Deer all over North America are dying due to a mysterious disease that slowly renders the animals’ nervous systems useless.
Scientists are really worried that the infection could find its way to humans.
Chronic wasting disease — also known as “zombie deer disease” — was initially discovered in 1967 in Fort Collins, Colorado, and since then had infected wild herds in 24 states and Canada, also in South Korea and Norway, NPR reported.
“CWD transmits from animal to animal via prions, misfolded proteins that cause other proteins to misfold around them,” NPR reported. “Many prion diseases don’t tend to just harm specific species, but also evolve to overcome those limitations.”
In some herds, up to half of the animals are prions carriers.
However, direct contact is not the only way prions transmit. According to The New York Times, ill animals and cadavers are liable to spread prions via plants and soil, which may be covered with deformed proteins for many years, perhaps even more than 10 years.
An infected animal can live 2 years before showing symptoms — such as a vacant stare, thick saliva, ribs showing or drooping heads — all which become apparent.
So far, no human illnesses as a result of the disease has been reported, and scientists do not have conclusive proof that infected meat has ever be harmful to people, suggesting there exist a “species barrier” between humans and deer.
Researchers led by Mark Zabel, an associate director at Colorado State University’s Prion Research Center, discovered macaque monkeys who had eaten infected deer got infected with the disease, that’s the first time the disease was proven to get transmited to a primate through meat.
“While most research show a huge species barrier, this current study prove otherwise and that barrier may not be as huge as we once thought,” Matt Dunfee, head of the Chronic Wasting Disease Alliancein Fort Collins, Colorado, told NPR.
Zabel and his team also discovered the prions found in the “zombie disease,” which scientists are aware of for about 50 years, are perhaps still changing, “which leads us believing it’s just a matter of time before a prion emerges to spread to humans,” NPR reported.
Picking an example, Mad cow disease, is a prion disease that changed from scrapie, a deadly disease that infect sheep. Immediately the prions were transmitted to cows, the cows grows a prion disease of their own (mad cow disease).
And when humans ate the beef from those infected cows, they generate prions in their own brains. As at 2016, according to the Food and Drug Administration, 231 people died from this condition.
Zabel feels the only way to eradicate CWD prions is to set controlled fires. But “there is a lot that are still unknown and not understood about the disease,” Zabel said in an interview with The New York Times.
According to Michael Miller, senior wildlife veterinarian for Colorado Parks and Wildlife, mule deer transmission tripled towards the end of 2017, and CWD continues to prevail in Colorado.
Public health workers in the area have been controlling for CWD and human brain-wasting diseases, like Creutzfeldt-Jakob disease.
However, since the past 21 years, growing rates of both diseases have not influenced human health. This pop up to a question, how close are scientists are to the cure or vaccine?
Yet, as a precaution, Dunfee told NPR, “if you hunt in a region where CWD is found, ensure your animal is tested. If it turns out positive, do not eat the meat.”
Read more about Prion Ecology here