Most Americans have heard of ebola, anthrax and the Spanish flu, all of which are deadly pathogens that have killed millions of people over the decades.
However, there are some diseases caused by toxins that are not so well-known, yet have the capacity to sicken and kill both people and animals in great numbers.
Prions, which are misshapen proteins, are toxins that can pose a serious health risk to humans, cervids (deer, elk and moose) and also to livestock where, in cattle, they manifest as mad cow disease (BSE).
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It seems we are currently faced with an emerging challenge to our North American deer, elk and moose herds from such a prion-based disease.
The prion infections in deer, elk and moose (“cervids” collectively) are causing chronic wasting disease (CWD), a very serious illness that can kill. And recent experiments with monkeys suggest it may be communicable to humans.
If livestock are co-mingled with cervids grazing upon infected grasses and brush (suspected prion vectors), it may only be a matter of time before prions start moving from cervids and their grazing environments into our livestock. In fact, one of the world’s leading scientific investigators into prion infections wants to start burning grasses to eliminate suspected grass-borne vectors of CWD, according to the New York Times.
In addition to potentially affecting the $10 billion annual hunting industry in America, CWD and infectious prion diseases certainly have the potential to devastate the livestock industry. Prions are the infectious agents that can manifest as mad cow disease in cattle and “scrapies” in sheep.
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Prions are particularly worrisome compared to bacteria and viruses because there is no known effective treatment for them and because they can be transmitted into animals from contaminated grasses and brush by ingestion. They can also be potentially transmitted between animals via contact with other environmental vectors. In the environment, prions can remain infectious for long periods of time compared to some bacteria and viruses.
The fact that we currently have very little surveillance data (in most geographical areas none) as to the scope and level of infection already present in America and its cervid herds makes the problem even more serious.
According to Dr. Mark Zabel, there is very little data on which locations across America may be CWD enzootic-areas!
We really have no idea to what extent CWD is present in local and West Coast cervids and in the grazing environments in and around our forests. And there are already deer and elk that arguably show symptoms of CWD around the Western states.
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Dr. Zabel told me that the symptoms of prion disease can easily be mistaken for other causes, such as selenium deficiency. And given the complexity of the diagnoses and limited laboratory facilities able to make such diagnoses, prion diseases can be easily overlooked, allowing them to extend into other animal populations.
According to a Scientific American article, misdiagnoses of prion-involved disease in humans may be more widespread than previously believed:
In the human form of mad cow disease, called Creutzfeldt-Jakob, a person’s brain deteriorates — literally developing holes that cause rapidly progressing dementia. The condition is fatal within one year in 90 percent of cases. The culprits behind the disease are prions — misfolded proteins that can induce normal proteins around them to also misfold and accumulate. Scientists have known that these self-propagating, pathological proteins cause some rare brain disorders, such as kuru in Papua New Guinea. But growing evidence suggests that prions are at play in many, if not all, neurodegenerative disorders, including Alzheimer’s, Huntington’s and Parkinson’s, also marked by aggregations of malformed proteins.
Also, a recent article published in USA Today’s Wisconsin Farmer discussed another disturbing study about prions and CWD:
Three of five macaques that were fed infected white-tailed deer meat over a three-year period tested positive for CWD.The meat fed to the macaques represented the human equivalent of eating a seven-ounce steak per month.
It is quite important to note that among large North American herbivores, wild horses and American native species are uniquely immune to prions, arguably through some evolutionary process here in America which we do not yet understand.
And by abating grasses and brush (each horse consuming 30 pounds of dry grass and brush daily), one of the suspected prion vectors, wild horses can meaningfully reduce environmental prions affecting other grazing animals, including cervids. This is important because the rate of infection for this prion disease is believed to be dose-related. Such grazing by wild horses also has the added benefit of reducing the fuels (grass and brush) for catastrophic wildfires.
In light of this, the Bureau of Land Management’s notion of removing even more wild horses from public lands to increase and extend grazing areas for cattle and sheep into known grazing areas where cervids are present, such a move is clearly a “bad idea” according to Dr. Zabel.
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Grazing livestock in proximity to cervids may subject cattle and sheep to prion infections, which may initially be very difficult to perceive or diagnose short of a laboratory analysis, and potentially thereafter, infecting humans that have ingested the meat of any infected animals.
However, I defer to one of the world’s leading experts on the subject, Dr. Zabel, who addressed that concern via the email thread below in which I ask him about co-mingling cattle and sheep in areas grazed by cervids:
Sorry I missed you. I was collecting samples in the backcountry in RMNP. You are absolutely right and I would strongly discourage any cattle from grazing in CWD endemic areas. Really short-sighted and bad idea until we know further how prions jump species barriers. Cattle ranchers would not like the bad publicity if the media and beef consumers found out that cattle are mingling with cervids, especially in confirmed CWD enzoonitc areas.
Hope this helps,
On Jul 12, 2017, at 21:16, Capt. William E. Simpson wrote:
If you can find the time, I think we should have a discussion about how involved you and/or your team would like to be in studying a deployment of wild horses into an ecosystem alongside cervids. And if so, it may be important to survey the existing animals in the area(s) before the horses are deployed in developing some baseline data.
You’re the expert so you’ll have to tell me, but it seems logical that there may be some vector/biological path from the prions causing CWD in cervids to potentially infect livestock via some form of transmission, possibly from cattle and sheep being on grazing lands and sharing water sources with infected cervids? The cattle industry cannot afford any further BSE or similar out breaks (one sick cow with ‘mad-cow shuts the industry down), and they are pushing the USFS hard to graze more cattle in immediate proximity to cervids, sharing grazing and water sources. I think that may be unwise until completed surveys have been conducted and pathways for transmission have been fully explored.
From my relatively ignorant perspective on potential transmission paths, it seems reasonable to think that the cattle/sheep industry would;
1. Want to avoid grazing cattle and sheep in close proximity to cervids, at least or until cervid populations could be surveyed for prions and rates of infection; and,
2. Begin the study of equids and cervids co-existing in an ecosystem to determine what aspect of the evolutionary mutualism has and may continue to benefit cervids through equid mutualism, and possibly determine what mechanism led to the horse’s acquired an immunity to the prions…and if there is a potential cure that can be applied; gene therapy… epigenetic path to resistance?
The USFS, BLM and the Cattle industry might be inclined to help fund such surveys and studies for the obvious reasons…
Now, there are fewer than 100,000 American wild horses in total. Fifty thousand of those wild horses are ranging free in America. However, Interior Secretary Ryan Zinke is considering sending the balance of all the remaining American wild horses at the BLM corrals, about 40,000 horses to slaughterhouses. We seem to be facing a very serious time-sensitive issue where the BLM is considering slaughtering — soon — the only known cost-effective solution to a potential problem with a national scope, this emerging prion problem.
So what happens if Secretary Zinke allows slaughter of the only animals that can cost-effectively abate the prion vectors in the wilderness and forest lands of the BLM and Forestry Service? Who knows? But on its face, I think it has disaster written all over it. It reminds me of a forester who told me that “BLM” stands for “Bureau of Large Mistakes.”
Killing the only potential natural and readily available solution to a couple of very serious emerging problems seems like the “bad idea” of all time to me!
Let’s examine the benefits of harnessing the natural abilities of wild horses to once again serve mankind, by using them instead of killing them:
- Releasing the 40,000-plus wild horses from BLM corrals into selected wilderness areas where there are no current livestock grazing permits saves the BLM about $50 million annually in costs related to keeping the horses corralled.
- Mitigating wildfire fuels saves the insurance industry hundreds of millions annually in losses as a small fraction of their current multi-billion-dollar losses.
- Less fuel means less fire, and less fire means less fire-suppression costs to the Forestry Service, which spends half of their budget on fires, and savings to USFS and BLM-DOI translates to taxpayer savings.
- Grass and brush abatement by wild horses (immune to prions) may alter prion disease vectors and prevent introduction into game animals (deer-elk-moose) that are now succumbing to the prion-caused chronic wasting disease, which is great news for hunting lobbies ($10 billion annually).
- Having the immune wild horses abate excess grasses and brush may also may provide some fire-walling against transmission of emerging prion diseases into domestic livestock herds from deer and elk, which may in turn potentially inhibit prions from infecting humans.
- Releasing wild horses back into the wilderness and creating a pilot program to study their affect on CWD may also lead to some insights and methodologies for protecting livestock and cervids long-term.
- Last but not least, Wild horses and burros provide highly beneficial symbiotic mutualisms to all of their historical ecosystems and add to the aesthetics and tradition of the American wilderness. This final statement is consistent with the Congressional preamble to the 1971 Wild Burro and Horse Protection Act.THE WILD FREE-ROAMING HORSES AND BURROS ACT OF 1971 (PUBLIC LAW 92-195) §1331. Congressional findings and declaration of policy
Congress finds and declares that wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of the West; that they contribute to the diversity of life forms within the Nation and enrich the lives of the American people; and that these horses and burros are fast disappearing from the American scene. It is the policy of Congress that wild free-roaming horses and burros shall be protected from capture, branding, harassment, or death; and to accomplish this they are to be considered in the area where presently found, as an integral part of the natural system of the public lands.”
Concerned readers should write, email and call their local representatives, state representative and especially DOI Secretary Zinke and Agriculture Secretary Sonny Purdue, and weigh in on the pending decision to slaughter the relatively few remaining wild horses.
Horses have served mankind over the millennia and are a gift from our Creator.
God’s law, which is above man’s law, and which is codified in the Bible, clearly states that eating horses is forbidden, according to Leviticus 11 and Deuteronomy 14.
Eating horses or burros is also forbidden under all other Mosaic laws.
Is it too much to ask that our own government and its agencies do what’s right for everyone for a change? Given the many misinformed and obtuse state and federal policies currently operating, is it just a matter of time before mad cow disease returns?
The views expressed in this opinion article are solely those of their author and are not necessarily either shared or endorsed by the owners of this website.