Deadly Feasts by Richard Rhodes tells the story of a disease class known as Transmissible Spongiform Encephalopies (TSE's).
"Transmissible" since TSE's spread by ingestion of even small amounts of diseased animal tissue, in some forms even from species to species. The agent is a deformed protein acting analogous to a crystal seed, causing the animal's own version of the protein to take its shape. The proteins are found in nerve cells, which Rhodes is clear to point out, are also in the muscle eaten as meat. "Spongiform" because the cell damage creates holes in nerve fibers—they end up looking literally like sponges. "Encephalopy" because the result is a destruction of brain tissues gradually and inevitably leading to death. Because the agent is just a protein, it is very resistant to normal forms of sterilization such as UV radiation and high (well beyond typical cooking) temperatures.
One form of TSE is Bovine Spongiform Encephalopy (BSE), popularly known as "mad cow disease," an ongoing health problem in the UK. This strain was propagated as cows were fed to cows , eventually requiring the destruction of the entire population of some ten million cattle. But due to the negligence (indeed, some say criminal negligence) of the Tory government and the livestock industry, this was not before the disease had begun spreading to humans through the consumption of tainted beef.
In humans, the resulting disease is known as CJD (Creutzfeldt-Jakob Disease). The symptoms start with dizziness and palsy, only slowly moving on to seizures, dementia, then complete loss of muscle control, coma and death. In all TSE variants it is 100% fatal, there is no known cure. Some two dozen in the UK have contracted the BSE-derived disease. However, the incubation period follows a Gaussian (bell-shaped) distribution, with the median measured in decades. Thus, the peak rate of CJD contraction could be 15 or 20 years away, with tens of thousands or (in the most extreme estimates) even hundreds of thousands of cases.
This would be similar to the plague ('Kuru') among the Fore tribes of New Guinea which began in the 1950's, and eventually devastated their population. Woman and children engaged in cannibal funeral rites. Even after (by 1960) being persuaded to give up this practice, elder survivors continue to come down with the disease because of the long incubation times. It is not, however, passed from mother to child through birth.
The obvious question is whether an outbreak could occur in the U.S. Rhodes reports,
[cannibalistic recycling of animals] continues in the United States for the same reason it continues in Britain even as the death count rises: because the meat industry and its allies in government assess the risk differently from the scientists and physicans who know most about the TSE's.Namely, the meat industry thinks we're safe because British livestock have been culled from our herds. Regulation also now compels them to stop the once-common practice of using sick "downer" cows as cow food. However, this does not eliminate the risk, as the parts used for food may be from cattle that did not yet show symptoms of sickness. It also ignores ways the disease is transmissible between species, such as sheep offal (including brains) fed to cattle.
Furthermore, outbreaks in 1963 and 1984 on mink farms fed by downers strongly suggest that there may be a native U.S. form of BSE. If so, it may be only a matter of time before it propagates up the food chain. Rhodes collects evidence that many other mammal species such as oxen and deer can suffer from native TSE strains.
It's strange and remarkable that this fatal flaw exists... a very curious biological phenomenon.