Definitions (Food Safety: BSE and cJD)

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BSE and CJD: Definitions

Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease is a brain disease in cattle.

Creutzfeldt–Jakob Disease or CJD is the brain disease in humans (human mad cow disease).  CJD can be variant CJD. This was linked with BSE in the U.K. in 1996 as discussed in the announcement by the Health Minister in March 1996.  CJD can also be sporadic or classical and appears to occur in a random manner.  The incidence of sporadic CJD was 1 in a million or less.  It is possible that the increased incidence of sporadic CJD is linked to BSE.

Chronic Wasting Disease (CWD) is the brain disease in deer, elk and moose.  This group of diseases are TSE’s: Transmissible Spongiform Encephalopathies. This is a general term which covers a range of brain diseases in animals and humans. TSE’s are prion diseases and prions are infectious proteins. These infectious proteins cause disease by crowding in a ‘dense cluster’ outside of brain cells.

Variant CJD could be caused by BSE through beef consumption. BSE has been linked to mechanically recovered meat (MRM). This is a meat product which is made by forcing beef though a machine to separate any meat from the bone. It is also known as mechanically separated meat and was banned, in 1995, according to the U.K. Food Standards Agency.  Vaccines may also be relevant to some cases of vCJD in the United Kingdom.

Kuru is a transmissible spongiform encephalopathy (TSE) caused by prions found in humans.  It was found in a tribe in Papua New Guinea and as a human brain disease it has helped explain variant CJD. In particular, the disease affected people decades after transmission of the disease. This pattern may repeat itself with vCJD.  The origin of the disease was due to the tribe's consumption of a deceased individual's brain. Such brains were contaminated from individuals who had sporadic CJD.  Ingestion of prion particles can cause the disease. It is possible that the disease was also transmitted through open sores and cuts on hands as members of the tribe dealt with deceased relatives.

Scrapie is a TSE found in sheep and goats and was found in the 18th century and does not seem to be linked to humans and variant CJD.

Major Concerns:  How many people have died from CJD?  

The measurement of CJD deaths has been contested and may increase in future years.  One of the concerns, was whether CJD was avoidable. If this was the case, then it makes the hazard more painful; with regret from knowing that the disease could have been avoided.  Improved accountability of scientists, and greater public control over science, is needed so that greater care is taken.  This should avoid the emergence of similar hazards in the future. 

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