Of Mad Cows, Cannibals, and New Life Forms
Jan. 25, 2001 -- Mad cow disease, kuru, and Creutzfeldt-Jakob disease are all diseases that make the brain degenerate into a spongy mess; they can be transmitted by contact with infected animal or human tissue. Mad cow disease is believed to be carried in feed made of animal by-products and can infect both the cow and the human who eats the cow's meat.
The scary thing is that the meat you eat from your local supermarket or fast-food chain does not necessarily come from an American cow -- or even from one cow, making it possible that contaminated meat from a foreign country could end up on your grill. Even scarier is the fact that there is no good test to detect the agents -- called prions -- that cause the disease.
It is important to realize that even if the worst predictions come true, the number of people who will actually get the disease is likely to be quite small. This is because of the way in which the disease is transmitted and the preventive efforts of governmental agencies worldwide. So while I am concerned about the safety of our food supply, the story here is the story of the prion.
Please deglaze those eyes, and we can begin.
A mysterious disease in Papua New Guinea was reported around the turn of the 20th century but remained largely uninvestigated until the 1950s. Researchers studying the tribes there found that members of one tribe were dying of an unusual brain illness. Initial reports were that the disease commonly infected women, who initially lost their ability to walk and use their hands in a coordinated fashion. Later, they couldn't walk at all, started to lose their speech, had outbursts of laughter, and lost control over their emotions. Patients eventually lost all control over their muscles and died as a matter of course.
People from neighboring tribes, who lived in the same area and came into regular contact with members of the affected tribe, did not get the disease. The scientists looked at differences between the tribes and discovered one big one.
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.