laila Kirkpatrick
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Rami A Dalloul
- Avian Immunobiology Laboratory, Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
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46
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Vinkler M, Leon AE, Kirkpatrick L, Dalloul RA, Hawley DM. Differing House Finch Cytokine Expression Responses to Original and Evolved Isolates of Mycoplasma gallisepticum. Front Immunol 2018; 9:13. [PMID: 29403495 PMCID: PMC5786573 DOI: 10.3389/fimmu.2018.00013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/04/2018] [Indexed: 01/25/2023] Open
Abstract
The recent emergence of the poultry bacterial pathogen Mycoplasma gallisepticum (MG) in free-living house finches (Haemorhous mexicanus), which causes mycoplasmal conjunctivitis in this passerine bird species, resulted in a rapid coevolutionary arms-race between MG and its novel avian host. Despite extensive research on the ecological and evolutionary dynamics of this host-pathogen system over the past two decades, the immunological responses of house finches to MG infection remain poorly understood. We developed seven new probe-based one-step quantitative reverse transcription polymerase chain reaction assays to investigate mRNA expression of house finch cytokine genes (IL1B, IL6, IL10, IL18, TGFB2, TNFSF15, and CXCLi2, syn. IL8L). These assays were then used to describe cytokine transcription profiles in a panel of 15 house finch tissues collected at three distinct time points during MG infection. Based on initial screening that indicated strong pro-inflammatory cytokine expression during MG infection at the periorbital sites in particular, we selected two key house finch tissues for further characterization: the nictitating membrane, i.e., the internal eyelid in direct contact with MG, and the Harderian gland, the secondary lymphoid tissue responsible for regulation of periorbital immunity. We characterized cytokine responses in these two tissues for 60 house finches experimentally inoculated either with media alone (sham) or one of two MG isolates: the earliest known pathogen isolate from house finches (VA1994) or an evolutionarily more derived isolate collected in 2006 (NC2006), which is known to be more virulent. We show that the more derived and virulent isolate NC2006, relative to VA1994, triggers stronger local inflammatory cytokine signaling, with peak cytokine expression generally occurring 3-6 days following MG inoculation. We also found that the extent of pro-inflammatory interleukin 1 beta signaling was correlated with conjunctival MG loads and the extent of clinical signs of conjunctivitis, the main pathological effect of MG in house finches. These results suggest that the pathogenicity caused by MG infection in house finches is largely mediated by host pro-inflammatory immune responses, with important implications for the dynamics of host-pathogen coevolution.
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Affiliation(s)
- Michal Vinkler
- Faculty of Science, Department of Zoology, Charles University, Prague, Czechia
| | - Ariel E. Leon
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Laila Kirkpatrick
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Rami A. Dalloul
- Avian Immunobiology Laboratory, Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Dana M. Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
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47
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Kutzer MAM, Kurtz J, Armitage SAO. Genotype and diet affect resistance, survival, and fecundity but not fecundity tolerance. J Evol Biol 2017; 31:159-171. [DOI: 10.1111/jeb.13211] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/06/2017] [Accepted: 11/12/2017] [Indexed: 11/29/2022]
Affiliation(s)
- M. A. M. Kutzer
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
| | - J. Kurtz
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
| | - S. A. O. Armitage
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
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48
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Leon AE, Hawley DM. Host Responses to Pathogen Priming in a Natural Songbird Host. ECOHEALTH 2017; 14:793-804. [PMID: 28766063 PMCID: PMC5726927 DOI: 10.1007/s10393-017-1261-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 06/14/2017] [Accepted: 06/14/2017] [Indexed: 06/07/2023]
Abstract
Hosts in free-living populations can experience substantial variation in the frequency and dose of pathogen exposure, which can alter disease progression and protection from future exposures. In the house finch-Mycoplasma gallisepticum (MG) system, the pathogen is primarily transmitted via bird feeders, and some birds may be exposed to frequent low doses of MG while foraging. Here we experimentally determined how low dose, repeated exposures of house finches to MG influence host responses and protection from secondary high-dose challenge. MG-naive house finches were given priming exposures that varied in dose and total number. After quantifying host responses to priming exposures, all birds were given a secondary high-dose challenge to assess immunological protection. Dose, but not the number of exposures, significantly predicted both infection and disease severity following priming exposure. Furthermore, individuals given higher priming doses showed stronger protection upon secondary, high-dose challenge. However, even single low-dose exposures to MG, a proxy for what some birds likely experience in the wild while feeding, provided significant protection against a high-dose challenge. Our results suggest that bird feeders, which serve as sources of infection in the wild, may in some cases act as "immunizers," with important consequences for disease dynamics.
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Affiliation(s)
- Ariel E Leon
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA.
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA
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49
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Rogalski MA, Gowler CD, Shaw CL, Hufbauer RA, Duffy MA. Human drivers of ecological and evolutionary dynamics in emerging and disappearing infectious disease systems. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0043. [PMID: 27920388 DOI: 10.1098/rstb.2016.0043] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2016] [Indexed: 01/03/2023] Open
Abstract
Humans have contributed to the increased frequency and severity of emerging infectious diseases, which pose a significant threat to wild and domestic species, as well as human health. This review examines major pathways by which humans influence parasitism by altering (co)evolutionary interactions between hosts and parasites on ecological timescales. There is still much to learn about these interactions, but a few well-studied cases show that humans influence disease emergence every step of the way. Human actions significantly increase dispersal of host, parasite and vector species, enabling greater frequency of infection in naive host populations and host switches. Very dense host populations resulting from urbanization and agriculture can drive the evolution of more virulent parasites and, in some cases, more resistant host populations. Human activities that reduce host genetic diversity or impose abiotic stress can impair the ability of hosts to adapt to disease threats. Further, evolutionary responses of hosts and parasites can thwart disease management and biocontrol efforts. Finally, in rare cases, humans influence evolution by eradicating an infectious disease. If we hope to fully understand the factors driving disease emergence and potentially control these epidemics we must consider the widespread influence of humans on host and parasite evolutionary trajectories.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.
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Affiliation(s)
- Mary A Rogalski
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Camden D Gowler
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Clara L Shaw
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ruth A Hufbauer
- College of Agricultural Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Meghan A Duffy
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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50
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Thomason CA, Mullen N, Belden LK, May M, Hawley DM. Resident Microbiome Disruption with Antibiotics Enhances Virulence of a Colonizing Pathogen. Sci Rep 2017; 7:16177. [PMID: 29170421 PMCID: PMC5701009 DOI: 10.1038/s41598-017-16393-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/13/2017] [Indexed: 01/06/2023] Open
Abstract
There is growing evidence that symbiotic microbes play key roles in host defense, but less is known about how symbiotic microbes mediate pathogen-induced damage to hosts. Here, we use a natural wildlife disease system, house finches and the conjunctival bacterial pathogen Mycoplasma gallisepticum (MG), to experimentally examine the impact of the ocular microbiome on host damage and pathogen virulence factors during infection. We disrupted the ocular bacterial community of healthy finches using an antibiotic that MG is intrinsically resistant to, then inoculated antibiotic- and sham-treated birds with MG. House finches with antibiotic-disrupted ocular microbiomes had more severe MG-induced conjunctival inflammation than birds with unaltered microbiomes, even after accounting for differences in conjunctival MG load. Furthermore, MG cultures from finches with disrupted microbiomes had increased sialidase enzyme and cytadherence activity, traits associated with enhanced virulence in Mycoplasmas, relative to isolates from sham-treated birds. Variation in sialidase activity and cytadherence among isolates was tightly linked with degree of tissue inflammation in hosts, supporting the consideration of these traits as virulence factors in this system. Overall, our results suggest that microbial dysbiosis can result in enhanced virulence of colonizing pathogens, with critical implications for the health of wildlife, domestic animals, and humans.
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Affiliation(s)
| | - Nathan Mullen
- Department of Biomedical Sciences, University of New England, Biddeford, ME, USA
| | - Lisa K Belden
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Meghan May
- Department of Biomedical Sciences, University of New England, Biddeford, ME, USA
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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