•The fuel which science runs on is ignorance – there are always more mysteries to solve.
• Scrapie is an incurable disease that affects sheep, causing symptoms of lunacy and eventual death.
• For many years, the cause of scrapie remained a mystery to scientists. It was eventually determined that the disease was transmissible, but its origins remained unknown.
• In 1962, one scientist suggested that scrapie might be an inherited and transmissible disease – an idea which was met with resistance from the scientific community.
• By studying a similar brain-wasting disease affecting people in Papua New Guinea, it was finally determined that scrapie (and by extension other similar diseases) could indeed be passed down through generations via infected meat
•Kuru is a disease that was common among women and children in New Guinea and appeared among relatives of victims, married relations, and blood relatives.
• Robert Klitzman identified three clusters of deaths which included only those who attended certain funerals of kuru victims in the 1940s and 1950s.
• If kuru was a form of scrapie, then it should be possible to transmit it from people to animals by direct injection into the brain. In 1962 his colleague, Joe Gibbs, began a long series of experiments to try to infect chimpanzees and monkeys with kuru from the brains of dead Fore people.
• The first two chimpanzees sickened and died within two years of the injections with symptoms like those of kuru victims. Their symptoms were like those of kuru victims.
•Stanley Prusiner won a Nobel prize for his theory that prions, which are proteins with the ability to resist digestion by enzymes, cause scrapie-like diseases.
• Prions have the capacity to change the shape of other normal prions into versions of itself.
• The different symptoms of different prion diseases result from the erosion of different parts of the brain.
• Science has been able to determine that there is a species barrier between transmission of disease between mice and hamsters, for example.
• What is not known about prion disease includes: why there is a species barrier; how does the gene change its strain as it moves through a new species; why does onset seem dose-dependent?
•In the late 1970s or early 1980s, British manufacturers of processed cattle food began to incorporate misshapen prions into their product.
• This led to the first cases of ‘mad-cow disease’ in 1986.
• By 1992, the cattle problem was effectively solved, although the peak of the epidemic was still to come because of the five-year lag between infection and symptoms.
• In 1996, it was announced that ten people had died of a form of prion disease that looked suspiciously as if it had been transmitted from beef during the dangerous period.
• The government ordered a ‘selective cull’of 100,000 more cattle in 1997.
• As I write [the author’s note], it is still uncertain how many people will die of ‘new-variant’ CJD.
•CJD is a disease that kills many people every year, and its cause is still unknown.
• Some experts believe that the disease is caused by beef products, while others believe it’s just random chance.
• Prions are self-replicating molecules that don’t use DNA, and they can cause serious diseases like CJD.