Memorandum of Understanding of Content of Meeting between.
Representatives of NSA, Sheep, Veterinary Society (SVS) and Dr Paul Kitching
Head of Department of Exotic Diseases R&D at institute of Animal Health,
Purbritght, on April 2Oth 2001.
1. Bearing in mind that since the previous meeting between the group and Dr Kitching a number of new "experts" had achieved a degree of public prominence. Clarification was sought as to the position of Purbright and its personnel in terms of world ranking on FMD issues. It was confirmed that Pubright was the acknowledged pre-eminent centre of technical and scientific excellence on FMD, not only for the UK but also for other countries of the world. Equally, that Dr Alex Donaldson and Dr Paul Kitching were the pre-eminent experts on FMD throughout the world.
2. Following on from the foregoing, opinion was sought: of the way in which the epidemic was spreading (now apparently on a reducing plane); the various forecasting models which had been put in place; the public discussion which was taking place on vaccination to control the disease; and what the implications were for the disease to spread, forecast, to lift again, when cattle stock particularly, were going to be turned out during the course of the next: few weeks.
(a) Noted that there was a total difference between any of the modeling forecasts and actual outturn. Whereas a number of hypothesis were possible the most likely reason for the quite serious discrepancy was the fact that the different reactions to the disease between species had not been taken account of in the modeling process. Important also to recognise that it was unlikely that the disease establishment period or when it had entered and spread had been taken proper note of with the start point likely to have been earlier than originally admitted. The implications of this were relatively important especially from the standpoint that the epidemic would have established itself and been spreading for some days, possibly weeks, before controls were put in place and many of these would have become operable later than optimum.
(b.) Whereas the issue of vaccinating sheep had been explored in the earlier meeting (9th April, report of 3rd April meeting) a great deal of interest had been taken in the prospect of protecting cattle by vaccination during the next few weeks prior to turnout time. To understand this aspect of the epidemic it was important to consider the fact that the contiguous cull! 3km zone cull had been introduced on the back of a modeling prediction, which had been fundamentally flawed (viz. para 2a).
Not only was it a fact that the number of sheep infected was very low, but a number of infected animals were being missed due partly to inadequate follow up low up in the absence of a constant epidemiological surveillance during the early stages far more stock had been removed resulting in a totally overloaded system. To clarify this it is important to note that at least 25% of the samples submitted from infected premises are not registering as positives. When this is swelled by the considerable number of associated contiguous and 3km premises it is quite reasonable to question its validity in the first place but especially important to question whether 3km culling or contiguous curling without proper risk assessment has any validity in the future process of containing and reducing the scale of the outbreak except insofar as the greater the number of animals removed the less there will be left to become infected i.e. the same strategy in the prevention of road accidents would entail the removal of motorists and vehicles.
It is also important to recognise that the movement standstill order would have had A significant influence as a great many of the flocks, which had been infected, would have gone through their period of high infectivity and the only evidence of the fact that they had contracted the disease was that If subjected to a serological test they would show blood antibodies. In this context it Is worth noting that as the standstill order came into place on Friday 23rd February, some 8 weeks ago, and that the number of new infections since that time would have been minimal, the likelihood of cattle meeting viremic sheep at turnout time (say end of April) would be small to say the least.
The other aspect which is worth noting is that as sheep are the least infective of cattle sheep and pigs, and that buy quite a considerable margin, there is a relatively low risk of sheep infecting cattle at this stage in the progression of the disease and that risk can be even further reduced by carrying Out a proper Risk Assessment (a concept advocated and developed by the SVS) on farms where sheep and cattle have normally been farmed together. It becomes clear that this strategy of establishing when sheep might have had any dangerous contact and working with an enlightened veterinary surgeon developing an individual farm least risk policy under regular surveillance might provide a sensible means of making progress.
It is against this background therefore of an epidemic which was started by pigs, but which was centred ultimately in sheep where its ability to sustain itself is very limited, that we need to take a view about the wisdom of vaccinating cattle.
In the first place it is worth drawing attention to the fact that it is not proposed to deploy the vaccine to control the disease per se, rather it is proposed to deploy the vaccine to contribute to the control of the disease. The significant difference being that it "contributes" as opposed to carries out the control function on its own.
It was therefore in the context of vaccinating cattle for the above purpose in Cumbria and Devon that the discussion needed to take place.
The first aspect to be looked at was the question of the possibility of using the high efficiency vaccine (mare than twice the normal strength) as a single shot instead of the normally used double dose where a first injection is given to start the process and another given a few weeks later to provide the boost which completed the immunity. Noted that the single shot high effective vaccine would create a better and more immediate barrier to the disease so that it accomplished in one hit what would normally require two.
The second aspect to be discussed was that if vaccination was to be used, why limit to Cumbria and Devon. Noted that there was considered to be a high level of virus in those counties (?atmospheric?) and the idea of vaccinating in those countries was to give added protection to Cattle at turning out time.
2 NSA DRAFT
The comparatively low level of virus in other areas contraindicated the use of Vaccine on a pan GB basis. In discussion the view was taken that there had already been a severe reduction in livestock numbers in Devon and Cumbria and the likelihood of spread from direct animal source would be less likely than in other areas. As a consequence, on balance, it seemed less rather than more sensible to vaccinate cattle in those areas especially against the background that sheep were likely to have gone past their viremic period.
The other aspect, which needed to be brought into the equation, was the economic implications. Whereas it was clear from the Deputy Chief Vet, Mr Richard Cawthorne, that the Standing Veterinary Committee (SVC) of the EU had given Great Britain "carte blanche" in view of its island status to get on with controlling the disease by whatever means sensible to UK authorities, there would be economic repercussions, for Instance at a previous meeting that day (Friday 20th April) a senior manager from Nestle's had indicated that about 80% of their milk based products were exported and there was absolute resistance at this stage to products which had any association, either with products from infected cattle or else from vaccinates.
The conclusion was reached that under the foregoing circumstances it was hard to see what place the process of vaccination had which would be universally beneficial.
3. Discussion took place on positive clinical diagnoses which had taken place on the basis of old lesions and that sheep had been slaughtered as a consequence when subsequent examination had shown that these lesions had not been attributable to FMD. Noted that a part of this aspect was associated with the political imperative to clear whole areas of the disease due to the need to get the tourist industry back into gear. It was clear that there had been a degree of over reaction in this area and the slaughter of such stock had been exacerbated by the contiguous and 3k culls consequent upon an original misdiagnosis.
Moves were now in hand to rapidly boost the facility for serological testing with a predicted capacity of some 1OO,OOO tests per week over a set of 6 surveys.
It was likely that this testing facility would remain in place and in use until the disease was cleared.
4. On the subject of spread by wild deer, the view was expressed that this was unlikely to cause any problems due to the fact that the viral emission rate from deer was similar to sheep and on a risk assessment basis would be unlikely to cause problems to cattle and an even lower possibility of being the cause of problems to sheep.
5. During a discussion on the issue of dividing the country into zones for the purpose of establishing clean areas which might then be In a position to trade, attention was drawn to the fact that there were quite dear rules laid down as to how the dean zones would be divided from "dirty" zones for the' purposes of intra-community and international trade.
A fundamental part of this was that a 10k buffer zone between the two areas would need to be established and if I roads between the zones would be subjected to constant monitoring i.e. border controls. The view was taken that the possibility of establishing such zones would be difficult and expensive and balanced against medium or long term advantage hard to justify.
6. The subject of using samples of urine and faeces as a means of checking for FMD) was discussed as the concept had been floated by an American vet working in UK who had read of this being used In Russia.
Noted that its success or failure depended on PH levels. If PH level was below 6 the virus would not last long enough for it to be tested, if it was over 7 it could be a Possibility. A quick test was however being developed similar (but not the same) to a litmus test and this appeared to be encouraging. (PCR kit?)
7. In a fairly broad ranging summary of the outbreak Dr Kitching expressed the personal view that the FMD) Would be dying out in the national flock, as the level of virus in sheep would not enable it to be sustained. If however a sheep was to infect cattle, this would then raise the level of the virus generally in that locality and could effectively boost it to the point at which it might pose a threat. This was one of the dangers of using cattle as sentinels for the disease and it was likely therefore that serology would provide the most acceptable means of checking during the run up to clearance,
a. Due to the fact that FMD) Was likely to have passed through sheep and at worse they would be emitting a very low level of virus, if any, the possibility of sheep posing a risk to cattle was likely to be low and could be reduced even further by subjecting individual farms and those contiguous to a proper risk assessment.
b. The question of vaccinating cattle did not seem to provide any tangible benefit, which did not have a countervailing disbenefit. On balance therefore at this stage in the outbreak it was not thought to be beneficial.
c. The establishment of clean areas especially for trade purposes was not an option, which should be undertaken lightly. There were benefits but there would be a high cost in setting up a system, which would need to be dismantled as soon as circumstances allowed. The balance therefore was likely to lie with refining the present system and working towards re-establishing the whole country as a clean area.
d. The modeling systems should be revised to take account of differences between species and the husbandry systems. Important that this should receive urgent attention due to the fact that epidemiological modeling provided the basis upon which FMD clearance was founded. Bearing in mind that the epidemiology might vary form area to area it might be sensible also to have models built upon local area studies. These should however cross-refer to, neighbouring localities i.e. North West should cross over to North East and vice versa.
e. 3k cull and contiguous cull without risk assessment and serology should be abandoned forthwith.
f. Risk assessment should now assume a very high priority in getting farms back to work.
g. Note should be taken at all times of the differences which exist between FMD virus in cattle, sheep and pigs.