| Abstrakt: |
In large parts of the northern hemisphere, multiple deer species coexist, and management actions can strongly influence wild deer communities. Such changes may also indirectly influence other species in the community, such as small mammals and birds, because deer can have strong effects on their habitats and resources. Deer, small mammals and birds play an important role in the dynamics of tick-borne zoonotic diseases. It is, however, relatively underexplored how the abundance and composition of vertebrate communities may affect the outbreak potential, maintenance and circulation of tick-borne pathogens. In this study we focus on the outbreak potential by exploring how the basic reproduction number R0for different tick-borne pathogens depends on host community composition. We used published data on co-varying roe deer (Capreolus capreolus) and fallow deer (Dama dama) densities following a hunting ban, and different small mammal and bird densities, to investigate how the change in host community influences the R0of four tick-borne pathogens: one non-zoonotic, namely Anaplasma phagocytophilumecotype 2, and three zoonotic, namely A. phagocytophilumecotype 1, Borrelia afzeliiand Borrelia garinii. We calculated R0using a next generation matrix approach, and used elasticities to quantify the contributions to R0of the different groups of host species. The value of R0for A. phagocytophilumecotype 1 was higher with high fallow deer density and low roe deer density, while it was the other way round for A. phagocytophilumecotype 2. For B. afzelii, R0was mostly related to the density of small mammals and for B. gariniiit was mostly determined by bird density. Our results show that the effect of species composition is substantial in the outbreak potential of tick-borne pathogens. This implies that also management actions that change this composition, can (indirectly and unintentionally) affect the outbreak potential of tick-borne diseases. |
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