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    Of Mad Cows, Cannibals, and New Life Forms


    The affected individuals were cannibals. Women in this tribe were the main participants in removing the victims' arms and legs, stripping the muscle, removing the ... well, you get the picture. Either they were ingesting a toxin, which seemed unlikely since the -- there is no delicate way to say this -- people being eaten did not suffer from the malady, or they were ingesting some kind of infectious agent that was inactive in the host.

    So the search was on to find the host. For nearly 30 years, scientists tried identifying the infectious agent and failed, despite using every technique successful in identifying bacteria, viruses, yeast, and other infectious agents. They did finally succeed in identifying something that was infectious, but they couldn't figure out what it was, other than the fact that it seemed to have protein in it.

    This is where things get really interesting. Every living thing has DNA and RNA. Even viruses, the smallest known living things, have at least one of the two, since these acids form the genes that are essential to creating and fostering life on this planet. Scientists fried the infectious agent using ultraviolet rays and ionizing radiation -- in effect destroying the DNA and RNA. The infectious agent survived.

    Imagine an astronomer willing to consider that the Earth has two moons. It was about as heretical for a biologist to consider that there may be a life form with no genes. But that was what the evidence indicated, and so, in the best traditions of science, researchers slogged away for a further 15 years and finally identified the infectious agent -- a protein, nothing more or less. Scientists subjected this protein to several more years of the third degree using enzymes, heat, and all the other techniques that protein detectives use to interrogate their suspects.

    Today, nearly a hundred years after the initial reports, we know what this protein, called a prion, looks like. We also know that it may replicate like a virus by borrowing the equipment it needs from the host. We do not know if this can be called a new life form or not -- that may end up being a debate between scientists and philosophers.

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