The removal of individuals from an infected population (culling) is a common strategy used to eradicate wildlife diseases. The manipulation of host density can impose strong selective pressures on pathogen virulence by changing the ecological conditions, thus affecting the effectiveness of eradication programs. We present an analysis of the effect of virulence evolution on culling by extending a susceptible-infected model to the case of competing strains with superinfection. To assess both short- and long-term effects, we first carried out the analysis on an ecological timescale, with a two-strain competition model; then we explore the dynamics of a continuum of pathogenic strains on evolutionary timescales using a quantitative genetics approach (when infection and evolutionary processes occur on comparable timescales) and a game-theoretic approach (when evolutionary processes occur on a slower scale).We demonstrate that the competition among pathogenic variants in the presence of superinfection affects outcome of culling campaigns, since increased host mortality may select for less virulent strains able to establish in sparser populations. This can lead to the counterintuitive result that disease abundance and prevalence may even increase with culling, thus making the eradication of infections considerably less likely. This is particularly relevant in the case of zoonoses where higher prevalence and abundance of pathogens in wild reservoirs may increase the risk of spillover in livestock and humans.

Bolzoni, L.; De Leo, G.A. (2013). Unexpected consequences of culling on the eradication of wildlife diseases: the role of virulence evolution. THE AMERICAN NATURALIST, 181 (3): 301-313. doi: 10.1086/669154 handle: http://hdl.handle.net/10449/21790

Unexpected consequences of culling on the eradication of wildlife diseases: the role of virulence evolution

Bolzoni, Luca;
2013-01-01

Abstract

The removal of individuals from an infected population (culling) is a common strategy used to eradicate wildlife diseases. The manipulation of host density can impose strong selective pressures on pathogen virulence by changing the ecological conditions, thus affecting the effectiveness of eradication programs. We present an analysis of the effect of virulence evolution on culling by extending a susceptible-infected model to the case of competing strains with superinfection. To assess both short- and long-term effects, we first carried out the analysis on an ecological timescale, with a two-strain competition model; then we explore the dynamics of a continuum of pathogenic strains on evolutionary timescales using a quantitative genetics approach (when infection and evolutionary processes occur on comparable timescales) and a game-theoretic approach (when evolutionary processes occur on a slower scale).We demonstrate that the competition among pathogenic variants in the presence of superinfection affects outcome of culling campaigns, since increased host mortality may select for less virulent strains able to establish in sparser populations. This can lead to the counterintuitive result that disease abundance and prevalence may even increase with culling, thus making the eradication of infections considerably less likely. This is particularly relevant in the case of zoonoses where higher prevalence and abundance of pathogens in wild reservoirs may increase the risk of spillover in livestock and humans.
Wildlife disease
Disease control
Culling
Superinfection
Virulence evolution
Adaptive dynamics
Settore BIO/07 - ECOLOGIA
2013
Bolzoni, L.; De Leo, G.A. (2013). Unexpected consequences of culling on the eradication of wildlife diseases: the role of virulence evolution. THE AMERICAN NATURALIST, 181 (3): 301-313. doi: 10.1086/669154 handle: http://hdl.handle.net/10449/21790
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10449/21790
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