Coinfection Timing Drives Host Population Dynamics through Changes in Virulence.

Area of Science:

• Plant pathology
• Ecology
• Epidemiology

Background:

• Multiple parasite infections (coinfections) are common in nature.
• The order of parasite invasion can influence within-host competition and disease severity.
• The impact of coinfection timing on host population dynamics remains largely unquantified.

Purpose of the Study:

• To investigate the influence of coinfection timing on host population dynamics.
• To determine if simultaneous versus sequential virus infections differentially affect host populations.
• To assess the importance of considering coinfection timing in epidemiological models.

Main Methods:

• Utilized a model system of two viruses infecting barley.
• Compared disease severity and within-host parasite concentrations in simultaneous and sequential infections.
• Developed a susceptible-infected epidemiological model to simulate host population dynamics under different coinfection scenarios.

Main Results:

• Simultaneous virus coinfections were significantly more damaging to barley hosts than sequential coinfections.
• Priority effects influenced within-host parasite concentrations but not transmission parameters.
• Coinfection timing demonstrated a context-dependent effect on projected host population dynamics.

Conclusions:

• Coinfection timing can significantly impact host population dynamics, contrary to previous assumptions.
• Epidemiological models that ignore coinfection timing may overestimate disease impacts.
• Further research is needed to understand the context-specific effects of coinfection timing across diverse host-parasite systems.