BSE: Other TSEs - Scrapie - Q&A
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General
Q. What is scrapie?
A. A transmissible spongiform encephalopathy present in the national flock and in many other countries for hundreds of years. It causes a fatal degeneration of the brain of sheep and goats.
Q. Does scrapie have to be reported?
A. Yes. Since January 1993 in response to the EC directive governing trade between EU Member States in sheep and goats (91/68/EEC), and now in response to Regulation (EC) 999/2001.
Q. When are sheep affected by scrapie?
A. The incubation period appears to depend upon both the isolate of scrapie agent involved and the genotype (genetic constitution) of the sheep. Most cases occur between 2 and 5 years. Cases are rare below 18 months but can occur. Most 'prime' lamb is slaughtered well within the first year of life.
Q. How do sheep get scrapie?
A. Scrapie is infectious but the precise agent and its method of transmission are not yet fully understood. It is believed that infection can survive in pens and on pasture and is resistant to most disinfectants.
Q. Do goats get scrapie?
A. Yes, often in association with scrapie in sheep. Since the disease became notifiable in 1993 only 8 cases have been confirmed in goats in Britain.
Q. Why has there been an increase in the number of cases since 1995?
A. There was probably a level of under-reporting, both of the initial suspect in a flock and subsequent cases. Between 1993 and 1996, only the first case in a two year period was submitted for laboratory confirmation, so this could have been seen as a discouragement to report second and subsequent cases. Much of the increase in notifications since 1995 could also be due to the encouragement of farmers by research workers to notify cases, which improved case ascertainment within a few heavily affected flocks. However, the number of farms reporting confirmed cases has shown the opposite trend, falling between 1993 and 1995 then remaining relatively constant. Thus the trend is for fewer farms, each reporting more individual suspect cases than previously. There is no evidence whether this is a genuine concentration of the disease in fewer flocks, an artefact caused by changes in the sheep industry or an increasing stigma associated with reporting the disease.
Q. Which other countries have reported sheep with scrapie?
A. Scrapie has been reported in many sheep producing regions worldwide. Reporting depends on effective surveillance and the availability of laboratory testing facilities. It has been compulsory to notify scrapie in European Union Member States since 1993 and, in recent times, has been reported in Austria, Belgium, France, Germany, Greece, Ireland, Italy, the Netherlands and Spain. Scrapie is a also notifiable disease in about 50% of non-EU countries and there have been official reports of cases occurring in the USA, Canada, the Czech Republic, Cyprus, Switzerland, Iceland, Israel, Japan, Moldova and Norway. There have also been unofficial reports of scrapie in Chile, Denmark, Estonia, Hungary, Latvia, Lithuania, Poland and Portugal. Australia and New Zealand are widely regarded as being free from scrapie.
Q. How can scrapie be controlled?
A. Methods may include selective culling of affected flocks or family lines, prompt removal of afterbirths from lambing pens, and the use of genotyping (a test which looks at the genetic susceptibility to the disease) to breed resistant stock.
Q. Will the Government encourage the use of scrapie genotyping?
A. Yes. In the Action Plan for Farming announced on 30 March 2000 the Government said it would work for the reduction in scrapie as recommended by SEAC and noted that breeding based on ram genotyping has been shown to be a promising approach. Following a three-month consultation exercise conducted between 28 July - 31 October 2000 on proposals for a breeding programme for genetic resistance to TSEs - the National Scrapie Plan for Great Britain has been finalised and is now underway.
Q. What are the current statutory controls for scrapie affected animals?
A. Sheep suspected of having any scrapie-like illness are placed under movement restrictions and compulsorily slaughtered unless an alternative diagnosis is made. Compensation is payable for the slaughter of suspect animals. In addition, on a purely precautionary basis, tissues designated as specified risk material are removed at the abattoir and destroyed.
Q. What is the Voluntary Scrapie Flocks Scheme VSFS (VSFS)?
A. The National Scrapie Plan VSFS aims to eliminate scrapie on historically affected holdings and prevent future outbreaks of the disease by genotyping affected flocks and culling scrapie susceptible sheep. Members then only use scrapie resistant sheep for breeding. Information on scrapie genotypes is available on the NSP website.
Q. Who can join the VSFS?
A. The Voluntary Scrapie Flocks Scheme is open to flock owners whose flocks have had a confirmed case of scrapie between July 1998 and the date EU compulsory measures apply, 20 July 2004 in England and Scotland (end of October 2004 in Wales).
Q. What is the Compulsory Scrapie Flocks Scheme (CSFS)?
A. The National Scrapie Plan CSFS implements compulsory EU wide measures set out in EU Regulation 1915/2003. The aim of the Regulation is to eradicate scrapie from scrapie affected flocks by culling animals that have susceptible genotypes and by breeding for resistance using animals with the most resistant genotypes. Goat herds affected are culled.
Q. Who must comply with the CSFS?
A. The CSFS applies to any holding that has a case of scrapie reported from 20 July 2004 in England and Scotland (end of October 2004 in Wales) that is subsequently confirmed. Further details of the scheme and can be found at Compulsory Scrapie Flocks Scheme.
Q. Is there any evidence of maternal transmission of scrapie in sheep?
A. Transmission of scrapie from one animal to another is known to occur. The means of transmission is not firmly established. Maternal transmission is not ruled out as a possible route, but we do not have firm evidence that it does occur.
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Scientific advice
Q. What is SEAC's latest advice on scrapie and BSE and sheep?
A. In February 2000 SEAC conducted a review of the key research related to scrapie and BSE in sheep. The Committee agreed that further work needed to be done on screening sheep for evidence of infection with the BSE agent but concluded that at present there was no need for further public health controls. At their meeting in September 2000 they made recommendations on scrapie surveillance. In November 2000 SEAC agreed to set up a working group to consider the progress of a National Scrapie Plan for Great Britain. SEAC considered their conclusions in February 2001 and members concluded with the sub group that the NSP based on selective breeding was a valid and important approach and should proceed; however the sub group considered that if experimental results come to light that implied genetically resistant sheep were able to replicate and harbour the scrapie agent the NSP should be reviewed.
Q. What had SEAC previously advised on TSEs and sheep?
A. SEAC considered the potential risk to human health from TSEs in sheep in July 1996. Their advice focused on the possibility that BSE can be transmitted to sheep. They recommended that the brains of sheep, from any source, aged over six months be removed from the human food chain. This was implemented in legislation introduced in September 1996, since consolidated with Specified Risk Material legislation.
In May 1997, in light of the possible risk of BSE in sheep and goats, SEAC recommended 3 initiatives to improve the surveillance of scrapie in sheep and goats:-
(i) A compulsory slaughter and compensation scheme for sheep or goats suspected of having scrapie. (In place since July 1998).
(ii) An abattoir survey. Tissues from almost 3,000 sheep from abattoirs were sampled between August 1997 and August 1998. No definitive scrapie was confirmed. The findings were published in The Veterinary Record on 01 April 2000 (vol. 146, 391-395).
(iii) A postal survey. An independent and anonymous survey of 11,500 sheep farmers to gather information on the incidence of scrapie was conducted at the end of 1998. Preliminary findings were published in The Veterinary Record on 02 October 1999 (vol.145, no 14). Subsequent analyses have been published in Proc. R.Soc. Lond. B (1999), (vol. 266, 2531-2538), The Veterinary Record 15 April 2000, (vol.146, 455-461) and Nature on 10 August 2000 (vol. 406, no. 6796, 584-585).
In July 1998 SEAC reviewed the position and advised that no further action needed to be taken to protect public/animal health, and that additional work was needed to determine extent of scrapie, and strains involved. They set up a sub-group to take this forward.
In April 1999 the sub group published a report on Research & Surveillance for TSEs in sheep. Twenty recommendations were made, the most important relate to:
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improving ascertainment and diagnosis of TSEs in sheep
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developing/validation new methods to differentiate scrapie strains and BSE
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defining criteria for diagnosing clinical and sub-clinical TSE infections
[General] [Scientific advice] [Slaughter scheme] [Abattoir survey] [Postal survey]
Compulsory slaughter and compensation scheme
Q. What is it?
A. The Compulsory Slaughter and Compensation Scheme is one arm of the three tier approach recommended by SEAC to improve surveillance of scrapie. Under the scheme the slaughter of sheep and goats suspected of being affected with scrapie is compulsory and compensation is payable for the loss of an animal. DEFRA is responsible for disposing of the carcases.
The scheme also implements some of the requirements of EU Commission Decision 98/272/EC on epidemiological-surveillance of TSEs, which came into force in May 1998.
Q. What legislation currently provides for the compulsory slaughter scheme?
A. There are three Statutory Instruments:
- The TSE (England) Regulations 2002
- The TSE (Scotland) Regulations 2002
- The TSE (Wales) Regulations 2002
Q. How is the sheep industry affected by the slaughter scheme?
A. The compulsory slaughter and compensation scheme did not introduce any significant additional financial burdens on the sheep industry; the requirement to notify suspect cases has been a statutory one since 1993, although slaughter had not been compulsory. Sheep farmers benefit from compensation payments for animals slaughtered under the scheme.
Q. What is the compulsory slaughter and compensation scheme expected to achieve?
A. The compulsory slaughter and compensation scheme improves the surveillance of scrapie by the removal of disincentives to the farmer for reporting scrapie. The scheme improved controls on affected animals and helps to provide additional information and materials for the study of the disease.
Q. What are owners required to do if they suspect that one or more of their sheep may have scrapie?
A. Owners who suspect that they have sheep affected with scrapie should contact their local Animal Health Divisional Office. A Veterinary Officer from the AHDO will then visit the flock to inspect the suspect animal(s).
Q. Are all suspicions of scrapie required to be notified?
A. Yes. It is not just the first animal in a particular period that has to be notified. Every suspect animal must be notified so that a Veterinary Officer can inspect it to confirm or rule out the suspicion of scrapie. Compensation is paid for each animal compulsorily slaughtered.
Q. What happens if the DEFRA vet decides that an animal is affected with scrapie?
A. The Veterinary Officer will place a Movement Restriction on the affected animal. Animals with Movement Restrictions in place will be tagged. If necessary for welfare reasons the veterinary officer may slaughter the animal on farm. The Animal Health Office will arrange for the animal or carcase to be transported to a Veterinary Investigation Centre (VIC).
Q. What are the procedures upon positive diagnosis of a scrapie?
A. The regulations require every animal clinically diagnosed as affected with scrapie to be delivered to a VIC for laboratory diagnosis. In some cases the suspect will be transported alive. In cases where the suspect’s welfare would be compromised by transport, it will be slaughtered and the carcase delivered to a VIC. The VIC will remove material for laboratory diagnosis and destroy the carcases.
Q. What happens if the DEFRA vet decides that an animal is not affected with scrapie?
A. If the animal is not affected with scrapie no movement restrictions will be enforced. The animal will not be slaughtered.
Q. What happens if the DEFRA vet’s inspection is inconclusive?
A. If a diagnosis is inconclusive the Veterinary Officer will serve a Movement Restriction Order, valid for 28 days. The animal will be tagged. The Veterinary Officer will revisit the animal within the 28 days.
If a diagnosis is inconclusive the animal may still be slaughtered if this proves necessary for welfare reasons. In this circumstance compensation will be payable at the cull ewe market rate, on an ex-gratia basis, provided that laboratory diagnosis is positive.
Q. What if an animal recovers after an inconclusive diagnosis?
A. If on a revisit the Veterinary Officer is satisfied that an animal is not affected with scrapie then the Movement Restriction will be lifted.
Q. What if a suspect animal is pregnant?
A. If a suspect animal is pregnant and the Veterinary Officer serves a Movement Restriction Order, the following conditions will apply:
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the animal must be isolated from all other animals during labour and for 72 hours afterwards in accommodation approved by the vet;
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the placenta, discharges and bedding must be buried or burned; and
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the accommodation must be cleansed and disinfected afterwards in accordance with the guidance of the Veterinary Officer.
Q. Who will dispose of the carcases?
A. Veterinary Investigation Centres will arrange disposal of the carcases.
Q. Why not treat animals rather than slaughter them?
A. There is no effective treatment for scrapie.
Q. What are the compensation arrangements?
A. Under the terms of The TSE (England) Regulations 2002, The TSE (Scotland) Regulations 2002 and The TSE (Wales) Regulations 2002, the owners of animals compulsorily slaughtered are eligible to receive a compensation payment. The payment is £30 for a cull animal and £90 for any other animal.
In cases where an animal is clinically diagnosed by a Veterinary Officer as affected by scrapie, but this cannot be confirmed by laboratory diagnosis, owners may be eligible to receive a greater compensation payment not exceeding £400. Owners will be advised (before the suspect is slaughtered) of the possible need for documentary evidence of the animal’s value.
Q. Why is there a £400 limit on the higher rate of compensation? Pedigree animals are frequently worth much more than this.
A. The animals were showing signs of a serious neurological disease when they were slaughtered and would very likely have died anyway. It is expected that owners of valuable animals would have private insurance arrangements in place.
Q. Will reporting suspect cases place any restrictions on the rest of a flock?
A. Not normally. Only the affected animal will be restricted. However, the legislation does provide powers for a Veterinary Inspector to prohibit the movement of any flock, where he has reasonable grounds for believing that the movement of any sheep or goat from that flock may give rise to the spread of disease.
The current rules for trade in breeding sheep with other EC partners currently remain unchanged. (No export of breeding sheep for 2 years from the last confirmation of scrapie on a holding).
Q. When do you expect to use the powers to restrict a flock?
A. When we have a better understanding of the disease, or have alternative diagnostic tests available, there may be a need to restrict additional animals while we investigate the flock.
Q. Does this legislation apply only to commercial flocks?
A. No. The only exemptions are for research establishments where scrapie is deliberately introduced into animals for experimental purposes.
Q. Why was this scheme introduced in 1998 if scrapie has been present in sheep for over 200 years?
A. Advice from SEAC to implement a compulsory slaughter scheme was given in May 1997. They considered that there was a need to improve the surveillance and understanding of the disease. Commission Decision 98/272/EC subsequently required us to do so.
Q. Why were animals suffering from scrapie not subject to compulsory slaughter regulations from the time that the disease was made notifiable in 1993?
A. Scrapie was made a notifiable disease in compliance with EC Directive 91/68/EEC on intra-Community Trade. This Directive did not require compulsory slaughter. SEAC advised in May 1997 that a compulsory slaughter and compensation scheme be introduced. Commission Decision 98/272/EC (made on 23 April 1998) subsequently required all Member States to compulsorily slaughter sheep and goats suspected of having scrapie.
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Abattoir survey
Q. What was the abattoir survey?
A. The abattoir survey investigated tissues from sheep slaughtered at a number of abattoirs in Great Britain for signs of scrapie. A random sample of around 3000 sheep were sampled.
Q. What surveillance has been carried out since?
A. A programme of testing
for scrapie in sheep began in January 2002 to test 3,000 fallen stock
and 15,000 sheep aged over 18 months destined for human consumption. The
testing of 20,000 of the human consumption animals has been combined with
an abattoir survey recommended by SEAC where additional tissues will also
be taken. From 01 April the testing requirement was extended to 60,000
abattoir and 6,000 fallen stock sheep.
Q. When did the abattoir survey take place?
A. The sheep were sampled between August 1997 and August 1998.
Q. Where were the findings of the abattoir survey published?
A. The findings were published in The Veterinary Record on 01 April 2000.
Q. Why was the abattoir survey carried out?
A. To establish the possible occurrence and prevalence of scrapie infection in sheep sent for slaughter. It was recommended by SEAC as part of a strategy to improve scrapie surveillance.
Q. How were the sheep in the abattoir survey tested?
A. Using two types of test on all samples:
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histological - examinations of brain under a microscope for characteristic patterns of damage, and
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SAF examination - under an electron microscope for structures called Scrapie Associated Fibrils.
Q. Was any scrapie found in sheep going for slaughter?
A. No unequivocal positive cases were found of nearly 3,000 brains tested. The sample was scientifically designed to give a 95% level of confidence that if the level of scrapie infection in sheep at abattoirs was 1% it would be detected.
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Postal survey
Q. What was the Postal Survey?
A. An anonymous survey by postal questionnaire of 11,500 randomly selected sheep farms to gain further information on the incidence of scrapie. It was conducted independently for the then MAFF by the Agricultural Development Advisory Service (ADAS). Neither the then MAFF or ADAS knew the identity of participating farmers.
Q. Where were the findings of the postal survey published?
A. The preliminary findings were published in a paper entitled 'Scrapie Occurrence in Great Britain' published in The Veterinary Record on 02 October 1999 (vol.145, no 14). Subsequent papers have been published in Proc. R.Soc. Lond. B (1999), (vol. 266, 2531-2538), The Veterinary Record 15 April 2000, (vol.146, 455-461) and Nature on 10 August 2000 (vol. 406, no. 6796, 584-585).
Q. What were the objectives of the postal survey?
A. The survey objectives were to help:
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determine proportion of flocks in Great Britain that have had scrapie cases
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determine the characteristics of scrapie affected flocks
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obtain demographic information about sheep populations
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assess farmers' attitudes to scrapie
Q. When was the postal survey carried out?
A. During November - December 1998.
Q. Who carried out the postal survey?
A. After a tendering process a contract to conduct the survey was awarded to ADAS. They were closely involved in the design and conduct of the survey and were assisted by a Committee comprising experts from the Veterinary Laboratories Agency (VLA), the Institute for Animal Health (IAH), and MAFF.
Q. Who participated in the survey?
A. 11,554 anonymous and randomly selected sheep farmers in Great Britain.
Q. How many of the farmers responded?
A. 61.4% of the questionnaires (7,090) were returned which for a survey of this type was very encouraging. Both SEAC and the Scrapie Information Group were impressed by this response rate.
Q. How was such a high response rate achieved?
A. The experts involved took great care in designing the questionnaires to be easy to complete. They were sent out at a time that industry advised would be least disruptive. The survey was also endorsed by industry (the Scrapie Information Group, including the National Sheep Association). Reminder letters were also used. It was also made clear that the survey was completely anonymous with those involved with the conduct of the survey and analyses of the data having no way of knowing which farmers were contacted.
Q. Why was the survey anonymous?
A. The incidence of scrapie is difficult to assess in part because some farmers will be reluctant to report cases for fear of consequent loss of trade and also the symptoms can be confused with other diseases. Pilot surveys used to inform the design of this survey suggested an anonymous survey as one method to assess the incidence of scrapie and farmers' knowledge of the disease.
Q. How many of the farmers in this survey reported scrapie on their farms?
A. 2.4% of the farmers who responded believed that they had recently seen a case of scrapie on their farm - i.e. in the 12 months prior to the survey (Nov '98).
Q. So most sheep farmers have not seen scrapie on their farms?
A. The survey shows that the vast majority of sheep farmers even if asked anonymously report that they have not seen scrapie on their farms.
Q. But how does this survey finding compare with the actual reporting of scrapie?
A. If accurate, this suggests that only 13% of farmers (likely to have had a case of scrapie on their farm last year) actually report their suspicion of the presence of scrapie.
Q. Could farmers be confusing scrapie with other diseases?
A. This is possible. Scrapie can be difficult to diagnose in live animals (23% of reports last year were subsequently confirmed not to be scrapie). Many of the symptoms on their own could be indicative of other diseases, but it must be appreciated that a farmer who has reason to suspect scrapie is required to report it, whatever the eventual diagnosis.
DEFRA will prosecute whenever it is clear that a farmer has knowingly refused to notify the authorities where he had grounds to suspect that he had a case of scrapie in his flock.
Q. What is DEFRA doing to encourage the identification and reporting of scrapie?
A. The reporting rate suggested by this survey is unacceptably low. DEFRA are therefore very conscious of the need to take all possible steps to ensure that any suspicion of scrapie is reported. Initiatives in place or to be introduced are:-
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Compulsory slaughter - with compensation - for sheep or goats suspected of having scrapie was introduced in July 1998.
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A video on the clinical signs of scrapie is available from the DEFRA publications catalogue. It was sent to State Veterinary Service Animal Health Offices for training purposes who publicised its availability to veterinary practices and sheep farmers.
- To encourage the notification of animals suspected of having scrapie,
the rates of compensation under the compulsory slaughter scheme were
increased in December 2001 to £30 for a cull animal and £90
for any other animal.
- An advisory note for farmers on scrapie was published in November
1999. The note explains:-
- why it is important to report the disease
- that scrapie is notifiable, with severe penalties for not reporting it;
- the symptoms;
- the notification procedures;
- that slaughter is compulsory slaughter, that compensation is paid.
- A poster will be produced, to be displayed in markets, veterinary
practices etc which will further publicise the fact that scrapie is
notifiable, and where to go for further information and advice.
Q. Have there been similar surveys into scrapie in the EU?
A. We are not aware of any similar surveys on this scale.
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Page last reviewed: 20 October 2008
Page last modified: 04 August 2004