Importance of Sequence and Timing in Parasite Coinfections

Coinfections by multiple parasites predominate in the wild. Interactionsbetween parasites can be antagonistic, neutral, or facilitative, and they canhave significant implications for epidemiology, disease dynamics, and evolu-tion of virulence. Coinfections commonly result from sequential exposure ofhosts to different parasites. We argue that the sequential nature of coinfectionsis important for the consequences of infection in both natural and man-madeenvironments. Coinfections accumulate during host lifespan, determining thestructure of the parasite infracommunity. Interactions within the parasite com-munity and their joint effect on the host individual potentially shape evolution ofparasite life-history traits and transmission biology. Overall, sequential coin-fections have the potential to change evolutionary and epidemiological out-comes of host–parasite interactions widely across plant and animal systems.