BSE is short for Bovine Spongiform Encephalopathy. It is commonly known as 'mad cow disease' and affects adult cattle. Although BSE only develops in cattle, it belongs to a particular group of diseases, several of which can affect people.
It usually takes four to six years for cattle infected with BSE to show signs of the disease. BSE attacks the brain and central nervous system of the animal before eventually killing it.
What danger is BSE to people?
The most well known disease that affects humans in the group of diseases that includes BSE is Creutzfeldt-Jakob Disease (CJD). This is a rare and fatal form of dementia that mainly occurs in people between the ages of 40 and 80.
CJD is not a new disease, but in 1996, scientists discovered a new strain of CJD that occurs mainly in younger people. Because of this, the new illness in humans is known as variant CJD or vCJD.
The appearance of vCJD in the UK, where there was a high number of BSE cases in cattle, suggested that there might be a direct link between BSE and vCJD. Some people who have developed vCJD are known to have eaten meat that could have been infected with BSE. Researchers concluded that the most likely origin of vCJD was people eating meat infected with BSE. Like BSE in cattle, vCJD is always fatal.
Since vCJD first appeared in the UK, studies have been put in place to answer questions about vCJD, such as how people are affected by the disease and how long it takes for individuals exposed to the illness to be affected by it.
There are strict controls in place in the UK, and throughout Europe, to protect people from possible exposure to BSE. The Food Standards Agency monitors these controls and publicises any breaches as well as the actions taken to avoid further failures.
How is the risk from BSE being controlled?
Since the late 1980s, the Government, and more recently the European Commission, has introduced and strengthened controls to reduce the risk of people eating beef and meat products that might be infected with BSE.
The controls are based on current scientific knowledge and are designed to reduce the risk to an extremely low level, although the risk from BSE cannot be removed completely.
A key job for the Food Standards Agency is to make sure that these controls are working effectively.
The main control is the removal from the food chain of the parts of cattle most likely to contain BSE. These parts are known as Specified Risk Material (SRM). These controls form part of the harmonised regulations that apply in all European Union (EU) countries.
Since November 2005, another control, the BSE testing of older animals was introduced. It means that cattle aged over 30 months at slaughter are allowed into the food chain only if they test negative for BSE. Testing helps to protect consumers from BSE because any animals found to be positive will be removed and destroyed.
From 1996 until November 2005 cattle aged over thirty months were simply banned from entering the food chain. This ban was replaced by BSE testing because, with the marked decline in BSE and the introduction of BSE testing, the risk from UK cattle born after August 1996 is now very low.
Cattle born before August 1996, when a reinforced ban on feed containing meat-and-bone meal (MBM) was introduced, will remain excluded from the food supply. See 'Where does BSE come from?' for more on MBM.
Where does BSE come from?
Despite much research, no one can say with certainty where BSE came from, although several theories exist.
Most experts agree that BSE was spread by cattle eating feed that contained meat-and-bone meal (MBM) made from BSE-infected tissues. Experiments have shown that cattle can contract BSE if they are fed infected brain tissue.
The practice of feeding MBM to cattle and all other farm livestock has been banned since 1996.
How widespread is BSE?Since 1999 cases of BSE have been confirmed in the following countries: Austria, Belgium, Canada, Czech Republic, Denmark, Falkland Islands, France, Finland, Germany, Greece, Ireland, Israel, Italy, Japan, Liechtenstein, Luxembourg, the Netherlands, Oman, Poland, Portugal, Slovakia, Slovenia, Spain, Switzerland and the United States of America.
Currently there have been more cases in the UK than anywhere else in the world, with a total of about 180,000 cases to date. The epidemic in the UK has been in decline for many years and by 2002 the total number of new cases had fallen to its lowest point since record keeping began in 1988. The number of cases continued to fall in 2003 and 2004.
Why was BSE so common in the UK before effective controls were introduced?We still do not know how BSE started in the UK. But extensive use of MBM in cattle feed in this country meant that, once it started, BSE spread rapidly.
Imported beef and meat products
All EU countries must ensure that beef and beef products comply with controls designed to reduce the risk of BSE.
In order to be imported into the EU, meat and meat products must have to be certified to show that all SRM has been removed.
To help consumers know where the beef they buy comes from, the Food Standards Agency has issued guidance on labelling meat. Beef labelling regulations, which cover cuts of beef and minced meat, require the origin of beef to be given.
Can sheep and goats get BSE?
In January 2005 the European Commission confirmed that BSE had been found in one goat that had died in France in 2002. The UK’s Department for Environment, Food and Rural Affairs also announced on 8 Feb 2005 that it is possible that one Scottish goat, which died in 1990, may have had BSE. Further tests will take up to two years to confirm this.
BSE has not been found in the current UK goat population, nor in 140,000 goats tested across Europe since 2002, apart from the French finding.
It is now understood that BSE infection could have been spread through the feeding of meat and bone meal (MBM) to farm animals. A full ban on the use of MBM to farmed animals was introduced in the UK in 1996. This ban was subsequently extended across Europe in 2001.
This could explain how the two goats could have got BSE, as in both cases the goats were alive before the respective animal feed bans were introduced.
Few, if any, goats born before 1990 are likely to still be alive today.
No goat that shows signs of any brain disease such as BSE is permitted to enter the food chain. There are also controls in place to remove some of the parts of a goat that could contain BSE infectivity, such as the spinal cord. However, the current BSE controls would not remove all of the possible infectivity, and it is not known whether it is possible for BSE to pass down through the generations in goats or whether it can be transmitted through the environment.
The European Commission is steeping up the testing of goats to determine if the French case is an isolated incident. The European Food Safety Authority will consider the results of this enhanced testing across Europe.
BSE has never been found in the UK sheep flock. However, some sheep ate the same feed (MBM) that is thought to have given cattle BSE, and laboratory research has shown that sheep can be infected artificially with BSE. There is, therefore, a possible risk that BSE is in sheep. As a precautionary measure, therefore, SRM must also be removed from sheep entering the food chain.
The Food Standards Agency advice continues to be that we are not advising against the consumption of sheep or goat meat or dairy products.