The Overlooked Science Of Chronic Wasting Disease

By Tom Remington

Chronic Wasting Disease (CWD) is deadly to deer, elk and moose. It is found most prevalently in deer and in particular the mule deer. Nobody of course wants it and not enough is being done to stop it. When you compare the studies done on CWD with other similar diseases, such as mad cow disease, it becomes quite clear that too many assumptions are made about CWD and therefore we have to ask ourselves if the information we are spreading about CWD is accurate and moving us in the right direction.

Wikipedia describes CWD this way.

Most cases of CWD occur in adult animals. The disease is progressive and always fatal. The most obvious and consistent clinical sign of CWD is weight loss over time. Behavioral changes also occur in the majority of cases, including decreased interactions with other animals, listlessness, lowering of the head, blank facial expression, and repetitive walking in set patterns. In elk, behavioral changes may also include hyperexcitability and nervousness. Affected animals continue to eat grain but may show decreased interest in hay. Excessive salivation and grinding of the teeth also are observed. Most deer show increased drinking and urination.

As I said a moment ago, we may be assuming too much and not paying close enough attention to what is actually taking place around us. One of the most common practices used by officials in attempts to limit or eradicate CWD from areas known to be infested is the systematic slaughter of infected animals. It is believed that by locating diseased animals and killing them off, will reduced and eventually eliminate the spread of the disease. But is this working?

Back last March, the Colorado Division of Wildlife announced it was going to end its practice of culling CWD infected deer and elk herds.

The DOW, with the guidance of Mike Miller, the agency’s leading scientist on CWD, had targeted areas where the disease seemed more prevalent and killed off many of the deer and elk in those herds believing this would slow or stop the spread of the disease. Now that a few years have passed and data has been collected, there is no significant information that says it did any good.

Colorado was one of the first states to identify CWD in its deer and elk and when they began a program of culling its herds, other states followed suit as they discovered the presence of the disease, assuming Colorado was doing the right thing. This has become part of the problem in dealing with this disease. Without sounding disrespectful to the scientists working on this problem, it sometimes appears as a case of the blind leading the blind.

Good science will not depend on assumptions. All aspects and studies must be considered in making judgments. Without the resources to fully study every angle of this disease, too often we just rely on what the other guy is doing and saying and assuming they might be right. Where would we be today if this attitude was commonplace among scientists?

When you combine assumption with the unfortunate reality that CWD has become a political tool and weapon, then science gets a back seat. Like with any political issue, those involved tend to pick and choose “facts” that support their agenda. While this may achieve some kind of political end result for those playing the game, it does absolutely nothing to combat the deadly disease.

I will almost guarantee that if you sat down in a room full of people who have some knowledge of CWD, eventually the conversation will come around to how the disease started and how it is spread. I can almost for certainty guarantee that the fingers will be pointed at domestic elk and deer ranches and it is understandable why these people would say that. It’s what they have been told and read about for years.

Before anyone goes painting a picture here that I am an expert trying to persuade people that I know what’s going on, let me explain one thing. I’m not a scientist but I am a logically thinking person. I understand the importance of considering all aspects of any issue and that’s all I’m asking readers to do. If you care about CWD, as most people indicate they do, then wouldn’t it seem too that you would really want to find a cure for CWD? Isn’t it also intelligent thinking to consider every angle before rendering a final decision? To do this, we have to leave politics out.

We must first take a look at how CWD was discovered initially and the steps taken that showed where geographically CWD has appeared since. CWD was first discovered in a research facility in Colorado in the late 1960s. To be fair, it has never been determined how the infected deer became that way. Once again assumptions were made.

As scientists began to learn how to recognize the outward signs of CWD, they also discovered more about the disease and how to test animals to determine if they were infected. Of course we know that the only way presently to positively test an animal for CWD is to first kill it because the test involves examination of the brain.

From this very moment in time, it has been assumed that CWD is formed only in enclosed facilities such as this lab in Colorado or places like livestock ranches. But is this actually true?

One study that has been pretty much disregarded in the debate about CWD was conducted by the Colorado Division of Wildlife Wildlife Research Center. The first most important part of their study report indicates that CWD occurs naturally.

Surveillance and epidemic modeling were used to study chronic wasting disease (CWD), a transmissible spongiform encephalopathy that occurs naturally among sympatric, free-ranging deer (Odocoileus spp.) and Rocky Mountain elk (Cervus elaphus nelsoni) populations in contiguous portions of northeastern Colorado and southeastern Wyoming (USA).

What this is saying is that according to the models they used, they concluded that this disease that can be transmitted from one deer to another, happens naturally among free-ranging deer and elk. If this is true, then why do we want to continually focus our blame on penned livestock ranches?

The second very important part of the report is the conclusions made by the study group.

Both field and model data supported the importance of lateral transmission in CWD dynamics. Based on prevalence, spatial distribution, and modeling, we suggest CWD has been occurring in northeastern Colorado and southeastern Wyoming for >30 yr, and may be best represented as an epizootic with a protracted time-scale.

This study was completed in 2000 and they determined that CWD has been around for more than 30 years. This of course would support the information that CWD was first recognized in a lab in Colorado in the late 1960s. Epizootic means that the disease occurs in large numbers of deer and elk simultaneously and protracted describes this as being something this is extended out over a long period of time. In other words, CWD doesn’t appear this year and then is gone the next.

Just from this information we could conclude that 1). the disease occurs naturally among deer and elk; 2). CWD is transmitted from one deer or elk to another deer or elk; 3). the disease occurs in several animals at one time over an extended period of time.

One thing we must remember in debating CWD. The disease was not discovered through testing wild and free-ranging deer and elk. We can also determine that CWD was never discovered until it was found in a lab in Colorado in the 1960s. Can we fairly conclude that CWD was born in the 1960s in a lab in Colorado?

According to this one study, the disease occurs naturally. Unless science can show that the first time the disease ever existed was in this lab, then we can conclude one of two things. Either the disease occurred naturally at that time in that lab or it occurred naturally in other deer living near the facility and it was transmitted to the laboratory animals.

Testing for CWD never began on wild animals until sometime later, after the discovery of the disease. In some states, random testing of deer and elk are still not done on game harvested by hunters. In states that have domestic elk and deer ranches, most of them have a very good system of testing animals to track any presence of disease. In Idaho for example, every domestic elk that is killed must be tested for CWD. To date, no CWD has ever been present in its animals.

So why do we want to blame the domestic ranches for the cause and spread of CWD? Probably because we have been told repeatedly that this is where the disease always shows up. Well, this is true because this is the first place the animals were tested for the disease. Once discovered in some of the facilities, then and only then, did officials begin testing wild animals in and around those facilities. When those results came back positive in some cases, we were quick to blame the ranchers when in reality we could have just as easily pointed the finger at the naturally occurring CWD in wild and free-ranging elk and deer. Often times those who wish to blame domestic ranches for the spread of CWD, toss out maps and figures that show that CWD has been found in free-ranging deer and elk next to deer and elk ranches. This actually proves nothing. Once again it only shows that once the disease was found at the ranch, testing began outside the ranch.

Of course the finger pointing at the rancher becomes that much easier when politics rears its ugly head. Some of these ranches offer hunting opportunities which doesn’t sit well with hunters concerned about fair chase and that’s understandable. But when these individuals and groups decide they want to legislate fair chase, the gloves come off and seldom does the general public get the truth.

I’m not saying that CWD first came from free-ranging deer and elk nor am I going to say it comes from domestic deer and elk. The information that we have is available to everyone and we can make our own conclusions. Before we make those conclusions, we should consider ALL information available, that is, if we are really concerned about the disease more than our personal agendas.

Tom Remington