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Generalism and the evolution of parasite virulence
Helen C Leggett1, Angus Buckling, Gráinne H Long
1Department of Zoology, Oxford University, South Parks Road, Oxford, OX1 3PS, UK; Biosciences, University of Exeter, Cornwall Campus, Penryn, TR10 9EZ, UK.
Trends in Ecology & Evolution
|August 24, 2013
Summary
Parasite host range influences virulence evolution through generalism costs, infection multiplicity, maladaptive virulence, and host availability. This research integrates host range with life-history to predict emerging disease virulence.
Area of Science:
- Evolutionary ecology
- Parasitology
- Disease dynamics
Background:
- Parasite virulence, the harm parasites inflict on hosts, is a key factor in host-parasite coevolution.
- The range of hosts a parasite can infect (host range or generalism) is known to influence virulence but the precise mechanisms are debated.
Purpose of the Study:
- To explore how parasite host range directly impacts observed levels of parasite virulence.
- To propose novel hypotheses for the evolutionary ecology of virulence by integrating host range with life-history evolution.
Main Methods:
- Conceptual analysis integrating parasite infectivity range with life-history evolution.
- Examination of four proposed mechanisms: costs of generalism, multiplicity of infection, maladaptive virulence, and host availability.
Main Results:
- Parasite generalism can directly affect virulence through various pathways, including trade-offs in infectivity and transmission.
- The interplay between host range and host availability can significantly shape virulence evolution.
- Maladaptive virulence may arise in generalist parasites due to factors beyond direct host exploitation.
Conclusions:
- Integrating parasite host range into life-history evolution provides a robust framework for understanding virulence.
- This framework generates testable predictions for the virulence of emerging infectious diseases, particularly those arising from host shifts.
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