1
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Godinho DP, Rodrigues LR, Lefèvre S, Magalhães S, Duncan AB. Coinfection accelerates transmission to new hosts despite no effects on virulence and parasite growth. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230139. [PMID: 38913066 DOI: 10.1098/rstb.2023.0139] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 04/29/2024] [Indexed: 06/25/2024] Open
Abstract
One of the fundamental aims of ecological, epidemiological and evolutionary studies of host-parasite interactions is to unravel which factors affect parasite virulence. Theory predicts that virulence and transmission are correlated by a trade-off, as too much virulence is expected to hamper transmission owing to excessive host damage. Coinfections may affect each of these traits and/or their correlation. Here, we used inbred lines of the spider mite Tetranychus urticae to test how coinfection with T. evansi impacted virulence-transmission relationships at different conspecific densities. The presence of T. evansi on a shared host did not change the relationship between virulence (leaf damage) and the number of transmitting stages (i.e. adult daughters). The relationship between these traits was hump-shaped across densities, both in single and coinfections, which corresponds to a trade-off. Moreover, transmission to adjacent hosts increased in coinfection, but only at low T. urticae densities. Finally, we tested whether virulence and the number of daughters were correlated with measures of transmission to adjacent hosts, in single and coinfections at different conspecific densities. Traits were mostly independent, meaning that interspecific competitors may increase transmission without affecting virulence. Thus, coinfections may impact epidemiology and parasite trait evolution, but not necessarily the virulence-transmission trade-off.This article is part of the theme issue 'Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics'.
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Affiliation(s)
- Diogo P Godinho
- cE3c: Centre for Ecology, Evolution, and Environmental Changes, Faculty of Sciences; CHANGE - Global Change and Sustainability Institute, University of Lisbon, Lisboa, Portugal
- Current address, Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal
| | - Leonor R Rodrigues
- cE3c: Centre for Ecology, Evolution, and Environmental Changes, Faculty of Sciences; CHANGE - Global Change and Sustainability Institute, University of Lisbon, Lisboa, Portugal
| | - Sophie Lefèvre
- Institut des Sciences de l'Évolution, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Sara Magalhães
- cE3c: Centre for Ecology, Evolution, and Environmental Changes, Faculty of Sciences; CHANGE - Global Change and Sustainability Institute, University of Lisbon, Lisboa, Portugal
| | - Alison B Duncan
- Institut des Sciences de l'Évolution, Université de Montpellier, CNRS, IRD, Montpellier, France
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2
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Baines CB, Shaw AK. Parasite prevalence is determined by infection state- and risk-dependent dispersal of the host. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230130. [PMID: 38913060 DOI: 10.1098/rstb.2023.0130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 04/05/2024] [Indexed: 06/25/2024] Open
Abstract
The spread of parasites and the emergence of disease are currently threatening global biodiversity and human welfare. To address this threat, we need to better understand those factors that determine parasite persistence and prevalence. It is known that dispersal is central to the spatial dynamics of host-parasite systems. Yet past studies have typically assumed that dispersal is a species-level constant, despite a growing body of empirical evidence that dispersal varies with ecological context, including the risk of infection and aspects of host state such as infection status (parasite-dependent dispersal; PDD). Here, we develop a metapopulation model to understand how different forms of PDD shape the prevalence of a directly transmitted parasite. We show that increasing host dispersal rate can increase, decrease or cause a non-monotonic change in regional parasite prevalence, depending on the type of PDD and characteristics of the host-parasite system (transmission rate, virulence, and dispersal mortality). This result contrasts with previous studies with parasite-independent dispersal which concluded that prevalence increases with host dispersal rate. We argue that accounting for host dispersal responses to parasites is necessary for a complete understanding of host-parasite dynamics and for predicting how parasite prevalence will respond to changes such as human alteration of landscape connectivity. This article is part of the theme issue 'Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics'.
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Affiliation(s)
- Celina B Baines
- Department of Ecology and Evolutionary Biology, University of Toronto , Toronto, Ontario M5S 3B2, Canada
| | - Allison K Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota , St Paul, MN 55108, USA
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3
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Poulin R, Salloum PM, Bennett J. Evolution of parasites in the Anthropocene: new pressures, new adaptive directions. Biol Rev Camb Philos Soc 2024. [PMID: 38984760 DOI: 10.1111/brv.13118] [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: 01/23/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024]
Abstract
The Anthropocene is seeing the human footprint rapidly spreading to all of Earth's ecosystems. The fast-changing biotic and abiotic conditions experienced by all organisms are exerting new and strong selective pressures, and there is a growing list of examples of human-induced evolution in response to anthropogenic impacts. No organism is exempt from these novel selective pressures. Here, we synthesise current knowledge on human-induced evolution in eukaryotic parasites of animals, and present a multidisciplinary framework for its study and monitoring. Parasites generally have short generation times and huge fecundity, features that predispose them for rapid evolution. We begin by reviewing evidence that parasites often have substantial standing genetic variation, and examples of their rapid evolution both under conditions of livestock production and in serial passage experiments. We then present a two-step conceptual overview of the causal chain linking anthropogenic impacts to parasite evolution. First, we review the major anthropogenic factors impacting parasites, and identify the selective pressures they exert on parasites through increased mortality of either infective stages or adult parasites, or through changes in host density, quality or immunity. Second, we discuss what new phenotypic traits are likely to be favoured by the new selective pressures resulting from altered parasite mortality or host changes; we focus mostly on parasite virulence and basic life-history traits, as these most directly influence the transmission success of parasites and the pathology they induce. To illustrate the kinds of evolutionary changes in parasites anticipated in the Anthropocene, we present a few scenarios, either already documented or hypothetical but plausible, involving parasite taxa in livestock, aquaculture and natural systems. Finally, we offer several approaches for investigations and real-time monitoring of rapid, human-induced evolution in parasites, ranging from controlled experiments to the use of state-of-the-art genomic tools. The implications of fast-evolving parasites in the Anthropocene for disease emergence and the dynamics of infections in domestic animals and wildlife are concerning. Broader recognition that it is not only the conditions for parasite transmission that are changing, but the parasites themselves, is needed to meet better the challenges ahead.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Priscila M Salloum
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Jerusha Bennett
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
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4
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Zilio G, Deshpande JN, Duncan AB, Fronhofer EA, Kaltz O. Dispersal evolution and eco-evolutionary dynamics in antagonistic species interactions. Trends Ecol Evol 2024; 39:666-676. [PMID: 38637209 DOI: 10.1016/j.tree.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/04/2024] [Accepted: 03/20/2024] [Indexed: 04/20/2024]
Abstract
Dispersal evolution modifies diverse spatial processes, such as range expansions or biological invasions of single species, but we are currently lacking a realistic vision for metacommunities. Focusing on antagonistic species interactions, we review existing theory of dispersal evolution between natural enemies, and explain how this might be relevant for classic themes in host-parasite evolutionary ecology, namely virulence evolution or local adaptation. Specifically, we highlight the importance of considering the simultaneous (co)evolution of dispersal and interaction traits. Linking such multi-trait evolution with reciprocal demographic and epidemiological feedbacks might change basic predictions about coevolutionary processes and spatial dynamics of interacting species. Future challenges concern the integration of system-specific disease ecology or spatial modifiers, such as spatial network structure or environmental heterogeneity.
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Affiliation(s)
- Giacomo Zilio
- Institut des Sciences de l'Evolution - Montpellier (ISEM), University of Montpellier, CNRS, IRD, Montpellier, France; Centre d'Ecologie Fonctionelle et Evolutive (CEFE), University of Montpellier, CNRS, Montpellier, France.
| | - Jhelam N Deshpande
- Institut des Sciences de l'Evolution - Montpellier (ISEM), University of Montpellier, CNRS, IRD, Montpellier, France
| | - Alison B Duncan
- Institut des Sciences de l'Evolution - Montpellier (ISEM), University of Montpellier, CNRS, IRD, Montpellier, France
| | - Emanuel A Fronhofer
- Institut des Sciences de l'Evolution - Montpellier (ISEM), University of Montpellier, CNRS, IRD, Montpellier, France
| | - Oliver Kaltz
- Institut des Sciences de l'Evolution - Montpellier (ISEM), University of Montpellier, CNRS, IRD, Montpellier, France.
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5
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Pak D, Kamiya T, Greischar MA. Proliferation in malaria parasites: How resource limitation can prevent evolution of greater virulence. Evolution 2024; 78:1287-1301. [PMID: 38581661 DOI: 10.1093/evolut/qpae057] [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: 12/15/2023] [Revised: 03/28/2024] [Accepted: 04/04/2024] [Indexed: 04/08/2024]
Abstract
For parasites, robust proliferation within hosts is crucial for establishing the infection and creating opportunities for onward transmission. While faster proliferation enhances transmission rates, it is often assumed to curtail transmission duration by killing the host (virulence), a trade-off constraining parasite evolution. Yet in many diseases, including malaria, the preponderance of infections with mild or absent symptoms suggests that host mortality is not a sufficient constraint, raising the question of what restrains evolution toward faster proliferation. In malaria infections, the maximum rate of proliferation is determined by the burst size, the number of daughter parasites produced per infected red blood cell. Larger burst sizes should expand the pool of infected red blood cells that can be used to produce the specialized transmission forms needed to infect mosquitoes. We use a within-host model parameterized for rodent malaria parasites (Plasmodium chabaudi) to project the transmission consequences of burst size, focusing on initial acute infection where resource limitation and risk of host mortality are greatest. We find that resource limitation restricts evolution toward higher burst sizes below the level predicted by host mortality alone. Our results suggest resource limitation could represent a more general constraint than virulence-transmission trade-offs, preventing evolution towards faster proliferation.
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Affiliation(s)
- Damie Pak
- Department of Ecology and Evolutionary Biology, Cornell University, 215 Tower Rd, Ithaca, NY 14853, United States
| | - Tsukushi Kamiya
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
- HRB Clinical Research Facility, University of Galway, Ireland
| | - Megan A Greischar
- Department of Ecology and Evolutionary Biology, Cornell University, 215 Tower Rd, Ithaca, NY 14853, United States
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6
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Cuevas-Zuviria B, Fraile A, García-Arenal F. An Agent-Based Model Shows How Mixed Infections Drive Multiyear Pathotype Dynamics in a Plant-Virus System. PHYTOPATHOLOGY 2024; 114:1276-1288. [PMID: 38330173 DOI: 10.1094/phyto-06-23-0214-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Mathematical models are widely used to understand the evolution and epidemiology of plant pathogens under a variety of scenarios. Here, we used this approach to analyze the effects of different traits intrinsic and extrinsic to plant-virus interactions on the dynamics of virus pathotypes in genetically heterogeneous plant-virus systems. For this, we propose an agent-based epidemiological model that includes epidemiologically significant pathogen life-history traits related to virulence, transmission, and survival in the environment and allows for integrating long- and short-distance transmission, primary and secondary infections, and within-host pathogen competition in mixed infections. The study focuses on the tobamovirus-pepper pathosystem. Model simulations allowed us to integrate pleiotropic effects of resistance-breaking mutations on different virus life-history traits into the net costs of resistance breaking, allowing for predictions on multiyear pathotype dynamics. We also explored the effects of two control measures, the use of host resistance and roguing of symptomatic plants, that modify epidemiological attributes of the pathogens to understand how their populations will respond to evolutionary pressures. One major conclusion points to the importance of pathogen competition within mixed-infected hosts as a component of the overall fitness of each pathogen that, thus, drives their multiyear dynamics.
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Affiliation(s)
- Bruno Cuevas-Zuviria
- Centro de Biotecnología y Genómica de Plantas (CBGP UPM-INIA/CSIC), Universidad Politécnica de Madrid (UPM) and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (CBGP UPM-INIA/CSIC), Universidad Politécnica de Madrid (UPM) and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas (CBGP UPM-INIA/CSIC), Universidad Politécnica de Madrid (UPM) and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, 28223 Pozuelo de Alarcón, Madrid, Spain
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7
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Prat M, Jeanneau M, Rakotoarivony I, Duhayon M, Simonin Y, Savini G, Labbé P, Alout H. Virulence and transmission vary between Usutu virus lineages in Culex pipiens. PLoS Negl Trop Dis 2024; 18:e0012295. [PMID: 38935783 PMCID: PMC11236178 DOI: 10.1371/journal.pntd.0012295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 07/10/2024] [Accepted: 06/14/2024] [Indexed: 06/29/2024] Open
Abstract
Usutu virus (USUV) is a zoonotic arbovirus infecting mainly wild birds. It is transmitted by ornithophilic mosquitoes, mainly of the genus Culex from birds to birds and to several vertebrate dead-end hosts. Several USUV lineages, differing in their virulence have emerged in the last decades and now co-circulate in Europe, impacting human populations. However, their relative transmission and effects on their mosquito vectors is still not known. We thus compared the vector competence and survival of Culex pipiens mosquitoes experimentally infected with two distinct USUV lineages, EU2 and EU3, that are known to differ in their virulence and replication in vertebrate hosts. Infection rate was variable among blood feeding assays but variations between EU2 and EU3 lineages were consistent suggesting that Culex pipiens was equally susceptible to infection by both lineages. However, EU3 viral load increased with viral titer in the blood meal while EU2 viral load was high at all titers which suggest a greater replication of EU2 than EU3 in mosquito. While their relative transmission efficiencies are similar, at least at low blood meal titer, positive correlation between transmission and blood meal titer was observed for EU3 only. Contrary to published results in vertebrates, EU3 induced a higher mortality to mosquitoes (i.e. virulence) than EU2 whatever the blood meal titer. Therefore, we found evidence of lineage-specific differences in vectorial capacity and virulence to both the vector and vertebrate host which lead to balanced propagation of both viral lineages. These results highlight the need to decipher the interactions between vectors, vertebrate hosts, and the diversity of arbovirus lineages to fully understand transmission dynamics.
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Affiliation(s)
- Maxime Prat
- Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier-CNRS-IRD, Montpellier, France
- UMR ASTRE, Univ Montpellier, INRAE-CIRAD, Montpellier, France
| | | | | | - Maxime Duhayon
- UMR ASTRE, Univ Montpellier, INRAE-CIRAD, Montpellier, France
| | - Yannick Simonin
- Pathogenesis and Control of Chronic Infections, Université de Montpellier-INSERM-EFS, Montpellier, France
| | - Giovanni Savini
- OIE Reference Centre for West Nile Disease, Istituto Zooprofilattico Sperimentale "G. Caporale", Teramo, Italy
| | - Pierrick Labbé
- Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier-CNRS-IRD, Montpellier, France
| | - Haoues Alout
- UMR ASTRE, Univ Montpellier, INRAE-CIRAD, Montpellier, France
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8
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Aleksandrowicz A, Kjærup RB, Grzymajło K, Martinez FG, Muñoz J, Borowska D, Sives S, Vervelde L, Dalgaard TS, Kingsley RA, Kolenda R. FdeC expression regulates motility and adhesion of the avian pathogenic Escherichia coli strain IMT5155. Vet Res 2024; 55:70. [PMID: 38822378 PMCID: PMC11143625 DOI: 10.1186/s13567-024-01327-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 05/04/2024] [Indexed: 06/03/2024] Open
Abstract
Adaptation of avian pathogenic E. coli (APEC) to changing host environments including virulence factors expression is vital for disease progression. FdeC is an autotransporter adhesin that plays a role in uropathogenic Escherichia coli (UPEC) adhesion to epithelial cells. Expression of fdeC is known to be regulated by environmental conditions in UPEC and Shiga toxin-producing E. coli (STEC). The observation in a previous study that an APEC strain IMT5155 in which the fdeC gene was disrupted by a transposon insertion resulted in elevated adhesion to chicken intestinal cells prompted us to further explore the role of fdeC in infection. We found that the fdeC gene prevalence and FdeC variant prevalence differed between APEC and nonpathogenic E. coli genomes. Expression of the fdeC gene was induced at host body temperature, an infection relevant condition. Disruption of fdeC resulted in greater adhesion to CHIC-8E11 cells and increased motility at 42 °C compared to wild type (WT) and higher expression of multiple transporter proteins that increased inorganic ion export. Increased motility may be related to increased inorganic ion export since this resulted in downregulation of YbjN, a protein known to supress motility. Inactivation of fdeC in APEC strain IMT5155 resulted in a weaker immune response in chickens compared to WT in experimental infections. Our findings suggest that FdeC is upregulated in the host and contributes to interactions with the host by down-modulating motility during colonization. A thorough understanding of the regulation and function of FdeC could provide novel insights into E. coli pathogenesis.
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Affiliation(s)
- Adrianna Aleksandrowicz
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | | | - Krzysztof Grzymajło
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | | | - Javier Muñoz
- Proteomics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Present Address: Cell Signaling and Clinical Proteomics Group, Biobizkaia Health Research Institute, Barakaldo, Spain
- Present Address: Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Dominika Borowska
- Division of Immunology, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Samantha Sives
- Present Address: Cell Signaling and Clinical Proteomics Group, Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Lonneke Vervelde
- Division of Immunology, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | | | - Robert A Kingsley
- Quadram Institute Biosciences, Norwich Research Park, Norwich, UK
- University of East Anglia, Norwich, UK
| | - Rafał Kolenda
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland.
- Quadram Institute Biosciences, Norwich Research Park, Norwich, UK.
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9
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Chen W, Jiang X, Liang W, Bai H, Xu M, Liu Z, Yi L, Liu Y, Huang Y, Zhang Y, Xu L, Xie B, Zhang N, Yu J, Lu J, Xiao H, Li X. SARS-CoV-2 Omicron Variants Show Attenuated Neurovirulence Compared with the Wild-Type Strain in Elderly Human Brain Spheroids. RESEARCH (WASHINGTON, D.C.) 2024; 7:0376. [PMID: 38741604 PMCID: PMC11089278 DOI: 10.34133/research.0376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 04/13/2024] [Indexed: 05/16/2024]
Abstract
Infection with severe acute respiratory syndrome coronavirus 2 Omicron variants still causes neurological complications in elderly individuals. However, whether and how aging brains are affected by Omicron variants in terms of neuroinvasiveness and neurovirulence are unknown. Here, we utilize resected paracarcinoma brain tissue from elderly individuals to generate primary brain spheroids (BSs) for investigating the replication capability of live wild-type (WT) strain and Omicron (BA.1/BA.2), as well as the mechanisms underlying their neurobiological effects. We find that both WT and Omicron BA.1/BA.2 are able to enter BSs but weakly replicate. There is no difference between Omicron BA.1/BA.2 and WT strains in neurotropism in aging BSs. However, Omicron BA.1/BA.2 exhibits ameliorating neurological damage. Transcriptional profiling indicates that Omicron BA.1/BA.2 induces a lower neuroinflammatory response than WT strain in elderly BSs, suggesting a mechanistic explanation for their attenuated neuropathogenicity. Moreover, we find that both Omicron BA.1/BA.2 and WT strain infections disrupt neural network activity associated with neurodegenerative disorders by causing neuron degeneration and amyloid-β deposition in elderly BSs. These results uncover Omicron-specific mechanisms and cellular immune responses associated with severe acute respiratory syndrome coronavirus 2-induced neurological complications.
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Affiliation(s)
- Weikang Chen
- Department of Neurosurgery,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Xiaobing Jiang
- Department of Neurosurgery/Neuro-Oncology, State Key Laboratory of Oncology in South China,
Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center (SYSUCC), Guangzhou 510000, China
| | - Wei Liang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Haojie Bai
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Mingze Xu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Zhe Liu
- Guangdong Provincial Institution of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 510000, China
| | - Lina Yi
- Guangdong Provincial Institution of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 510000, China
| | - Yanming Liu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Yanxia Huang
- Department of Neurosurgery,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Yongxin Zhang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Lixia Xu
- Department of Oncology,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Baoshu Xie
- Department of Neurosurgery,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Nu Zhang
- Department of Neurosurgery,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Jun Yu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
- Department of Medicine and Therapeutics and Institute of Digestive Disease, State Key Laboratory of Digestive Disease,
The Chinese University of Hong Kong, Hong Kong SAR 999077, China
| | - Jing Lu
- Guangdong Provincial Institution of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 510000, China
| | - Haipeng Xiao
- Department of Endocrinology,
The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Xiaoxing Li
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
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10
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Franz M, Regoes RR, Rolff J. How infection-triggered pathobionts influence virulence evolution. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230067. [PMID: 38497269 PMCID: PMC10945393 DOI: 10.1098/rstb.2023.0067] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/28/2023] [Indexed: 03/19/2024] Open
Abstract
Host-pathogen interactions can be influenced by the host microbiota, as the microbiota can facilitate or prevent pathogen infections. In addition, members of the microbiota can become virulent. Such pathobionts can cause co-infections when a pathogen infection alters the host immune system and triggers dysbiosis. Here we performed a theoretical investigation of how pathobiont co-infections affect the evolution of pathogen virulence. We explored the possibility that the likelihood of pathobiont co-infection depends on the evolving virulence of the pathogen. We found that, in contrast to the expectation from classical theory, increased virulence is not always selected for. For an increasing likelihood of co-infection with increasing pathogen virulence, we found scenario-specific selection for either increased or decreased virulence. Evolutionary changes, however, in pathogen virulence do not always translate into similar changes in combined virulence of the pathogen and the pathobiont. Only in one of the scenarios where pathobiont co-infection is triggered above a specific virulence level we found a reduction in combined virulence. This was not the case when the probability of pathobiont co-infection linearly increased with pathogen virulence. Taken together, our study draws attention to the possibility that host-microbiota interactions can be both the driver and the target of pathogen evolution. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- Mathias Franz
- Institute of Biology, Freie Universität Berlin, Berlin 14195, Germany
| | - Roland R. Regoes
- Institute of Integrative Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Jens Rolff
- Institute of Biology, Freie Universität Berlin, Berlin 14195, Germany
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11
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Wilber MQ, DeMarchi JA, Briggs CJ, Streipert S. Rapid Evolution of Resistance and Tolerance Leads to Variable Host Recoveries following Disease-Induced Declines. Am Nat 2024; 203:535-550. [PMID: 38635360 DOI: 10.1086/729437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
AbstractRecoveries of populations that have suffered severe disease-induced declines are being observed across disparate taxa. Yet we lack theoretical understanding of the drivers and dynamics of recovery in host populations and communities impacted by infectious disease. Motivated by disease-induced declines and nascent recoveries in amphibians, we developed a model to ask the following question: How does the rapid evolution of different host defense strategies affect the transient recovery trajectories of hosts following pathogen invasion and disease-induced declines? We found that while host life history is predictably a major driver of variability in population recovery trajectories (including declines and recoveries), populations that use different host defense strategies (i.e., tolerance, avoidance resistance, and intensity-reduction resistance) experience notably different recoveries. In single-species host populations, populations evolving tolerance recovered on average four times slower than populations evolving resistance. Moreover, while populations using avoidance resistance strategies had the fastest potential recovery rates, these populations could get trapped in long transient states at low abundance prior to recovery. In contrast, the recovery of populations evolving intensity-reduction resistance strategies were more consistent across ecological contexts. Overall, host defense strategies strongly affect the transient dynamics of population recovery and may affect the ultimate fate of real populations recovering from disease-induced declines.
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12
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Mansueto G, Fusco G, Colonna G. A Tiny Viral Protein, SARS-CoV-2-ORF7b: Functional Molecular Mechanisms. Biomolecules 2024; 14:541. [PMID: 38785948 PMCID: PMC11118181 DOI: 10.3390/biom14050541] [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: 02/26/2024] [Revised: 04/01/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
This study presents the interaction with the human host metabolism of SARS-CoV-2 ORF7b protein (43 aa), using a protein-protein interaction network analysis. After pruning, we selected from BioGRID the 51 most significant proteins among 2753 proven interactions and 1708 interactors specific to ORF7b. We used these proteins as functional seeds, and we obtained a significant network of 551 nodes via STRING. We performed topological analysis and calculated topological distributions by Cytoscape. By following a hub-and-spoke network architectural model, we were able to identify seven proteins that ranked high as hubs and an additional seven as bottlenecks. Through this interaction model, we identified significant GO-processes (5057 terms in 15 categories) induced in human metabolism by ORF7b. We discovered high statistical significance processes of dysregulated molecular cell mechanisms caused by acting ORF7b. We detected disease-related human proteins and their involvement in metabolic roles, how they relate in a distorted way to signaling and/or functional systems, in particular intra- and inter-cellular signaling systems, and the molecular mechanisms that supervise programmed cell death, with mechanisms similar to that of cancer metastasis diffusion. A cluster analysis showed 10 compact and significant functional clusters, where two of them overlap in a Giant Connected Component core of 206 total nodes. These two clusters contain most of the high-rank nodes. ORF7b acts through these two clusters, inducing most of the metabolic dysregulation. We conducted a co-regulation and transcriptional analysis by hub and bottleneck proteins. This analysis allowed us to define the transcription factors and miRNAs that control the high-ranking proteins and the dysregulated processes within the limits of the poor knowledge that these sectors still impose.
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Affiliation(s)
- Gelsomina Mansueto
- Dipartimento di Scienze Mediche e Chirurgiche Avanzate, Università della Campania, L. Vanvitelli, 80138 Naples, Italy;
| | - Giovanna Fusco
- Istituto Zooprofilattico Sperimentale del Mezzogiorno, 80055 Portici, Italy;
| | - Giovanni Colonna
- Medical Informatics AOU, Università della Campania, L. Vanvitelli, 80138 Naples, Italy
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13
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Carlsson F, Råberg L. The germ theory revisited: A noncentric view on infection outcome. Proc Natl Acad Sci U S A 2024; 121:e2319605121. [PMID: 38578984 PMCID: PMC11047106 DOI: 10.1073/pnas.2319605121] [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] [Indexed: 04/07/2024] Open
Abstract
The germ theory states that pathogenic microorganisms are responsible for causing infectious diseases. The theory is inherently microbe-centric and does not account for variability in disease severity among individuals and asymptomatic carriership-two phenomena indicating an important role for host variability in infection outcome. The basic tenet of the germ theory was recently challenged, and a radically host-centric paradigm referred to as the "full-blown host theory" was proposed. According to this view, the pathogen is reduced to a passive environmental trigger, and the development of disease is instead due to pre-existing immunodeficiencies of the host. Here, we consider the factors that determine disease severity using established knowledge concerning evolutionary biology, microbial pathogenesis, and host-pathogen interactions. We note that the available data support a noncentric view that recognizes key roles for both the causative microbe and the host in dictating infection outcome.
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Affiliation(s)
| | - Lars Råberg
- Department of Biology, Lund University, Lund223 62, Sweden
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14
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Northrup GR, White A, Parratt SR, Rozins C, Laine AL, Boots M. The evolutionary dynamics of hyperparasites. J Theor Biol 2024; 582:111741. [PMID: 38280543 DOI: 10.1016/j.jtbi.2024.111741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/14/2023] [Accepted: 01/16/2024] [Indexed: 01/29/2024]
Abstract
Evolutionary theory has typically focused on pairwise interactions, such as those between hosts and parasites, with relatively little work having been carried out on more complex interactions including hyperparasites: parasites of parasites. Hyperparasites are common in nature, with the chestnut blight fungus virus CHV-1 a well-known natural example, but also notably include the phages of important human bacterial diseases. We build a general modeling framework for the evolution of hyperparasites that highlights the central role that the ability of a hyperparasite to be transmitted with its parasite plays in their evolution. A key result is that hyperparasites which transmit with their parasite hosts (hitchhike) will be selected for lower virulence, trending towards hypermutualism or hypercommensalism. We examine the impact on the evolution of hyperparasite systems of a wide range of host and parasite traits showing, for example, that high parasite virulence selects for higher hyperparasite virulence resulting in reductions in parasite virulence when hyperparasitized. Furthermore, we show that acute parasite infection will also select for increased hyperparasite virulence. Our results have implications for hyperparasite research, both as biocontrol agents and for their role in shaping community ecology and evolution and moreover emphasize the importance of understanding evolution in the context of multitrophic interactions.
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Affiliation(s)
- Graham R Northrup
- Center for Computational Biology, College of Engineering, University of California, Berkeley, CA, USA.
| | - Andy White
- Maxwell Institute for Mathematical Sciences, Heriot-Watt University, Edinburgh, UK; Department of Mathematics, Heriot-Watt University, Edinburgh, UK
| | - Steven R Parratt
- Department of Ecology, Evolution and Behaviour, University of Liverpool, Liverpool, UK
| | - Carly Rozins
- Department of Science and Technology Studies, Division of Natural Science, York University, Toronto, Ontario, Canada
| | - Anna-Liisa Laine
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Finland; Department of Evolutionary Biology and Environmental Studies, University of Zurich, Switzerland
| | - Mike Boots
- Department of Integrative Biology, University of California Berkeley, CA, USA; Center for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, UK
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15
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Carvalho T, Belasen AM, Toledo LF, James TY. Coevolution of a generalist pathogen with many hosts: the case of the amphibian chytrid Batrachochytrium dendrobatidis. Curr Opin Microbiol 2024; 78:102435. [PMID: 38387210 DOI: 10.1016/j.mib.2024.102435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 12/22/2023] [Accepted: 01/21/2024] [Indexed: 02/24/2024]
Abstract
Generalist pathogens maintain infectivity in numerous hosts; how this broad ecological niche impacts host-pathogen coevolution remains to be widely explored. Batrachochytrium dendrobatidis (Bd) is a highly generalist pathogenic fungus that has caused devastating declines in hundreds of amphibian species worldwide. This review examines amphibian chytridiomycosis host-pathogen interactions and available evidence for coevolution between Bd and its numerous hosts. We summarize recent evidence showing that Bd genotypes vary in geographic distribution and virulence, and that amphibian species also vary in Bd susceptibility according to their geographic distribution. How much variation can be explained by phenotypic plasticity or genetic differences remains uncertain. Recent research suggests that Bd genotypes display preferences for specific hosts and that some hosts are undergoing evolution as populations rebound from Bd outbreaks. Taken together, these findings suggest the potential for coevolution to occur and illuminate a path for addressing open questions through integrating historical and contemporary genetic data.
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Affiliation(s)
- Tamilie Carvalho
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Anat M Belasen
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, United States
| | - L Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, São Paulo, Brazil
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States.
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16
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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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17
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Dewan KK, Harvill ET. Koch's curse: How models of extreme pathology bias studies of host-pathogen interactions. PLoS Pathog 2024; 20:e1011997. [PMID: 38489258 PMCID: PMC10942049 DOI: 10.1371/journal.ppat.1011997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024] Open
Affiliation(s)
- Kalyan K. Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Eric T. Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
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18
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Erdos Z, Studholme DJ, Sharma MD, Chandler D, Bass C, Raymond B. Manipulating multi-level selection in a fungal entomopathogen reveals social conflicts and a method for improving biocontrol traits. PLoS Pathog 2024; 20:e1011775. [PMID: 38527086 PMCID: PMC10994555 DOI: 10.1371/journal.ppat.1011775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 04/04/2024] [Accepted: 03/09/2024] [Indexed: 03/27/2024] Open
Abstract
Changes in parasite virulence are commonly expected to lead to trade-offs in other life history traits that can affect fitness. Understanding these trade-offs is particularly important if we want to manipulate the virulence of microbial biological control agents. Theoretically, selection across different spatial scales, i.e. between- and within-hosts, shapes these trade-offs. However, trade-offs are also dependent on parasite biology. Despite their applied importance the evolution of virulence in fungal parasites is poorly understood: virulence can be unstable in culture and commonly fails to increase in simple passage experiments. We hypothesized that manipulating selection intensity at different scales would reveal virulence trade-offs in a fungal pathogen of aphids, Akanthomyces muscarius. Starting with a genetically diverse stock we selected for speed of kill, parasite yield or infectivity by manipulating competition within and between hosts and between-populations of hosts over 7 rounds of infection. We characterized ancestral and evolved lineages by whole genome sequencing and by measuring virulence, growth rate, sporulation and fitness. While several lineages showed increases in virulence, we saw none of the trade-offs commonly found in obligately-killing parasites. Phenotypically similar lineages within treatments often shared multiple single-nucleotide variants, indicating strong convergent evolution. The most dramatic phenotypic changes were in timing of sporulation and spore production in vitro. We found that early sporulation led to reduced competitive fitness but could increase yield of spores on media, a trade-off characteristic of social conflict. Notably, the selection regime with strongest between-population competition and lowest genetic diversity produced the most consistent shift to early sporulation, as predicted by social evolution theory. Multi-level selection therefore revealed social interactions novel to fungi and showed that these biocontrol agents have the genomic flexibility to improve multiple traits-virulence and spore production-that are often in conflict in other parasites.
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Affiliation(s)
- Zoltan Erdos
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | | | - Manmohan D. Sharma
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - David Chandler
- School of Life Sciences, The University of Warwick, Coventry, United Kingdom
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Ben Raymond
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
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19
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Kürschner T, Scherer C, Radchuk V, Blaum N, Kramer‐Schadt S. Resource asynchrony and landscape homogenization as drivers of virulence evolution: The case of a directly transmitted disease in a social host. Ecol Evol 2024; 14:e11065. [PMID: 38380064 PMCID: PMC10877554 DOI: 10.1002/ece3.11065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/22/2024] Open
Abstract
Throughout the last decades, the emergence of zoonotic diseases and the frequency of disease outbreaks have increased substantially, fuelled by habitat encroachment and vectors overlapping with more hosts due to global change. The virulence of pathogens is one key trait for successful invasion. In order to understand how global change drivers such as habitat homogenization and climate change drive pathogen virulence evolution, we adapted an established individual-based model of host-pathogen dynamics. Our model simulates a population of social hosts affected by a directly transmitted evolving pathogen in a dynamic landscape. Pathogen virulence evolution results in multiple strains in the model that differ in their transmission capability and lethality. We represent the effects of global change by simulating environmental changes both in time (resource asynchrony) and space (homogenization). We found an increase in pathogenic virulence and a shift in strain dominance with increasing landscape homogenization. Our model further indicated that lower virulence is dominant in fragmented landscapes, although pulses of highly virulent strains emerged under resource asynchrony. While all landscape scenarios favoured co-occurrence of low- and high-virulent strains, the high-virulence strains capitalized on the possibility for transmission when host density increased and were likely to become dominant. With asynchrony likely to occur more often due to global change, our model showed that a subsequent evolution towards lower virulence could lead to some diseases becoming endemic in their host populations.
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Affiliation(s)
- Tobias Kürschner
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
| | - Cédric Scherer
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
| | - Viktoriia Radchuk
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
| | - Niels Blaum
- Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
| | - Stephanie Kramer‐Schadt
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
- Institute of EcologyTechnische Universität BerlinBerlinGermany
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20
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Pinotti F, Lourenço J, Gupta S, Das Gupta S, Henning J, Blake D, Tomley F, Barnett T, Pfeiffer D, Hoque MA, Fournié G. EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networks. PLoS Comput Biol 2024; 20:e1011375. [PMID: 38381804 PMCID: PMC10911595 DOI: 10.1371/journal.pcbi.1011375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 03/04/2024] [Accepted: 02/06/2024] [Indexed: 02/23/2024] Open
Abstract
The rapid intensification of poultry production raises important concerns about the associated risks of zoonotic infections. Here, we introduce EPINEST (EPIdemic NEtwork Simulation in poultry Transportation systems): an agent-based modelling framework designed to simulate pathogen transmission within realistic poultry production and distribution networks. We provide example applications to broiler production in Bangladesh, but the modular structure of the model allows for easy parameterization to suit specific countries and system configurations. Moreover, the framework enables the replication of a wide range of eco-epidemiological scenarios by incorporating diverse pathogen life-history traits, modes of transmission and interactions between multiple strains and/or pathogens. EPINEST was developed in the context of an interdisciplinary multi-centre study conducted in Bangladesh, India, Vietnam and Sri Lanka, and will facilitate the investigation of the spreading patterns of various health hazards such as avian influenza, Campylobacter, Salmonella and antimicrobial resistance in these countries. Furthermore, this modelling framework holds potential for broader application in veterinary epidemiology and One Health research, extending its relevance beyond poultry to encompass other livestock species and disease systems.
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Affiliation(s)
| | - José Lourenço
- Católica Biomedical Research, Católica Medical School, Universidade Católica Portuguesa, Lisbon, Portugal
| | | | - Suman Das Gupta
- School of Veterinary Science, The University of Queensland, Queensland, Australia
- Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Joerg Henning
- School of Veterinary Science, The University of Queensland, Queensland, Australia
| | - Damer Blake
- Royal Veterinary College, London, United Kingdom
| | - Fiona Tomley
- Royal Veterinary College, London, United Kingdom
| | - Tony Barnett
- Royal Veterinary College, London, United Kingdom
- The Firoz Lalji Centre for Africa, London School of Economics and Political Science, London, United Kingdom
| | - Dirk Pfeiffer
- Royal Veterinary College, London, United Kingdom
- City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Md. Ahasanul Hoque
- Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Guillaume Fournié
- Royal Veterinary College, London, United Kingdom
- INRAE, VetAgro Sup, UMR EPIA, Université de Lyon, Marcy l’Etoile, 69280, France
- INRAE, VetAgro Sup, UMR EPIA, Université Clermont Auvergne, Saint Genès Champanelle, 63122, France
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21
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Naresh M, Purkayastha A, Dasgupta I. P4 protein of an Indian isolate of rice tungro bacilliform virus modulates gene silencing. Virus Genes 2024; 60:55-64. [PMID: 38055154 DOI: 10.1007/s11262-023-02039-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023]
Abstract
Plant hosts and their viral pathogens are engaged in a constant cycle of defense and counter-defense as part of a molecular arms race, principal among them being the plant RNAi defense and the viral RNAi suppressor counter-defense. Rice tungro bacilliform virus (RTBV), member of the family Caulimoviridae, genus Tungrovirus, species Tungrovirus oryzae, infects rice in South- and Southeast Asia and causes severe symptoms of stunting, yellow-orange discoloration and twisting of leaf tips. To better understand the possible counter-defensive roles of RTBV against the host RNAi defense system, we explored the ability of the P4 protein of an Indian isolate of RTBV to act as a possible modulator of RNAi. Using a transient silencing and silencing suppression assay in Nicotiana benthamiana, we show that P4 not only displays an RNAi suppressor function, but also potentially enhances RNAi. The results also suggests that the N-terminal 168 amino acid residues of P4 are sufficient to maintain RNAi suppressor activity. Taken together with the earlier reports this work strengthens the view that the P4 protein carries out RNAi suppressor and a potential RNAi enhancer function.
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Affiliation(s)
- Madhvi Naresh
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India
| | - Arunima Purkayastha
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
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22
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Aulsebrook LC, Wong BBM, Hall MD. Pharmaceutical pollution alters the cost of bacterial infection and its relationship to pathogen load. Proc Biol Sci 2024; 291:20231273. [PMID: 38196353 PMCID: PMC10777164 DOI: 10.1098/rspb.2023.1273] [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: 06/08/2023] [Accepted: 12/01/2023] [Indexed: 01/11/2024] Open
Abstract
The relationship between pathogen proliferation and the cost of infection experienced by a host drives the ecology and evolution of host-pathogen dynamics. While environmental factors can shape this relationship, there is currently limited knowledge on the consequences of emerging contaminants, such as pharmaceutical pollutants, on the relationship between a pathogen's growth within the host and the damage it causes, termed its virulence. Here, we investigated how exposure to fluoxetine (Prozac), a commonly detected psychoactive pollutant, could alter this key relationship using the water flea Daphnia magna and its bacterial pathogen Pasteuria ramosa as a model system. Across a variety of fluoxetine concentrations, we found that fluoxetine shaped the damage a pathogen caused, such as the reduction in fecundity or intrinsic growth experienced by infected individuals, but with minimal change in average pathogen spore loads. Instead, fluoxetine modified the relationship between the degree of pathogen proliferation and its virulence, with both the strength of this trade-off and the component of host fitness most affected varying by fluoxetine concentration and host genotype. Our study underscores the potential for pharmaceutical pollution to modify the virulence of an invading pathogen, as well as the fundamental trade-off between host and pathogen fitness, even at the trace amounts increasingly found in natural waterways.
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Affiliation(s)
- Lucinda C. Aulsebrook
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Bob B. M. Wong
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Matthew D. Hall
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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23
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Kuno G. Mechanisms of Yellow Fever Transmission: Gleaning the Overlooked Records of Importance and Identifying Problems, Puzzles, Serious Issues, Surprises and Research Questions. Viruses 2024; 16:84. [PMID: 38257784 PMCID: PMC10820296 DOI: 10.3390/v16010084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/12/2023] [Accepted: 12/29/2023] [Indexed: 01/24/2024] Open
Abstract
In viral disease research, few diseases can compete with yellow fever for the volume of literature, historical significance, richness of the topics and the amount of strong interest among both scientists and laypersons. While the major foci of viral disease research shifted to other more pressing new diseases in recent decades, many critically important basic tasks still remain unfinished for yellow fever. Some of the examples include the mechanisms of transmission, the process leading to outbreak occurrence, environmental factors, dispersal, and viral persistence in nature. In this review, these subjects are analyzed in depth, based on information not only in old but in modern literatures, to fill in blanks and to update the current understanding on these topics. As a result, many valuable facts, ideas, and other types of information that complement the present knowledge were discovered. Very serious questions about the validity of the arbovirus concept and some research practices were also identified. The characteristics of YFV and its pattern of transmission that make this virus unique among viruses transmitted by Ae. aegypti were also explored. Another emphasis was identification of research questions. The discovery of a few historical surprises was an unexpected benefit.
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Affiliation(s)
- Goro Kuno
- Formerly at the Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
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24
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Lear L, Padfield D, Hesse E, Kay S, Buckling A, Vos M. Copper reduces the virulence of bacterial communities at environmentally relevant concentrations. ENVIRONMENT INTERNATIONAL 2023; 182:108295. [PMID: 37980880 DOI: 10.1016/j.envint.2023.108295] [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: 07/05/2023] [Revised: 09/13/2023] [Accepted: 10/27/2023] [Indexed: 11/21/2023]
Abstract
Increasing environmental concentrations of metals as a result of anthropogenic pollution are significantly changing many microbial communities. While there is evidence metal pollution can result in increased antibiotic resistance, the effects of metal pollution on the virulence of bacterial communities remains largely undetermined. Here, we experimentally test whether metal stress alters the virulence of bacterial communities. We do this by incubating three wastewater influent communities under different environmentally relevant copper concentrations for three days. We then quantify the virulence of the community phenotypically using the Galleria mellonella infection model, and test if differences are due to changes in the rate of biomass accumulation (productivity), copper resistance, or community composition (quantified using 16S amplicon sequencing). The virulence of the communities was found to be reduced by the highest copper concentration, but not to be affected by the lower concentration. As well as reduced virulence, communities exposed to the highest copper concentration were less diverse and had lower productivity. This work highlights that metal pollution may decrease virulence in bacterial communities, but at a cost to diversity and productivity.
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Affiliation(s)
- Luke Lear
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom.
| | - Dan Padfield
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom
| | - Elze Hesse
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom
| | - Suzanne Kay
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom
| | - Angus Buckling
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom
| | - Michiel Vos
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom
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25
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Murray GGR, Hossain ASMM, Miller EL, Bruchmann S, Balmer AJ, Matuszewska M, Herbert J, Hadjirin NF, Mugabi R, Li G, Ferrando ML, Fernandes de Oliveira IM, Nguyen T, Yen PLK, Phuc HD, Zaw Moe A, Su Wai T, Gottschalk M, Aragon V, Valentin-Weigand P, Heegaard PMH, Vrieling M, Thein Maw M, Thidar Myint H, Tun Win Y, Thi Hoa N, Bentley SD, Clavijo MJ, Wells JM, Tucker AW, Weinert LA. The emergence and diversification of a zoonotic pathogen from within the microbiota of intensively farmed pigs. Proc Natl Acad Sci U S A 2023; 120:e2307773120. [PMID: 37963246 PMCID: PMC10666105 DOI: 10.1073/pnas.2307773120] [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: 05/22/2023] [Accepted: 10/02/2023] [Indexed: 11/16/2023] Open
Abstract
The expansion and intensification of livestock production is predicted to promote the emergence of pathogens. As pathogens sometimes jump between species, this can affect the health of humans as well as livestock. Here, we investigate how livestock microbiota can act as a source of these emerging pathogens through analysis of Streptococcus suis, a ubiquitous component of the respiratory microbiota of pigs that is also a major cause of disease on pig farms and an important zoonotic pathogen. Combining molecular dating, phylogeography, and comparative genomic analyses of a large collection of isolates, we find that several pathogenic lineages of S. suis emerged in the 19th and 20th centuries, during an early period of growth in pig farming. These lineages have since spread between countries and continents, mirroring trade in live pigs. They are distinguished by the presence of three genomic islands with putative roles in metabolism and cell adhesion, and an ongoing reduction in genome size, which may reflect their recent shift to a more pathogenic ecology. Reconstructions of the evolutionary histories of these islands reveal constraints on pathogen emergence that could inform control strategies, with pathogenic lineages consistently emerging from one subpopulation of S. suis and acquiring genes through horizontal transfer from other pathogenic lineages. These results shed light on the capacity of the microbiota to rapidly evolve to exploit changes in their host population and suggest that the impact of changes in farming on the pathogenicity and zoonotic potential of S. suis is yet to be fully realized.
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Affiliation(s)
- Gemma G. R. Murray
- Department of Genetics, Evolution and Environment, University College London, LondonWC1E 6BT, United Kingdom
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | | | - Eric L. Miller
- Department of Biology, Haverford College, Haverford, PA19041
| | - Sebastian Bruchmann
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Andrew J. Balmer
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Marta Matuszewska
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
- Department of Medicine, University of Cambridge, CambridgeCB2 2QQ, United Kingdom
| | - Josephine Herbert
- Centre for Enzyme Innovation, University of Portsmouth, PortsmouthPO1 2DD, United Kingdom
| | - Nazreen F. Hadjirin
- Nuffield Department of Population Health, University of Oxford, OxfordOX3 7LF, United Kingdom
| | - Robert Mugabi
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Ganwu Li
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Maria Laura Ferrando
- Animal Sciences Department, Wageningen University, 6700 AHWageningen, The Netherlands
| | | | - Thanh Nguyen
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phung L. K. Yen
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ho D. Phuc
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Aung Zaw Moe
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Thiri Su Wai
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Marcelo Gottschalk
- Département de Pathologie et Microbiologie, Université de Montréal, QuébecJ2S 2M2, Canada
| | - Virginia Aragon
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal, Campus de la Universitat Autònoma de Barcelona, Barcelona08193, Spain
- OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Barcelona08193, Spain
| | - Peter Valentin-Weigand
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover30559, Germany
| | - Peter M. H. Heegaard
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby2800, Denmark
| | - Manouk Vrieling
- Wageningen Bioveterinary Research, 8221 RALelystad, The Netherlands
| | - Min Thein Maw
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | | | - Ye Tun Win
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Ngo Thi Hoa
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, OxfordOX3 7LG, United Kingdom
- Microbiology Department and Center for Tropical Medicine Research, Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam
| | - Stephen D. Bentley
- Parasites and Microbes Programme, Wellcome Sanger Institute, CambridgeCB10 1RQ, United Kingdom
| | - Maria J. Clavijo
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Jerry M. Wells
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
- Animal Sciences Department, Wageningen University, 6700 AHWageningen, The Netherlands
| | - Alexander W. Tucker
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Lucy A. Weinert
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
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Metz JAJ, Boldin B. Immunity-driven evolution of virulence and diversity in respiratory diseases. Evolution 2023; 77:2392-2408. [PMID: 37592809 DOI: 10.1093/evolut/qpad145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/19/2023] [Accepted: 07/30/2023] [Indexed: 08/19/2023]
Abstract
The time-honored paradigm in the theory of virulence evolution assumes a positive relation between infectivity and harmfulness. However, the etiology of respiratory diseases yields a negative relation, with diseases of the lower respiratory tract being less infective and more harmful. We explore the evolutionary consequences in a simple model incorporating cross-immunity between disease strains that diminishes with their distance in the respiratory tract, assuming that docking rate follows the match between the local mix of cell surface types and the pathogen's surface and cross-immunity the similarity of the pathogens' surfaces. The assumed relation between fitness components causes virulent strains infecting the lower airways to evolve to milder more transmissible variants. Limited cross-immunity, generally, causes a readiness to diversify that increases with host population density. In respiratory diseases that diversity will be highest in the upper respiratory tract. More tentatively, emerging respiratory diseases are likely to start low and virulent, to evolve up, and become milder. Our results extend to a panoply of realistic generalizations of the disease's ecology to including additional epitope axes. These extensions allow us to apply our results quantitatively to elucidate the differences in diversification between rhino- and coronavirus caused common colds.
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Affiliation(s)
- Johan A J Metz
- Advancing Systems Analysis Program, International Institute of Applied Systems Analysis (IIASA), Laxenburg, Austria
- Mathematical Institute, Leiden University, Leiden, The Netherlands
- Institute of Biology, Leiden University, Leiden, The Netherlands
- Netherlands Centre for Biodiversity, Naturalis, Leiden, The Netherlands
- Complexity Science and Evolution Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Japan
| | - Barbara Boldin
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia
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Miele L, Evans RML, Cunniffe NJ, Torres-Barceló C, Bevacqua D. Evolutionary Epidemiology Consequences of Trait-Dependent Control of Heterogeneous Parasites. Am Nat 2023; 202:E130-E146. [PMID: 37963120 DOI: 10.1086/726062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
AbstractDisease control can induce both demographic and evolutionary responses in host-parasite systems. Foreseeing the outcome of control therefore requires knowledge of the eco-evolutionary feedback between control and system. Previous work has assumed that control strategies have a homogeneous effect on the parasite population. However, this is not true when control targets those traits that confer to the parasite heterogeneous levels of resistance, which can additionally be related to other key parasite traits through evolutionary trade-offs. In this work, we develop a minimal model coupling epidemiological and evolutionary dynamics to explore possible trait-dependent effects of control strategies. In particular, we consider a parasite expressing continuous levels of a trait-determining resource exploitation and a control treatment that can be either positively or negatively correlated with that trait. We demonstrate the potential of trait-dependent control by considering that the decision maker may want to minimize both the damage caused by the disease and the use of treatment, due to possible environmental or economic costs. We identify efficient strategies showing that the optimal type of treatment depends on the amount applied. Our results pave the way for the study of control strategies based on evolutionary constraints, such as collateral sensitivity and resistance costs, which are receiving increasing attention for both public health and agricultural purposes.
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Chardès V, Mazzolini A, Mora T, Walczak AM. Evolutionary stability of antigenically escaping viruses. Proc Natl Acad Sci U S A 2023; 120:e2307712120. [PMID: 37871216 PMCID: PMC10622963 DOI: 10.1073/pnas.2307712120] [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: 05/08/2023] [Accepted: 08/24/2023] [Indexed: 10/25/2023] Open
Abstract
Antigenic variation is the main immune escape mechanism for RNA viruses like influenza or SARS-CoV-2. While high mutation rates promote antigenic escape, they also induce large mutational loads and reduced fitness. It remains unclear how this cost-benefit trade-off selects the mutation rate of viruses. Using a traveling wave model for the coevolution of viruses and host immune systems in a finite population, we investigate how immunity affects the evolution of the mutation rate and other nonantigenic traits, such as virulence. We first show that the nature of the wave depends on how cross-reactive immune systems are, reconciling previous approaches. The immune-virus system behaves like a Fisher wave at low cross-reactivities, and like a fitness wave at high cross-reactivities. These regimes predict different outcomes for the evolution of nonantigenic traits. At low cross-reactivities, the evolutionarily stable strategy is to maximize the speed of the wave, implying a higher mutation rate and increased virulence. At large cross-reactivities, where our estimates place H3N2 influenza, the stable strategy is to increase the basic reproductive number, keeping the mutation rate to a minimum and virulence low.
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Affiliation(s)
- Victor Chardès
- Laboratoire de Physique de l’École Normale Supérieure, CNRS, Paris Sciences & Lettres University, Sorbonne Université, and Université Paris-Cité, 75005Paris, France
- Center for Computational Biology, Flatiron Institute, New York, NY10010
| | - Andrea Mazzolini
- Laboratoire de Physique de l’École Normale Supérieure, CNRS, Paris Sciences & Lettres University, Sorbonne Université, and Université Paris-Cité, 75005Paris, France
| | - Thierry Mora
- Laboratoire de Physique de l’École Normale Supérieure, CNRS, Paris Sciences & Lettres University, Sorbonne Université, and Université Paris-Cité, 75005Paris, France
| | - Aleksandra M. Walczak
- Laboratoire de Physique de l’École Normale Supérieure, CNRS, Paris Sciences & Lettres University, Sorbonne Université, and Université Paris-Cité, 75005Paris, France
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29
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Biruksew A, Demeke A, Birhanu Z, Golassa L, Getnet M, Yewhalaw D. Schoolchildren with asymptomatic malaria are potential hotspot for malaria reservoir in Ethiopia: implications for malaria control and elimination efforts. Malar J 2023; 22:311. [PMID: 37845680 PMCID: PMC10580533 DOI: 10.1186/s12936-023-04736-7] [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: 07/14/2023] [Accepted: 09/30/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Schoolchildren with asymptomatic malaria infections often go undiagnosed and untreated, serving as reservoirs for infection that hamper malaria control and elimination efforts. In this context, little is known about the magnitude of asymptomatic malaria infections in apparently healthy schoolchildren in Ethiopia. This study was aimed at determining the prevalence of asymptomatic malaria infection and its associated factors in apparently healthy schoolchildren in Ethiopia. METHODS From September 2021 to January 2022, a school-based cross-sectional study was conducted on 994 apparently healthy schoolchildren (aged 6-15 years) selected from 21 primary schools in the Gomma district, of Jimma zone, southwestern Oromia, Ethiopia. A multi-stage sampling technique was used to select schools and participants. After allocating the total sample proportionally to each school and then to each grade, participants were selected using the lottery method from a list of student records (rosters). Finger-pricked blood samples were collected for microscopy blood film preparation and malaria rapid diagnostic test (RDT) (SD Bioline Malaria Ag Pf/Pv). Moreover, dry blood spots (DBSs) were prepared onto filter papers for quantitative real time polymerase chain reaction (qPCR) analysis. RESULTS As determined by RDT and microscopy, the prevalence of asymptomatic malaria was 2.20% and 1.51%, respectively. Using qPCR, the overall prevalence was 5.03% (50/994). Of this, Plasmodium falciparum, Plasmodium vivax and mixed infections accounted for 90%, 6% and 4%, respectively. Submicroscopic asymptomatic malaria infection was also accounted for 70% (35/50) of the overall prevalence. Household head age, nighttime outdoor activities of household heads, family history of malaria, absence of insecticide-treated nets (ITN), and presence of stagnant water around the houses are all significantly associated with asymptomatic malaria infections among schoolchildren. CONCLUSIONS This study found that both RDT and microscopy underestimated the prevalence of asymptomatic malaria in schoolchildren. However, qPCR was able to detect even low levels of parasitaemia and revealed a higher prevalence of asymptomatic submicroscopic malaria infections. The findings imply that schoolchildren with asymptomatic malaria infection are potential hotspot for malaria reservoir that fuels ongoing transmission. Therefore, it is imperative to include schoolchildren and schools in malaria intervention package and equally important is the adoption of more advanced and sensitive diagnostic tools, which would be crucial for successful malaria control and elimination efforts. Targeted interventions for asymptomatic malaria-infected schoolchildren can provide invaluable support to the National Malaria Control Programme in controlling and eventually eliminating the disease.
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Affiliation(s)
- Abdissa Biruksew
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIRC), Jimma University, Jimma, Ethiopia
| | | | - Zewdie Birhanu
- Department of Health, Behavior, and Society, Faculty of Public Health, Institute of Health Jimma University, Jimma, Ethiopia
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Masrie Getnet
- Department of Biostatistics and Epidemiology, Faculty of Public Health, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIRC), Jimma University, Jimma, Ethiopia
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30
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O'Neill X, White A, Boots M. The evolution of parasite virulence under targeted culling and harvesting in wildlife and livestock. Evol Appl 2023; 16:1697-1707. [PMID: 38020874 PMCID: PMC10660816 DOI: 10.1111/eva.13594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/27/2023] [Accepted: 09/01/2023] [Indexed: 12/01/2023] Open
Abstract
There is a clear need to understand the effect of human intervention on the evolution of infectious disease. In particular, culling and harvesting of both wildlife and managed livestock populations are carried out in a wide range of management practices, and they have the potential to impact the evolution of a broad range of disease characteristics. Applying eco-evolutionary theory we show that once culling/harvesting becomes targeted on specific disease classes, the established result that culling selects for higher virulence is only found when sufficient infected individuals are culled. If susceptible or recovered individuals are targeted, selection for lower virulence can occur. An important implication of this result is that when culling to eradicate an infectious disease from a population, while it is optimal to target infected individuals, the consequent evolution can increase the basic reproductive ratio of the infection, R 0 , and make parasite eradication more difficult. We show that increases in evolved virulence due to the culling of infected individuals can lead to excess population decline when sustainably harvesting a population. In contrast, culling susceptible or recovered individuals can select for decreased virulence and a reduction in population decline through culling. The implications to the evolution of virulence are typically the same in wildlife populations, that are regulated by the parasite, and livestock populations, that have a constant population size where restocking balances the losses due to mortality. However, the well-known result that vertical transmission selects for lower virulence and transmission in wildlife populations is less marked in livestock populations for parasites that convey long-term immunity since restocking can enhance the density of the immune class. Our work emphasizes the importance of understanding the evolutionary consequences of intervention strategies and the different ecological feedbacks that can occur in wildlife and livestock populations.
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Affiliation(s)
- Xander O'Neill
- Department of MathematicsMaxwell Institute for Mathematical Sciences, Heriot‐Watt UniversityEdinburghUK
| | - Andy White
- Department of MathematicsMaxwell Institute for Mathematical Sciences, Heriot‐Watt UniversityEdinburghUK
| | - Mike Boots
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- Centre for Ecology and Conservation, BiosciencesUniversity of ExeterCornwallUK
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31
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Poulin R. Model worms: knowledge gains and risks associated with the use of model species in parasitological research. Parasitology 2023; 150:967-978. [PMID: 37853764 PMCID: PMC10941210 DOI: 10.1017/s0031182023000963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/20/2023]
Abstract
Model parasite species, whose entire life cycle can be completed in the laboratory and maintained for multiple generations, have played a fundamental role in our understanding of host–parasite interactions. Yet, keeping parasites in laboratory conditions may expose them to unnatural evolutionary pressures, and using laboratory cultures for research is therefore not without limitations. Using 2 widely-used model helminth species, the cestode Hymenolepis diminuta and the nematode Heligmosomoides polygyrus, I illustrate the caution needed when interpreting experimental results on model species. I first review more than 1200 experimental studies published on these species in the past 4 decades, to determine which research areas they have contributed to. This is followed by an examination of the institutional laboratory cultures that have provided the parasites used in these studies. Some of these have persisted for decades and accounted for a substantial proportion of published studies, whereas others have been short-lived. Using information provided by the curators of active cultures, I summarize data on their origins and maintenance conditions. Finally, I discuss how laboratory cultures may have been subject to the influence of evolutionary genetic processes, such as founder effects, genetic drift and inbreeding. I also address the possibility that serial passage through laboratory hosts across multiple generations has exerted artificial selection on several parasite traits, resulting in genetic and phenotypic divergence among laboratory cultures, and between these cultures and natural parasite populations. I conclude with recommendations for the continued usage of laboratory helminth cultures aimed at maximizing their important contribution to parasitological research.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
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32
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Brook CE, Rozins C, Guth S, Boots M. Reservoir host immunology and life history shape virulence evolution in zoonotic viruses. PLoS Biol 2023; 21:e3002268. [PMID: 37676899 PMCID: PMC10484437 DOI: 10.1371/journal.pbio.3002268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 07/21/2023] [Indexed: 09/09/2023] Open
Abstract
The management of future pandemic risk requires a better understanding of the mechanisms that determine the virulence of emerging zoonotic viruses. Meta-analyses suggest that the virulence of emerging zoonoses is correlated with but not completely predictable from reservoir host phylogeny, indicating that specific characteristics of reservoir host immunology and life history may drive the evolution of viral traits responsible for cross-species virulence. In particular, bats host viruses that cause higher case fatality rates upon spillover to humans than those derived from any other mammal, a phenomenon that cannot be explained by phylogenetic distance alone. In order to disentangle the fundamental drivers of these patterns, we develop a nested modeling framework that highlights mechanisms that underpin the evolution of viral traits in reservoir hosts that cause virulence following cross-species emergence. We apply this framework to generate virulence predictions for viral zoonoses derived from diverse mammalian reservoirs, recapturing trends in virus-induced human mortality rates reported in the literature. Notably, our work offers a mechanistic hypothesis to explain the extreme virulence of bat-borne zoonoses and, more generally, demonstrates how key differences in reservoir host longevity, viral tolerance, and constitutive immunity impact the evolution of viral traits that cause virulence following spillover to humans. Our theoretical framework offers a series of testable questions and predictions designed to stimulate future work comparing cross-species virulence evolution in zoonotic viruses derived from diverse mammalian hosts.
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Affiliation(s)
- Cara E. Brook
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Carly Rozins
- Department of Science, Technology, and Society, York University, Toronto, Canada
| | - Sarah Guth
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Mike Boots
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America
- Biosciences, University of Exeter, Penryn, United Kingdom
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33
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Tomilova OG, Kryukov VY, Kryukova NA, Tolokonnikova KP, Tokarev YS, Rumiantseva AS, Alekseev AA, Glupov VV. Effects of passages through an insect or a plant on virulence and physiological properties of the fungus Metarhizium robertsii. PeerJ 2023; 11:e15726. [PMID: 37583910 PMCID: PMC10424674 DOI: 10.7717/peerj.15726] [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: 04/11/2023] [Accepted: 06/18/2023] [Indexed: 08/17/2023] Open
Abstract
Species of the genus Metarhizium are characterized by a multitrophic lifestyle of being arthropod parasites, rhizosphere colonizers, endophytes, and saprophytes. The process of adaptation to various organisms and substrates may lead to specific physiological alterations that can be elucidated by passaging through different hosts. Changes in virulence and cultivation properties of entomopathogenic fungi subcultured on different media or passaged through a live insect host are well known. Nevertheless, comparative in-depth physiological studies on fungi after passaging through insect or plant organisms are scarce. Here, virulence, plant colonization, hydrolytic enzymatic activities, toxin production, and antimicrobial action were compared between stable (nondegenerative) parent strain Metarhizium robertsii MB-1 and its reisolates obtained after eight passages through Galleria mellonella larvae or Solanum lycopersicum or after subculturing on the Sabouraud medium. The passaging through the insect caused similar physiological alterations relative to the plant-based passaging: elevation of destruxin A, B, and E production, a decrease in protease and lipase activities, and lowering of virulence toward G. mellonella and Leptinotarsa decemlineata as compared to the parent strain. The reisolates passaged through the insect or plant showed a slight trend toward increased tomato colonization and enhanced antagonistic action on tomato-associated bacterium Bacillus pumilus as compared to the parental strain. Meanwhile, the subculturing of MB-1 on the Sabouraud medium showed stability of the studied parameters, with minimal alterations relative to the parental strain. We propose that the fungal virulence factors are reprioritized during adaptation of M. robertsii to insects, plants, and media.
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Affiliation(s)
- Oksana G. Tomilova
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
- All-Russian Institute of Plant Protection, St. Petersburg, Russia
| | - Vadim Y. Kryukov
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
| | | | | | - Yuri S. Tokarev
- All-Russian Institute of Plant Protection, St. Petersburg, Russia
| | | | - Alexander A. Alekseev
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia
| | - Viktor V. Glupov
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
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34
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Burie JB, Ducrot A, Griette Q. Asymptotic behavior of an epidemic model with infinitely many variants. J Math Biol 2023; 87:40. [PMID: 37561157 DOI: 10.1007/s00285-023-01975-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 05/09/2023] [Accepted: 07/22/2023] [Indexed: 08/11/2023]
Abstract
We investigate the long-time dynamics of a SIR epidemic model with infinitely many pathogen variants infecting a homogeneous host population. We show that the basic reproduction number [Formula: see text] of the pathogen can be defined in that case and corresponds to a threshold between the persistence ([Formula: see text]) and the extinction ([Formula: see text]) of the pathogen population. When [Formula: see text] and the maximal fitness is attained by at least one variant, we show that the systems reaches an endemic equilibrium state that can be explicitly determined from the initial data. When [Formula: see text] but none of the variants attain the maximal fitness, the situation is more intricate. We show that, in general, the pathogen is uniformly persistent and any family of variants that have a fitness which is uniformly lower than the optimal fitness, eventually gets extinct. We derive a condition under which the total pathogen population converges to a limit which can be computed explicitly. We also find counterexamples that show that, when our condition is not met, the total pathogen population may converge to an unexpected value, or the system can even reach an eternally transient behavior where the total pathogen population between several values. We illustrate our results with numerical simulations that emphasize the wide variety of possible dynamics.
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Affiliation(s)
| | - Arnaud Ducrot
- Normandie Univ, UNIHAVRE, LMAH, FR-CNRS-3335, ISCN, 76600, Le Havre, France
| | - Quentin Griette
- Normandie Univ, UNIHAVRE, LMAH, FR-CNRS-3335, ISCN, 76600, Le Havre, France.
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35
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Zinck CB, Raveendram Thampy P, Uhlemann EME, Adam H, Wachter J, Suchan D, Cameron ADS, Rego ROM, Brisson D, Bouchard C, Ogden NH, Voordouw MJ. Variation among strains of Borrelia burgdorferi in host tissue abundance and lifetime transmission determine the population strain structure in nature. PLoS Pathog 2023; 19:e1011572. [PMID: 37607182 PMCID: PMC10473547 DOI: 10.1371/journal.ppat.1011572] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 09/01/2023] [Accepted: 07/23/2023] [Indexed: 08/24/2023] Open
Abstract
Pathogen life history theory assumes a positive relationship between pathogen load in host tissues and pathogen transmission. Empirical evidence for this relationship is surprisingly rare due to the difficulty of measuring transmission for many pathogens. The comparative method, where a common host is experimentally infected with a set of pathogen strains, is a powerful approach for investigating the relationships between pathogen load and transmission. The validity of such experimental estimates of strain-specific transmission is greatly enhanced if they can predict the pathogen population strain structure in nature. Borrelia burgdorferi is a multi-strain, tick-borne spirochete that causes Lyme disease in North America. This study used 11 field-collected strains of B. burgdorferi, a rodent host (Mus musculus, C3H/HeJ) and its tick vector (Ixodes scapularis) to determine the relationship between pathogen load in host tissues and lifetime host-to-tick transmission (HTT). Mice were experimentally infected via tick bite with 1 of 11 strains. Lifetime HTT was measured by infesting mice with I. scapularis larval ticks on 3 separate occasions. The prevalence and abundance of the strains in the mouse tissues and the ticks were determined by qPCR. We used published databases to obtain estimates of the frequencies of these strains in wild I. scapularis tick populations. Spirochete loads in ticks and lifetime HTT varied significantly among the 11 strains of B. burgdorferi. Strains with higher spirochete loads in the host tissues were more likely to infect feeding larval ticks, which molted into nymphal ticks that had a higher probability of B. burgdorferi infection (i.e., higher HTT). Our laboratory-based estimates of lifetime HTT were predictive of the frequencies of these strains in wild I. scapularis populations. For B. burgdorferi, the strains that establish high abundance in host tissues and that have high lifetime transmission are the strains that are most common in nature.
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Affiliation(s)
- Christopher B. Zinck
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Prasobh Raveendram Thampy
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Eva-Maria E. Uhlemann
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hesham Adam
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Jenny Wachter
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Danae Suchan
- Institute for Microbial Systems and Society, Faculty of Science, University of Regina, Regina, Saskatchewan, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan, Canada
| | - Andrew D. S. Cameron
- Institute for Microbial Systems and Society, Faculty of Science, University of Regina, Regina, Saskatchewan, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan, Canada
| | - Ryan O. M. Rego
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Dustin Brisson
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Catherine Bouchard
- Public Health Risk Sciences, National Microbiology Laboratory, Public Health Agency of Canada, St Hyacinthe, Quebec, Canada
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de Médecine Vétérinaire, Université de Montréal, Montreal, Canada
| | - Nicholas H. Ogden
- Public Health Risk Sciences, National Microbiology Laboratory, Public Health Agency of Canada, St Hyacinthe, Quebec, Canada
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de Médecine Vétérinaire, Université de Montréal, Montreal, Canada
- Centre de recherche en santé publique (CReSP), Université de Montréal, Montreal, QC, Canada
| | - Maarten J. Voordouw
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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36
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Noh S, Larson ER, Covitz RM, Chen A, Mazumder PR, Peck RF, Hamilton MC, Dettmann RA. Facultative symbiont virulence determines horizontal transmission rate without host strain specificity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528903. [PMID: 36824889 PMCID: PMC9949114 DOI: 10.1101/2023.02.16.528903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
In facultative symbioses, only a fraction of hosts are associated with a symbiont. Understanding why specific host and symbiont strains are associated can inform us of the evolutionary forces affecting facultative symbioses. Possibilities include ongoing host-symbiont coevolution driven by reciprocal selection, or priority effects that are neutral in respect to the host-symbiont interaction. We hypothesized that ongoing host-symbiont coevolution would lead to higher fitness estimates for naturally co-occurring (native) host and symbiont combinations compared to nonnative combinations. We used the Dictyostelium discoideum - Paraburkholderia bonniea system to test this hypothesis. P. bonniea features a reduced genome size relative to another Paraburkholderia symbiont of D. discoideum, indicating a significant history of coevolution with its host. Facultative symbionts may experience continued genome reduction if coevolution is ongoing, or their genome size may have reached a stable state if the symbiosis has also stabilized. Our work demonstrates that ongoing coevolution is unlikely for D. discoideum and P. bonniea. The system instead represents a stable facultative symbiosis. Specifically associated host and symbiont strains in this system are the result of priority effects, and presently unassociated hosts are simply uncolonized. We find evidence for a virulence-transmission trade-off without host strain specificity, and identify candidate virulence factors in the genomes of P. bonniea strains that may contribute to variation in benevolence.
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Affiliation(s)
- Suegene Noh
- Biology Department, Colby College, Waterville, Maine, USA
| | | | - Rachel M. Covitz
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Anna Chen
- Biology Department, Colby College, Waterville, Maine, USA
| | | | - Ron F. Peck
- Biology Department, Colby College, Waterville, Maine, USA
| | - Marisa C. Hamilton
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina, USA
| | - Robert A. Dettmann
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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37
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Zanni V, Frizzera D, Marroni F, Seffin E, Annoscia D, Nazzi F. Age-related response to mite parasitization and viral infection in the honey bee suggests a trade-off between growth and immunity. PLoS One 2023; 18:e0288821. [PMID: 37459342 PMCID: PMC10351714 DOI: 10.1371/journal.pone.0288821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
Host age at parasites' exposure is often neglected in studies on host-parasite interactions despite the important implications for epidemiology. Here we compared the impact of the parasitic mite Varroa destructor, and the associated pathogenic virus DWV on different life stages of their host, the western honey bee Apis mellifera. The pre-imaginal stages of the honey bee proved to be more susceptible to mite parasitization and viral infection than adults. The higher viral load in mite-infested bees and DWV genotype do not appear to be the drivers of the observed difference which, instead, seems to be related to the immune-competence of the host. These results support the existence of a trade-off between immunity and growth, making the pupa, which is involved in the highly energy-demanding process of metamorphosis, more susceptible to parasites and pathogens. This may have important implications for the evolution of the parasite's virulence and in turn for honey bee health. Our results highlight the important role of host's age and life stage at exposure in epidemiological modelling. Furthermore, our study could unravel new aspects of the complex honey bee-Varroa relationship to be addressed for a sustainable management of this parasite.
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Affiliation(s)
- Virginia Zanni
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
| | - Davide Frizzera
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
| | - Fabio Marroni
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
| | - Elisa Seffin
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
| | - Desiderato Annoscia
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
| | - Francesco Nazzi
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali (DI4A), Università degli Studi di Udine, Udine, Italy
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38
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Jensen CH, Weidner J, Giske J, Jørgensen C, Eliassen S, Mennerat A. Adaptive host responses to infection can resemble parasitic manipulation. Ecol Evol 2023; 13:e10318. [PMID: 37456066 PMCID: PMC10349281 DOI: 10.1002/ece3.10318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/22/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Using a dynamic optimisation model for juvenile fish in stochastic food environments, we investigate optimal hormonal regulation, energy allocation and foraging behaviour of a growing host infected by a parasite that only incurs an energetic cost. We find it optimal for the infected host to have higher levels of orexin, growth and thyroid hormones, resulting in higher activity levels, increased foraging and faster growth. This growth strategy thus displays several of the fingerprints often associated with parasite manipulation: higher levels of metabolic hormones, faster growth, higher allocation to reserves (i.e. parasite-induced gigantism), higher risk-taking and eventually higher predation rate. However, there is no route for manipulation in our model, so these changes reflect adaptive host compensatory responses. Interestingly, several of these changes also increase the fitness of the parasite. Our results call for caution when interpreting observations of gigantism or risky host behaviours as parasite manipulation without further testing.
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Affiliation(s)
| | | | - Jarl Giske
- Department of Biological SciencesUniversity of BergenBergenNorway
| | | | - Sigrunn Eliassen
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Adèle Mennerat
- Department of Biological SciencesUniversity of BergenBergenNorway
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Lindsay RJ, Holder PJ, Talbot NJ, Gudelj I. Metabolic efficiency reshapes the seminal relationship between pathogen growth rate and virulence. Ecol Lett 2023; 26:896-907. [PMID: 37056166 PMCID: PMC10947253 DOI: 10.1111/ele.14218] [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: 11/16/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/15/2023]
Abstract
A cornerstone of classical virulence evolution theories is the assumption that pathogen growth rate is positively correlated with virulence, the amount of damage pathogens inflict on their hosts. Such theories are key for incorporating evolutionary principles into sustainable disease management strategies. Yet, empirical evidence raises doubts over this central assumption underpinning classical theories, thus undermining their generality and predictive power. In this paper, we identify a key component missing from current theories which redefines the growth-virulence relationship in a way that is consistent with data. By modifying the activity of a single metabolic gene, we engineered strains of Magnaporthe oryzae with different nutrient acquisition and growth rates. We conducted in planta infection studies and uncovered an unexpected non-monotonic relationship between growth rate and virulence that is jointly shaped by how growth rate and metabolic efficiency interact. This novel mechanistic framework paves the way for a much-needed new suite of virulence evolution theories.
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Affiliation(s)
| | | | - Nicholas J. Talbot
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUK
| | - Ivana Gudelj
- Biosciences and Living Systems InstituteUniversity of ExeterExeterUK
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40
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Franz M, Armitage SAO, Rolff J, Regoes RR. Virulence decomposition for bifurcating infections. Proc Biol Sci 2023; 290:20230396. [PMID: 37161327 PMCID: PMC10170194 DOI: 10.1098/rspb.2023.0396] [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: 02/17/2023] [Accepted: 04/06/2023] [Indexed: 05/11/2023] Open
Abstract
A fundamental goal in infection biology is to understand the emergence of variation in pathogen virulence-here defined as the decrease in host fitness caused by a pathogen. To uncover the sources of such variation, virulence can be decomposed into both host- and pathogen-associated components. However, decomposing virulence can be challenging owing to complex within-host pathogen dynamics such as bifurcating infections, which recently received increased empirical and theoretical attention. Bifurcating infections are characterized by the emergence of two distinct infection types: (i) terminal infections with high pathogen loads resulting in rapid host death, and (ii) persistent infections with lower loads and delayed host death. Here, we propose to use discrete mixture models to perform separate virulence decompositions for each infection type. Using this approach, we reanalysed a recently published experimental dataset on bacterial load and survival in Drosophila melanogaster. This analysis revealed several advantages of the new approach, most importantly the generation of a more comprehensive picture of the varying sources of virulence in different bacterial species. Beyond this application, our approach could provide valuable information for ground-truthing and improving theoretical models of within-host infection dynamics, which are developed to predict variation in infection outcome and pathogen virulence.
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Affiliation(s)
- Mathias Franz
- Institute of Biology, Freie Universität Berlin, D-14195 Berlin, Germany
| | | | - Jens Rolff
- Institute of Biology, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Roland R. Regoes
- Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
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41
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Bouman JA, Venner CM, Walker C, Arts EJ, Regoes RR. Per-pathogen virulence of HIV-1 subtypes A, C and D. Proc Biol Sci 2023; 290:20222572. [PMID: 37161335 PMCID: PMC10170192 DOI: 10.1098/rspb.2022.2572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
HIV-1 subtypes differ in their clinical manifestations and the speed in which they spread. In particular, the frequency of subtype C is increasing relative to subtypes A and D. We investigate whether HIV-1 subtypes A, C and D differ in their per-pathogen virulence and to what extend this explains the difference in spread between these subtypes. We use data from the hormonal contraception and HIV-1 genital shedding and disease progression among women with primary HIV infection study. For each study participant, we determine the set-point viral load value, CD4+ T cell level after primary infection and CD4+ T cell decline. Based on both the CD4+ T cell count after primary infection and CD4+ T cell decline, we estimate the time until AIDS. We then obtain our newly introduced measure of virulence as the inverse of the estimated time until AIDS. After fitting a model to the measured virulence and set-point viral load values, we tested if this relation varies per subtype. We found that subtype C has a significantly higher per-pathogen virulence than subtype A. Based on an evolutionary model, we then hypothesize that differences in the primary length of infection period cause the observed variation in the speed of spread of the subtypes.
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Affiliation(s)
- Judith A Bouman
- Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Colin M Venner
- Department of Microbiology and Immunology, Western University, London, Ontario N6A 3K7, Canada
| | - Courtney Walker
- Department of Microbiology and Immunology, Western University, London, Ontario N6A 3K7, Canada
| | - Eric J Arts
- Department of Microbiology and Immunology, Western University, London, Ontario N6A 3K7, Canada
| | - Roland R Regoes
- Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
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42
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Fieldman T. Evolutionary principles for modifying pathogen virulence. Crit Rev Microbiol 2023:1-12. [PMID: 37146153 DOI: 10.1080/1040841x.2023.2203766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Current methods for combatting infectious diseases are largely limited to the prevention of infection, enhancing host immunity (via vaccination), and administration of small molecules to slow the growth of or kill pathogens (e.g. antimicrobials). Beyond efforts to deter the rise of antimicrobial resistance, little consideration is given to pathogen evolution. Natural selection will favor different levels of virulence under different circumstances. Experimental studies and a wealth of theoretical work have identified many likely evolutionary determinants of virulence. Some of these, such as transmission dynamics, are amenable to modification by clinicians and public health practitioners. In this article, we provide a conceptual overview of virulence, followed by the analysis of modifiable evolutionary determinants of virulence including vaccinations, antibiotics, and transmission dynamics. Finally, we discuss both the importance and limitations of taking an evolutionary approach to reducing pathogen virulence.
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Affiliation(s)
- Tom Fieldman
- Clinical Microbiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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43
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Hasik AZ, King KC, Hawlena H. Interspecific host competition and parasite virulence evolution. Biol Lett 2023; 19:20220553. [PMID: 37130550 PMCID: PMC10734695 DOI: 10.1098/rsbl.2022.0553] [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: 11/23/2022] [Accepted: 04/17/2023] [Indexed: 05/04/2023] Open
Abstract
Virulence, the harm to hosts caused by parasite infection, can be selected for by several ecological factors acting synergistically or antagonistically. Here, we focus on the potential for interspecific host competition to shape virulence through such a network of effects. We first summarize how host natural mortality, body mass changes, population density and community diversity affect virulence evolution. We then introduce an initial conceptual framework highlighting how these host factors, which change during host competition, may drive virulence evolution via impacts on life-history trade-offs. We argue that the multi-faceted nature of both interspecific host competition and virulence evolution still requires consideration and experimentation to disentangle contrasting mechanisms. It also necessitates a differential treatment for parasites with various transmission strategies. However, such a comprehensive approach focusing on the role of interspecific host competition is essential to understand the processes driving the evolution of virulence in a tangled bank.
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Affiliation(s)
- Adam Z. Hasik
- Jacob Blaustein Center for
Scientific Cooperation, Ben-Gurion University of the
Negev, 8499000 Midreshet Ben-Gurion,
Israel
| | - Kayla C. King
- Department of Biology,
University of Oxford, 11a Mansfield Road,
Oxford OX1 3SZ, UK
| | - Hadas Hawlena
- Mitrani Department of Desert
Ecology, Swiss Institute for Dryland Environmental and Energy Research, The
Jacob Blaustein Institutes for Desert Research, Ben-Gurion
University of the Negev, 849900 Midreshet Ben-Gurion,
Israel
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44
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Gomes B, Dias M, Cervantes R, Pena P, Santos J, Vasconcelos Pinto M, Viegas C. One Health Approach to Tackle Microbial Contamination on Poultries-A Systematic Review. TOXICS 2023; 11:374. [PMID: 37112601 PMCID: PMC10142658 DOI: 10.3390/toxics11040374] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
This study reports the search of available data published regarding microbial occupational exposure assessment in poultries, following the PRISMA methodology. Air collection through filtration was the most frequently used. The most commonly used passive sampling method was material collection such as dust, cages, soils, sediment, and wastewater. Regarding assays applied, the majority of studies comprised culture-based methods, but molecular tools were also frequently used. Screening for antimicrobial susceptibility was performed only for bacteria; cytotoxicity, virological and serological assays were also performed. Most of the selected studies focused on bacteria, although fungi, endotoxins, and β-glucans were also assessed. The only study concerning fungi and mycotoxins reported the carcinogenic mycotoxin AFB1. This study gives a comprehensive overview of microbial contamination in the poultry industry, emphasizing this setting as a potential reservoir of microbial pathogens threatening human, animal, and environmental health. Additionally, this research helps to provide a sampling and analysis protocol proposal to evaluate the microbiological contamination in these facilities. Few articles were found reporting fungal contamination in poultry farms worldwide. In addition, information concerning fungal resistance profile and mycotoxin contamination remain scarce. Overall, a One Health approach should be incorporated in exposure assessments and the knowledge gaps identified in this paper should be addressed in further research.
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Affiliation(s)
- Bianca Gomes
- CE3C—Center for Ecology, Evolution and Environmental Change, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
| | - Marta Dias
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Renata Cervantes
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Pedro Pena
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Joana Santos
- CISAS—Center for Research and Development in Agrifood Systems and Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal
| | - Marta Vasconcelos Pinto
- CISAS—Center for Research and Development in Agrifood Systems and Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal
- Polytechnic Institute of Coimbra, Escola Superior de Tecnologia da Saúde de Coimbra, Rua 5 de Outubro, 3046-854 Coimbra, Portugal
| | - Carla Viegas
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
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45
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Chen J, Gu C, Ruan Z, Tang M. Competition of SARS-CoV-2 variants on the pandemic transmission dynamics. CHAOS, SOLITONS, AND FRACTALS 2023; 169:113193. [PMID: 36817403 PMCID: PMC9915129 DOI: 10.1016/j.chaos.2023.113193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
SARS-CoV-2 has produced various variants during its ongoing evolution. The competitive behavior driven by the co-transmission of these variants has influenced the pandemic transmission dynamics. Therefore, studying the impact of competition between SARS-CoV-2 variants on pandemic transmission dynamics is of considerable practical importance. In order to formalize the mechanism of competition between SARS-CoV-2 variants, we propose an epidemic model that takes into account the co-transmission of competing variants. The model focuses on how cross-immunity influences the transmission dynamics of SARS-CoV-2 through competitive mechanisms between strains. We found that inter-strain competition affects not only both the final size and the replacement time of the variants, but also the invasive behavior of new variants in the future. Due to the limited extent of cross-immunity in previous populations, we predict that the new strain may infect the largest number of individuals in China without control interventions. Moreover, we also observed the possibility of periodic outbreaks in the same lineage and the possibility of the resurgence of previous lineages. Without the invasion of a new variant, the previous variant (Delta variant) is projected to resurgence as early as 2023. However, its resurgence may be prevented by a new variant with a greater competitive advantage.
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Affiliation(s)
- Jiaqi Chen
- Department of Systems Science, Business School, University of Shanghai for Science and Technology, Shanghai, 200093, China
| | - Changgui Gu
- Department of Systems Science, Business School, University of Shanghai for Science and Technology, Shanghai, 200093, China
| | - Zhongyuan Ruan
- Institute of Cyberspace Security, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Ming Tang
- School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, China
- Shanghai Key Laboratory of Multidimensional Information Processing, East China Normal University, Shanghai, 200241, China
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46
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Melero I, González R, Elena SF. Host developmental stages shape the evolution of a plant RNA virus. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220005. [PMID: 36744567 PMCID: PMC9979778 DOI: 10.1098/rstb.2022.0005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Viruses are obligate pathogens that entirely rely on their hosts to complete their infectious cycle. The outcome of viral infections depends on the status of the host. Host developmental stage is an important but sometimes overlooked factor impacting host-virus interactions. This impact is especially relevant in a context where climate change and human activities are altering plant development. To better understand how different host developmental stages shape virus evolution, we experimentally evolved turnip mosaic virus (TuMV) on Arabidopsis thaliana at three different developmental stages: vegetative (juvenile), bolting (transition) and reproductive (mature). After infecting plants with an Arabidopsis-naive or an Arabidopsis-well-adapted TuMV isolate, we observed that hosts in later developmental stages were prone to faster and more severe infections. This observation was extended to viruses belonging to different genera. Thereafter, we experimentally evolved lineages of the naive and the well-adapted TuMV isolates in plants from each of the three developmental stages. All evolved viruses enhanced their infection traits, but this increase was more intense in viruses evolved in younger hosts. The genomic changes of the evolved viral lineages revealed mutation patterns that strongly depended on the founder viral isolate as well as on the developmental stage of the host wherein the lineages were evolved. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- Izan Melero
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain
| | - Rubén González
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain
| | - Santiago F. Elena
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain,The Santa Fe Institute, Santa Fe 87501, NM, USA
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Hector TE, Gehman ALM, King KC. Infection burdens and virulence under heat stress: ecological and evolutionary considerations. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220018. [PMID: 36744570 PMCID: PMC9900716 DOI: 10.1098/rstb.2022.0018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
As a result of global change, hosts and parasites (including pathogens) are experiencing shifts in their thermal environment. Despite the importance of heat stress tolerance for host population persistence, infection by parasites can impair a host's ability to cope with heat. Host-parasite eco-evolutionary dynamics will be affected if infection reduces host performance during heating. Theory predicts that within-host parasite burden (replication rate or number of infecting parasites per host), a key component of parasite fitness, should correlate positively with virulence-the harm caused to hosts during infection. Surprisingly, however, the relationship between within-host parasite burden and virulence during heating is often weak. Here, we describe the current evidence for the link between within-host parasite burden and host heat stress tolerance. We consider the biology of host-parasite systems that may explain the weak or absent link between these two important host and parasite traits during hot conditions. The processes that mediate the relationship between parasite burden and host fitness will be fundamental in ecological and evolutionary responses of host and parasites in a warming world. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- T. E. Hector
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - A.-L. M. Gehman
- Hakai Institute, End of Kwakshua Channel, Calvert Island, BC Canada, V0N 1M0,Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC Canada, V6T 1Z4
| | - K. C. King
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
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Apari P, Földvári G. Domestication and microbiome succession may drive pathogen spillover. Front Microbiol 2023; 14:1102337. [PMID: 37007505 PMCID: PMC10065160 DOI: 10.3389/fmicb.2023.1102337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/02/2023] [Indexed: 03/19/2023] Open
Abstract
Emerging infectious diseases have posed growing medical, social and economic threats to humanity. The biological background of pathogen spillover or host switch, however, still has to be clarified. Disease ecology finds pathogen spillovers frequently but struggles to explain at the molecular level. Contrarily, molecular biological traits of host-pathogen relationships with specific molecular binding mechanisms predict few spillovers. Here we aim to provide a synthetic explanation by arguing that domestication, horizontal gene transfer even between superkingdoms as well as gradual exchange of microbiome (microbiome succession) are essential in the whole scenario. We present a new perspective at the molecular level which can explain the observations of frequent pathogen spillover events at the ecological level. This proposed rationale is described in detail, along with supporting evidence from the peer-reviewed literature and suggestions for testing hypothesis validity. We also highlight the importance of systematic monitoring of virulence genes across taxonomical categories and in the whole biosphere as it helps prevent future epidemics and pandemics. We conclude that that the processes of domestication, horizontal gene transfer and microbial succession might be important mechanisms behind the many spillover events driven and accelerated by climate change, biodiversity loss and globalization.
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Affiliation(s)
- Péter Apari
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
| | - Gábor Földvári
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
- Centre for Eco-Epidemiology, National Laboratory for Health Security, Budapest, Hungary
- *Correspondence: Gábor Földvári,
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Carabelli AM, Peacock TP, Thorne LG, Harvey WT, Hughes J, Peacock SJ, Barclay WS, de Silva TI, Towers GJ, Robertson DL. SARS-CoV-2 variant biology: immune escape, transmission and fitness. Nat Rev Microbiol 2023; 21:162-177. [PMID: 36653446 PMCID: PMC9847462 DOI: 10.1038/s41579-022-00841-7] [Citation(s) in RCA: 225] [Impact Index Per Article: 225.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2022] [Indexed: 01/19/2023]
Abstract
In late 2020, after circulating for almost a year in the human population, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibited a major step change in its adaptation to humans. These highly mutated forms of SARS-CoV-2 had enhanced rates of transmission relative to previous variants and were termed 'variants of concern' (VOCs). Designated Alpha, Beta, Gamma, Delta and Omicron, the VOCs emerged independently from one another, and in turn each rapidly became dominant, regionally or globally, outcompeting previous variants. The success of each VOC relative to the previously dominant variant was enabled by altered intrinsic functional properties of the virus and, to various degrees, changes to virus antigenicity conferring the ability to evade a primed immune response. The increased virus fitness associated with VOCs is the result of a complex interplay of virus biology in the context of changing human immunity due to both vaccination and prior infection. In this Review, we summarize the literature on the relative transmissibility and antigenicity of SARS-CoV-2 variants, the role of mutations at the furin spike cleavage site and of non-spike proteins, the potential importance of recombination to virus success, and SARS-CoV-2 evolution in the context of T cells, innate immunity and population immunity. SARS-CoV-2 shows a complicated relationship among virus antigenicity, transmission and virulence, which has unpredictable implications for the future trajectory and disease burden of COVID-19.
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Affiliation(s)
| | - Thomas P Peacock
- Department of Infectious Disease, St Mary's Medical School, Imperial College London, London, UK
| | - Lucy G Thorne
- Division of Infection and Immunity, University College London, London, UK
| | - William T Harvey
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK
- Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Joseph Hughes
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK
| | - Sharon J Peacock
- Department of Medicine, University of Cambridge, Addenbrookes Hospital, Cambridge, UK
| | - Wendy S Barclay
- Department of Infectious Disease, St Mary's Medical School, Imperial College London, London, UK
| | - Thushan I de Silva
- Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, UK
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London, UK
| | - David L Robertson
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK.
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Rodríguez‐Hernández K, Álvarez‐Mendizábal P, Chapa‐Vargas L, Escobar F, Dáttilo W, Santiago‐Alarcon D. Infection intensity shapes specialization and beta diversity of haemosporidian–bird networks across elevations. Ecosphere 2023. [DOI: 10.1002/ecs2.4481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
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