Within-host interference competition can prevent invasion of rare parasites
Quigley, Benjamin J. Z.
Brown, Sam P.
Leggett, Helen C.
Scanlan, Pauline D.
Cambridge University Press
Competition between parasite species or genotypes can play an important role in the establishment of parasites in new host populations. Here, we investigate a mechanism by which a rare parasite is unable to establish itself in a host population if a common resident parasite is already present (a 'priority effect'). We develop a simple epidemiological model and show that a rare parasite genotype is unable to invade if coinfecting parasite genotypes inhibit each other's transmission more than expected from simple resource partitioning. This is because a rare parasite is more likely to be in multiply-infected hosts than the common genotype, and hence more likely to pay the cost of reduced transmission. Experiments competing interfering clones of bacteriophage infecting a bacterium support the model prediction that the clones are unable to invade each other from rare. We briefly discuss the implications of these results for host-parasite ecology and (co)evolution.
Multiplicity of infection , MOI , Interference competition , Positive frequency dependence , Bacteria , Phage
Quigley, B. J. Z., Brown, S. P., Leggett, H. C., Scanlan, P. D. and Buckling, A. (2017) 'Within-host interference competition can prevent invasion of rare parasites', Journal of Parasitology, 145(6), pp. 770-774. doi: 10.1017/S003118201700052X
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