Could deer “zombie” disease spread to people?
“Deer zombie disease” sounds like part of a line uttered by a distraught lab technician or mad scientist in an especially terrible horror movie. However, this is not something out of a bad horror script, nor is it science fiction. There is indeed a “zombie” disease which affects deer (and could maybe adapt to infect other creatures, including human beings) in our very own, utterly normal, reality.
Chronic wasting disease
The more accurate, less frightening, name scientists have given to this disease is simply “chronic wasting disease” or CWD. The first case of chronic wasting disease was first discovered in the late 1960s at a research facility located in Colorado. Members of a herd of captive mule deer were the first victims of the disease, but it soon was found in individuals among the wild populations of elk and white-tailed deer, as well as other mule deer. Chronic wasting disease is believed to be spread by uninfected animals coming into contact with contaminated urine, blood, saliva, or any other bodily fluids.
The way in which chronic wasting disease spreads is still unknown to scientists, as is the origin of the condition. Even the cause of the symptoms is still being studied, but they are believed to be caused by a prion. Prions are a mishappen form of a normal protein used by a living thing’s body in the regular course of its growth, development, and/or its day-to-day life. Proteins are one of the basic building blocks of a body, so any disease which affects them can be incredibly dangerous. Prion-caused conditions are rare and extremely hard to treat, with scientists only starting to make headway in recent years into creating treatments in the few prion diseases which affect people.
Chronic wasting disease is considered to be an “always fatal” condition. Every deer that suffers from the “deer zombie disease” dies from it unless something else kills it first (and even then, the degenerative effects of the disease probably played a role in its death). Chronic wasting disease is classified by scientists as a transmissible spongiform encephalopathy, one of only twelve known diseases of this type (including “mad cow disease”). Transmissible spongiform encephalopathies are characterized by being caused by prions and affecting the brains of the sufferers, often leading to many small holes forming throughout the cortex of their brain, giving it a “spongy” look. This is one reason why such diseases are sometimes nicknamed “zombie” diseases.
Deer who have chronic wasting disease go through a long, slow deterioration. The first symptoms noticeable in an infected deer are difficulties coordinating movement. The individual will lose weight in a chronic, unstoppable manner. Some deer salivate and urinate excessively, which may help to increase the spread of the disease. Nearly all cases of chronic wasting disease also entail behavioral changes in the suffering deer as their brains become full of holes. These behavioral issues may include decreased socialization with other animals, unusual lowering of the head, listlessness, heightened nervousness, tremors, and repetitive patterns of movement. There is no cure known for the condition, nor do scientists have any preventative measures beyond isolating or killing infected individuals.
Potential for a zombie apocalypse?
As of today, there have not been any cases of chronic wasting disease spreading to human beings. However, scientists continue to warn officials and the public that there is the possibility of the condition spreading to people through the consumption of contaminated meat. The risks of this happening are somewhat highlighted by the panic over “mad cow disease” spreading to humans in a similar fashion just a few years ago.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, met with lawmakers in Minnesota earlier this year to warn them about the dangers of chronic wasting disease. Osterholm informed them that it is quite likely we will have documented cases of chronic wasting disease in humans in the next few years and that it is even possible such cases will not stay isolated but could become part of an epidemic.
Chronic wasting disease has now been discovered in 24 of the 50 United States, as well as in Northern Europe, Canada, and possibly transported to South Korea in elk meant for farming. This means that the disease has footholds in two different continents and potentially a third. If the condition spread to people, it could do so in vast numbers, incredibly quickly.
Some measures have been taken to slow the spread of chronic wasting disease, both in attempt to safeguard the animal populations, as well as to lessen the likelihood (and potential damage) of it spreading to humans. In Northern Carolina, strict regulations have been put into effect for anyone transporting any part of a cervid (the scientific name for the deer family) carcass. Indiana has increased monitoring for the disease, though has not yet made testing mandatory. In areas of Michigan and Illinois where the disease is known to be affecting the deer population, hunters are being asked to bring their kills in for testing.
While no cases of chronic wasting disease have shown in up in humans yet, experts have conducted lab experiments (because that always ends well in zombie movies) to see if the disease could potentially affect us. What they have found is that, in a petri dish, prions from an infected sample from a deer could infect human cells. So, while a zombie apocalypse is not likely, it is not at all impossible.