The dynamics of parasite incidence across host species

摘要

Whilst it is well known that many parasites occasionally switch from one host species to another and thus spread within a host clade, the patterns of spread and the observed heterogeneity in parasite incidence between host taxa are not well understood. Here, we develop a simple stochastic model as a first attempt to understand these 'incidence dynamics'. Based on the empirically supported assumption that the probability of successful transmission from an infected to a new host species declines with increasing genetic distance between them, we study the impact of different phylogenetic histories of the host clade on the pattern of spread and the average incidence of the parasites. Our results suggest that host phylogeny alone can lead to heterogeneous parasite incidence.