Volume 6: Human Health, 1989-96
6. Events from 1 April to 31 December 1995: human health returns to the agenda
Developing knowledge on BSE and CJD
CJD developments: farmers and young people
Born after the ban cases of BSE (BABs)

6.243 This section gives a brief account of the main developments between April and December 1995 regarding knowledge of BSE, particularly those with possible human health implications, and developments on CJD. These developments are discussed in more detail in other volumes, particularly vol. 2: Science and vol. 8: Variant CJD.

CJD developments: farmers and young people ¹

6.244 As described in vol. 8: Variant CJD, from 1991 to 1994 the CJD Surveillance Unit (CJDSU) recorded the deaths of three dairy farmers from CJD. All had confirmed cases of BSE in their herds.

6.245 On 13 January 1995 SEAC held a special meeting to consider the significance of the death of a third dairy farm worker case from CJD. They concluded that the occurrence of CJD in three dairy farm workers with BSE in their dairy herds within the first five years of the CJDSU's surveillance study was a matter of concern, given the low probability of this happening by chance. However, there was no evidence to suggest that these were other than sporadic cases. ²

6.246 SEAC concluded that more information was needed before firmer conclusions could be drawn. However, SEAC agreed that the Government did not need to revise the measures taken to safeguard public health against occupational and other possible routes of exposure to BSE.

6.247 The second suspect case of CJD in a teenager was referred for an opinion to the CJDSU in May 1995. ³ The first suspect case notified to the Unit had been identified in early 1994, as described in Chapter 5. A third case of CJD in a young person was referred to the Unit in August 1995. ⁴

6.248 At its meeting of 8 September 1995, SEAC discussed CJD in young people. The minutes of the meeting noted:

It was the Committee's view that the presentation of CJD in adolescents is exceptional but not without precedent. CJD has occurred in adolescents in other countries which are free from BSE and it would therefore be premature to conclude that its occurrence in a teenager in the UK was indicative of transmission of BSE. The Committee agreed that these cases should be studied in great detail and it should consider whether they had any implications for the cause or management of the disease. ⁵

6.249 On 29 September 1995 the press reported the third case of CJD in a dairy farmer, ⁶ and the CMO was informed of a suspected fourth case. ⁷ The fourth case involved a farmer who had kept a beef suckler herd which had a single case of BSE in 1991. SEAC considered the fourth case during a special meeting on 4 October 1995. The following conclusions were reached:

• there had been a worrying number of cases in farmers exposed to cattle with BSE. However, if there were an occupational link, there would be other occupations that might be expected to be at greater risk, and there was no evidence for this;
• the stage was being reached where it was difficult to explain the cases as a chance phenomenon. However, although significant, the absolute risk remained extremely low;
• the evidence in the current case was exposure to BSE for a short period. There was also the likely presence of meat and bonemeal fed to poultry before 1990;
• it was unclear whether the potential risk factor might be association with animals with BSE or the food given to them (it was known that some farmers ate small amounts of calf and cattle feed but not whether they also ate pig and poultry feed). It was suggested that there might be a problem with dust from feed but that this should be more of a problem with feed compounders;
• given that there was a problem relating the cases to a causal link, the transmission studies were particularly important;
• it was still necessary to make a final diagnosis of CJD in the possible 4th case. ⁸

6.250 On 23 October 1995 the Daily Mail reported the fourth case of CJD in a cattle farmer. ⁹ Later that day SEAC released a public statement:

It was difficult to explain this as simply a chance phenomenon. There is a statistical excess of cases in cattle farmers compared with the general population but the absolute risk, even for cattle farmers, is extremely low at about 2 cases per million per year. There may be other explanations for such an association besides infection with BSE, and the Committee noted that there are no reported cases in other occupational groups such as veterinarians who might be expected to be similarly exposed. ¹⁰

6.251 SEAC also released a statement on CJD in adolescents on the same day:

We note that two cases of CJD have been diagnosed in adolescents in the UK. It is not possible to draw any conclusions from this, as confirmed cases of CJD have been found in the same age group in other countries. In addition, the two cases had no exposure to risk factors for CJD and no contact with BSE. It is essential, however, to study the patients in great detail and consider whether there are any implications for the cause or management of the disease. ¹¹

6.252 In October 1995 a 29-year-old patient was referred to the CJDSU. ¹² By 14 December 1995 the Unit had identified ten suspect cases of CJD in patients aged under 50 years. ¹³ By 31 December 1995 only three of these cases had been confirmed neuropathologically as CJD, although none had been confirmed as vCJD (new variant CJD) because the phenotype had not been recognised at the time. ¹⁴

Born after the ban cases of BSE (BABs)

6.253 As shown in vol. 16: Reference Material, born after the ban (BABs) cases - that is, cattle born after the ruminant feed ban was introduced that nevertheless succumbed to BSE - had reached a peak in 1994, with 11,569 cases. During 1995 a further 10,369 BABs were recorded. Throughout 1995, MAFF investigated possible deficiencies in the implementation of the ruminant feed ban, including the possibility of cross-contamination in feed mills. MAFF's response to BABs is described in more detail in vol. 5: Animal Health, 1989-96.

6.254 During its 18th meeting, on 10 February 1995, SEAC had considered papers which revealed that cross-contamination at feed mills had occurred in the past, and which also suggested that this was the main reason for BABs. ¹⁵ At its 19th meeting, on 21 June 1995, SEAC was advised of MAFF's programme of unannounced surveillance visits to slaughterhouses to assess compliance with the SBO ban. ¹⁶ In relation to what was known so far, the minutes record:

So far, on the basis of a very small sample, it appeared there were some problems with the separation of SBOs and that less than 50% were complying with staining requirements. ¹⁷

6.255 The minutes record that the Committee considered that BABs might be explained by contamination of animal feed with SBO:

The Committee was very concerned at these reports given the previous understanding that the position had been satisfactory. It was now recognised that previous reports based on pre-arranged visits to premises had given a falsely reassuring picture. The Committee felt that, if there was evidence that something was going wrong, action should be taken as a matter of the highest priority. The best hypothesis for the continuing number of BABs now seemed to be that SBOs had continued to leak through the system. If this was the case, BAB cases could continue until 2000. ¹⁸