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Integrating resistance and tolerance to parasitic infection with life-history theory

English title Integrating resistance and tolerance to parasitic infection with life-history theory
Applicant Koella Jacob
Number 169842
Funding scheme Project funding (Div. I-III)
Research institution Institut de Biologie Faculté des Sciences Université de Neuchâtel
Institution of higher education University of Neuchatel - NE
Main discipline Ecology
Start/End 01.11.2016 - 31.03.2020
Approved amount 678'000.00
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Keywords (4)

life-history theory; resistance to parasitic infection; tolerance to parasitic infection; resource ecology

Lay Summary (German)

Lead
Wie Wirte sich gegen Parasiten schützen ist ein zentraler Aspekt der Epidemiologie. Dieses Forschungsprojekt untersucht, wie die Evolution verschiedene Mechanismen dieses Schutzes beeinflusst.
Lay summary

Es gibt zwei grundsätzliche Mechanismen, mit denen sich ein Wirt gegen eine Parasiteninfektion wehren kann: entweder er vermindert die Anzahl Parasiten ins einem Körper durch seine Resistenz oder er vermindert den Schaden, der durch eine gegebene Anzahl Parasiten verursacht wird, durch seine Toleranz. Beide Mechanismen erhöhen die Gesundheit des Wirts, aber nur die Resistenz vermindert die Transmission. Die zwei Mechanismen haben deshalb verschiedene Auswirkungen auf die Epidemiologie und Evolution der Parasiten. Deshalb ist ein Verständnis wie sie vom Wirt reguliert werden und wie sie voneinander abhängen unabdingbar für die evolutive Epidemiologie.

Ich schlage vor, dass wir die Resistent und die Toleranz besser Verstehen können, wenn wir sie zusammen mit den evolutiven Strategien der ‘Lebensgeschichte’ (auf Englisch: life history) untersuchen. In der klassischen Theorie wird untersucht, wie ein Wirt seine Ressourcen verteilt auf Wachstum und Fortpflanzung; wir müssen nun zusätzlich das Verwenden der Ressourcen für die Verteidigung gegen den Parasiten anschauen.  Dazu werde nich die klassische Theorie mit physiologischen Ideen verbinden, vor allem mit der Idee, dass der oxidative Stress, der notwendigerweise durch den Metabolismus entsteht, die Immunantwort (und somit der Resistenz), die Fortpflanzung und das  Überleben (und somit der Toleranz) verbindet.

Das allgemeine Ziel ist somit eine Theorie der Parasiten-Wirts-Interaktionen zu entwickeln, die physiologische Ideen über Nutzung der Ressourcen und Immunität mit evokativen Ideen der Fortpflanzung und Mortalität verbindet. 

Direct link to Lay Summary Last update: 10.10.2016

Responsible applicant and co-applicants

Employees

Publications

Publication
Larval exposure to a pyrethroid insecticide and competition for food modulate the melanisation and antibacterial responses of adult Anopheles gambiae
Hauser Gaël, Koella Jacob C. (2020), Larval exposure to a pyrethroid insecticide and competition for food modulate the melanisation and antibacterial responses of adult Anopheles gambiae, in Scientific Reports, 10(1), 1364-1364.
Consequences of larval competition and exposure to permethrin for the development of the rodent malaria Plasmodium berghei in the mosquito Anopheles gambiae
Hauser Gaël, Thiévent Kevin, Koella Jacob C. (2020), Consequences of larval competition and exposure to permethrin for the development of the rodent malaria Plasmodium berghei in the mosquito Anopheles gambiae, in Parasites & Vectors, 13(1), 107-107.
The ability of Anopheles gambiae mosquitoes to bite through a permethrin-treated net and the consequences for their fitness
Hauser Gaël, Thiévent Kevin, Koella Jacob C. (2019), The ability of Anopheles gambiae mosquitoes to bite through a permethrin-treated net and the consequences for their fitness, in Scientific Reports, 9(1), 8141-8141.
The interaction between permethrin exposure and malaria infection affects the host-seeking behaviour of mosquitoes
Thiévent Kevin, Hauser Gaël, Elaian Obada, Koella Jacob C. (2019), The interaction between permethrin exposure and malaria infection affects the host-seeking behaviour of mosquitoes, in Malaria Journal, 18(1), 79-79.
The relationship between size and longevity of the malaria vector Anopheles gambiae (s.s.) depends on the larval environment
Barreaux Antoine M. G., Stone Chris M., Barreaux Priscille, Koella Jacob C. (2018), The relationship between size and longevity of the malaria vector Anopheles gambiae (s.s.) depends on the larval environment, in Parasites & Vectors, 11(1), 485-485.
Host genotype and environment affect the trade-off between horizontal and vertical transmission of the parasite Edhazardia aedis
Zilio Giacomo, Thiévent Kevin, Koella Jacob C. (2018), Host genotype and environment affect the trade-off between horizontal and vertical transmission of the parasite Edhazardia aedis, in BMC Evolutionary Biology, 18(1), 59-59.
The Role of the Environment in the Evolution of Tolerance and Resistance to a Pathogen
Zeller Michael, Koella Jacob C. (2017), The Role of the Environment in the Evolution of Tolerance and Resistance to a Pathogen, in The American Naturalist, 190(3), 389-397.
Larval environment influences vector competence of the malaria mosquito Anopheles gambiae
BarreauxAntoine M.G., BarreauxPriscille, ThiéventKevoin, KoellaJacob C. (2016), Larval environment influences vector competence of the malaria mosquito Anopheles gambiae, in Malaria World Journal, 7, 8.

Collaboration

Group / person Country
Types of collaboration
Ifakara Health Institute Tanzania (Africa)
- Publication
- Research Infrastructure

Associated projects

Number Title Start Funding scheme
192786 Resource ecology of the growth and virulence of parasites 01.05.2020 Project funding (Div. I-III)
144207 Resource ecology of host-parasite interactions and evolution 01.02.2013 Project funding (Div. I-III)
183365 Ultra High Performance Liquid Chromatography-High Resolution Tandem Mass Spectrometry (UHPLC-HRMS/MS) for metabolomics and identification of bioactive molecules 01.10.2019 R'EQUIP

Abstract

To minimise a parasite’s impact on health, hosts can attack the parasite developing within them to reduce the parasite load or they can reduce the damage caused by a given parasite load. The distinction between these two defences - resistance and tolerance - is attracting increasing attention by parasitologists and evolutionary biologists. Much of their work deals with genetic correlations between resistance and tolerance, how the environment can shape these correlations, and how these correlations feed into the epidemiological dynamics to shape evolution. Yet disentangling resistance and tolerance, and understanding their implications for the co-evolution of hosts and parasites remains problematic.I suggest that we can improve our understanding of resistance and tolerance by combining physiological and evolutionary approaches in an integrated picture of the host’s life-history and its response to parasitic infection, focusing on how a host allocates its resources to the development, reproduction and defence. Thus, I will attempt to move our ideas about the evolution of host defence from a basis that relies on observed relationships between resistance and tolerance to one that integrates physiological and evolutionary ideas with resource ecology and life-history theory. My project combines theory and experiments with two biological systems: (i) the microsporidian Vavraia culicis and its host, the mosquito Aedes aegypti and (ii) the malaria parasite Plasmodium falciparum and its mosquito vector Anopheles gambiae. It has four aims. 1. Predict the optimal life-history and defence. I will adapt and extend a model of ontogenetic growth, which is based on the balance of energy during the host’s development, by letting the host allocate energy to an innate immune system and including the within-host dynamics of the parasite and its by the immune response. Main outputs will be how the parasite’s growth rate and host’s environment affect the patterns of resistance and tolerance. 2. Give input to the model with experiments that investigate several of the central aspects of the approach, with questions linking immunity and defence on the one hand with metabolism and energetic utilisation on the other hand. What is the impact of diet on immune-competence and on resistance and tolerance? How does oxidative stress interact with the defence mechanisms of the mosquito? Does stimulation of the immune system affect defence, nutrient levels and oxidative stress?3. Test predictions of model. I will use experimental evolution to test predictions of the model about the optimal allocation to growth and to defence against parasitic infection.4. Answer whether mosquitoes choose their diet to increase protection against malaria. Sugar-feeding on plants forms an important part of the diet of mosquitoes. Do different plants offer different levels of immune-competence and resistance? Do mosquitoes shift their preference for plants from those that enhance their longevity when uninfected to those that enhance their defence against malaria when infected?
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