The term “chronic wasting disease” is daunting, even if you aren’t aware of the symptoms behind the condition. “Wasting” can conjure up a mental picture of patients wasting away. Similarly, “chronic” implies long-term victim suffering without any opportunity for a cure.
So, what exactly is chronic wasting disease and is the fear behind it warranted?
The Science Behind Chronic Wasting Disease
When you take a look at the scientific facts behind chronic wasting disease (CWD), the outlook is grim. Found in members of the deer family, CWS causes degeneration of the animal’s brain tissue over time, resulting in aberrant behavior, drastic wasting away of the body, a complete loss of bodily functions, and eventual death. The change in appearance and behavior is such that some people even refer to CWS as “zombie deer disease.”
Recently, Professor Debbie McKenzie of the University of Alberta, Canada’s Department of Biological Sciences, presented an online lecture for the Center for Infectious Diseases and Policy at the University of Minnesota. In it, she revealed some truly alarming facts about CWD:
1. CWD Prions Are Contagious
CWD is what’s known as a transmissible spongiform encephalopathy (TSE) – a progressive, neurodegenerative disorder that causes changes in the spongiform grey matter of the brain and its associated neurons. Researchers believe CWD and other TSEs are caused by prions – pathogens that not only disrupt the normal protein folding that is crucial to everyday bodily chemistry reactions, but they can also cause erroneous or misfolding. Protein stability plays a key part in understanding the molecular basis of different diseases. When certain brain proteins misfold in the presence of CWD prions, the zombie-like stumbling, wandering, and drastic weight loss occurs until death inevitably claims the animal.
2. CWD Changes and Adapts
One of Professor McKenzie’s primary revelations about CWD during the University of Minnesota lecture is that researchers believe CWD prions can change over time and modify themselves to more drastically affect the animal and to infect related animals. For instance, a prion found prevalently in a mule deer can alter itself over time for transmission to closely related deer of other species. As prion proteins continue this brand of self-genetic variation, they can infect more and more animals of various species.
3. CWD Presence Increases Over Time
Professor McKenzie warns that over time, CWD presence will increase. That is, the longer the disease persists in the wild, the larger the increase in the infection rate in its hosts. The prion is released in the various bodily excretions of an infected animal and can then enter the soil and water supplies where it remains infectious. It can then be ingested by other animals, which is a great indicator that cases of CWD will continue to increase over time.
Scary Implications for Humans
Professor McKenzie maintains that while the unknown barrier that has thus far prevented this disease from making the jump to humans seems formidable, she fears such a jump could occur at some point in the future. CWD is constantly changing and would likely have a much longer incubation period in humans, resulting in a critical loss in research time once the prion learns how to infect humans. More research is needed to identify the specific mechanisms preventing CWD’s spread to humans, as well as the method by which infectious prions reproduce. Through a comprehensive protein analysis, it is hoped that additional information can be used to contain this alarming disease.