Scientific Opinion on BSE/TSE infectivity in small ruminant tissues

Andréoletti, Olivier; Budka, Herbert; Bunčić, S.; Collins, J. D.; Griffin, John M.; Hald, Tine; Havelaar, Arie; Hope, James; Klein, Günter; Müller‐Graf, Christine; Nguyen-Thé, Christophe; McLauchlin, James; Nørrung, Birgit; Peixe, Luı́sa; Maradona, Miguel Prieto; Ricci, Antonia; Sofos, John N.; Threlfall, John; Vågsholm, Ivar; Vanopdenbosch, Emmanuel

doi:10.2903/j.efsa.2010.1875

Cited by 14 publications

(10 citation statements)

References 97 publications

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“…Country 19871988198919901991199219931994199519961997199819992000200120102014 With regard to atypical BSE, there is a low occurrence of both H-type and L-type over time. Because of the introduction of mandatory discriminatory testing and the retrospective discriminatory testing of cases, 96.6% of all cases confirmed between 2003 and 2015 have been subject to discriminatory testing.…”

Section: Eusr On Transmissible Spongiform Encephalopathies In 2015mentioning

confidence: 99%

“…Looking at the total number of cases by type and surveillance target group (Figure 12), CS cases are reported more frequently among the NSHC target group than among the other surveillance target groups. Year 20102014Total 200220102014 Total EU Figure 13 shows the evolution of the proportion of cases (per 10,000 tests) in non-infected flocks, which has remained stable over the last 10 years.…”

Section: Tse Surveillance In Small Ruminantsmentioning

confidence: 99%

“…It is clear that some MS only detected classical cases while others detected only atypical cases. The CS/AS plot can be interpreted under the assumption that the occurrence of AS is homogeneously distributed in the EU and that the occurrence of AS is not influenced by breeding programmes (EFSA BIOHAZ Panel, 2010, 2014. There are a number of MS for which the CS/AS ratio has decreased over time, for example, Germany, France, Ireland, the Netherlands and the UK (this is shown by a decrease in the ratios crossing the line at 1, in which the number of cases of CS and AS would be equal).…”

Section: Tse Surveillance In Small Ruminantsmentioning

confidence: 99%

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The European Union summary report on data of the surveillance of ruminants for the presence of transmissible spongiform encephalopathies (TSEs) in 2015

Boelaert¹,

Hugas²,

Pelaez³

et al. 2016

EFS2

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This report of EFSA presents the results of surveillance activities on transmissible spongiform encephalopathies (TSEs) in bovine animals, sheep and goats as well as genotyping data in sheep, carried out in 2015 in the EU and in three non‐Member States (non‐MS). Since 2001, approximately 114 million cattle in the EU have been tested for bovine spongiform encephalopathy (BSE) according Regulation (EC) 999/2001. In 2015, 1.4 million bovine animals were tested and five cases were detected in four MS (Ireland: one case; Slovenia: one case; Spain: one case; and the United Kingdom: two cases) and one case was detected in Norway. Two cases (in Ireland and the United Kingdom) were affected by classical BSE and both cases were born after the EU‐wide feed ban enforced in 2001. The remaining four cases were atypical BSE cases (three H‐BSE type and one L‐BSE type). Since 2002, approximately 8.4 million small ruminants have been tested during the EU‐wide surveillance for scrapie. In 2015, 319,638 sheep and 135,857 goats were tested. In total, 641 scrapie cases in sheep were detected in 18 MS while 1,052 scrapie cases in goats were detected in nine MS, respectively. In two non‐MS (Iceland and Norway), 40 scrapie cases in sheep were detected. Although in a number of MS the decrease in classical scrapie is clear, at the EU level there is no clear decreasing trend in the occurrence of scrapie in small ruminants. Results obtained from genotyping in sheep confirm that cases of classical scrapie are clustered among certain genotypes, and animals with these genotypes seem to account for less than 20% of the European randomly sampled sheep population. In total, 580 samples from species other than domestic ruminants were tested for TSE in three MS, all with negative results.

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Section: Eusr On Transmissible Spongiform Encephalopathies In 2015mentioning

confidence: 99%

Section: Tse Surveillance In Small Ruminantsmentioning

confidence: 99%

Section: Tse Surveillance In Small Ruminantsmentioning

confidence: 99%

See 1 more Smart Citation

The European Union summary report on data of the surveillance of ruminants for the presence of transmissible spongiform encephalopathies (TSEs) in 2015

Boelaert¹,

Hugas²,

Pelaez³

et al. 2016

EFS2

View full text Add to dashboard Cite

show abstract

“…There is a paucity of relevant data related to CS dissemination in sheep of other genotypes. However, the data that do exist indicate that in other genotypes the dissemination kinetics of the PrP Sc is slower, and in some cases there is also no LRS involvement (EFSA BIOHAZ Panel, 2010 brainstem samples from animals infected for less than a year are therefore likely to test negative. However, this should not affect the overall sensitivity of the diagnostic test in VRQ/VRQ animals since the minimum age for testing is 18 months of age, if it is assumed that infection occurs at or shortly after birth.…”

Section: Sensitivity Of the Screening Diagnostic Tests (Rapid Tests) mentioning

confidence: 99%

Evaluation of the application of Finland to be recognised as having a negligible risk of classical scrapie

2015

EFS2

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Finland submitted a request to the European Commission to be recognised as a Member State with negligible risk of classical scrapie. EFSA has been asked to assess if Finland in its application has demonstrated for a period of at least seven years proposed/in the future, that a sufficient number of ovine and caprine animals over 18 months of age, representative of slaughtered, culled or found dead on farm animals, have been tested annually, to provide a 95% level of confidence of detecting classical scrapie if it is present in that population at a prevalence rate exceeding 0.1%. A risk-based approach using scenario tree modelling with stochastic simulations was applied. There is lack of data on the actual performance of the approved tests in field conditions, especially in sheep. Alternative scenarios were explored extending the range from the sensitivity provided by the past EU evaluations of screening diagnostic tests to a sensitivity of 50%, consistent with published data obtained under field conditions in infected goat populations. Using data provided by Finland in its application, the estimated parameters of the scenario tree model and the range of values of sensitivity, it is concluded that Finland has not tested annually a sufficient number of small ruminants to meet the requirement. Based on the expected number of samples to be tested in 2015 and future years, Finland would test a sufficient number of animals to meet the requirement if the actual test sensitivity under field conditions was at least 90%. It is recommended that specific analytical approaches should be agreed upon for use by other MS when preparing their applications for the recognition of the negligible risk of classical scrapie, and that data on the sensitivity of screening diagnostic tests in field conditions should be generated where possible.

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“…Most of the published data related to PrP Sc dissemination dynamics in sheep naturally affected with CS were obtained in sheep bearing the VRQ/VRQ genotype (for details see EFSA BIOHAZ Panel, 2010). In these animals, lymphoreticular system (LRS) involvement starts in the gut in the first months post exposure, and thereafter spreads to all lymph nodes, reaching a plateau around six months post infection.…”

Section: Parameters Common To All Msmentioning

confidence: 99%

Evaluation of the application of Denmark to be recognised as having a negligible risk of classical scrapie

2015

EFS2

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Denmark submitted a request to the European Commission to be recognised as a Member State with negligible risk of classical scrapie. EFSA has been asked to assess if Denmark in its application has demonstrated for a period of at least seven years proposed/in the future, that a sufficient number of ovine and caprine animals over 18 months of age, representative of slaughtered, culled or found dead on farm animals, have been tested annually, to provide a 95% level of confidence of detecting classical scrapie if it is present in that population at a prevalence rate exceeding 0.1%. A risk-based approach using scenario tree modelling with stochastic simulations was applied. There is lack of data on the actual performance of the approved tests in field conditions, especially in sheep. Alternative scenarios were explored extending the range from the sensitivity provided by the past European Union evaluations of screening diagnostic tests to a sensitivity of 50%, consistent with published data obtained under field conditions in infected goat populations. Using data provided by Denmark in its application, the estimated parameters of the scenario tree model and the range of values of sensitivity, it is concluded that Denmark has not tested annually a sufficient number of small ruminants to meet the requirement. Based on the expected number of samples to be tested in 2015 and future years, Denmark would not test a sufficient number of animals to meet the requirement. It is recommended that specific analytical approaches should be agreed upon for use by other Member States when preparing their applications for the recognition of the negligible risk of classical scrapie, and that data on the sensitivity of screening diagnostic tests in field conditions should be generated where possible.

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Scientific Opinion on BSE/TSE infectivity in small ruminant tissues

Cited by 14 publications

References 97 publications

The European Union summary report on data of the surveillance of ruminants for the presence of transmissible spongiform encephalopathies (TSEs) in 2015

The European Union summary report on data of the surveillance of ruminants for the presence of transmissible spongiform encephalopathies (TSEs) in 2015

Evaluation of the application of Finland to be recognised as having a negligible risk of classical scrapie

Evaluation of the application of Denmark to be recognised as having a negligible risk of classical scrapie

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