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Researchers: Wolves Might Slow Spread of CWD
William G. Davis writes "According to this AP article, researchers are now suggesting that wolves might be able to slow the spread of chronic wasting disease (CWD) in deer. Chronic wasting disease is the name commonly given to spongiform encephalopathy (prion disease) in deer and elk (basically, mad cow disease in deer). The article explains how wolves typically look for weaknesses in their prey, and since prion disease causes that, wolves might target the sick animals. One has to wonder, though, about the potential ramifications of having dangerous predators exposed to this brain-wasting illness, and what type of 'unusual behavior' they'll start to exhibit."
Being at the top of the food chain doesn't stop your corpse being eaten by scavengers, does it?
I had understood that "Mad Cow" is only transmitted by eating the brains of an infected animal. Ranched cattle would acquire it as they are sometimes feed the brains of previously slaughtered cattle, but how exactly do deer and other wildlife transmit it?
Is there another transmission vector, or do deer etc in fact eat the brains of their own dead?
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I'd guess any wolf that began to have symptoms of such a serious disease would simply starve to death in fairly short order
True. And there's lots of literature supporting the idea that predators and scavengers tend to have very good defenses against the diseases that affect their prey. Part of the defenses are powerful digestive systems that leave few cells intact and chop up most proteins and DNA into small pieces. They also have some of the best immune systems on the planet.
The explanation is fairly simple. If you're a predator or scavenger, you often eat food that was weakened or killed by disease. This puts strong selective pressure on your species in favor of defenses against those diseases.
I've read a couple of articles on the semi-exception that the top predator on the planet (Homo sap) seems to be a partial exception. This is generally explained as an artifact of our recent conversion to predation. We do have some predator adaptations, but we haven't had time to evolve them fully.
There is a bit of debate about this, though. For example, studies of wild chimp populations haved turned up data showing that they actually do get a significant part of their protein by eating small animals. So our predatory ancestry probably goes back at least 5 million years. But still, we are primates, and it wasn't all that long ago that our ancestors were vegetarians.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Curing a single kind of prionic disease requires creating a substance that catalyzes a reverse transformation from the variant (prionic) protein form to the normal protein form. Since the original transformation is possible, the reverse transformation is surely also possible, and can probably be made energetically favorable with the right kind of agents. While it may be easier to describe than to implement, I still think it sounds a lot easier than curing cancer, and not out of reach of current biotechnology research.
There is an interesting twist on this with Komodo Dragons. Their mouth is specially designed to trap bits of rotting flesh. This breeds several dozen varieties of bacteria including some of the most virulent and deadly bacteria on earth. Flesh eating necrotizing bacteria, blood-born bacteria causing sepsis, bacteria that knock out the immune system, an entire host of different nasties.
One bite from a Komodo and it's saliva introduces all of these infections at once. A bite victim almost inevitably dies within one to three days. No known antibiotic can cure an established infection.
The exciting part of the story is that Komodo Dragons obviously must have evolved an amazingly powerful defense to all of these bacteria. An expedition was sent to collect some Komodo blood and work is ongoing. They have isolated multiple anti-bacterial compounds and hopefully they will be able to make incredibly powerful new antibiotics available in a few years.
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That estimate is based on the false assumption that any trait present in modern chimps was also present in the common ancestor of chimps and humans. Chimps have evolved as much in the last 5 million years as we have. They may have discovered hunting as recently as we did - it's even possible that they learned to hunt by imitating humans.
CWD is prevalent in ranching areas. I theorize that the deer and elk are eating livestock feed on occasion when the opportunity presents itself - a very common occurance.
Keep in mind that chicken and pork feed use ground up animal protein, including brains of down animals. All approved by the USDA. It is just cattle feed that is not supposed to contain animal protein. In fact in the Washington casem, i would bet that the cow in question at one time dined on swine feed.
Large numbers of dear and elk contact the disease simply because they live long enough for the disease to manifest itself (3 - 5 years)
Comforting is it not?