Abstract:

Emerging infectious diseases, most of which are zoonoses involving multiple host species, have been increasing at an unprecedented rate during the last 50 years. These diseases impact both public health, animal husbandry, and wildlife conservation. Generally, species vary considerably in their competence for transmitting pathogens, thus the host community composition can potentially influence the pathogen transmission dynamics and disease risk. The relationships between host diversity, as the most important index for host community composition, and disease risk (i.e. the diversity-disease relationships) is an important topic in disease ecology. Particularly, the dilution effect (i.e. increased host diversity can reduce disease risk) has attracted wide attention. While the dilution effect hypothesis has been supported by many empirical studies, its generality is still under active debates. In this article, we introduce the mechanisms underlying the dilution effect, and the prerequisites for its generality. We then reviewed the research progress on the diversity-disease relationship in three directions: ① the scale-dependence of the dilution effect; ② the relationship between species’ reservoir competence and local extinction risk; and ③ the identity effect of host diversity. In addition, we also summarized the current extension of the diversity-disease relationships: from species diversity to phylogenetic diversity, and from the risk of single disease to the disease burden. Finally, we consider that the future studies should try to explore the effects of habitat fragmentation, non-host, and community functional diversity on the diversity-disease relationships.

Key words: emerging infectious diseases, diversity-disease relationship, dilution effect, phylogenetic diversity, disease burden