Volume 8: Variant CJD
5. Emergence of variant CJD
Chronological account of the emergence of vCJD
1989
'The first farmer' - August 1992
'The second farmer' - July 1993
First young suspect case of CJD (Case A) - January 1994
'The third farmer' - December 1994
Second young suspect case of CJD (Case D) - May 1995 (later confirmed as vCJD)
Third young suspect case of CJD (Case E) - August 1995 (later confirmed as vCJD)
The fourth farmer - September 1995

1989

5.3 The first report of an association of a case of CJD with a farm, after the emergence of BSE in 1986, was on 13 October 1989. Dr Pickles wrote to Dr Will relaying a conversation she had with a neuropathologist. The conversation concerned a case of CJD in a woman said to be associated with a farm where there had been cases of BSE. The neuropathologist was uncertain about her age, initially claiming her to be 36, but later suggesting that she could have been older. Dr Pickles commented:

When I hear more, I will pass on the details to you, but you may hear from your own grapevine contacts in any case. Let's hope Dr Timperley [the neuropathologist] got the age wrong by several decades. And let's also hope the media do not hype it up before we have a chance to investigate in adequate detail. ¹

5.4 Later that month, on 26 October 1989, a CJD case was mentioned in a minute from Sir Donald Acheson, (CMO) to Mr Roger (now Lord) Freeman (Minister, DH). Sir Donald informed him of the CJD case, a 60-year-old woman, who was said to be associated with a farm where there had been BSE cases. ² (This may have been the case referred to by Dr Pickles, but this is not stated in the minute.) He noted that Dr Will would be making 'appropriate enquiries'. ³

5.5 Sir Donald also commented upon the lack of press interest, but pointed out that if questions arose, the response would be not to comment on individual cases and reiterate that the risk was remote. He suggested using the analogy that scrapie had infected sheep many years ago with no 'apparent hazard to humans'. ⁴ The minute also advised that the Government was already taking steps in view of the remote possibility of transmission of BSE to man. ⁵

5.6 The results of Dr Will's investigations into this case were relayed by Dr Pickles on 20 November 1989 to Sir Donald. She stated that Dr Will's conclusion was that 'any connection between this patient and any bovine condition was tenuous'. ⁶ She further commented that no further action was required.

'The first farmer' - August 1992

5.7 At the beginning of August 1992, Dr Will confidentially informed Dr Ailsa Wight (DH, senior medical officer with responsibility for TSEs), that a probable case of CJD had occurred in a 60-year-old farmer whose farm, in the Manchester area, had a history of BSE. Dr Wight passed on this information to Sir Kenneth Calman (CMO) on 13 August 1992, stating that the CJD patient was alive and had been visited by the CJDSU. ⁷ Although unconfirmed, the diagnosis was considered likely to be CJD on clinical grounds. Dr Wight advised that:

There is no direct evidence that the two events (BSE and CJD) are linked and Dr Will feels they are probably a coincidence. Despite the rarity of CJD, it was perhaps only a matter of time before this situation arose, given the large numbers of people employed in the agricultural and related industries, and the fact that BSE cases now total over 65,000. ⁸

5.8 This 'first case' of CJD in a cattle farmer was discussed by SEAC ⁹ at their 13th meeting on 15 October 1992. ¹⁰ Dr Will informed the meeting that one of the farmer's cows had confirmed BSE in 1989 and that the farmer had developed CJD two years later. ¹¹

5.9 Dr Will informed SEAC that he intended to publish a report of his study of this case in a scientific journal 'which would probably draw the conclusion that there was no evidence that this was not a chance occurrence of normal disease'. Dr Will also reported that his studies at the CJDSU had failed to reveal a correlation between occupational backgrounds and CJD to date. ¹²

5.10 On 22 October 1992, a minute from Mr Thomas Murray (SEAC DH Secretariat) informed the Secretary of State about the SEAC meeting and the fact that the farmer had now died. ¹³ He noted that the diagnosis of CJD had been confirmed by pathology and that the CJDSU had also ruled out iatrogenic or familial CJD, as well as exposure to cattle brain. He commented that the SEAC meeting had come 'to the view that all indications suggested that it was a typical sporadic case of CJD. However in view of the history it is hoped to carry out further laboratory studies to try to confirm this.'

5.11 Dr Will published his report of the case, 'Creutzfeldt-Jakob Disease in an Individual Occupationally Exposed to BSE', as a letter in The Lancet on 6 March 1993. ¹⁴ The letter concluded that 'CJD in our case is most likely to have been a chance finding and a causal link with BSE is at most conjectural'. The letter noted that the only possible direct route of cross-contamination was that the farmer had drunk pooled milk from his herd which included that from the affected cow, but that epidemiological evidence had largely precluded milk as a route of transmission in spongiform encephalopathies.

5.12 This letter created much media interest over the following few days, and its contents were reported in The Times, ¹⁵ Today, ¹⁶ Daily Express, ¹⁷ Daily Mail, ¹⁸ and Daily Telegraph which also reported Mr Kevin Taylor (Assistant Chief Veterinary Officer, MAFF) stating 'I don't think that a link between this case and BSE is even conjectural' and rejecting fears that the farmer might have contracted the illness from milk. ¹⁹

5.13 On 10 March 1993, Mr Jimmy Young of BBC Radio 2, interviewed microbiologist Professor Richard Lacey, who commented that:

The good news is that this farmer, I think, got it too soon. If BSE produces this disease in people it will take, perhaps, another 5 or 10 years. So I think this is a one-off coincidence and I don't think this farmer got his disease, CJD, from BSE. But nevertheless the underlying worries remain and I think it's reasonable that this issue should be discussed. ²⁰

5.14 The Second Annual Report of the CJDSU, published in July 1993, concluded that: ²¹

This is most likely to have been a chance occurrence rather than indicating any causal link with BSE.

5.15 It further noted that:

A farmer's wife who was diagnosed in 1992 had worked on a small holding for over 20 years but there had not been a case of BSE in the herd (Wilesmith, Personal Communication). ²²

'The second farmer' - July 1993

5.16 In early July 1993, Dr Will informed DH of a 'second' case of CJD in a farmer with BSE in his herd. The diagnosis had been confirmed by brain biopsy. ²³

5.17 Dr Wight described the case in a minute sent on 12 July 1993 to the private secretaries to Baroness Cumberlege and Sir Kenneth Calman. The minute was copied to others in DH and to Mr Howard of MAFF. The 64-year-old dairy farmer from the West Country was thought to have had at least two BSE cases in his herd, which were diagnosed in 1992. He was also thought to have assisted in calving and to have drunk the milk from his herd. His clinical symptoms had begun in May 1993. She commented that the history did not suggest anything other than a sporadic case of CJD but that DH was taking expert advice on the case. ²⁴

5.18 On 19 July 1993, Mr Kevin Taylor (MAFF) minuted the private secretary to Mrs Gillian Shephard, the MAFF Minister, in a response to a request for more detailed briefing. ²⁵ He noted that neither Dr Will nor the CJDSU intended to publicise the case at that time unless it attracted media attention, as they intended to include the information in their Third Annual Report due in approximately one year, ie, July 1994.

5.19 The minute attached a briefing note for the Minister. This specifically mentioned the consideration of occupational exposure to BSE as discussed in the CJDSU's Second Annual Report which concluded that:

. . . current information does not suggest that occupation is linked to an increased risk of developing CJD and it includes occupations which might involve an increased exposure to the agent of BSE. ²⁶

5.20 On 20 July 1993, SEAC held a meeting to consider this 'second case'. ²⁷ They decided that a connection between occupation and CJD was unlikely and no conclusions could be drawn from the available statistical information. A paper by Professor Smith was presented which concluded that 'the observation of two cases in workers in dairy farms with BSE-infected herds is disquieting, but the evidence is insufficient at this stage to draw any definite conclusions'. ²⁸

5.21 On 12 August 1993, the Daily Mail and Today publicised the story of the 'second case' of CJD in a dairy farmer. ²⁹ Both named the farmer and reported a DH spokesman saying that the Government's experts had considered the case and 'agreed that there are no features that give cause for undue concern'. The spokesman had also commented that it was most unlikely that there was any direct link between BSE and CJD in the patient.

5.22 In September 1993, the case study of this 'second farmer' was published in The Lancet. This letter gave the farmer's age as 54. ³⁰

5.23 At the next meeting of SEAC on 7 October 1993, the case was reconsidered. ³¹ It was agreed that if a third case of CJD appeared in a farmer with BSE in his herd, a full Committee meeting would need to be convened. ³² SEAC could not identify any further risk factors that a farmer might be exposed to, in general, and specifically with regard to the two cases, other than those previously considered. ³³

5.24 In September 1994, the CJDSU published its Third Annual Report. This noted that case reports had been published on two dairy farmers with CJD who had had BSE in their herds. It indicated that a study of the occupations of CJD patients had provided no evidence that working with animals or animal products was associated with an increased risk of CJD. ³⁴

First young suspect case of CJD (Case A) - January 1994

5.25 On 13 January 1994, an article in Today reported a case of brain disease in a 16-year-old girl, and claimed that she was the youngest victim of CJD. ³⁵ We refer to her in this chapter as case 'A'.

5.26 The same day, Dr Roger Skinner (Principal Medical Officer, DH) minuted Dr Jeremy Metters (Deputy CMO, DH) informing him that Dr Will suspected that the case reported in the newspaper was one he had become aware of three months previously. Dr Will had said that the girl had an undiagnosed progressive degenerative brain disease and that it would be classified as a 'possible' case of CJD. ³⁶ The minute also noted that, if the case was definitely CJD, it would be the youngest case reported in the UK in the past 23 years. However, there had been cases of CJD in teenagers (one from the US, others from the rest of the world) from places where BSE is not found.

5.27 Dr Wight produced a note on 14 January 1994 for Dr Michael McGovern (Private Secretary to the CMO) and other DH officials. ³⁷ The note stated:

Points on this particular case

1. Diagnosis not confirmed. Clinically could be consistent with CJD, but EEG is not typical. Biopsy performed and shows spongiform change and astrogliosis (as in CJD). Staining for abnormal prion protein is negative.

2. Duration of the disease so far about 1 year - longer than average (4 months). Aged 15 years at onset of illness. No family history of similar illness.

3. If diagnosis of CJD can be confirmed, this will be post-mortem on histopathological examination (but even this may not be definitive). Patient's course static over last 3 months.

5.28 Under the heading 'Age of Onset' Dr Wight commented, 'If confirmed as CJD, this is [the] youngest patient seen in the UK in 23 years (1970-93) since data [were] collected'. Her note had a separate heading for 'Comparison with young onset cases in world literature'. Here she noted that Creutzfeldt's first patient was 23 years old (reported in 1920), and that there were other cases of CJD in young people which predated the emergence of BSE. These were a 20-year-old female and a 16-year-old female in the US and a 19-year-old female in France. ³⁸

5.29 On 26 January 1994, the Chief Medical Officer (CMO) released a statement in response to the media attention about this young CJD case. This stated that 'no-one knows what illness she is suffering from' and that 'on the basis of the work done so far, there is no evidence whatever that BSE causes CJD'. ³⁹

5.30 At its 16th meeting on 26 January 1994, SEAC considered information on Case A. ⁴⁰ Dr Will presented the case saying the tests were inconclusive and that the case was possible CJD. Transmission studies were recommended should the patient be shown at post-mortem to have CJD. Additional information was discussed including that there was no history of human growth hormone, no family history, unpasteurised milk had been consumed by the patient, and she had worked in a cattery. It was subsequently confirmed that there had been no FSE cases locally and, specifically, none from this cattery.

5.31 At the same meeting, Dr Will informed the Committee that he had applied for MRC funding for transmission studies using the brain material from the two dairy farmers with CJD (see paragraphs 5.7-5.24). ⁴¹

5.32 On the evening of 26 January 1994, Channel 4 Television screened an episode of 'Dispatches' featuring the case of the 16-year-old girl (case A). As well as interviewing her family, the programme interviewed both Dr Gareth Roberts, a neuropathologist at St Mary's Hospital, London, and Dr Tyrrell. On 15 April 1994 a report on Case A was published by the World Health Organisation. ⁴²

'The third farmer' - December 1994

5.33 A 'third case' associated with farming where cattle in the herd had contracted BSE concerned a farm worker from Cornwall who had died in early December 1994, aged 54. There had been two confirmed cases of BSE on the farm, in August 1991 and October 1992. Additionally, a cow sold off the farm in December 1987 had been diagnosed with BSE in September 1988. ⁴³

5.34 On 1 December 1994, the case was reported in the local newspaper, The Cornishman, while the patient was still in hospital. ⁴⁴

5.35 On 19 December 1994, Mr Charles Lister, DH, minuted the private secretary to Baroness Cumberlege with information about this possible 'third case in farmers/farm workers who have had BSE cases in their herds'. ⁴⁵ This minute enclosed the article from The Cornishman and was copied to DH officials and to Mr Eddy at MAFF. He noted that diagnosis would not be confirmed until post mortem, but the Surveillance Unit thought it highly likely to be CJD.

5.36 On the same day, Mr Thomas Eddy, MAFF secretary to SEAC, passed the newspaper article and basic information about the case on to MAFF Ministers and officials. ⁴⁶

5.37 On 13 January 1995, SEAC held a special meeting to discuss the significance of this third case of CJD in a farmer in the first four years of surveillance. ⁴⁷ Dr Sheila Gore, an epidemiologist from the MRC Biostatistic Unit, was invited as an independent expert.

5.38 Detailed consideration was given to the case itself and the epidemiological implications. Dr Will commented that the post-mortem results were not yet available, but it was highly likely that the diagnosis of CJD would be confirmed. He stated that the man had no significant medical history and that he had worked as a farm labourer on the same dairy farm since 1955:

The man was known to have assisted with calving but never with any operative procedure; he rarely drank unpasteurised milk and never from BSE-affected animals. It was not known if he had ever eaten cattle feed. ⁴⁸

5.39 As to the epidemiological significance of the case, the members recalled the advice given by Professor Smith after SEAC had considered the second case of CJD in a farmer:

Professor Smith had advised that if four cases arose in the first 5 years of the surveillance scheme the possibility of an association which was not due to chance had to be given very serious consideration. ⁴⁹

5.40 Dr Gore commented that:

If the adult incidence of sporadic CJD in the UK was taken as one case per million (the figure used by Professor Smith) and if the same incidence applied to workers on dairy farms with BSE-affected herds, then the probability of observing three or more definite CJD cases in such workers in England and Wales in 5 years was low: 4 in 1,000. The probability was higher if the calculation was made using the total number of dairy farm workers in England and Wales. However, this was considered to be less relevant as the only reported cases of CJD in dairy farm workers since 1990 had been in lifetime dairy workers all with BSE-affected herds.

5.41 However, Dr Gore also said that the calculation of this probability had been based on the information to hand. She recommended that:

1. The number of dairy farmers should be put on a UK basis.
2. It should be established whether the figure used for the proportion of herds with one or more cases of BSE applied to the UK or to England and Wales only.
3. Actual CJD figures should be used for 1990 to 1994 rather than the guesstimate of one case per million.

5.42 The Committee concluded that the occurrence of CJD in three dairy farm workers, with BSE in their dairy herds, within the first five years of the surveillance study, was a matter of concern given the low probability of this happening by chance. ⁵⁰ However, there was no evidence to suggest that these were other than sporadic cases. The Committee expressed a wish for further information before making firmer conclusions, and recommended the following work to be undertaken as a matter of priority:

1. Further statistical analysis broken down by age, comparing the relative risks of developing CJD between farmers and other workers in contact with animals, and other occupational groups without such contact.
2. Study of the working practices of risk occupation groups, eg, farmers' contact with cattle feed dust.
3. Incidence of CJD in UK farmers compared with countries with little or no BSE.
4. Transmission studies with brain material from the third farmer.

5.43 It was concluded that the case did not require the Government to revise the measures taken to safeguard public health against occupational and other possible routes of exposure to BSE.

5.44 A draft DH statement was prepared to respond to any media enquiries. ⁵¹ This confirmed that SEAC had considered the case to be a sporadic form of CJD. However, as this was the third case of a farmer with CJD, they wished to undertake further statistical analysis.

5.45 On 16 January 1995, Mr Eddy minuted the private secretary to the MAFF Minister, Mr William Waldegrave, outlining the discussion at the SEAC meeting and advising that MAFF was cooperating with DH in the further statistical analysis by providing information on the age distribution of farmers. The DH draft statement was also provided with this minute. ⁵²

5.46 On 19 January 1995, Mr Lister sent a further note to the private secretaries for the CMO and Baroness Cumberlege advising that the post-mortem results were positive for CJD. ⁵³ The note also included previous advice from an epidemiologist that if four cases in farmers emerged within the first five years of surveillance the possibility of an association not due to chance must be given very serious consideration.

5.47 On 10 February 1995, SEAC discussed the case of the third farmer at their 18^th Meeting. ⁵⁴ The minutes of the meeting record that Dr Tyrrell emphasised that transmission studies in mice and strain typing in mice of isolates from the three CJD cases in dairy farmers should be given the highest priority (see vol. 2: Science for an example of strain typing). ⁵⁵ This would involve brain material from the cases being inoculated into the brains of mice and looking to see if the clinical features and neuropathology were similar to BSE in mice, therefore suggesting a link between BSE and these cases of CJD.

5.48 Dr Will provided preliminary information that this third case of CJD in a farmer did not have a mutation of the PrP gene. This excluded the case being familial CJD and suggested that the most likely diagnosis would be sporadic CJD. However, the patient was a codon 129 valine-valine homozygote, which was a less usual genotype for sporadic cases (see paragraph 4.29). Dr Will also indicated his wish to publish the details of this third case in a scientific journal.

5.49 Dr Will further commented on the likely clinical presentation if BSE was to transmit to humans via the oral route. He expected presentation to be as a cerebellar syndrome with ataxia, ⁵⁶ like that seen in peripherally induced iatrogenic CJD cases such as human growth hormone cases. The three dairy farmer cases were all typical of sporadic CJD, ie, a rapidly developing dementia.

5.50 The details of this third case in a dairy farmer were published in The Lancet on 30 September 1995 by the CJDSU. The farm worker had suffered a three-month history of forgetfulness, altered behaviour, slurring of speech, ataxia and myoclonus. ⁵⁷ There was marked cognitive impairment. ⁵⁸ The lack of a relevant medical history or family history of CJD and the information that the farmer was homozygous for valine at codon 129 of the prion protein gene were also reported. ⁵⁹

Second young suspect case of CJD (Case D) - May 1995 (later confirmed as vCJD)

5.51 In the first quarter of 1995, two suspected cases of CJD in people under 50 were referred to the CJD Surveillance Unit. ⁶⁰ We shall call them 'B' and 'C'. ⁶¹

5.52 A second suspect case of CJD in a teenager was identified in May 1995 when a brain biopsy, which provided no definite diagnosis on review, was referred for an opinion to the CJD Surveillence Unit. ⁶² Dr Will told the Inquiry that despite the equivocal histology, attempts were made to obtain clinical information because of the remarkably young age of this patient. ⁶³ It was eventually established that there was no family history of dementing or ataxic illness and no history of exposure to human pituitary-derived hormone, neurosurgical procedures, or tissue grafting. ⁶⁴ We shall refer to this patient as 'D'.

5.53 Dr James Ironside (CJDSU) gave oral evidence to the Inquiry about his examination of the biopsy. ⁶⁵ He recalled the brain biopsy material being sent to him by a colleague at the National Hospital of Neurology and Neurosurgery, London. He noted that microscopic assessment of the neuropathology showed 'very little to suggest that this was in fact a case of CJD at all'. The features of spongiform change were not really present and there were none of the florid plaques or other features which were later to be associated with variant CJD. He added:

However, using the antibodies to PrP, using the immunocytochemical technique, there was a positive reaction and this was a finding that we had really not encountered before. I discussed this case with my colleague, Dr Bell, and we felt that the case could not be diagnosed definitively, but of course, since there was a positive reaction, that raised the possibility that this was a form of human prion disease, and that further investigations, as Dr Will suggests, were required. In particular, we wondered, in view of the age of the patient, and the somewhat unusual findings in the biopsy, if there was an underlying genetic abnormality that might explain this, because we were aware that in cases of familial CJD, the age of onset and the pathological features can often be unusual. ⁶⁶

5.54 Following the death of D on 21 May 1995, CJD was confirmed histopathologically by the hospital in Bath where he was treated. ⁶⁷

5.55 The 19th meeting of SEAC was held on 21 June 1995. Dr Will was unable to attend. There does not appear to have been any discussion of patient D or any other cases of CJD in young people. ⁶⁸

Third young suspect case of CJD (Case E) - August 1995 (later confirmed as vCJD)

5.56 Dr Will, in his statement to the Inquiry, noted:

A . . . young patient was referred to the Unit from another centre in August 1995 after a brain biopsy confirmed the diagnosis of CJD. Information on this case was obtained by the usual methodology. It is of note that young patients with CJD, including teenagers, had previously been identified in other countries in the past. ⁶⁹

5.57 We shall refer to this patient as 'E'. Dr Will added that the cases of the patients we have designated 'D' and 'E' were published in letters to The Lancet in October 1995, and that plaques were described in reports of the neuropathology in these cases.

5.58 On 11 August 1995, Mr Lister minuted the private secretaries to Baroness Cumberlege and the CMO concerning the purposed 12 August broadcasting of a 'World in Action' programme about CJD in teenagers and dairy farm workers. ⁷⁰ This programme was to publicise the third case of CJD in a dairy farm worker and Mr Lister was concerned about the likely renewed press coverage of the area.

5.59 Dr Will received the histology report on a brain biopsy from case E on 1 September 1995. ⁷¹ The report stated that:

The histology is that of a prion disease (spongiform encephalopathy). It is not possible to subclassify further this case on such a small cortical biopsy'.

Dr Will wrote to Dr Ironside on the same day:

The crucial issue in this case is whether the pathological changes as reported are really typical for sporadic CJD . . . do you think that the appearances as described are similar to the plaques we sometimes see in the cortex of growth hormone recipients and would you accept their appearances as described as being within our normal experience for sporadic cases.

5.60 Dr Will stated in written evidence to the Inquiry:

I have no exact memory of the subsequent conversation, but I do recall that we had no reason to disagree with the pathology report and that it was not, at that stage, possible to say that the neuropathological changes were distinct from previous experience. ⁷²

5.61 The 20th meeting of SEAC was held on 8 September 1995. The papers for the meeting included the fourth annual report of the CJD Surveillance Unit. This recorded at page 25:

Comment was made in the last Report regarding a case of suspect CJD in an adolescent. The diagnosis in this individual remains uncertain and may depend on eventual histological examination of the brain. It is unusual for patients with CJD to survive for longer than 12 months.

The diagnosis of CJD has recently been confirmed in a 19-year-old individual and detailed investigations are currently in progress (this case is not included in the overall analysis for this year's annual report as the patient was identified after 30 April 1995). The occurrence of CJD in a patient of this age is exceptional but not without precedent (see Possible Creutzfeldt-Jakob Disease in an Adolescent, Weekly Epidemiological Record 1994, 15, 105-12). CJD has been described previously in two adolescents in the United Stated of America which is free of BSE and in one adolescent in France which was free of BSE at the time of the patient's clinical illness. It would therefore be premature to conclude that the occurrence of CJD in an adolescent in the United Kingdom was indicative of transmission of BSE.

5.62 The teenagers mentioned in the Report were A and D above. At the meeting, SEAC were informed of a suspected case of CJD in a teenager (17 years old). ⁷³ This was case E. The minutes recorded:

. . . the pathology and clinical features of the patient, who remains in a coma, are atypical for CJD.

. . . 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.

5.63 On 29 September 1995, various newspapers reported the third case of CJD in a dairy farmer. ⁷⁴ Reference was made to a letter published in The Lancet (dated 30 September 1995) by Dr (now Professor) Smith (LSHTM).

5.64 The letter reported:

The occurrence of CJD in another dairy farmer with a potential occupational exposure to BSE is clearly a matter of concern. Statistical analysis indicates that the probability of discovering three or more dairy farmers with CJD by chance since 1990 in England and Wales ranges from 0.09 to 0.0002, depending on the occupational denominator (individuals who work on farms to full-time workers on BSE-affected dairy farms). ⁷⁵

5.65 Statistics for CJD in European farmers were also reported in the 30 September 1995 edition of The Lancet. ⁷⁶ The paper concluded that 'there is no differential increase in the risk of CJD to farmers in the UK through potential occupational contact with cases of BSE'. On the continent there was also a slightly higher proportion of cases of CJD arising in farmers. ⁷⁷ This indicated that in the UK, CJD in farmers had probably not arisen from transmission of BSE. ⁷⁸

The fourth farmer - September 1995

5.66 On 28 September 1995, Dr Wright minuted the private secretary to the CMO about a probable fourth case of CJD in a farmer. The 59-year-old beef farmer lived in North Wales and was alive when the case was reported to the CMO. The farm, which had a 70-strong suckler herd, had a confirmed case of BSE about four years previously in a 4½ to 5-year-old cow. ⁷⁹

5.67 The minute recorded the urgency of dealing with the issue as the case was in the public domain and BBC Wales were making a programme referring to the case. ⁸⁰ An urgent meeting of SEAC was called for the following week.

5.68 On 4 October 1995, SEAC held a special meeting to discuss this further suspected case of CJD in a cattle farmer. ⁸¹ Professor Smith (LSHTM) and Dr Cousens (LSHTM) were in attendance to provide the Committee with expert epidemiological advice. ⁸²

5.69 Dr Will advised that although the Unit had initially clarified the case as probable CJD, he felt that it was more appropriate to look at it as a suspect case. Consideration was given by SEAC to European data that showed 12 cases of BSE in France, along with a progressive neurological disease in a farmer associated with one of those cases. (In the eventuality, this farmer was not diagnosed with CJD. At the beginning of January 2000, there had been no reported cases of CJD in farmers in France where BSE had been found in that farmer's herd.)

5.70 Mr Wilesmith gave SEAC information about the farm associated with the possible UK fourth case of CJD under discussion. The farm had not been visited by MAFF. It had one case of BSE in a purchased animal which died in September 1991. From available information, the animals had not been fed on concentrates (although this had not been double-checked). It was thought, however, that the farm did have a big poultry battery unit, which may have meant that ruminant-derived feed was available on the farm.

5.71 Dr Cousens made a presentation of the epidemiology. ⁸³ He had calculated age specific mortality rates for sporadic CJD from 1990 to 1994 and applied these to data on farmers to calculate the expected number of sporadic CJD cases in farmers. The following conclusions were reached:

1. there had been an alarming number of cases in farmers who had had contact with cattle with BSE. However, other occupational groups, expected to carry greater risk (eg, abattoir workers, veterinary surgeons), did not appear to be affected;
2. it was now difficult to explain the cases as a chance phenomenon. Yet the absolute risk still remained extremely low;
3. it was unclear whether the possible risk factor might be associated with cattle with BSE or the food given to them; and
4. as there was a problem with establishing a causal link, transmission studies would be extremely important.

5.72 At this meeting, Dr Wight invited members of SEAC to make a fairly clear statement on how they viewed the significance of a fourth case and to consider whether they were satisfied that nothing else needed to be done in terms of practical measures. ⁸⁴ In evidence to the Inquiry, Dr Wight said that trying to get a clear statement as to what would be a significant number of cases in farmers was bound to be difficult. She said, 'I do not think that SEAC any more than anybody else had any idea how to make sense of this at this stage.' ⁸⁵ At the meeting, Dr Tyrrell's response was that although numbers were higher than expected, they were still extremely small. It would be irrational to take specific measures at the moment. Members of SEAC agreed to draw up a statement which the Department of Health could issue in response to media inquiries. ⁸⁶ The text of the statement included the following: ⁸⁷

The Committee concluded that it was difficult to explain this simply as a chance phenomenon. There is a statistical excess in cattle farmers compared with the general population but the absolute risk, even for 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 recorded cases in other occupational groups such as veterinarians who might be expected to be similarly exposed. They also noted that the surveillance of CJD elsewhere in Europe has shown a similar incidence of CJD in farmers, including dairy farmers, in countries with no or very few cases of BSE. They therefore felt that it was important to undertake further epidemiological studies to detect any particular risk factors which might be involved, and reiterated their advice that the UK cases of CJD in cattle farmers and the strain of agent recovered from them should be studied in detail.

The Committee have asked for further work to be done, but have not altered their advice to Government on the precautions necessary to protect either the public health, including farmers, and animal health.

5.73 Mr Eddy minuted the MAFF Minister and Parliamentary Secretaries advising them of the outcome of the SEAC meeting. ⁸⁸ He commented that SEAC had concluded that it would be worrying if the fourth case of CJD in a farmer from a BSE farm was confirmed.

The chances of four CJD cases occurring randomly in farmers with BSE in their herds was . . . [since 1990] around 3/10,000. The Committee therefore concluded that it was difficult to explain the incidence as a chance phenomenon. This is a change to the Committee's position; it had said that the most likely explanation of the three previous cases of CJD in dairy farm workers was that they were chance phenomena. ⁸⁹

5.74 Mr Eddy also stated that the SEAC did not recommend changes to any of the measures currently in place to protect human and animal health, including those of farmers and others handling cattle and BSE suspects.

5.75 On the same day, Mr Eddy prepared a second minute which was sent to Dr Matthews and Mr Keith Meldrum (CVO) amongst others about discussions during the SEAC meeting. ⁹⁰ Mr Eddy included a list of four ways in which the farmers might have been exposed to BSE that might have then led to their infection with CJD:

1. cattle were excreting the agent in some form - no evidence for this;
2. meat and bone meal (MBM) in cattle feed - if so this would affect pig and poultry farmers equally (these feeds also contained MBM);
3. normal food - unclear why this discriminated in favour of farmers, although farmers could have been exposed to foods that other people might not have been routinely exposed to, such as unpasteurised milk; and
4. contact with animals - possibly animals killed on the farm.

5.76 These four possible routes of infection had been discussed at the SEAC meeting but it was agreed that none of these routes were particularly plausible.