Differential sources of host species heterogeneity influence the transmission and control of multihost parasites

Daniel G Streicker,Amy B Pedersen,Andy Fenton,Richard Ostfeld

doi:10.1111/ele.12122

Daniel G Streicker, Amy B Pedersen + Show 2 more

Open Access

https://doi.org/10.1111/ele.12122

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Abstract

Controlling parasites that infect multiple host species often requires targeting single species that dominate transmission. Yet, it is rarely recognised that such ‘key hosts’ can arise through disparate mechanisms, potentially requiring different approaches for control. We identify three distinct, but not mutually exclusive, processes that underlie host species heterogeneity: infection prevalence, population abundance and infectiousness. We construct a theoretical framework to isolate the role of each process from ecological data and to explore the outcome of different control approaches. Applying this framework to data on 11 gastrointestinal parasites in small mammal communities across the eastern United States reveals variation not only in the magnitude of transmission asymmetries among host species but also in the processes driving heterogeneity. These differences influence the efficiency by which different control strategies reduce transmission. Identifying and tailoring interventions to a specific type of key host may therefore enable more effective management of multihost parasites.

Highlights

The majority of parasites, including many that cause emerging human, domestic animal and wildlife diseases, infect multiple host species (Cleaveland et al 2001; Pedersen et al 2005; Woolhouse & Gaunt 2007)
Differences in host species’ abundance, exposure and susceptibility imply that each species is unlikely to contribute to parasite transmission (Haydon et al 2002; Altizer et al 2003)
Many studies have revealed the presence of key host species among the communities of potential hosts

Summary

Introduction

The majority of parasites, including many that cause emerging human, domestic animal and wildlife diseases, infect multiple host species (Cleaveland et al 2001; Pedersen et al 2005; Woolhouse & Gaunt 2007). If heterogeneities among host species are severe, certain species may contribute disproportionately to transmission and become a ‘key host’, responsible for long-term parasite persistence and infection of sympatric host species. Because of heterogeneities among the mammalian hosts of Borrelia burgdorferi, the causative agent of Lyme disease, shifts in host community composition that reduce the number of tick bites on highly infectious white-footed mice (Peromyscus leucopus) can reduce Lyme disease prevalence in ticks and humans (LoGuidice et al 2003). Rabies virus infections in wild carnivores in the Serengeti depend on viral maintenance by domestic dogs, so vaccinating dogs is expected to alleviate epizootics in wildlife (Lembo et al 2007)

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