A world without parasites: exploring the hidden ecology of infection

Parasites have historically been considered a scourge, deserving of annihilation. Although parasite eradications rank among humanity's greatest achievements, new research is shedding light on the collateral effects of parasite loss. Here, we explore a "world without parasites": a thought experiment for illuminating the ecological roles that parasites play in ecosystems. While there is robust evidence for the effects of parasites on host individuals (eg affecting host vital rates), this exercise highlights how little we know about the influence of parasites on communities and ecosystems (eg altering energy flow through food webs). We present hypotheses for novel, interesting, and general effects of parasites. These hypotheses are largely untested, and should be considered a springboard for future research. While many uncertainties exist, the available evidence suggests that a world without parasites would be very different from the world we know, with effects extending from host individuals to populations, communities, and even ecosystems.

A Community-Ecology Framework for Understanding Vector and Vector-Borne Disease Dynamics

The integration of community ecology into the understanding and management of vectors and vector-borne diseases has largely occurred only recently. This compendium examines a variety of community interactions that can affect vector or vector-borne disease dynamics. They include: the importance of risk of predation, risk of ectoparasatism, competition, interactions of competition with transgenic control, apparent competition mediated through vectors, indirect effects of pesticides, vector diversity, and parasite diversity within a vector. In this paper, we summarize these studies and introduce several additional important questions in need of further exploration.