Exploring How a Generalist Pathogen and Within-Host Priority Effects Alter the Risk of Being Infected by a Specialist...

Area of Science:

• Ecology
• Epidemiology
• Mathematical Biology

Background:

• Infectious disease risk for a host can be influenced by the presence of other host and pathogen species.
• Indirect interactions between pathogens, both within a single host and across host populations, can modify disease transmission dynamics.

Purpose of the Study:

• To investigate how within-host and between-host pathogen interactions affect a focal host's infection risk.
• To explore the impact of a generalist pathogen and its alternative host on the risk of infection by a specialist pathogen in a focal host.

Main Methods:

• Utilized an SI-type epidemiological model.
• Modeled two host species and two environmentally transmitted pathogens.
• One pathogen was a specialist on the focal host, while the other was a generalist.

Main Results:

• Demonstrated that within-host priority effects influence the production of specialist infectious propagules.
• Identified monotonic, unimodal, and U-shaped relationships between specialist and generalist infectious propagule densities.
• Observed overcompensation in infectious propagule density due to increased host mortality, driven by within-host priority effects.

Conclusions:

• Within-host pathogen interactions, specifically priority effects, play a crucial role in determining a focal host's infection risk.
• The presence of a generalist pathogen and its alternative host can significantly alter the transmission dynamics of a specialist pathogen.
• Understanding these complex interactions is vital for predicting and managing infectious disease spread in multihost-multipathogen systems.