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An anonymous postal survey was conducted in 2002 to estimate the proportion of farms in Great Britain affected with scrapie and to gather information on the likely risk factors for the occurrence of the disease; the response rate was 53 per cent. The survey showed that 1 per cent of the respondents thought they had had scrapie in their flock in the previous 12 months, and that 12 per cent thought they had had scrapie in the past. The results of the survey were consistent with the results of a similar survey carried out in 1998, and with notification patterns, but in 1998 approximately 3 per cent of farmers reported having had scrapie in the previous 12 months. It is not clear whether the apparent decrease in the prevalence of scrapie is real or whether it may be due to factors such as sampling biases, or to the increasing knowledge of the signs of scrapie shown by the respondents in 2002.

The accuracy of somatic cell counts in milk samples was investigated in four studies. First, the counts recorded by one milk buyer in one supply over six months ranged from 105,000 to 401,000 cells/ml with no apparent changes in the volume of milk consigned or the level of mastitis in the herd that would explain this wide range. Secondly, the counts in daily samples from one bulk milk supply for 28 days ranged from 84,000 to 282,000 cells/ml, again with no apparent changes in the performance of the herd to explain the wide range. Thirdly, the replicated counts recorded for one sample by three separate laboratories agreed closely; however, when a sample with a high cell count was interspersed then two of the three laboratories reported high cell counts suggestive of 'carry-over' in excess of the 2 per cent 'allowable' Finally, cell count data from three separate laboratories on samples from 21 cows for 33 days revealed problems with the misidentification of samples on the farm in 1 per cent of the samples, and misidentification and mishandling of 1 to 2.6 per cent of the samples in the laboratories. All three laboratories differentiated samples from cows with subclinical and clinical mastitis, but the mean cell count of the uninfected cows varied between the laboratories with one of them recording statistically significantly higher counts over the period.

Scrapie is a fatal transmissible spongiform encephalopathy (TSE) of sheep and goats which is thought to be caused by a conformational change of the normal prion protein to its pathological isoform. It has been speculated that this change may be mediated by an interaction between the prion protein and various trace elements, in particular manganese and copper, and that the levels of trace elements in soils may therefore be risk factors for TSEs. This hypothesis was tested by comparing the level of trace elements in the soils on farms with and without scrapie and on those with a higher and lower incidence of the disease. The levels of trace elements were obtained from the UK's National Soil Inventory and deficiencies reported by farmers. The results provide no evidence that trace elements are risk factors for scrapie on farms, and the variations in the levels of trace elements in soils at regional scales do not account for the regional differences in the prevalence of scrapie.

In 1998, a questionnaire was sent to 11,554 British sheep farmers to determine how many believed that scrapie cases had occurred in their flock; 61.4 per cent of them responded anonymously. The results indicated that 14.9 per cent of farmers with more than 30 breeding ewes thought that they had ever experienced scrapie in their flock and 2.7 per cent thought that they had had cases in the past 12 months. A comparison of these results with the number of farmers reporting suspect scrapie cases to MAFF, in accordance with the statutory requirement, suggests that only 13 per cent of farmers who suspect that they may have cases of scrapie are currently reporting them. Scrapie occurred in all regions of the country but there was an apparent regional variation. Larger farms and those with purebred sheep appeared to be at greater risk of having cases. Other differences between affected and unaffected farms included lambing practices and sheep purchasing policy. On the majority of farms the first case occurred in a purchased animal. The survey also revealed a need for the provision of further information about scrapie to farmers.