Tripartite interactions: how immunity, microbiota and pathogens interact and affect pathogen virulence evolution

2022 ◽  
Author(s):  
Sophie AO Armitage ◽  
Elke Genersch ◽  
Dino P McMahon ◽  
Charlotte Rafaluk-Mohr ◽  
Jens Rolff
Keyword(s):  
Pathogen Virulence ◽  
Virulence Evolution ◽  
Tripartite Interactions

scholarly journals Experimental manipulation of population-level MHC diversity controls pathogen virulence evolution inMus musculus

2018 ◽  
Vol 31 (2) ◽  
pp. 314-322 ◽  
Author(s):  
D. H. Cornwall ◽  
J. L. Kubinak ◽  
E. Zachary ◽  
D. L. Stark ◽  
D. Seipel ◽  
...  
Keyword(s):  
Population Level ◽  
Experimental Manipulation ◽  
Pathogen Virulence ◽  
Virulence Evolution ◽  
Mhc Diversity

scholarly journals Vaccine-driven virulence evolution: consequences of unbalanced reductions in mortality and transmission and implications for pertussis vaccines

2019 ◽  
Vol 16 (161) ◽  
pp. 20190642 ◽  
Author(s):  
Ian F. Miller ◽  
C. Jessica Metcalf
Keyword(s):  
Mathematical Modelling ◽  
Bordetella Pertussis ◽  
Burden Of Disease ◽  
Individual Variability ◽  
Disease Symptoms ◽  
Pathogen Virulence ◽  
Modelling Framework ◽  
Virulence Evolution ◽  
Heterogeneous Effects ◽  
Current Concerns

Many vaccines have heterogeneous effects across individuals. Additionally, some vaccines do not prevent infection, but reduce disease-associated mortality and transmission. Both of these factors will alter selection pressures on pathogens and thus shape the evolution of pathogen virulence. We use a mathematical modelling framework to show that (i) the balance of how vaccines reduce transmission versus mortality and (ii) individual variability in protection conferred both shape the evolution of pathogen virulence. Epidemiological (burden of disease) and evolutionary (pathogen virulence) outcomes are both worse when vaccines confer smaller reductions in transmission than in mortality. Furthermore, outcomes are modulated by variability in vaccine effects, with increased variability limiting the extent of virulence evolution but in some cases preventing eradication. These findings are pertinent to current concerns about the global resurgence of pertussis and the efficacy of pertussis vaccines, as the two classes of these vaccines may reduce disease symptoms without preventing infection and differ in their ability to reduce transmission. Furthermore, these findings point to the importance of generating precise predictions for virulence evolution in Bordetella pertussis (and other similar pathogens) by incorporating empirical characterizations of vaccine effects into models capturing the epidemiological details of this system.

scholarly journals Contrasting evolution of virulence and replication rate in an emerging bacterial pathogen

2019 ◽  
Vol 116 (34) ◽  
pp. 16927-16932 ◽  
Author(s):  
Luc Tardy ◽  
Mathieu Giraudeau ◽  
Geoffrey E. Hill ◽  
Kevin J. McGraw ◽  
Camille Bonneaud
Keyword(s):  
Host Resistance ◽  
Bacterial Pathogen ◽  
Mediating Effect ◽  
Replication Rate ◽  
House Finches ◽  
Pathogen Virulence ◽  
Virulence Evolution ◽  
Evolution Of Virulence ◽  
Immune Manipulation ◽  
The Relationship

Host resistance through immune clearance is predicted to favor pathogens that are able to transmit faster and are hence more virulent. Increasing pathogen virulence is, in turn, typically assumed to be mediated by increasing replication rates. However, experiments designed to test how pathogen virulence and replication rates evolve in response to increasing host resistance, as well as the relationship between the two, are rare and lacking for naturally evolving host–pathogen interactions. We inoculated 55 isolates of Mycoplasma gallisepticum, collected over 20 y from outbreak, into house finches (Haemorhous mexicanus) from disease-unexposed populations, which have not evolved protective immunity to M. gallisepticum. We show using 3 different metrics of virulence (body mass loss, symptom severity, and putative mortality rate) that virulence has increased linearly over >150,000 bacterial generations since outbreak (1994 to 2015). By contrast, while replication rates increased from outbreak to the initial spread of resistance (1994 to 2004), no further increases have occurred subsequently (2007 to 2015). Finally, as a consequence, we found that any potential mediating effect of replication rate on virulence evolution was restricted to the period when host resistance was initially increasing in the population. Taken together, our results show that pathogen virulence and replication rates can evolve independently, particularly after the initial spread of host resistance. We hypothesize that the evolution of pathogen virulence can be driven primarily by processes such as immune manipulation after resistance spreads in host populations.

scholarly journals Deciphering the Monilinia fructicola Genome to Discover Effector Genes Possibly Involved in Virulence

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 568
Author(s):  
Laura Vilanova ◽  
Claudio A. Valero-Jiménez ◽  
Jan A.L. van Kan
Keyword(s):  
Brown Rot ◽  
Biological Properties ◽  
Effector Proteins ◽  
Stone Fruit ◽  
Rna Seq ◽  
Sequencing Technology ◽  
Pathogen Virulence ◽  
Effector Genes ◽  
Gene Models ◽  
High Quality Genome

Brown rot is the most economically important fungal disease of stone fruits and is primarily caused by Monilinia laxa and Monlinia fructicola. Both species co-occur in European orchards although M. fructicola is considered to cause the most severe yield losses in stone fruit. This study aimed to generate a high-quality genome of M. fructicola and to exploit it to identify genes that may contribute to pathogen virulence. PacBio sequencing technology was used to assemble the genome of M. fructicola. Manual structural curation of gene models, supported by RNA-Seq, and functional annotation of the proteome yielded 10,086 trustworthy gene models. The genome was examined for the presence of genes that encode secreted proteins and more specifically effector proteins. A set of 134 putative effectors was defined. Several effector genes were cloned into Agrobacterium tumefaciens for transient expression in Nicotiana benthamiana plants, and some of them triggered necrotic lesions. Studying effectors and their biological properties will help to better understand the interaction between M. fructicola and its stone fruit host plants.

scholarly journals Pupal cannibalism by worker honey bees contributes to the spread of deformed wing virus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco Posada-Florez ◽  
Zachary S. Lamas ◽  
David J. Hawthorne ◽  
Yanping Chen ◽  
Jay D. Evans ◽  
...  
Keyword(s):  
Honey Bees ◽  
Control Strategies ◽  
Virus Transmission ◽  
Experimental Conditions ◽  
Colony Losses ◽  
Viral Pathogen ◽  
Deformed Wing Virus ◽  
Hygienic Behaviour ◽  
Pathogen Virulence ◽  
Comprehensive Knowledge

AbstractTransmission routes impact pathogen virulence and genetics, therefore comprehensive knowledge of these routes and their contribution to pathogen circulation is essential for understanding host–pathogen interactions and designing control strategies. Deformed wing virus (DWV), a principal viral pathogen of honey bees associated with increased honey bee mortality and colony losses, became highly virulent with the spread of its vector, the ectoparasitic mite Varroa destructor. Reproduction of Varroa mites occurs in capped brood cells and mite-infested pupae from these cells usually have high levels of DWV. The removal of mite-infested pupae by worker bees, Varroa Sensitive Hygiene (VSH), leads to cannibalization of pupae with high DWV loads, thereby offering an alternative route for virus transmission. We used genetically tagged DWV to investigate virus transmission to and between worker bees following pupal cannibalisation under experimental conditions. We demonstrated that cannibalization of DWV-infected pupae resulted in high levels of this virus in worker bees and that the acquired virus was then transmitted between bees via trophallaxis, allowing circulation of Varroa-vectored DWV variants without the mites. Despite the known benefits of hygienic behaviour, it is possible that higher levels of VSH activity may result in increased transmission of DWV via cannibalism and trophallaxis.

scholarly journals On the diverse and opposing effects of nutrition on pathogen virulence

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191220 ◽  
Author(s):  
Victoria L. Pike ◽  
Katrina A. Lythgoe ◽  
Kayla C. King
Keyword(s):  
Infectious Disease ◽  
Immune System ◽  
Meta Analysis ◽  
Anthropogenic Factors ◽  
Anthropogenic Activity ◽  
Pathogen Virulence ◽  
Disease Outcomes ◽  
Host Nutrition ◽  
Opposing Effects ◽  
The Impact

Climate change and anthropogenic activity are currently driving large changes in nutritional availability across ecosystems, with consequences for infectious disease. An increase in host nutrition could lead to more resources for hosts to expend on the immune system or for pathogens to exploit. In this paper, we report a meta-analysis of studies on host–pathogen systems across the tree of life, to examine the impact of host nutritional quality and quantity on pathogen virulence. We did not find broad support across studies for a one-way effect of nutrient availability on pathogen virulence. We thus discuss a hypothesis that there is a balance between the effect of host nutrition on the immune system and on pathogen resources, with the pivot point of the balance differing for vertebrate and invertebrate hosts. Our results suggest that variation in nutrition, caused by natural or anthropogenic factors, can have diverse effects on infectious disease outcomes across species.

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