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Zinner D, Paciência FMD, Roos C. Host-Parasite Coevolution in Primates. Life (Basel) 2023; 13:823. [PMID: 36983978 PMCID: PMC10058613 DOI: 10.3390/life13030823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 01/26/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Organisms adapt to their environment through evolutionary processes. Environments consist of abiotic factors, but also of other organisms. In many cases, two or more species interact over generations and adapt in a reciprocal way to evolutionary changes in the respective other species. Such coevolutionary processes are found in mutualistic and antagonistic systems, such as predator-prey and host-parasite (including pathogens) relationships. Coevolution often results in an "arms race" between pathogens and hosts and can significantly affect the virulence of pathogens and thus the severity of infectious diseases, a process that we are currently witnessing with SARS-CoV-2. Furthermore, it can lead to co-speciation, resulting in congruent phylogenies of, e.g., the host and parasite. Monkeys and other primates are no exception. They are hosts to a large number of pathogens that have shaped not only the primate immune system but also various ecological and behavioral adaptions. These pathogens can cause severe diseases and most likely also infect multiple primate species, including humans. Here, we briefly review general aspects of the coevolutionary process in its strict sense and highlight the value of cophylogenetic analyses as an indicator for coevolution.
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Affiliation(s)
- Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077 Göttingen, Germany
- Department of Primate Cognition, Georg-August-University of Göttingen, 37077 Göttingen, Germany
- Leibniz Science Campus Primate Cognition, 37077 Göttingen, Germany
| | | | - Christian Roos
- Gene Bank of Primates and Primate Genetics Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077 Göttingen, Germany
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2
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Herrera JP, Moody J, Nunn CL. Predicting primate-parasite associations using exponential random graph models. J Anim Ecol 2023; 92:710-722. [PMID: 36633380 DOI: 10.1111/1365-2656.13883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/07/2022] [Indexed: 01/13/2023]
Abstract
Ecological associations between hosts and parasites are influenced by host exposure and susceptibility to parasites, and by parasite traits, such as transmission mode. Advances in network analysis allow us to answer questions about the causes and consequences of traits in ecological networks in ways that could not be addressed in the past. We used a network-based framework (exponential random graph models or ERGMs) to investigate the biogeographic, phylogenetic and ecological characteristics of hosts and parasites that affect the probability of interactions among nonhuman primates and their parasites. Parasites included arthropods, bacteria, fungi, protozoa, viruses and helminths. We investigated existing hypotheses, along with new predictors and an expanded host-parasite database that included 213 primate nodes, 763 parasite nodes and 2319 edges among them. Analyses also investigated phylogenetic relatedness, sampling effort and spatial overlap among hosts. In addition to supporting some previous findings, our ERGM approach demonstrated that more threatened hosts had fewer parasites, and notably, that this effect was independent of hosts also having a smaller geographic range. Despite having fewer parasites, threatened host species shared more parasites with other hosts, consistent with loss of specialist parasites and threat arising from generalist parasites that can be maintained in other, non-threatened hosts. Viruses, protozoa and helminths had broader host ranges than bacteria, or fungi, and parasites that infect non-primates had a higher probability of infecting more primate species. The value of the ERGM approach for investigating the processes structing host-parasite networks provided a more complete view on the biogeographic, phylogenetic and ecological traits that influence parasite species richness and parasite sharing among hosts. The results supported some previous analyses and revealed new associations that warrant future research, thus revealing how hosts and parasites interact to form ecological networks.
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Affiliation(s)
- James P Herrera
- Duke Lemur Center SAVA Conservation, Duke University, Durham, North Carolina, USA
| | - James Moody
- Department of Sociology, Duke University, Durham, North Carolina, USA
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA.,Duke Global Health Institute, Duke University, Durham, North Carolina, USA
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3
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How do biases in sex ratio and disease characteristics affect the spread of sexually transmitted infections? J Theor Biol 2021; 527:110832. [PMID: 34252402 DOI: 10.1016/j.jtbi.2021.110832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 05/05/2021] [Accepted: 07/06/2021] [Indexed: 01/05/2023]
Abstract
The epidemiology of sexually transmitted infections (STIs) is inherently linked to host mating dynamics. Studies across many taxa show that adult sex ratio, a major determinant of host mating dynamics, is often skewed - sometimes strongly - toward males or females. However, few predictions exist for the effects of skewed sex ratio on STI epidemiology, and none when coupled with sex biased disease characteristics. Here we use mathematical modelling to examine how interactions between sex ratio and disease characteristics affect STI prevalence in males and females. Notably, we find that while overall disease prevalence peaks at equal sex ratios, prevalence per sex peaks at skewed sex ratios. Furthermore, disease characteristics, sex-biased or not, drive predictable differences in male and female STI prevalence as sex ratio varies, with higher transmission and lower virulence generally increasing differences between the sexes for a given sex ratio. Our work reveals new insights into how STI prevalence in males and females depends on a complex interaction between host population sex ratio and disease characteristics.
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Abbate JL, Gladieux P, Hood ME, de Vienne DM, Antonovics J, Snirc A, Giraud T. Co-occurrence among three divergent plant-castrating fungi in the same Silene host species. Mol Ecol 2018; 27:10.1111/mec.14805. [PMID: 30030861 PMCID: PMC6340787 DOI: 10.1111/mec.14805] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 06/21/2018] [Accepted: 07/05/2018] [Indexed: 01/04/2023]
Abstract
The competitive exclusion principle postulates that different species can only coexist in sympatry if they occupy distinct ecological niches. The goal of this study was to understand the geographical distribution of three species of Microbotryum anther-smut fungi that are distantly related but infect the same host plants, the sister species Silene vulgaris and S. uniflora, in Western Europe. We used microsatellite markers to investigate pathogen distribution in relation to host specialization and ecological factors. Microbotryum violaceo-irregulare was only found on S. vulgaris at high elevations in the Alps. Microbotryum lagerheimii could be subdivided into two genetically differentiated clusters, one on S. uniflora in the UK and the second on S. vulgaris in the Alps and Pyrenees. The most abundant pathogen species, M. silenes-inflatae, could be subdivided into four genetic clusters, co-occurring in the Alps, the UK and the Pyrenees, and was found on both S. vulgaris and S. uniflora. All three fungal species had high levels of homozygosity, in agreement with the selfing mating system generally observed in anther-smut fungi. The three pathogen species and genetic clusters had large range overlaps, but occurred at sites with different elevations, temperatures and precipitation levels. The three Microbotryum species thus do not appear to be maintained by host specialization or geographic allopatry, but instead may occupy different ecological niches in terms of environmental conditions.
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Affiliation(s)
- Jessica L. Abbate
- UMR MIVEGEC, IRD 224, CNRS, Université de Montpellier, F-34394 Montpellier, France
- UMR UMMISCO, IRD 209, UPMC, F-93143 Bondy, France
| | - Pierre Gladieux
- Laboratoire Ecologie Systématique et Evolution, Univ. Paris Sud, CNRS, AgroParisTech, Université Paris Saclay, Orsay, F-91400 France
- INRA, UMR BGPI, Bâtiment K; Campus International de Baillarguet, F-34398, Montpellier, France
| | - Michael E. Hood
- Biology Department, McGuire Life Sciences Building, Amherst College, Rts 9 & 116, Amherst, MA USA 01002-5000
| | - Damien M. de Vienne
- Laboratoire Ecologie Systématique et Evolution, Univ. Paris Sud, CNRS, AgroParisTech, Université Paris Saclay, Orsay, F-91400 France
- Laboratoire de Biométrie et Biologie Evolutive, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5558, Université Lyon 1, F-69622 Villeurbanne, France
- Université de Lyon, F-69000 Lyon, France
| | - Janis Antonovics
- University of Virginia, Dept. of Biology, Gilmer Hall, Charlottesville, VA 22904, USA
| | - Alodie Snirc
- Laboratoire Ecologie Systématique et Evolution, Univ. Paris Sud, CNRS, AgroParisTech, Université Paris Saclay, Orsay, F-91400 France
| | - Tatiana Giraud
- Laboratoire Ecologie Systématique et Evolution, Univ. Paris Sud, CNRS, AgroParisTech, Université Paris Saclay, Orsay, F-91400 France
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5
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Beyond R0 Maximisation: On Pathogen Evolution and Environmental Dimensions. Trends Ecol Evol 2018; 33:458-473. [DOI: 10.1016/j.tree.2018.02.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 02/03/2018] [Accepted: 02/13/2018] [Indexed: 01/28/2023]
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Antonovics J, Wilson AJ, Forbes MR, Hauffe HC, Kallio ER, Leggett HC, Longdon B, Okamura B, Sait SM, Webster JP. The evolution of transmission mode. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0083. [PMID: 28289251 PMCID: PMC5352810 DOI: 10.1098/rstb.2016.0083] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2016] [Indexed: 12/31/2022] Open
Abstract
This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.
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Affiliation(s)
- Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Anthony J Wilson
- Integrative Entomology group, Vector-borne Viral Diseases programme, The Pirbright Institute, Pirbright GU24 0NF, UK
| | - Mark R Forbes
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B7
| | - Heidi C Hauffe
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 S. Michele all'Adige, Trentino, Italy
| | - Eva R Kallio
- Department of Biological and Environmental Science, University of Jyvaskyla, PO Box 35, 40014 Jyvaskyla, Finland.,Department of Ecology, University of Oulu, PO Box 3000, 90014 Oulu, Finland
| | - Helen C Leggett
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Ben Longdon
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Beth Okamura
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW5 7BD, UK
| | - Steven M Sait
- School of Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Joanne P Webster
- Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases, Royal Veterinary College, University of London, London AL9 7TA, UK
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Abbate JL, Murall CL, Richner H, Althaus CL. Potential Impact of Sexual Transmission on Ebola Virus Epidemiology: Sierra Leone as a Case Study. PLoS Negl Trop Dis 2016; 10:e0004676. [PMID: 27135922 PMCID: PMC4852896 DOI: 10.1371/journal.pntd.0004676] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/08/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Sexual transmission of Ebola virus disease (EVD) 6 months after onset of symptoms has been recently documented, and Ebola virus RNA has been detected in semen of survivors up to 9 months after onset of symptoms. As countries affected by the 2013-2015 epidemic in West Africa, by far the largest to date, are declared free of Ebola virus disease (EVD), it remains unclear what threat is posed by rare sexual transmission events that could arise from survivors. METHODOLOGY/PRINCIPAL FINDINGS We devised a compartmental mathematical model that includes sexual transmission from convalescent survivors: a SEICR (susceptible-exposed-infectious-convalescent-recovered) transmission model. We fitted the model to weekly incidence of EVD cases from the 2014-2015 epidemic in Sierra Leone. Sensitivity analyses and Monte Carlo simulations showed that a 0.1% per sex act transmission probability and a 3-month convalescent period (the two key unknown parameters of sexual transmission) create very few additional cases, but would extend the epidemic by 83 days [95% CI: 68-98 days] (p < 0.0001) on average. Strikingly, a 6-month convalescent period extended the average epidemic by 540 days (95% CI: 508-572 days), doubling the current length, despite an insignificant rise in the number of new cases generated. CONCLUSIONS/SIGNIFICANCE Our results show that reductions in the per sex act transmission probability via abstinence and condom use should reduce the number of sporadic sexual transmission events, but will not significantly reduce the epidemic size and may only minimally shorten the length of time the public health community must maintain response preparedness. While the number of infectious survivors is expected to greatly decline over the coming months, our results show that transmission events may still be expected for quite some time as each event results in a new potential cluster of non-sexual transmission. Precise measurement of the convalescent period is thus important for planning ongoing surveillance efforts.
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Affiliation(s)
- Jessica L. Abbate
- Institute for Ecology and Evolution, University of Bern, Bern, Switzerland
- UMR MIVEGEC (UMR CNRS 5290, IRD 224, UM), Institute for Research of Development (IRD), Montpellier, France
- UMR UMMISCO (UMI 209 IRD-UPMC), Bondy, France
- * E-mail:
| | - Carmen Lia Murall
- Max-Planck Institute for Dynamics and Self-Organization, Gottingen, Germany
| | - Heinz Richner
- Institute for Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Christian L. Althaus
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
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Hamelin FM, Allen LJS, Prendeville HR, Hajimorad MR, Jeger MJ. The evolution of plant virus transmission pathways. J Theor Biol 2016; 396:75-89. [PMID: 26908348 DOI: 10.1016/j.jtbi.2016.02.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 12/30/2015] [Accepted: 02/12/2016] [Indexed: 01/12/2023]
Abstract
The evolution of plant virus transmission pathways is studied through transmission via seed, pollen, or a vector. We address the questions: under what circumstances does vector transmission make pollen transmission redundant? Can evolution lead to the coexistence of multiple virus transmission pathways? We restrict the analysis to an annual plant population in which reproduction through seed is obligatory. A semi-discrete model with pollen, seed, and vector transmission is formulated to investigate these questions. We assume vector and pollen transmission rates are frequency-dependent and density-dependent, respectively. An ecological stability analysis is performed for the semi-discrete model and used to inform an evolutionary study of trade-offs between pollen and seed versus vector transmission. Evolutionary dynamics critically depend on the shape of the trade-off functions. Assuming a trade-off between pollen and vector transmission, evolution either leads to an evolutionarily stable mix of pollen and vector transmission (concave trade-off) or there is evolutionary bi-stability (convex trade-off); the presence of pollen transmission may prevent evolution of vector transmission. Considering a trade-off between seed and vector transmission, evolutionary branching and the subsequent coexistence of pollen-borne and vector-borne strains is possible. This study contributes to the theory behind the diversity of plant-virus transmission patterns observed in nature.
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Affiliation(s)
- Frédéric M Hamelin
- Department of Ecology, Agrocampus Ouest, UMR1349 IGEPP, F-35042 Rennes, France.
| | - Linda J S Allen
- Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409-1042, USA
| | - Holly R Prendeville
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA
| | - M Reza Hajimorad
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996-4560, USA
| | - Michael J Jeger
- Division of Ecology and Evolution, Centre for Environmental Policy, Imperial College London, SL5 7PY, UK
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9
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Evolutionary suicide through a non-catastrophic bifurcation: adaptive dynamics of pathogens with frequency-dependent transmission. J Math Biol 2015; 72:1101-1124. [PMID: 26612110 DOI: 10.1007/s00285-015-0945-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 09/16/2015] [Indexed: 01/10/2023]
Abstract
Evolutionary suicide is a riveting phenomenon in which adaptive evolution drives a viable population to extinction. Gyllenberg and Parvinen (Bull Math Biol 63(5):981-993, 2001) showed that, in a wide class of deterministic population models, a discontinuous transition to extinction is a necessary condition for evolutionary suicide. An implicit assumption of their proof is that the invasion fitness of a rare strategy is well-defined also in the extinction state of the population. Epidemic models with frequency-dependent incidence, which are often used to model the spread of sexually transmitted infections or the dynamics of infectious diseases within herds, violate this assumption. In these models, evolutionary suicide can occur through a non-catastrophic bifurcation whereby pathogen adaptation leads to a continuous decline of host (and consequently pathogen) population size to zero. Evolutionary suicide of pathogens with frequency-dependent transmission can occur in two ways, with pathogen strains evolving either higher or lower virulence.
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Pastok D, Atkinson D, Hurst GD. Assessing the impact of male-killing bacteria on the spread of a sexually transmitted infection. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Bernhauerová V, Berec L. Role of trade-off between sexual and vertical routes for evolution of pathogen transmission. THEOR ECOL-NETH 2014. [DOI: 10.1007/s12080-014-0234-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Berec L, Maxin D. Fatal or Harmless: Extreme Bistability Induced by Sterilizing, Sexually Transmitted Pathogens. Bull Math Biol 2013; 75:258-73. [DOI: 10.1007/s11538-012-9802-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 11/30/2012] [Indexed: 11/24/2022]
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Antonovics J, Boots M, Abbate J, Baker C, McFrederick Q, Panjeti V. Biology and evolution of sexual transmission. Ann N Y Acad Sci 2011; 1230:12-24. [PMID: 21824163 DOI: 10.1111/j.1749-6632.2011.06127.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sexual reproduction brings together and recombines different genomes. Associated with these contacts is transmission of microorganisms and selfish genetic elements, many of which can be harmful to the host. In organisms with internal fertilization, sexually transmitted infections are caused by pathogens transmitted between the parents participating in mating. Sexual transmission has different epidemiological dynamics from nonsexual transmission in that it is less likely to be dependent on host density, there may be no population density threshold for disease increase, and it is more likely to lead to host extinction. Analysis of the evolutionary pathways that have led to the sexual mode of transmission in pathogens indicates that sexual transmission appears more often to be derived from nonsexual transmission, although the pathways are highly variable, and several groups of pathogens are exceptions to this rule. Sexual transmission has evolved from a wide variety of alternative transmission modes, although rarely from aerially transmitted diseases. More data are needed on the phylogeny and transmission mode of the relatives of sexually transmitted pathogens in order to guide development of animal models and comparative studies.
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Affiliation(s)
- Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903, USA.
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Are non-sexual models appropriate for predicting the impact of virus-vectored immunocontraception? J Theor Biol 2008; 250:281-90. [DOI: 10.1016/j.jtbi.2007.09.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 09/18/2007] [Accepted: 09/26/2007] [Indexed: 11/19/2022]
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15
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Ryder JJ, Miller MR, White A, Knell RJ, Boots M. Host-parasite population dynamics under combined frequency- and density-dependent transmission. OIKOS 2007. [DOI: 10.1111/j.2007.0030-1299.15863.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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17
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Field SG, Michiels NK. ACEPHALINE GREGARINE PARASITES (MONOCYSTIS SP.) ARE NOT TRANSMITTED SEXUALLY AMONG THEIR LUMBRICID EARTHWORM HOSTS. J Parasitol 2006; 92:292-7. [PMID: 16729685 DOI: 10.1645/ge-643r.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The precise transmission mode(s) of acephaline gregarines in their earthworm hosts has long been questioned, yet a rigorous experimental evaluation of sexual transmission is currently lacking. That Monocystis sp., a common gregarine parasite of the earthworm Lumbricus terrestris, infects the sexual organs of its host is suggestive of sexual transmission. Considering the divergent evolutionary consequences of various modes of transmission, excluding or proving sexual transmission in this host-parasite system is critical to fully understanding it. We cultured uninfected earthworms from cocoons and subsequently mated them to either an infected or uninfected partner (from the wild). We then compared these individuals with an orally infected group, which were infected using a newly developed gavage (oral injection) method. Our data have unambiguously established that (1) horizontal sexual transmission does not play a significant role in the transmission of Monocystis sp., and (2) oral transmission through the soil is likely the principal mode of transmission between earthworms. This finding is important to models of mate-choice because infection avoidance does not appear to drive mating decisions. Finally, we further report a successful and relatively simple method to obtain infection-free individuals, which can subsequently be infected via oral gavage and used in empirical studies.
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Affiliation(s)
- Stuart G Field
- Department of Evolutionary Biology, Institute of Animal Ecology & Evolution, Universität Münster, Hüfferstrasse 1, 48149 Münster, Germany.
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Bonds MH, Keenan DD, Leidner AJ, Rohani P. HIGHER DISEASE PREVALENCE CAN INDUCE GREATER SOCIALITY: A GAME THEORETIC COEVOLUTIONARY MODEL. Evolution 2005. [DOI: 10.1111/j.0014-3820.2005.tb01056.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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O'Keefe KJ. The evolution of virulence in pathogens with frequency-dependent transmission. J Theor Biol 2005; 233:55-64. [PMID: 15615619 DOI: 10.1016/j.jtbi.2004.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 08/30/2004] [Accepted: 09/15/2004] [Indexed: 11/25/2022]
Abstract
Frequency-dependent transmission is an important feature of diseases that are sexually transmitted or transmitted by a vector that actively searches for hosts. Here I describe the evolution of virulence in pathogens that have frequency-dependent transmission. I consider two components of virulence--an increase in host mortality due to infection, as is classically described, and a decrease in host fecundity due to infection, because frequency dependence is common among diseases that fully or partially sterilize their hosts. Theoretical predictions pertaining to host-pathogen numerical dynamics can be quite different between pathogens with frequency-dependent transmission and those with density-dependent transmission. In contrast, this study suggests that the principles governing the evolution of virulence that have been established in the context of density-dependent pathogens may also apply (qualitatively) to frequency-dependent pathogens. I examine the evolutionary trajectories of the mortality and sterility components of virulence as well as the role of spatial population structure in the evolution of the sterility component of virulence.
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Affiliation(s)
- Kara J O'Keefe
- Department of Ecology and Evolutionary Biology, Osborn Memorial Laboratories, Yale University, New Haven, CT 06520-8106, USA.
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Abstract
The concept of plant venereal disease is examined from definitional, operational and axiomatic viewpoints. The transmission of many plant pathogens occurs during the flowering phase and is effected either by pollinators or by wind dispersal of spores from inflorescences. Attraction of insects by pseudo-flowers or sugary secretions also serves to spread many diseases. Given the diversity of processes involved, a simple all-encompassing parallel with animal venereal diseases is not possible. Operationally establishing the routes of disease transmission, as well as quantifying the relative magnitudes of these different routes, remains critical for understanding disease dynamics and controlling spread in agricultural contexts. From an axiomatic viewpoint, sexually transmitted diseases are characterized by frequency-dependent transmission, transmission in the adult stage, and by virulence effects involving sterility rather than mortality. These characteristics serve to differentiate the dynamics and evolution of sexually transmitted diseases from that of other diseases and are features that are also shared by many pollinator-transmitted diseases. However, the majority of plant diseases that involve the reproductive structures show a rich biology that defies easy categorization. The experimental convenience of plants and their pathogens is likely to play an important role in understanding the evolution of disease traits, irrespective of what descriptive terms are applied to the natural history of the transmission process.
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Affiliation(s)
- Janis Antonovics
- Biology Department, University of Virginia, Charlottesville, Virginia 22904, USA.
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Bonds MH, Keenan DC, Leidner AJ, Rohani P. HIGHER DISEASE PREVALENCE CAN INDUCE GREATER SOCIALITY: A GAME THEORETIC COEVOLUTIONARY MODEL. Evolution 2005. [DOI: 10.1554/05-028.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Lloyd-Smith JO, Getz WM, Westerhoff HV. Frequency-dependent incidence in models of sexually transmitted diseases: portrayal of pair-based transmission and effects of illness on contact behaviour. Proc Biol Sci 2004; 271:625-34. [PMID: 15156921 PMCID: PMC1691637 DOI: 10.1098/rspb.2003.2632] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We explore the transmission process for sexually transmitted diseases (STDs). We derive the classical frequency-dependent incidence mechanistically from a pair-formation model, using an approximation that applies to populations with rapid pairing dynamics (such as core groups or non-pair-bonding animals). This mechanistic derivation provides a framework to assess how accurately frequency-dependent incidence portrays the pair-based transmission known to underlie STD dynamics. This accuracy depends strongly on the disease being studied: frequency-dependent formulations are more suitable for chronic less-transmissible infections than for transient highly transmissible infections. Our results thus support earlier proposals to divide STDs into these two functional classes, and we suggest guidelines to help assess under what conditions each class can be appropriately modelled using frequency-dependent incidence. We then extend the derivation to include situations where infected individuals exhibit altered pairing behaviour. For four cases of increasing behavioural complexity, analytic expressions are presented for the generalized frequency-dependent incidence rate, basic reproductive number (R0) and steady-state prevalence (i infinity) of an epidemic. The expression for R0 is identical for all cases, giving refined insights into determinants of invasibility of STDs. Potentially significant effects of infection-induced changes in contact behaviour are illustrated by simulating epidemics of bacterial and viral STDs. We discuss the application of our results to STDs (in humans and animals) and other infectious diseases.
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Affiliation(s)
- James O Lloyd-Smith
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA 94720-3200, USA.
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Altizer S, Nunn CL, Thrall PH, Gittleman JL, Antonovics J, Cunningham AA, Dobson AP, Ezenwa V, Jones KE, Pedersen AB, Poss M, Pulliam JR. Social Organization and Parasite Risk in Mammals: Integrating Theory and Empirical Studies. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2003. [DOI: 10.1146/annurev.ecolsys.34.030102.151725] [Citation(s) in RCA: 540] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sonia Altizer
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Charles L. Nunn
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Peter H. Thrall
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - John L. Gittleman
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Janis Antonovics
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Andrew A. Cunningham
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Andrew P. Dobson
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Vanessa Ezenwa
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Kate E. Jones
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Amy B. Pedersen
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Mary Poss
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
| | - Juliet R.C. Pulliam
- Department of Environmental Studies, Emory University, Atlanta, Georgia 30322;
- Section of Evolution and Ecology, University of California, Davis, California 95616;
- CSIRO-Plant Industry, Center for Plant Biodiversity Research, GPO Box 1600, Canberra ACT 2601, Australia;
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904;
- Institute of Zoology, Zoological Society of London, London, United Kingdom, NW1 4RY;
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Boots M, Knell RJ. The evolution of risky behaviour in the presence of a sexually transmitted disease. Proc Biol Sci 2002; 269:585-9. [PMID: 11916474 PMCID: PMC1690927 DOI: 10.1098/rspb.2001.1932] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sexually transmitted diseases (STDs) are widespread in nature, often sterilizing their hosts or causing other pathogenic effects. Despite this, there is a widespread occurrence of behaviours that are likely to increase the risk to an individual of contracting an STD. Here, we examine the evolution of behaviours such as promiscuity or mate choice that increase the risk of contracting an STD, but also provide a fitness benefit. As might be expected, the balance between risk and fitness benefit defines the optimal strategy, but this relationship is not straightforward. In particular, we often predict the coexistence of highly risky and highly risk-averse individuals. Surprisingly, very safe strategists that only suffer a small cost will tend to coexist with highly risky strategists rather than outcompete them as might have been expected. Rather than selecting for monogamy or for reduced mate choice, therefore, the presence of an STD may often lead to variability in either promiscuity or mate choice.
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Affiliation(s)
- Michael Boots
- Institute of Biological Sciences, University of Stirling, Stirling FK9 4LA, UK
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Poiani A, Wilks C. Sexually Transmitted Diseases: A Possible Cost of Promiscuity in Birds? ACTA ACUST UNITED AC 2000. [DOI: 10.1093/auk/117.4.1061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Aldo Poiani
- Department of Zoology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Colin Wilks
- Victorian Institute of Animal Science, Attwood, Victoria 3049, Australia
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26
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Striedter GF. Stepping into the same river twice: homologues as recurring attractors in epigenetic landscapes. BRAIN, BEHAVIOR AND EVOLUTION 2000; 52:218-31. [PMID: 9787221 DOI: 10.1159/000006565] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The reunification of embryology with evolutionary biology is impeded by the perception that a phylogenetic view of homology is incompatible with a developmental approach. This dichotomy disappears when developmental information is viewed not as pre-existing within the zygote but as being constructed during development. Developmental information can be depicted as the surface of an epigenetic landscape. An epigenetic landscape, in turn, can be viewed as a series of aligned energy landscapes that change shape and become more complex as development proceeds. In this view, individual valley bottoms are attractors in state space that tend to reappear reliably in successive generations. Phylogeny can therefore be conceptualized as a succession of epigenetic landscapes, and homologues can be identified as corresponding valleys that have reappeared reliably since their origin in a single ancestral population. Epigenetic homologues can be robust to phylogenetic changes in developmental mechanisms, precursors, and lower level characters. Although application of the epigenetic homology concept is complicated by the lack of explicit information about the topography of epigenetic landscapes, comparative biologists can learn to identify recurring ontogenetic patterns in a manner that is analogous to the identification of input patterns by attractor neural networks. The correspondence of epigenetic valleys is therefore not defined by any essential criteria but by their overlap in multidimensional state space. Whether corresponding valleys are homologous to each other must be determined by a phylogenetic analysis using cladistic methods. Among the general implications of epigenetic homology for comparative neurobiology is that the concept of 'field homology' should be used with caution when dealing with novel characters. A case study, applying an epigenetic perspective to understand the variation in monkey visual cortex observed after developmental perturbations, is presented in a final section to make the concept of epigenetic homology more concrete.
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Affiliation(s)
- G F Striedter
- Department of Psychobiology and Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697-4550, USA.
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Thrall PH, Antonovics J, Dobson AP. Sexually transmitted diseases in polygynous mating systems: prevalence and impact on reproductive success. Proc Biol Sci 2000; 267:1555-63. [PMID: 11007332 PMCID: PMC1690713 DOI: 10.1098/rspb.2000.1178] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies of disease in relation to animal mating systems have focused on sexual selection and the evolution of sexual reproduction. Relatively little work has examined other aspects of ecological and evolutionary relationships between host social and sexual behaviour, and dynamics and prevalence of infectious diseases; this is particularly evident with respect to sexually transmitted diseases (STDs). Here, we use a simulation approach to investigate rates of STD spread in host mating systems ranging from permanent monogamy to serial polygyny or polyandry and complete promiscuity. The model assumes that one sex (female) is differentially attracted to the other, such that groups of varying size are formed within which mating and disease transmission occur. The results show that equilibrium disease levels are generally higher in females than males and are a function of variance in male mating success and the likelihood of a female switching groups between mating seasons. Moreover, initial rates of disease spread (determining whether an STD establishes in a population) depend on patterns of host movement between groups, variance in male mating success and host life history (e.g. mortality rates). Male reproductive success can be reduced substantially by a sterilizing STD and this reduction is greater in males that are more 'attractive' to females. In contrast, females that associate with more attractive males have lower absolute fitness than females associating with less attractive males. Thus, the potential for STDs to act as a constraint on directional selection processes leading to polygyny (or polyandry) is likely to depend on the details of mate choice and group dynamics.
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Affiliation(s)
- P H Thrall
- Centre for Plant Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation--Division of Plant Industry, Canberra, ACT, Australia.
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