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Agriculture: Transmissible Spongiform Encephalopathy

Answer

Great Britain—the joint descriptive report for scrapie surveillance of sheep and goats in 2010, published on the Animal Health and Veterinary Laboratory Agency (AHVLA)'s website at http://vla.defra.gov.uk/science/docs/sci_tse_stats_scrapie.df, details the incidence and prevalence of classical and atypical scrapie in Great Britain between 2002 and 2010, with tables showing the numbers of animals tested each year, in each surveillance group. The next edition of the report, updated for 2011, will be published in the summer. In the mean time, a table published on the AHVLA's website at http://vla.defra.gov.uk/science/docs/sci_tse_stats_sheep.pdf details the numbers of sheep tested in each surveillance group in 2011 and January-February 2012. The summary below gives a brief comparison of the prevalence of classical and atypical scrapie in 2005 with that in 2007 and 2011: Classical scrapie—the prevalence of classical scrapie in healthy animals over 18 months of age slaughtered for human consumption (abattoir survey) has reduced by 66% between 2005 (0.1% of all animals tested) and 2011 (0.03%) but has remained unchanged between 2007 (0.02%) and 2011 (0.03%). The reductions in prevalence in this survey between these years are not statistically significant. In sheep over 18 months of age found dead on farm (fallen stock survey), the prevalence of classical scrapie has reduced by 92% between 2005 (0.32% of all animals tested) and 2011 (0.025%) and by 80% between 2007(0.13%) and 2011 (0.025%). The reductions in prevalence in this survey between these years are statistically significant. Atypical scrapie—the prevalence of atypical scrapie in healthy animals over 18 months of age slaughtered for human consumption (abattoir survey) experienced hardly any change between 2005 (0.14% of all animals tested) and 2011 (0.15%) although in 2007 it was 50% lower (0.07%) than in 2011 (0.15 %). The reduction in prevalence in this survey in 2007 is not statistically significant and could be due to sampling variability. In sheep over 18 months of age found dead on farm (fallen stock survey) , the prevalence of atypical scrapie experienced a 60% increase between 2005 (0.06% of all animals tested) and 2011 (0.1%) , and a 20% increase between 2007 (0.08%) and 2011 (0.1%). The increases in prevalence in this survey between these years are not statistically significant. It is important to remember that these figures correspond to the two sub-groups of the sheep population that are tested by the active surveillance system. The abattoir survey data represent the best approximation to the true prevalence of scrapie infection in the national sheep flock. Northern Ireland—no comparable report is available for Northern Ireland. Annual prevalence of scrapie in sheep, as a percentage of the population, is:

Year	Classical scrapie prevalence for active surveillance (%)	Overall classical scrapie prevalence (%)	Atypical scrapie prevalence for active surveillance (%)	Overall atypical classical scrapie prevalence (%)	Overall scrapie prevalence (%)
2002	0.000	0.000	0.000	0.000	0.000
2003	0.043	0.086	0.000	0.000	0.086
2004	0.000	0.139	0.000	0.000	0.139
2005	0.338	0.338	0.000	0.000	0.338
2006	0.171	0.303	0.019	0.019	0.322
2007	0.056	0.111	0.083	0.083	0.194
2008	0.048	0.048	0.096	0.096	0.144
2009	0.000	0.066	0.000	0.000	0.066
2010	0.000	0.000	0.000	0.000	0.000

The prevalence of classical scrapie in healthy animals over 18 months slaughtered for human consumption in Northern Ireland has been 0% over the past three years. The prevalence of atypical scrapie in healthy animals over 18 months slaughtered for human consumption in Northern Ireland was 0.164% (1 case) for 2011 and 0% over the previous two years. No cases of either classical or atypical scrapie have been found in sheep found dead on farms during the last three years. Details of confirmed cases of classical and atypical scrapie in Northern Ireland since 2000 are published at http://www.dardni.gov.uk/index/publications/pubs-dard-animal-health/publications_animal_health_ and_welfare-newpage-5.htm.

Secondary information

Type

Written question

Reference

16424; 736 c288-90WA

Session

2010-12

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Agriculture: Sheep Carcasses
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Agriculture: Transmissible Spongiform Encephalopathy
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Subjects

Sheep Transmissible encephalopathies

Contains statistics

Yes

Link

View this Written question on www.publications.parliament.uk