Project

Back to overview

Resource ecology of the growth and virulence of parasites

English title Resource ecology of the growth and virulence of parasites
Applicant Koella Jacob
Number 192786
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 01.05.2020 - 31.01.2024
Approved amount 656'250.00
Show all

Keywords (3)

resource ecology; parasite virulence; within-host dynamics

Lay Summary (French)

Lead
Les interactions entre les hôtes et les parasites sont régies par la manière dont les ressources disponibles pour l'hôte sont utilisées par le parasite pour sa propre croissance et par l'hôte pour sa défense contre l'infection. Notre but principal est de développer et tester une théorie qui décrit la compétition entre l'hôte et le parasite pour comprendre comment les ressources de l'hôte affectent sa survie.
Lay summary

Contenu et objectifs du travail de recherche 

Devrions-nous vraiment "affamer un rhume et nourrir une fièvre"? 

Une façon d’y répondre est de considérer comment les ressources limitées de l'hôte sont utilisées pour la croissance du parasite et pour la défense de l’hôte. Ainsi, la croissance du parasite et la mortalité due à l’infection émergent naturellement de la compétition pour les ressources. La façon dont les ressources affectent la mortalité dépendront fortement du fait que l'hôte soit tué par une charge parasitaire excessive, par une perte excessive de ressources au profit du parasite ou par une réponse immunitaire trop active qui contribue à son stress oxydant.  

L’objectif principal de ce projet est de développer la théorie et de la mettre en contact avec des expériences afin de comprendre comment la compétition pour les ressources au sein de l'hôte affecte la mort causée par le parasite, et en particulier dans quelles conditions la famine d'un parasite aide effectivement l'hôte à survivre.

Les expériences seront réalisées avec le microsporidien Vavraia culicis et son hôte, le moustique Aedes aegypti.

Contexte scientifique et social du projet de recherche 

Le projet est de la recherche fondamentale. En comprenant ce qui détermine les interactions entre les parasites et leurs hôtes, il aidera à comprendre l'épidémiologie des maladies infectieuses.

Direct link to Lay Summary Last update: 08.04.2020

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
144207 Resource ecology of host-parasite interactions and evolution 01.02.2013 Project funding (Div. I-III)
144207 Resource ecology of host-parasite interactions and evolution 01.02.2013 Project funding (Div. I-III)
169842 Integrating resistance and tolerance to parasitic infection with life-history theory 01.11.2016 Project funding (Div. I-III)

Abstract

Most of our ideas about the evolution of host-parasite systems are based on epidemiologically relevant traits - the rate of parasite-induced mortality, transmission rate and recovery rate - and on assumptions about their interactions. While this has given a useful framework that lets us formulate and test new ideas, it remains unsatisfying that we generally assume, rather than understand, the processes of the infection that underlie these traits and thus that determine epidemiology. One way towards this understanding is to consider how the host’s limited resources are used for the parasite’s growth and for the host’s defense against parasites and its development, thereby letting disease-induced mortality and other traits emerge naturally from the parasite’s dynamics.This proposal takes two approaches to look at the effects of resources on the dynamics of a parasite within its host. In a quantitative approach, it considers resources as a source of energy and studies how the energy budget within hosts influences the link between the parasite’s growth and the host’s mortality. In a qualitative approach, it asks whether the relative contributions of different nutrients (focusing on proteins and sugars), in addition to the energy content, influence the parasite’s development and the host’s response, and whether the host’s preference for nutrients lessens the damaging impact of the parasite.Within this framework I use theory and experiments with the microsporidian Vavraia culicis and its host, the mosquito Aedes aegypti to ask three questions. 1. How does a parasite kill its host? In a series of experiments I will try to disentangle the possible mechanisms underlying the host’s death - parasite load, depletion of resources, toxic effect of immune response, or oxidative stress, and whether resource availability affects the relative contribution of these mechanisms. 2. Can parasites adapt to grow optimally in different conditions? In particular, young and undernourished hosts offer few resources to the parasite, but may also have little resistance and be more sensitive to this damaging effects. I will study how parasites respond to the change of resource levels in growing hosts, and whether they can adapt to develop optimally. 3. Does self-treating of infected hosts (so changing the preference for nutrient contents of their food) lessen the impact of infection? I will first ask how protein and sugar affect the parasite’s development and virulence and the host’s immune response qualitatively through the ratio of nutrients) as well as quantitatively (through their overall quantity). I will then ask whether hosts prefer the nutrients that help them to decrease or avoid the detrimental effects of infection.The project will thus make an important contribution to understanding how resource availability affects epidemics, and it will help to understand one of the most important features of evolutionary parasitology: the trade-off between the parasite’s transmission and virulence.
-