Aggregation and environmental transmission in Chronic Wasting Disease

Area of Science:

• Epidemiology
• Mathematical Modeling
• Wildlife Disease Ecology

Background:

• Chronic Wasting Disease (CWD) spreads through direct and indirect transmission routes.
• Host social behavior significantly influences disease dynamics.
• Effective CWD management necessitates understanding etiological and behavioral factors.

Purpose of the Study:

• To develop a mathematical model for CWD transmission incorporating direct and indirect routes, and host aggregation.
• To analyze the impact of host behavior and disease parameters on CWD spread.
• To determine the disease elimination threshold.

Main Methods:

• Developed a strategic differential equation model for CWD.
• Incorporated direct and indirect transmission pathways and host aggregation.
• Calculated the basic reproduction number and performed sensitivity analysis using Latin hypercube sampling.

Main Results:

• Identified conditions for the existence of an endemic equilibrium.
• Demonstrated the absence of backward bifurcation and bistability under mild parameter assumptions.
• Found that CWD prevalence decreases with host aggregation.
• Observed that CWD prevalence increases with the environmental lifespan of the infectious agent.

Conclusions:

• The basic reproduction number serves as the disease elimination threshold for CWD.
• Host aggregation is a significant factor in reducing CWD prevalence.
• The environmental persistence of the infectious agent directly correlates with increased disease prevalence.