Chronic Wasting Disease

As the start of the hunting season for deer and elk approaches (general, not archery), Chronic Wasting Disease becomes increasingly relevant again.

Chronic Wasting Disease is a prion disease, fatal, with no known treatments. While there are no known transmissions to humans, the CDC recommends having elk, deer or moose tested if there’s known to be Chronic Wasting Disease in the area. If the animal tests positive, they recommend against consumption.

For a deer, sampling requires removing the lymph nodes, packaging them, and mailing them to the wildlife health lab in Bozeman. More detailed information about having an animal tested can be found here. Expect results to take about three weeks. A map of where Chronic Wasting Disease has been found in the state is here.

Prion diseases are in something of a unique category. A bacterial or fungal infection can usually be treated with an antibiotic or an antifungal medication. Both a bacteria and fungi are living things, made of cells the same way we are. Kill the cell, kill the organism, stop the infection. While antibiotic resistances can complicate the matter, the end objective is still fairly straightforward.

Viruses, such as the one that causes the flu, are more complicated. By the basic definition of “living thing” we teach to gradeschoolers, viruses are not living. We teach students that all livings things have cells. A virus doesn’t. A virus is not a cell, rather, it is a rogue piece of DNA, of the code of instructions that is at the heart of each cell. It inserts itself into the cell, and, not unlike a computer virus, takes it over and uses the cell to make and distribute copies of itself. How do you kill something that is not alive?

Antivirals are the classic treatment for viral infections, such as the flu, HIV, cold and cold sores. They don’t kill the virus, but they do decrease its ability to spread, which reduces the severity of the infection. Because the only way to eliminate a virus is to eliminate all of the cells its infecting, viral infections in long-lived cells are pretty much permanent (cold sores are an excellent example of this).

Prions are like viruses. They are larger, made up of proteins instead of DNA. Functionally, though, they are very similar. They warp other, similar proteins, until they take the same shape as the prion. Prions build up in neural tissue, that is in the brain and spinal column. While an animal with Chronic Wasting Disease will have prions throughout its body, the reason the disease is fatal is the build up in the brain.

There is no prion equivalent to antiviral medications. While there’s some promising research, prions and prion diseases are still a relatively recent discovery. Treatment is focused on alleviated symptoms, as prion diseases are currently incurable. Prion diseases are, fortunately, rare.