Chronic Wasting Disease Epidemic Among Deer Populations
Zoonotic diseases are infections that move from animals to people. These diseases are responsible for some of the world’s most deadliest epidemics, including the avian influenza and the plague.
In Wisconsin, an increasing number of deer are being diagnosed with the fatal Chronic Wasting disease. This diseases is always fatal as it causes the spongy degeneration of the infected animal’s brain. There are currently 380 registered commercial deer and elk operations in the state for breeding and hunting. According to state records, there have been 300 CWD-positive tests at 24 of these farms. This number has increased in the past few years as the Department of Agriculture, Trade, and Consumer protection began to let some facilities with animals continue to operate in 2013. As a result, the state’s government has now called for for aggressive new actions against CWD, including enhanced fencing requirements and restriction on deer movement. This disease is important to keep in mind as it not only threatens the state’s overall deer population, but also because it is still unclear whether or not this disease can be passed to humans.
In terms of biological contagion, the transmission of diseases is far too complicated to develop a concrete mechanism for it. Therefore, the random Branching Process Model is often used to determine who will come down with a disease. This is based on two factors: the branching factor (k) or how many people each person meets when potentially infected and the disease’s probability of spread (p). In this case, the state of Wisconsin’s initial actions in allowing these infected facilities to operate has increased CWD’s k factor by allowing a larger number of deer to come into contact with infected deer. This increases the disease’s basic reproduction number R0. However, the state’s proposed actions of fencing in infected deer, if implemented correctly, should reduce this factor once again as the contact between infected and healthy deer is limited.
http://www.startribune.com/disease-on-deer-farms-spreads-as-wisconsin-weakens-controls/501194331/