Microbes by Phillip K. Peterson

Author:Phillip K. Peterson
Language: eng
Format: epub
Tags: undefined
Publisher: Prometheus
Published: 2012-08-15T00:00:00+00:00

Variant Creutzfeldt–Jakob Disease (vCJD)

“Conventional people are roused to fury by departure from convention, largely because they regard such departure as a criticism of themselves.”—Bertrand Russell

The vCJD Epidemic

The epidemic of vCJD is one of the most astonishing and baffling of all the emerging infectious diseases. Not only was it caused by a highly controversial pathogen, but it broke the species barrier by jumping from cattle to humans. This was unprecedented for this kind of pathogen.

The cause of vCJD is a pathogenic protein, typically designated PrPSc. In 1982, neurologist and biochemist Stanley Prusiner hypothesized that similar proteins caused scrapie, a transmissible brain disease in sheep. This idea, which was considered scientific heresy at the time, set off a firestorm. His colleagues asked incredulously, How can a protein, without the help of nucleic acid (DNA or RNA), possibly reproduce?

But Prusiner turned out to be right. Vindication came in 1997 when he was awarded the Nobel Prize in Physiology or Medicine for his work on misfolded proteins called prions.[1] (Actually, even today some scientists remain skeptical of Prusiner’s hypothesis. Nonetheless, the evidence strongly supports it.)

Back in the 1980s, many scientific authorities also incorrectly argued that a devastating epidemic of bovine spongiform encephalopathy (BSE) in cattle—that is, mad cow disease—in the United Kingdom posed no threat to humans. That argument ended in 1995 when the outbreak of vCJD began and was quickly linked to BSE.

The first case of BSE in the world developed in 1994 in a cow on a farm in Sussex. As more cases accumulated in England, it became clear that the brain disease was similar to scrapie in sheep. Evidence soon suggested that the disease was spread when meat and bone meal from infected cattle was fed to calves.

Ultimately, the BSE epidemic in the United Kingdom was catastrophic. Between 1986 and 1998, more than 180,000 cattle were infected, and 4.4 million were slaughtered during the eradication program. Not only was this an overwhelming loss of life, but the economic losses to the beef industry, and to many thousands of farmers, were enormous.

Beginning in 1995, the first cases of vCJD in human beings were reported in the UK. As of May 2018, about 260 cases (all fatal) were reported worldwide. Most of the cases (178) occurred in the UK, with the remainder mainly in France (27 cases) and other European countries. Four cases were reported in the United States, two in Canada.

Epidemiological and scientific evidence linked almost all of these cases of vCJD to consumption of cattle products contaminated with the agent of BSE. Three cases in the UK were associated with blood transfusions.

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