March 5, 2021

Mad Cow Disease Spreads in Nervous System Before Detection

A new study in the American Journal of Pathology has shown that bovine spongiform encephalopathy (BSE), commonly known as “mad cow” disease”, spreads in the autonomic nervous system (ANS) to the central nervous system (CNS) before it can be detected. Mad cow is a fatal disease in cattle that can be transmitted to humans who eat infected tissue. There isn’t much that scientists know about the spread of the BSE prion in its early incubation period. Other studies have reported that the autonomic nervous system was affected only after the central nervous system is infected.

Cows in FieldThe autonomic nervous system controls involuntary actions, such as heart rate, blood pressure, and the functions of major organs. It consists of the sympathetic ANS, the parasymphathetic ANS, and the enteric nervous system. The central nervous system is the part that controls your brain and makes up your consciousness; it consists of the brain and spinal cord. It usually takes five years from infection before the disease can be detected. But in the study, 56 calves were infected orally with BSE; samples were collected every four months for the next three and a half years. Scientists found the pathological prion (a misfolded protein that is not alive) in the gut and in the ANS but not in the CNS.

Infection was found in the spinal cord of one animal only 16 months after infection. Dr. Martin H. Groschup, one of the study’s authors, said, “the clear involvement of the sympathetic nervous system illustrates that it plays an important role in the pathogenesis of BSE in cattle. Nevertheless, our results also support earlier research that postulated an early parasympathetic route for BSE.”

The study’s authors believe that there are three routes for the BSE prion to get to the brain: sympathetic, parasympathetic, and spinal cord, in order of importance. Knowing how the prion gets to the brain does have food safety implications.


  1. Helane Shields says

    Many news agencies still doesn’t get it – Alzheimer’s Disease (AD) is a prion disease with a US epidemic of 6 million victims-36 million world wide. Creutzfeldt Jakob Disease (CJD) is NOT the only transmissible human prion disease.

    Most prion diseases are acquired by eating infected food. That is why the infection originates in the gut and travels to the brain. Infectious prions can be found in muscle tissue. [Prusiner, et al ]

    BASE Per Robert Bazelle, NBC news, commenting on 4th USA mad cow:

    “Some experiments have shown that this rare disease (BASE) can jump from species to species, infecting lab mice and even non-human primates. The research also suggests that the infectious agent for the rare disease could be more virulent than BSE, more likely to appear in meat (classical BSE is mostly in brain and nervous tissue) and might be carried in milk. “

    However, it should also be noted that the infectious agent, although most highly concentrated in nervous tissue, can be found in virtually all tissues throughout the body, including blood. July 9, 2012

    Aging dairy cows with asymptomatic Bovine Amyloidotic Spongiform Encephalopathy (BASE) are regularly entering US food supply UNTESTED in huge industrial mixing vats of hamburger, each containing meat from 50 to 100 animals from multiple states and two to four countries.
    This is likely the route of human prion disease infection (AD).

    Helane Shields, Alton, NH

  2. Dave Louthan says

    I have always said the idea that you can trim the tonsils and pull the spinal cord and have safe healthy beef left over was a ridiculous notion.

    • Linda Larsen says

      I couldn’t find any info on which tissues scientists think could be “safe”, so I had to leave it at that. Since the autonomic nervous system is ingrained in muscles – who knows?

      • Dave Louthan says

        Well the going splat was they could pick out a few pieces of specified risk material, parts you wouldn’t eat anyhow, and the rest of the animal was healthy. Ridiculous. This will be very inconvenient to the producers if word leaks out. I doubt it will go anywhere though. People do not want to face the diseased cow thing so it is quite easy to lie to them.

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