Stability of within-host–parasite communities in a wild mammal system

Sarah C. L. Knowles,Andy Fenton,Owen L. Petchey,Trevor R. Jones,Amy B. Pedersen,Rebecca Barber

doi:10.1098/rspb.2013.0598

Abstract

Simultaneous infection by multiple parasite species is ubiquitous in nature. Interactions among co-infecting parasites may have important consequences for disease severity, transmission and community-level responses to perturbations. However, our current view of parasite interactions in nature comes primarily from observational studies, which may be unreliable at detecting interactions. We performed a perturbation experiment in wild mice, by using an anthelminthic to suppress nematodes, and monitored the consequences for other parasite species. Overall, these parasite communities were remarkably stable to perturbation. Only one non-target parasite species responded to deworming, and this response was temporary: we found strong, but short-lived, increases in the abundance of Eimeria protozoa, which share an infection site with the dominant nematode species, suggesting local, dynamic competition. These results, providing a rare and clear experimental demonstration of interactions between helminths and co-infecting parasites in wild vertebrates, constitute an important step towards understanding the wider consequences of similar drug treatments in humans and animals.

Highlights

Co-infection, where an individual host harbours multiple parasite species, is the rule rather than the exception in nature, and has been documented across diverse systems [1,2]
Few initial differences between treatment groups in parasite response variables were present, though these were found for Eimeria hungaryensis and pooled Bartonella spp. infection probability, as well as Eimeria apionodes intensity
Using a novel drug-based perturbation experimental approach, we provide a rare experimental demonstration of interaction between co-infecting parasite species in a wild vertebrate population, and show that, overall, the within-host –parasite communities examined were relatively stable to drug-based perturbation

Summary

Introduction

Co-infection, where an individual host harbours multiple parasite species, is the rule rather than the exception in nature, and has been documented across diverse systems [1,2]. The parasites infecting an individual host can be viewed as an ecological community, within which species may interact directly through chemical or physical interference, indirectly via ‘bottom-up’ processes (e.g. competition for shared host resources) or indirectly via ‘top-down’ processes (e.g. immune-mediated competition or facilitation) [3]. Such interspecific interactions are an important determinant of how communities respond to external events. These and other determinants of stability are well researched in several

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Results

Conclusion