WRITTEN QUESTION E-1981/96 by Hiltrud Breyer (V) to the Commission (17 July 1996)

Subject: Transmission of BSE

1. Is the Commission aware that in all types of BSE the various kinds of tissue become infectious long before the animal falls sick? How can young cattle (e.g. six-month old animals or cows up to the age of 30 months) therefore not be considered dangerous? Is it possible that pigs and poultry might also be infected - and infectious - without showing any symptoms and that they might be recognized as carriers?

2. Are special measures planned at EU level to protect consumers against meat from scrapie-infected sheep?

3. How certain is it that mutations of scrapie into BSE have not already occurred before transmission from one species to another?

4. Is it certain that no reinfection of sheep with BSE has occurred via the mutated pathogen?

5. How safe is sheepmeat for the consumer? Are there any indications that sheepmeat can pose a threat to health?

6. What can trigger off the mutation of the scrapie pathogen (e.g. organic phosphates when used to combat parasites, medicines, feedingstuffs containing harmful chemicals, etc.)? Have alternative hypotheses to the rendered meat theory been tested or are such hypotheses being tested? If so, what are they and what are the results?

Answer given by Mr Fischler on behalf of the Commission (26 November 1996)

1. In natural clinical cases of bovine spongiform encephalopathy (BSE), infectivity has so far been found only in the brain, eye and spinal cord. In calves infected experimentally, infectivity has also been found in part of the small intestine from six to eighteen months post infection. Infectivity has not been detected in the central nervous system below eighteen months of age. For this reason, all these tissues, as well as others which could also be infected according to the evidence from sheep scrapie and other tissues which could be contaminated, are removed and destroyed from all cattle over six months in the United Kingdom.

Recent evidence of maternal transmission is under review by the scientific veterinary committee. If their advice suggests a change in the risk assessment for young animals, the Commission will, of course, take appropriate action.

Attempts to transmit BSE to pigs and poultry by feeding BSE-infected material have been unsuccessful, and tissues from these exposed animals did not contain detectable infectivity. Pigs have, however, developed a spongiform encephalopathy following injection of BSE infected cattle brain material by multiple routes. Exposure of poultry by similar routes failed to create disease.

2. Sheep showing signs of scrapie may not be slaughtered in the Community for human consumption. Sheep infected with scrapie have been eaten for hundreds of years without apparently causing any disease in humans.

3. It is difficult to talk of mutations in relation to an agent whose nature is not yet established. There are at least 20 strains of scrapie, as determined by studies in susceptible mice.

4. The possibility of infection of sheep with BSE cannot be excluded, although there is less use of concentrated rations for sheep than for dairy cattle. Exposure of sheep by this route is likely to be low since the usual production systems are largely based on grass feeding.

5. Sheep meat has been consumed for centuries without any evidence of transmission of scrapie to people. The incidence of Creutzfeldt-Jakob disease is the same in countries which are free from scrapie as in countries with a high incidence of this disease. If there is any risk from BSE in sheep, then the infection would be expected to be confined to certain tissues of the body, based on recent scientific data. Accordingly, the Commission, on the basis of the advice from the scientific veterinary committee, has already informed the Council of its intention to make proposals to remove the tissues in question systematically from sheep and goats slaughtered throughout the Community.

6. The agent responsible for scrapie has not been identified and it is not known if it can mutate. Detailed epidemiological studies have been carried out to try to identify other risk factors for BSE, but none has been found. The possible influence of the products mentioned has been studied and rejected as a possible cause. In particular, these products are used extensively in all developed countries, and therefore any effect they would have would be seen elsewhere. This is not the case.