Bovine Spongiform Encephalopathy and Scrapie

Bovine spongiform encephalopathy and scrapie

OIE Reference Laboratory Reports

Activities in 2011

Part I: Summary of general activities related to the disease

1. Test(s) in use/or available for the specified disease/topic at your laboratory

2. Production and distribution of diagnostic reagents

R145, the AHVLA anti-PrP rat monoclonal antibody is commercially available. In house we have used approximately 1.5ml, and supplied 1ml externally to each of 4 international requestors.

The most commonly supplied material is BSE infected brain tissue as this is used for the development and evaluation of tests, and for batch control after approval. It is also used for regular proficiency testing conducted in Europe under the laboratory’s responsibilities as EU Community Reference Laboratory. Proficiency test samples for BSE and scrapie rapid tests are commercially available from VETQAS, the AHVLA QA Unit.

Part II: Activities specifically related to the mandate
of OIE Reference Laboratories

3. International harmonisation and standardisation of methods for diagnostic testing or the production and testing of vaccines

a) Establishment and maintenance of a network with other OIE Reference Laboratories designated for the same pathogen or disease and organisation of regular inter-laboratory proficiency testing to ensure comparability of results

·  We do not participate in any EQA run but other laboratories, but can participate in the one we organise (see below). The OIE reference laboratory in Switzerland is a regular participant in this EQA. We do share diagnostic opinion on request from other OIE reference laboratories in Canada and Japan, and also with the CWD reference laboratories in Canada and South Korea.

·  Interlaboratory test evaluations – see below

·  There are no vaccines for BSE or scrapie

b) Organisation of inter-laboratory proficiency testing with laboratories other than OIE Reference Laboratories for the same pathogens and diseases to ensure equivalence of results

·  We do not participate in any formal ring trials operated by other laboratories. However, the AHVLA-run EQA is administered by the independent VETQAS QA group, and we can therefore participate in our own schemes.

·  Annually the AHVLA organises EQA rounds for all EU member states (funded by the European Commission), which cover rapid tests, genotyping, discriminatory Western blot testing and confirmatory histopathology and immunohistochemistry testing for bovine and ovine TSE. Any countries which fail the initial EQA have personalised assistance with troubleshooting and, if necessary training, and must make alternative arrangements for retaining samples, or subcontracting the testing, until they pass a follow-up EQA. Non-EU countries and commercial laboratories can join in with any or all of these EQA activities on a cost-recovery (i.e. non-profit) basis. Switzerland, Norway and Iceland participate annually. Other countries have participated in the past (USA, Canada, Australia, South Korea) but not in 2011. Confirmatory testing methods are available on the reference laboratory website.

·  Rapid tests which can be used in the EU as part of surveillance programmes for BSE and scrapie are assessed by EFSA and listed in EU Regulations. AHVLA has participated in laboratory evaluation studies and EFSA working group assessment of company data during 2011. Approved test protocols are available on the AHVLA website. AHVLA also coordinates a batch testing system within the EU and releases batches for use after either testing with panels of samples or independent assessment of company data. Any changes to rapid test protocols for use in EU countries can only be made with AHVLA agreement following examination of supporting validation data to AHVLA. These changes are made in discussion with other international groups such as approval bodies in North America.

·  There are no vaccines for BSE or scrapie

4. Preparation and supply of international reference standards for diagnostic tests or vaccines

Standard reference materials officially recognised by OIE or other international bodies: None

Production of BSE–infected brain reference material for use particularly in the evaluation of new confirmatory methods has progressed. This now includes animals experimentally infected with H-BSE and L-BSE Source animals providing positive and negative controls are characterised by IHC, WB and ELISA, but not by infectivity titre. This reference bank will enable potential evaluation of new confirmatory test methods.

The AHVLA TSE archive holds extensive quantities of materials from BSE and scrapie-infected animals which it regularly supplies to both research groups and reference laboratories, as well as some manufacturers of commercial rapid tests.

5. Research and development of new procedures for diagnosis and control

Intracerebral challenges of sheep (of a range of genotypes) with H and L type BSE are ongoing. This will ultimately allow detailed characterisation of such TSE in sheep, and definition of appropriate diagnostic parameters, which will facilitate accurate and comprehensive surveillance and diagnosis. Animals are currently approximately 1500 days post challenge. All the sheep challenged with H-BSE are still alive. Several sheep challenged with L-BSE have now succumbed to disease. Preliminary study of these animals indicates that the clinical signs are very different from previously described ovine TSE, with sheep presenting with apparent muscle weakness/collapse as a predominant sign, Immunohistochemistry and WB both confirm these animals as positive, but with characteristics that are distinct from other defined ovine TSE. Several genotypes have now succumbed.

We are undertaking detailed biochemical and biological characterisation of confirmed BSE cases born after the UK reinforced feed ban (1996) to establish if this case population differs phenotypically from that of the main UK epidemic.

We have not undertaken any test or vaccine development.

6. Collection, analysis and dissemination of epizootiological data relevant to international disease control

In collaboration with the Cypriot authorities, and in discussion with EC and EFSA we are contributing to the execution of a study to determine aspects of genetic resistance to scrapie in goats, using a range of approaches from experimental challenge and field sampling to the modelling of the potential of breeding for resistance programmes using real population genetics data.

Following on from our demonstration that ovine scrapie could be transmitted experimentally via milk, we are currently investigating the potential for a similar route of transmission in goats.

We have not been required to confirm disease on behalf of any other country this year.

7. Maintenance of a system of quality assurance, biosafety and biosecurity relevant to the pathogen and the disease concerned

As described in previous sections, we provide an extensive range of EQA relevant to disease detection and characterisation. We have no formal system for maintaining biosafety and biosecurity, but we have provided ad hoc advice to a number of countries this year (Canada, China, Costa Rica, Cyprus, Egypt, Finland, Greece, Hungary, Iran, Israel, Japan, New Zealand, Portugal, Romania, South Korea, Sudan, Sweden, UAE and USA) on a range of topics including diagnostic methods, testing of food and biological products and laboratory decontamination.

8. Provision of consultant expertise to OIE or to OIE Member Countries

Contributions as required to the editing of the Manual chapters.

Ensuring that all advice on the AHVLA reference laboratory website is up to date.

9. Provision of scientific and technical training to personnel from other OIE Member Countries

The AHVLA provided an input to the training at the EU ‘Better Training for Safer Food’ courses held in September and December in Manchester, UK. Each course had approximately 30 participants.

No formal workshops or training courses have been offered directly by AHVLA this year, since this is ionly done subject to demand, and no requests have been received. The AHVLA EURL website is accessible to all countries, and OIE-specific front pages enable easy access to this site. Incorporated into the web site are a series of video clips of clinical BSE and scrapie in sheep and goats, which can be downloaded without limit. These remain very popular with visitors to the site. In addition a thirty minute narrated DVD of clinical signs and examination techniques for BSE is still available to purchase through the website. The web site is also populated with current methodologies for diagnostics. The web site address is http://vla.defra.gov.uk/science/sci_tse_oie.htm

We have no formal twinning agreements

10. Provision of diagnostic testing facilities to other OIE Member Countries

We are subcontracted to undertake all differential Western blotting and discriminatory IHC for Cyprus.

Holland will send to AHVLA all immunoblotting for positive cases should they arise (none this year).

All other diagnostic support is referral confirmatory second opinion.

11. Organisation of international scientific meetings on behalf of OIE or other international bodies

The AHVLA as EU RL holds an Annual Workshop, in London, (June 2011), for all EU Member state NRLs (2 participants from each member state, plus self-funding additional participants on request) at which emerging scientific issues and outcomes from the QA exercises are discussed, and future training needs identified. This is a closed meeting, and copies of the presentations are posted on a password protected website. An emerging topic of interest this year was the appriopriate decontamination of testing laboratories which were being de-commissioned.

The Prion2011 Conference was held in Montreal, Canada 16th – 19th May 2011 Several posters were presented and four AHVLA scientists gave oral presentations. One of the AHVLA scientists was one of the organisers and chairman for the satellite “TSE in Animals” workshop held on 15th May.

12. Participation in international scientific collaborative studies

Reference laboratory staff are participating in the following collaborative studies

·  Neuroprion Network of Excellence strain typing study (ongoing)

·  AHVLA is represented on the scientific advisory panels of the EU consortium PRIORITY (FP7) (ongoing)

·  A collaborative study between AHVLA and the Cypriot authorities on behalf of the EC and EFSA to investigate genetic resistance to scrapie in the Cypriot goat population (ongoing)

13. Publication and dissemination of information relevant to the work of OIE (including list of scientific publications, internet publishing activities, presentations at international conferences)

¡  Presentations at international conferences and meetings

Numerous oral and poster presentations by AHVLA staff at;

¡  112th British Neuropathology Society, London January,2011

¡  Prion 2011, (4 presentations, 11 posters) and associated satellite meetings, Montreal, May 2011.

¡  The EURL/NRL Annual Meeting, June 2011, UK

¡  Scottish TSE Network (various)

¡  AHVLA International Conference September 2011

¡  The Second Spanish National Prion Meeting, Madrid, December 2011

¡  Scientific publications in peer-reviewed journals

1.  Åkesson CP, McGovern G, Dagleish MP, Espenes A, McL Press C, Landsverk T, Jeffrey M. Exosome-producing follicle associated epithelium is not involved in uptake of PrPd from the gut of sheep (Ovis aries): an ultrastructural study.PLoS One. 2011;6(7):e22180. Epub 2011 Jul 18

2.  Beck KE, Cawthraw S, Saunders GC, Ellis R, Spiropoulos J (2011). Transmission of classical scrapie to wild-type mice: the influence of the ovine PrP sequence on lesion profiles. Arch Virol 156, 903-906.

3.  Beck KE, Sallis RE, Lockey R, Vickery C, Béringue V, Laude H, Holder TM Thorne L, Terry LA, Tout AC,Jayasena D, Griffiths PC, Cawthraw S, Ellis R, Balkema-Buschmann A, Groschup MH, Simmons MM, Spiropoulos (2011) Use of Murine Bioassay to Resolve Ovine Transmissible Spongiform Enchephalopathy Cases showing a Bovine Spongiform Encephalopathy Molecular Profile. Brain Pathology 2011 Sep 15. doi: 10.1111/j.1750-3639.2011.00526.x. [Epub ahead of print]

4.  Dagleish MP, Finlayson J, Steele PJ, Pang Y, Hamilton S, Eaton SL, Sales J, González L, Chianini F. Immunophenotype of Cells within Cervine Rectoanal Mucosa-Associated Lymphoid Tissue and Mesenteric Lymph Nodes.J Comp Pathol. 2011 Oct 13. [Epub ahead of print]

5.  Del Rio Vilas V.J., Ancelet S., Abellan J.J., Birch C.P.D., Richardson S. A (2010) Bayesian hierarchical analysis to compare classical and atypical scrapie surveillance data: 2002-2006. Preventive Veterinary Medicine. Vol 98 (1) 29-38.