# The effect of predation on the dynamics of Chronic Wasting Disease in deer

## TL;DR

This paper models the spread of Chronic Wasting Disease in deer and explores how predation by wolves and population control measures can effectively limit disease transmission, providing analytical and simulation insights.

## Contribution

It introduces a bifurcation analysis of CWD dynamics and evaluates wolves as a biological control strategy through modified Gillespie simulations.

## Key findings

- Wolves can effectively reduce CWD spread in cervid populations.
- Population control measures like hunting aid in disease management.
- Analytical probabilities of disease spread and elimination are provided.

## Abstract

Chronic Wasting Disease (CWD) is a neurological disease impacting deer, elk, moose, and other cervid populations and is caused by a misfolded protein known as a prion. CWD is difficult to control due to the persistence of prions in the environment. Prions can remain infectious for more than a decade and have been found in soil as well as other environmental vectors, such as ticks and plants. Here, we provide a bifurcation analysis of a mathematical model of CWD spread in a cervid population, and use a modification of the Gillespie algorithm to explore if wolves can be used as an ecological control strategy to limit the spread of the disease in several relevant scenarios. We then analytically compute the probability that the disease spreads given one infected member enters a fully healthy population and the probability of elimination, given a fully susceptible population and remaining prions in the environment. From our analysis, we conclude that wolves can be used as an effective control strategy to limit the spread of CWD in cervid populations, and hunting or other means of lowering the susceptible population are beneficial to controlling the spread of CWD, although it is important to note that inferring biologically relevant parameters from the existing data is an ongoing challenge for this system.