6.1 OIE conditions for a Scrapie free country
Conditions to be satisfied in order to be classed as a scrapie-free country as defined in the OIE International Animal Health Code Draft Chapter 3.3.8 on scrapie as existing at 1 June 1999, specifically as defined in Articles 126.96.36.199 1) – 5) inclusive and 188.8.131.52, 1), 3) and 4), are as follows:
The scrapie status of a flock, a zone or a country can only be determined by continuous surveillance and monitoring. [No serological tests are available.] Post mortem examination of brains of suspect animals is required to confirm the presence of disease [using histopathology and immunohistochemistry or western blot or scrapie associated fibrils (SAF) detection by electron microscopy].
The minimum requirements for effective surveillance are:
1) a high standard of official veterinary surveillance, reporting and regulatory control;
2) a Veterinary Administration with current knowledge of, and authority over, all establishments which contain sheep and goats in the whole country [and able to trace back the animals to their flock/herd of birth];
3) compulsory notification, clinical investigation and compulsory slaughter of suspect cases;
4) laboratory examination of brain material from clinically suspect animals which are slaughtered or which die, in accordance with the diagnostic techniques set out in the Manual;
5) maintenance of records including the number and results of all investigations for at least 7 years.
Scrapie free country or zone
Countries or zones may be considered free from scrapie if within the said territory:
1) for at least 6 years, the suspicion of disease has been [compulsorily] notifiable, there has been no confirmed case, and an effective and continuous surveillance system as referred to in Article 184.108.40.206 has been practised, including the examination in an approved laboratory of brain material from sheep and goats older than 18 months displaying signs of progressive neurologic disease in accordance with the diagnostic techniques set out in the Manual.
A sufficient number of investigations should be carried out annually, to provide a 95% level of confidence of detecting scrapie if it is present at a prevalence rate exceeding 0.1% out of the total number of all chronic wasting conditions in the population of sheep and goats older than 18 months of age (under study). It is assumed that the occurrence rate of chronic wasting conditions within the population of sheep and goats older than 18 months of age is at least 1%; or
2) all flocks have been accredited free using the scheme described below; (ARGENTINA is not wishing to utilise this option at the present time but may do so in the future)
3) the feeding to sheep and goats of meat-and-bone meal derived from ruminants originating from countries not free from animal transmissible spongiform encephalopathies (TSE) has been banned and [is] effectively enforced in the whole country for at least 5 years (period under study);
4) introductions of sheep and goats, semen and embryos/ova from countries or zones not free from scrapie are carried out in accordance with Article 220.127.116.11., Article 18.104.22.168., Article 22.214.171.124. or Article 126.96.36.199., as relevant.
6.2 ARTICLE 188.8.131.52 Statements supporting the case for Argentina
To support the contention that Argentina is a scrapie-free country, the following statements can be made and in regard to ARTICLE 184.108.40.206 of the Code:
6.2.1 Keeping up to date with current knowledge and diagnostic methods
Argentina fully understands the complexities of scrapie in sheep and goats (CHAPTER 2). Argentina continuously updates its knowledge of the disease, results of recent research and diagnostic methodology. Apart from using their own staff for this purpose, veterinarians, medical doctors, and TSE scientists of international reputation are consulted to ensure that Argentina is fully equipped for the purpose.
6.2.2 High standards of Official Veterinary surveillance, reporting and control
Argentina has a highly efficient State Animal Health Veterinary Service (SENASA) comprised of field and laboratory veterinarians and support staff who have considerable experience of animal disease control and surveillance. Working together as a team they have successfully eradicated foot and mouth disease (FMD) from the country by consistently ensuring high quality surveillance and control methods and strict border control over the importation of animals and animal products, thus maintaining the country free of the disease. The recommendations in the OIE International Animal Health Code chapter on FMD are followed. Annual or bi-annual inspection of animals by SENASA staff for the identification of sheep scab and for FMD surveillance (and blood testing) provides the basis of good clinical surveillance of all farm animals in Argentina. It is during these examinations that clinical inspection of all sheep and goats (as well as cattle) in Argentina is conducted for evidence of TSE (CHAPTER 3). The extensive awareness programme (CHAPTER 4) ensures that all livestock farmers, veterinarians and SENASA staff employed on these inspections are fully aware of the clinical signs of scrapie and BSE. Such examinations are supplemented with clinical examinations of animals at markets, abattoirs and other gatherings (CHAPTER 4) and of sheep and goats over 18 months of age reported to SENASA with progressive neurologic signs. SENASA has a sound knowledge of all the industries relevant to the control of TSE. SENASA also has administrative control of all livestock farms and premises, and, in so far as hygiene, safety and animal disease control are concerned, of the associated industries, including artificial insemination centres, embryo transfer facilities, medicinal products used in animals, abattoirs, rendering plants and feed premises. Laboratories that conduct official investigations and tests for animal TSE including scrapie are approved by SENASA and are under the direct control of SENASA.
6.2.3 Clinical inspection, laboratory diagnosis and record keeping
Clinical inspection, compulsory slaughter of animals suspected to have scrapie, BSE or any TSE, or which die or may have died from these diseases, and laboratory examination of brain material is carried out in every case using the diagnostic techniques set out in the current issue OIE Manual of Standards for diagnostic tests and vaccines (in preparation). All tests are conducted in laboratories approved by SENASA. Records of the number and results of these investigations are kept for a minimum period of seven years.
6.3 ARTICLE 220.127.116.11, 1), 3) and 4), statements supporting the case for Argentina
All exotic diseases, including scrapie, BSE and all animal TSE, and certain endogenous diseases have been notifiable in Argentina since 1900 under Law #3959 (Animal Health Law Enforcement Authority). Specific resolutions now specifically deal with scrapie (Resolution #695/96) and BSE (Resolution #172/97). Thus there has been a policy for the compulsory notification to the Competent Authority of scrapie, BSE and indeed all animal TSE continuously since 1900.
Failure to report the clinical suspicion of disease is a punishable offence under the Animal Health Act from 1900 (APPENDIX B). If a financial loss is incurred by a farmer as a result of Government intervention, e.g. compulsory slaughter of a sheep, there is provision for compensation. No charge is made to the owner for any laboratory examination. A balance is kept between punishment for non-compliance and compensation for loss, and is under continuous review. There is thus a strong motivation for sheep and goat farmers and zoo owners to ensure notification of suspect cases of scrapie, partly due to their historical and ethical approach to FMD notification upon which their livelihood depends.
6.3.2 Absence of clinical cases
There has been no recorded or reported clinical (or pathological) case of scrapie in sheep, goats or moufflon in Argentina since the XVIth century or before.
During this period, as more and more knowledge was gained about the disease the quality of surveillance has improved. This has been mainly at the clinical level (the essential aspect of surveillance for disease) and is due to the requirements for frequent inspections of all ruminant and porcine species by personnel trained to recognise FMD, scrapie and BSE. The additional visits made as part of the sheep scab control programme assist in this process. Since the advent of BSE, surveillance has included more examination of sheep and goats brains than hitherto and the number will be increased in the future (see below).
6.3.3 Continuous surveillance and monitoring
An effective and continuous surveillance and monitoring system is practised in Argentina (see also 6.2.2 above).
All farmed ruminant species (including CERVIDAE (deer) and CAMELIDAE (llamas, alpacas, vicunas and guanacos) are regularly and frequently inspected (once or twice a year) for evidence of FMD by trained personnel who are familiar with the clinical signs of scrapie. It is therefore unlikely that scrapie, would be missed if it occurred. Even a sporadic event (e.g. sporadic or familial scrapie, if these hypothetical forms exist as they do in man as naturally-occurring forms of CJD) would also be unlikely to be missed especially if there was transmission of that disease to other animals. Continuous clinical monitoring is the vital method to detect scrapie if it occurs. Furthermore any sheep or goats older than 18 months of age displaying signs of progressive neurologic disease are compulsorily destroyed and their brains are examined for the presence of TSE in SENASA-approved laboratories and using methods specified in the Manual. This is supplemented in Argentina by an increasing surveillance for scrapie by pathological methods mainly in sheep, but also in goats. Targeted populations provide brains (in the period April 1997-April 1999) and other tissues (under development) upon which diagnostic tests can be applied, e.g. histopathology of the brain, immunoblotting and immunocytochemistry of brain tissue. No test has yet given a positive result for TSE (TABLES 1 and 2).
Argentina recognises that surveillance for scrapie by these methods needs to be further developed and is doing so. This effort will ensure more brains from target populations are examined in future and the methods used will be the most sensitive available. The result will be to increase still further the confidence that Argentina is a scrapie-free country. The target number of brains to be examined in the year April 1997-April 1998 and April 1998-April 1999, will be based on TABLE I of the OIE Guidelines for continuous surveillance and monitoring of BSE (Appendix VIIIb of Document 65 SE/12/CS1, OIE 1997c). In subsequent years at least this number of brains will be examined and, in addition, other methods may be used depending on the stage of their scientific development and validation. A sufficient number of pathological examinations are carried out on brain material to provide a 95% level of confidence of detecting scrapie if it is present at a prevalence rate exceeding 0.1% out of the total number of chronic wasting conditions in the population of sheep and goats older than 18 months of age.
6.3.4 Ruminant MBM Feed Ban
The feeding of meat-and-bone meal (MBM) derived from ruminants from infected countries to sheep and goats has been banned in Argentina since July 1995 (RESOLUTIONS 429/90, 382/95, 203/96, 252/95 and 611/96, APPENDIX B) and effectively enforced.
Effective enforcement is the responsibility of port officers of SENASA and the Customs and Excise staff employed to detect illegal imports. In addition the feeding of ruminant protein to ruminant animals, even from indigenous safe sources of MBM is prohibited and gives a substantial increased confidence that any risk is at a very low level indeed. Enforcement of the law is verified by random sampling of ruminant feed in feed mills and on farm and by subjecting samples to either the microscopic test or ELISA for ruminant protein. No breaches of the regulations have been found following checks of over 102 samples in the period April 1997-June 1999.
6.3.5 Importation of sheep, goats, semen and embryos/ova
Importation of sheep, goats, semen and embryos/ova is effectively enforced and is the responsibility of port officers of SENASA and the Customs and Excise staff employed to detect illegal imports. Legal imports from all countries including those from countries or zones not free from scrapie are carried out in accordance with Articles 18.104.22.168, Article 22.214.171.124, Article 126.96.36.199 and Article 188.8.131.52 as relevant.
6.3.6 ABSENCE OF BSE IN CATTLE IN ARGENTINA AND ABSENCE OF ANY ANIMAL TSE IN ARGENTINA
EVIDENCE FOR THE ABSENCE OF BSE IN CATTLE IN ARGENTINA IS PROVIDED IN THE SISTER DOCUMENT "BSE RISK FACTORS IN ARGENTINA" AND IN A DOSSIER PRESENTED TO THE EUROPEAN COMMISSION. THE RESULTS OF THE CONTINUOUS SURVEILLANCE FOR BSE AND OTHER ANIMAL TSE IN ARGENTINA SHOW THAT NO CASES OF ANIMAL TSE OF ANY KIND HAVE BEEN DETECTED IN THE PERIOD FOLLOWIG PUBLICATION OF THESE DOCUMENTS.
6.4 CONCLUSION I
The criteria established in draft by the OIE for declaring a country as scrapie–free have been satisfied for Argentina. THERE IS ALSO NO EVIDENCE FOR THE OCCURRENCE OF BSE IN ANY SPECIES OR ANY OTHER ANIMAL TSE IN ARGENTINA.
6.5 ADDITIONAL ASSURANCES I
Additional assurances that scrapie does not exist in Argentina can be given namely:
6.6 CONCLUSION II
The national sheep flock in Argentina has a low risk of harbouring scrapie.
6.7 ADDITIONAL ASSURANCES II
6.8 CONCLUSION III
Additional guarantees beyond those required by the OIE can be given to support the view that Argentina is a scrapie-free country.
7. FINAL CONCLUSIONS
ARGENTINA IS A SCRAPIE-FREE COUNTRY AS DEFINED BY THE OIE.
ARGENTINA INTENDS TO STAY SCRAPIE-FREE BY ADOPTING SCIENTIFIC PRINCIPLES TO REDUCE THE RISK OF SCRAPIE OCCURRENCE AND BY CONTINUOUSLY CONDUCTING SURVEILLANCE AND MONITORING FOR THE PRESENCE OF THE DISEASE.
ARGENTINA HAS A POLICY OF CONTINUOUSLY DEVELOPING ITS MONITORING AND SURVEILLANCE FOR SCRAPIE TO PROVIDE THE BEST GUARANTEES FOR ITS CUSTOMERS AT HOME AND ABROAD.