Myth and Reality - Nicola Morris. Appendix 1 to "Understanding the 2001 foot and mouth epidemic"


In this section key details regarding the epidemic are discussed with the
aim of separating  the myths from the reality.

Details covered
:- Scale of the epidemic
                          The 24/48 hr cull targets
                          Local Spread
                          Accuracy of clinical diagnosis and reliability of laboratory tests
                          Anecdotal evidence concerning the Contiguous cull


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1.Scale of the epidemic

Myth
' The scale of this epidemic was unprecedented'
  Diane Organ EU Inquiry FOD

Reality
The scale of the slaughter was certainly unprecedented, 10509 premises (4.2 million adult animals)were slaughtered out; a further 2 million animals were slaughtered for welfare reasons. We know for certain in this epidemic there were animals on 1324 farms  which had foot and mouth disease or had had foot and mouth in the previous weeks. Only by analysing disease transmission will we establish how many, if any, of the other 9185 premises were infected or incubating the disease at slaughter.


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2. The 24/48 hr cull targets

Myth
We would normally have consulted the industry and all our other stakeholders before introducing legislation but it became clear during the summer that it was sometimes touch and go whether we stayed  on top of the disease, not least because it was touch and go whether we could maintain the 24 or 48 hour slaughter deadline.
Margaret Beckett: ( Hansard 12/11/01)

Reality
For the epidemic as a whole 474 (33%) infected farms were slaughtered within 24 hours, and 137 (4. 6%) contiguous dangerous contacts were slaughtered within 48 hours.


Slaughter times on IP (PQ 5479)
                                                                                       % IPs Slaughtered within
                                                                      24hrs    48hrs     72hrs     >72hrs          >96hrs
first 4 weeks                                                   10         40          65           80              100
first 9 weeks                                                   24          65          85           93              100
Epidemic as a whole                                        33         72           88          94              100

(only 1444 premises are included in these figures. ie. 582 are missing)

Slaughter times on Contiguous Premises (dangerous contacts) (PQ 5478)
                                                                                       % IPs Slaughtered within
                                                                      48hrs     72hrs       96         >96hrs             >120 hrs
first 4 weeks                                                     0            4           11          24                    100
first 9 weeks                                                     2          12           27           49                   100
Epidemic as a whole                                          5           29          50           71                   100

(table is based on data from 2966 premises)

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3. Local Spread

Until disease transmission is analysed for the truly infected premises, it is difficult to separate myth from reality. It is interesting to note that there appears to be a discrepancy between DEFRA's , Elliot Morley's, Prof Mark Woolhouse's
and the Imperial College team's views on local spread. That is: the distance the disease was spreading and also how it was spreading.

a) Distance
i) ' 78% of infected premises were within 3 km of another infected premises'
     NAO report 18/06/02 - data extracted from DEFRA's Epidemiology report of 21 Oct 2001

ii)  Some 45 per cent. of all outbreaks in the disease were within 1 to 2 km of the initial outbreak and 60 per cent. of
     all outbreaks were within 1 to 3 km.
     Elliot Morley ( Hansard 12/11/01)

iii)' 50% of new cases turned up in the immediate neighbourhood of a previous cases'
      Professor Woolhouse EFRA select Committee 7/11/01 (189) (neighbourhood is about 3km)

iv) The median distance of the original kernel was about 2 km (March model).
    'The median distance of the newly estimated kernel is about 4km. ' (October Model)
    Imperial College team- Nature 4/10/2001 vol 413

Comment on the Imperial College team's view.
My understanding of  the Imperial College models, is that  in the March model (ie. the one used to determine culling policy) the midpoint distance between index cases and secondary infections was about 2 km. When constructing the October model the Imperial team found that because the cases had been more accurately traced the spatial relationship between index cases and secondary infections was not as they had previously believed in March:-

'The newly estimated spatial kernel (October Model) differed significantly from that previously derived from the infectious contacts identified by DEFRA (March model) with considerably more long distance transmission events
being predicted. This implies significant biases in the DEFRA contact-tracing process, with closer contacts being more easily identified. '

They discovered that the midpoint distance between index premises and secondary premises was now about 4 km not 2 km. That is: contiguous farms were  less at risk then previously thought.


b) Method of spread
i)  The Department considered that most local spread was attributable either to aerosol  spread between animals or
    from contamination, for example of roads or common facilities, by poor biosecurity on leaving and returning to
    farms.
     NAO report 18/06/02 - data extracted from DEFRA's Epidemiology report of 21 Oct 2001

ii)  Spread was due to animal contact and short distance aerosol spread -March Model

     Spread was due to movement of animals, personnel or vehicles rather than through animal contact or aerosol spread
     - October model.
    Imperial College team- Nature 4/10/2001 vol 413

Reality
The reality is until the infected premises are analysed taking into account their laboratory test results ( that is 1324 definitely had FMD, 401 probably didn't and 301 may or may not  have had FMD) we can not say with any certainty  how the disease was spreading and over what distance.
However, we can say , all the published evidence suggests, that there were many more market related infections than initially thought and we now know that many of these infections were not traced  for weeks even months after they had occurred. In addition, there are several counties where there was very little disease transmission once the movement ban was implemented; though the scale of the slaughter in these counties suggests that DEFRA, incorrectly, believed at
the time that the disease was spreading.

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4. Accuracy of Clinical Diagnosis and Reliability of laboratory tests

i) Accuracy of clinical diagnosis
Myth
' 74% of infected premises confirmed on clinical grounds tested positive in the laboratory'
  NAO report

Reality
Clinical and Laboratory test results for the 2026 infected premises  (source JCC data analysis) Of the 2026 premises 171 had no clinical signs of disease, that is they were antibody positive only. Therefore 1855 premises were diagnosed clinically, the laboratory test results for these premises were: 1153 positive, 401 negative and 301 untested.
Therefore, of the 1855 confirmed on clinical grounds 62% tested positive in the laboratory.

ii) Reliability of Laboratory tests
'A negative test result does not necessarily mean that the premise was free from disease.
 JCC data analysis Page Street

This statement obviously is true, nothing is 100%, but it does need to be clarified

The reality of laboratory testing during 2001 UK FMD epidemic As far as I am aware nobody has challenged Dr Alex Donaldson's view of laboratory testing, as presented in his letter to the Vet record May 19.
 That is-
diagnostic material was good, particularly as blood samples were often submitted along with epithelium
material submitted was tested for virus, viraemia and/or antibody as appropriate
animals with FMD will have either virus or antibody or both in their blood.
'While it is never the intention that laboratory diagnosis would replace clinical diagnosis, we believe that laboratory support for a diagnosis of FMD in sheep, in particular, is essential'
'The extreme difficult of making a clinical diagnosis of FMD in sheep is, in our opinion, the explanation for the discrepancy between the field and laboratory diagnoses'.

Agricultural committee ( of EFRA select committee) 25/04/01
Mr Opik (MP) -' We were informed that laboratory tests were not necessarily reliable. We were told that if a vet diagnosed the disease slaughter went ahead,even if the result was negative in the laboratory, that negative result was not necessarily reliable'.
Dr Donaldson- After clarifying the importance of sampling technique etc in answer to the question could he say with greater than 90% confidence that the negative test was reliable
Dr Donaldson replied ' Absolutely'.

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Appendix 2      Anecdotal Evidence

1. Disease Transmission due to mismanagement
 Some examples:
Alan Richardson - vet working in Cumbria
-reported incidences where almost all the animals in a herd had clinical
disease because slaughter was delayed.
Devon Inquiry
- disease spread because of delays in slaughter
   eg. Mr & Mrs Webber p65; Mr & Mrs Thomas p63.

- vets carrying out surveillance visits may have been inadvertently
spreading disease.
   eg. Mr Baker p72; DS & L Joslin p64.

2. Illegal and unnecessary pre-emptive culling

i)   Statements from Solicitors (source PRU Animal Health Bill 12/12/2001)

 William Neville, a senior partner at Bristol solicitors, Burges Salmon,
said that comments by countryside minister, Elliot Morley, were "pathetic. "
Mr Neville stated that the Government had withdrawn from seven of the nine
cases in which his company represented farmers.   Mr Morley MP had claimed
that the Government had won "almost all" its legal battles with farmers.
Alayne Addy, the Exeter based solicitor "who assisted two hundred farmers to
resist the contiguous cull, has confirmed that none of these subsequently
developed the disease and that all have since been cleared by" laboratory
test.

ii)  Statements from Farmers and NFU

 In the submissions of Pat Innocent, "The cases on Burgess Salmon's books
were also all negative. " A further point made Alan and Rosie Beat that you
yourself had alleged on World at One "that farmers resisting the cull had
increased the spread of disease and that this had resulted in more slaughter
overall" and they said, "We know of no such instance, whereas in contrast,
there are literally hundreds of premises where the cull was resisted and
whose livestock have remained uninfected, such as those examples given
above. "
(PRU 12/12/01)

Let us consider the operation of the culling powers. Mr. Anthony Gibson, who
looks after matters for the NFU in the south-west, has said that the
Minister's accusation that farmers spread the disease by resisting the cull
is
"simply not true here in Devon. None of the herds or flocks which were saved
from the contiguous cull, either by direct or by legal action, subsequently
developed FMD. "
Reported in Hansard 12/11/01

The number of contiguous/dangerous contact farms where slaughter was
successfully resisted has never been quantified. Many like us did not need
to fight our cases through the courts, once it was obvious we weren't going
to give in, MAFF simply decided to leave us alone. Twelve months on I am
still hearing of   other farmers in the Three Counties  who resisted, yet at
the time we thought we were the only ones.
Nicola Morris  Worcester.


iii) Statements from MPs
 Mr. Peter Ainsworth: (Hansard 12/11/01 Col 625)
 For example, culling was due to take place on 34 farms in the Forest of
Dean, but it took place on only 18. A successful legal challenge by farmers
resulted in the Minister using his discretion to arrange for blood tests to
be carried out on the animals on the remaining 16 farms. Those animals were
saved from the cull, and it eventually turned out that none of the farms had
any infection at all.

Mr. Jack:(Hansard 12/11/01 col 626)
Let us consider those who have had to go to court to defend their interests.
Peter and Gillian Cave, who are farmers in the west country, were
successful. They saved 100 pedigree Devon cattle which were earmarked for
slaughter. They described the Government's approach as "jackboot tactics".
They said of the measures:
"This smacks of Nazi law, malicious and spiteful-you bloody well behave or
we'll get you. "
They are people under stress. The point about the need to win over the
hearts and minds of the rural community on these measures is well made by
such powerful statements from farmers who have been affected.

Mrs. Browning:(Hansard 12/11/ 01  col 631)
I am sure that that is true in broad principle. However, in terms of the
contiguous cull-I am about to say something very nice about the Minister(Mr
Morley)-I am grateful to the hon. Gentleman for the role that he played in
allowing me to see him to refer to three farms in my constituency. He
examined the issues and he intervened. I am pleased to tell him that the
farms are still running, with the animals on them. They did not get foot and
mouth disease and the hon. Gentleman's intervention was extremely helpful.
It was also extremely sensible. It was not until 19 days after an outbreak
that the farms, which were deemed to be contiguous, were approached on the
basis that the animals were to be slaughtered. It is clear that such an
approach 19 days after an outbreak defeats the object of a contiguous cull

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