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ORIGIN OF THE 2001 FOOT AND MOUTH DISEASE EPIDEMIC

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ORIGIN OF THE 2001 FOOT AND MOUTH DISEASE EPIDEMIC ...
ORIGIN OF THE 2001 FOOT AND MOUTH DISEASE EPIDEMIC

DEFRA has today placed on its website the results of its investigations into the how the 2001 FMD epidemic started and spread.

The origin for that outbreak is considered to have been a pig

finishing unit in the North-East of England. Thereafter, disease

spread via two routes. First, through the movement of diseased pigs

to holdings in Essex and Kent. Second, through windborne spread of

FMD virus to sheep on a neighbouring holding followed by their

subsequent sale via markets and dealers in Northern England. In the

course of these movements other sheep, people and vehicles, became

infected spreading disease widely throughout England, Wales and the

southern counties of Scotland.

The source of the virus responsible for the epidemic was most

probably meat or meat products infected or contaminated with the FMD

virus but it unlikely that the origin of this material and the route

by which it entered the UK will ever be identified.

ORIGIN OF THE UK FOOT AND MOUTH DISEASE EPIDEMIC IN 2001

Introduction

1. A full inquiry has been carried out into the origin of the 2001

Foot and Mouth Disease (FMD) epidemic in the UK. The conclusions

reached in this paper are based on information obtained as a result

of the investigations completed to date. These investigations

continue and any new information may result in the need to revise

some of the opinions expressed.

2. There have been genuine difficulties in establishing precise

timelines for events such as the introduction of infection onto key

premises such as outbreaks FMD/04, FMD/06 and FMD/01. These stem

from (a) difficulties in ageing FMD lesions in animals, (b)

determining when clinical disease was first evident on premises

such as FMD/04 and FMD/06 either because the animals that were

first infected were not present at the time disease was first

identified and investigated or because throughout the course of the

epidemic, cattle often acted as the first indicator of the presence

of disease that had gone unnoticed in sheep and (c) farmer

recollection of when they first thought animals were affected by

FMD as compared with other conditions. As a consequence, estimates

of when infection entered a premises are just that, estimates, and

represent theoretical ranges calculated on the basis of maximum and

minimum incubation times. Ultimately, judgements on the likely

sequence of events have had to be made on the totality of the

epidemiological information available.

Factors contributing to the size and extent of the epidemic

3. The uniqueness of this epidemic in terms of its size and

geographical extent is considered to have been due to a combination

of factors. These included:

- a delay in reporting suspicion of disease in pigs at the index case

- airborne infection of sheep on a premises nearby to the index case,

- movement of infected sheep through markets before the first case

was diagnosed,

- the fact that the above events took place at a time of year when

the climate favoured virus survival and when large numbers of sheep

were being marketed and moved around the country,

- the nature of the disease in sheep and critically the absence of

distinctive signs, compared with other classes of livestock,

- structural changes in the sheep industry which over a period of

years have resulted in an increase in the size of the national

flock, a reduction in the farm labour force resulting in greater

reliance on shared or contracted labour and the fact that >50% of

livestock holdings have sheep on them at some time of the year,

- the fact that sheep are regularly gathered throughout the year for

management purposes creating opportunities for disease spread

particularly if shared or contracted labour is used.

4. The initial movement of infected sheep through markets and

dealers led to multiple (effectively primary ) introductions of FMD

virus into major sheep keeping areas. Subsequent local spread from

these initial insertions of disease undoubtedly caused the majority

of cases in the epidemic.

Origin of the epidemic

5. Although the first FMD outbreak was confirmed in pigs in an

abattoir in Essex on 20 February (outbreak FMD/01), the origin for

that outbreak, and the index case for the whole epidemic, is

considered to have been a pig finishing unit at Burnside Farm,

Heddon on the Wall, Northumberland (outbreak FMD/04), which was

licensed to feed processed waste food under the Animal Byproducts

Order 1999. Disease was confirmed on these premises on 23 February

as a result of the epidemiological inquiry carried out into the

origin of outbreak FMD/01. Detailed investigations carried out on

24 February at Burnside Farm by FMD experts from the National and

World FMD Reference Laboratory, Institute for Animal Health,

Pirbright, revealed that the majority of pigs on the premises at

that time were infected with FMD but at different stages of the

disease. The expert's opinion was that some pigs had 12-day-old

lesions. This implies that disease was certainly present on 12

February and with an incubation period of 2-14 days it could have

been present from as early as 26 January. However, Burnside Farm

had moved pigs off the premises on two occasions between 8 and 22

February. With an ever-changing pig population and advancing

disease, it is possible that pigs that had recovered from the

initial, acute phase of the disease had already been sent to the

abattoir. The significance of this is that the pigs that had been

sent to slaughter may have had older disease than that evident on

the farm at the time of the 24 Februaryinvestigation, so disease

may have entered the premises earlier in January.

6. All possible means for the introduction of FMD into Burnside

Farm have been investigated. Investigations have shown no evidence

that disease was introduced to the farm by animals, people,

vehicles, equipment, vermin, wildlife etc. There was no evidence of

disease on premises within 3km of Burnside Farm which predates that

found there.

7. Having investigated and eliminated all other possible sources of

infection it is considered that the likeliest source of infection

for the pigs on Burnside Farm was meat or meat products containing

or contaminated with FMD virus and that the virus could have been

introduced to his pigs through the consumption of such material in

unprocessed or inadequately processed waste food or the consumption

of processed waste food contaminated with such material.

Subsequent spread of the disease

8. The epidemiological inquiry indicates that there were two routes

of spread from the Burnside Farm. First, the movement of diseased

pigs or pigs recovering from FMD on 8 and15 February resulted in

infection being transferred to Cheale's abattoir in Essex where the

first FMD outbreak (FMD/01) was confirmed on 20 February. Recovered

pigs in the post-acute phase of the disease could be difficult to

identify at ante-mortem inspection. The subsequent spread of

disease to holdings in Essex was a consequence of mechanical and

personnel transmission from the abattoir. Compared with the second

route of spread, this first route made only a small contribution to

the totality of outbreaks in the country as a whole.

9. Second, airborne spread of disease from Burnside Farm to sheep

on a nearby premises (Prestwick Hall Farm, Ponteland, outbreak

FMD/06) and the subsequent sale of 16 sheep, some of which were

inapparently infected, from these premises at Hexham market on 13

February. These s heep entered the marketing chain and were sold via

Hexham and Longtown markets and through dealers where they infected

other sheep, people or vehicles thereby spreading FMD virus widely

in England and Wales and the bordering counties of southern

Scotland.

10. Having investigated and eliminated all other possible sources

of infection, the likeliest source of infection for the animals on

Prestwick Hall Farm is considered to have been airborne virus from

infected pigs on Burnside Farm.

11. Epidemiological investigations of the other 2,025 outbreaks,

the majority of which were due to local spread after the initial

introduction of disease into an area, have shown no evidence of any

disease pre-dating outbreak FMD/04.

Other potential origins

12. A range of other potential origins, including the possibility

that disease was already present in GB before this epidemic, have

also been investigated. There is no evidence for the presence of

disease in the country prior to the index case, outbreak FMD/04.

Type of FMD virus

13. Genetic analysis of the FMD viruses isolated from outbreaks in

different parts of Great Britain, Northern Ireland, Ireland, the

Netherlands and France has shown only minor differences suggesting

that the same strain of virus (Type O, Pan- Asia) was responsible

for all the outbreaks in Europe during 2001.

14. Similarly, genetic analysis of the FMD viruses responsible for

the outbreaks in the UK and those in an earlier outbreak in South

Africa, indicated they were closely related if not identical.

However the epidemiology of the South African outbreak, the control

measures imposed and the strict control on imports of meat into the

UK indicate the most likely explanation is that the UK and South

African strains had a common origin in the Far East.

Introduction of FMD virus into Great Britain

15. A detailed analysis of potential rou tes of entry into Great

Britain indicates that the source of the virus for the 2001

epidemic was most probably infected or contaminated meat or meat

products. The probability of other sources is very low especially

with this strain of virus.

16. Whilst legal imports of meat or meat products are a theoretical

possibility as an origin of disease, the complex of risk management

measures makes the practical reality of this occurring extremely

unlikely. Legal imports have not taken place from any country where

the Type O, PanAsia strain of FMD virus occurs apart from South

Africa. It is highly improbable that disease was imported with

South African meat and the information available on imports from

South Africa would support this view.

17. It will never be possible to determine the exact route by which

the virus entered the country. Infected meat or meat products

imported as 'personal imports' are a possibility but it is more

likely that most will be consumed or discarded as domestic waste

and not find their way into animals. Even if they did end up being

included in food for livestock, proper observance of the

legislative controls covering the feeding of waste containing meat

or meat products, and which had been in place since 1973, should

prevent any virus reaching livestock. A total ban on the feeding of

catering waste containing meat or meat products was introduced

early in the 2001 epidemic.

18. Illegal shipments on a commercial scale are more likely to be

intended for wholesale outlets or sale to restaurants or canteens.

These are more likely to be refrigerated and illegally described as

food or dried, cured or salted and presented as non-food imports.

This increases the chance of the virus getting into catering waste

which if not properly cooked before feeding to livestock could

reach pigs in sufficient quantities to cause disease.

Conclusions

19. Based on the currently available evidence and following

detailed investigations it is concluded that:

- There was a single index case for the UK epidemic

- The source of the infection was infected meat/meat products

consumed by pigs on Burnside Farm (outbreak FMD/04

- Disease was present at Burnside farm on 12 February and was

probably present at the beginning of February/late January.

- The movement of infected pigs from Burnside farm on 8 and 15

February spread disease to pigs in the Essex abattoir (outbreak

FMD/01) from which disease spread to a limited number of other

farms in Essex and Kent.

- Windborne spread from Burnside Farm resulted in the transmission of

FMD virus to sheep at Prestwick Hall farm (outbreak FMD/06) and

their subsequent sale through Hexham and Longtown markets resulted

in infection being widely disseminated to other parts of the

country by animal or mechanical means.

- There is no evidence of the existence of FMD disease in the UK,

pre-dating the development of disease at Burnside farm.

- The source of the virus for the 2001 epidemic was most probably

infected or contaminated meat or meat products but it is unlikely

that the origin of this material or the route by which it entered

the UK and reached Burnside Farm will ever be identified.

20. A more detailed account of the investigations carried out into

the origin of the 2001 epidemic is provided in Annexes 1-7 to this

paper.

ANNEX 1

OVERVIEW OF THE 2001 FMD EPIDEMIC IN THE UK

Summary

1. A total of 2,026 cases of Foot and Mouth Disease (FMD) were

confirmed in Great Britain between 20 February and 30 September

2001. Although the first case to be confirmed was in pigs at an

abattoir in Essex (outbreak FMD/01), this was not the index or

primary case in the epidemic.

2. Epidemiological evidence suggests that the index case occurred

i n pigs on Burnside Farm, Heddon on the Wall, Northumberland

(outbreak FMD/04) which was licensed to feed waste food under the

Animal Byproducts Order 1991. Disease is thought to have been

introduced to this holding at the beginning of February or the end

of January 2001. It was subsequently spread in two ways. First, by

the movement of pigs to an Essex abattoir and from there by various

means to other farms in Essex and Kent. Second, airborne spread to

sheep at Prestwick Hall Farm, Ponteland, Northumberland (outbreak

FMD/06). Subsequent sale of infected sheep from Prestwick Hall

Farm, through markets at Hexham (Northumberland), and Longtown

(Cumbria), resulted in widespread dissemination of disease

throughout the rest of England and Wales and to bordering counties

in southern Scotland. The latter took place before the suspicion of

FMD in pigs at the Essex abattoir had been reported and the index

case traced and identified (Gibbens et al 2001)

3. The scale and temporal pattern of FMD cases in the first months

of the 2001 epidemic was similar to that in 1967/8. Both reflected

the practical problems of controlling epidemics characterised by

initial multiple seeding followed by local spread. Howeverthe

evidence suggests that in the 2001 epidemic, the index case

(outbreak FMD/04) was the source of infection for all other cases,

whereas the 1967/68 epidemic had a multi-centric origin in which a

number of pig farms were infected concurrently from the same

source. The peak of the 1967/68 epidemic was greater and occurred

earlier after the first case.

4. In the 2001 epidemic there was a delay between the introduction

of infection and the reporting of suspect disease to the

authorities. This contributed to the widespread dissemination of

disease and the scale of the epidemic (Gibbens et al 2001). In the

1967/68 outbreak disease was detected within 4 days of the onset of

c linical signs on the first affected farm (Northumberland Report,

Part 1, 1968). The only intervening outbreak in 1981 was detected

on the index farm and was restricted to a single farm (Donaldson

and others, 1982) .

Investigations

5. Each of the 2,026 FMD cases was subjected to a detailed clinical

and epidemiological investigation. This data and information was

used to estimate the age of the lesions at the time of reporting,

to evaluate the origin of infection for each premises and thereby

estimate the date on which infection was introduced to each

infected premises. Considerable effort, in terms of field

epidemiological research, has been put in to investigating the

early cases in order to provide substantive epidemiological

evidence, so far as is practically possible, to identify the index

case and therefore where infection was first introduced to the

country.

6. Initial spread of disease from the index case was by two routes,

the first linked to the movement of infected pigs from Burnside

Farm, Northumberland to Cheales Abattoir, Essex, the second

associated with airborne spread to sheep from Burnside Farm on a

nearby holding, Prestwick Hall Farm, and subsequent movement of

those sheep through market/dealer premises which was facilitated by

the relatively large market at Longtown and subsequent dealing.

7. The earliest case of FMD was identified at a pig finishing unit

located at Burnside Farm in Northumberland (Outbreak FMD/04) which

was licensed to feed waste food. This unit sent infected pigs to

Cheales Abattoir in Essex where FMD was confirmed on 20 February

2001 in pigs that had been in contact with pigs from Burnside Farm.

Before the possible presence of FMD in the country was reported to

the authorities on 19 February 2001, windborne spread of the virus

from Burnside Farm had infected sheep and cattle on nearby farms in

Northumberland includi ng Prestwick Hall Farm (outbreak FMD/06) that

was the second farm to show disease in Northumberland.

8. The accumulated epidemiological evidence suggests that movement

of infected sheep from Prestwick Hall Farm through markets, led to

the widespread dissemination of FMD throughout Great Britain.

Sixteen sheep from Prestwick Hall Farm, believed to be incubating

disease, together with 3 others, were sold through Hexham Market on

13 February. Onward tracing of the sheep from Prestwick Hall Farm

showed the group of 19 was split at Hexham Market and sold to two

dealers (lots of 7 and 10 sheep) and 2 local butchers (2 sheep).

One dealer sent the 7 sheep he bought to his home farm in

Lancashire where disease was confirmed on the 27th February

(outbreak FMD/15). The second sent the 10 sheep he bought, together

with 174 other sheep also bought at Hexham Market on 13th February,

for sale at Longtown market in Cumbria, on 15th February.

9. Thereafter disease was spread either by the movement of infected

animals or through the contamination of vehicles and people in this

initial transmission phase. The bulk of infected animals passing

through markets went through Longtown market; some infected sheep

passed through more than one market.

10. Examination of Longtown market's records showed that at least

24,500 sheep entered the market between 14 and 23 February and

could have been exposed to infection. Tracing of the 181 purchasers

of sheep at Longtown began on 25th February. This tracing exercise

was confounded by the immediate trading of sheep subsequent to

their formal sale in the market and subsequent inter-dealer trading

which increased the risk of transmission.

11. Movement of infected sheep out of Longtown market accounted

directly for the infection of at least 71 premises, including 20

sheep dealers' premises in Cumbria, Dumfries & Galloway, Devon,

Durham, Here ford and Lancashire and 3 abattoirs, 1 in Wales

(Anglesey) and 2 in Durham, by 23 February.

12. When it became clear that the presence of disease was not

confined to Essex, national animal movement controls were imposed

on 23 February. Subsequent epidemiological analysis has shown that

at least 57 farms were infected by the time the first outbreak was

confirmed on 20 February and at least 119 farms in 11 of the 12

mini-epidemics or geographical clusters of outbreaks that

characterised the epidemic as a whole, had been infected as a

result of 'infected animal' movements before national movement

controls were imposed on 23 February.

Epidemiological clustering of outbreaks

13. The greatest numbers of outbreaks occurred in Cumbria (893),

Devon (173), Dumfries & Galloway, Scotland (176) and North

Yorkshire (133), Co Durham (85), Powys, Wales (70) and

Northumberland (88). Collectively, outbreaks in these 7 counties

were responsible for 75.5% of all FMD outbreaks in Great Britain.

14. This reflects the original distribution of sheep that took

place via Longtown Market and subsequent spread by markets and

dealers during February and before the existence of disease in the

country had been recognised. These movements coupled with

subsequent local spread resulted in the epidemic resolving itself

into 12 epidemiological groups centred around outbreaks in

Anglesey, Cumbria, Devon, County Durham, Lancashire (East), Essex,

Hereford & Worcester, Northumberland, North Yorkshire, Wales

(Powys), Staffordshire and Yorkshire (Yorkshire and Lancashire).

15. Disease was introduced into Mid Wales when ewes destined for

Welshpool market were transported there in a contaminated lorry

that had carried infected sheep from Longtown Market the previous

day. The Staffordshire cluster of farms and dealers received

infected sheep from Longtown and Hexham markets, and infected

cattle from Northampton market. The Durham group was associated

with one infected dealer and two infected abattoirs.

16. Infected abattoirs were the main source for the Anglesey,

'Essex & Kent' and the 'Yorkshire & Lancashire' clusters of cases,

as well as the Wiltshire cluster. Sheep dealers were the primary

source of FMD for the Devon and Hereford clusters. In fact, a

dealer's premises in Devon became infected on 15/16 February as a

result of movement for Longtown market and this was the sole reason

for the introduction of infection into Devon and eastern Cornwall.

In Hereford this was compounded by further market distribution of

infected animals. The East Lancashire Group was infected by local

spread from the Settle subgroup in North Yorkshire into which

disease was introduced as a result of mechanical (vehicle)

transmission via a dealer with Longtown Market connections.

Conclusions

17. A study of FMD epidemics in unvaccinated populations in Europe

between 1965 and 1982 (Lorenz,1989) showed a median of 29 holdings

affected, indicating that outbreaks had usually been controlled

rapidly. However, under certain favourable conditions very large

epidemics could occur. The 2001 epidemic proved to be much larger

and with many more livestock holdings affected than might

reasonably have been expected or predicted following the

introduction of FMD virus into Great Britain.

18. The 2001 epidemic was largely sheep based and its size can be

attributed to a variety of factors which led to many, initially

undetected, secondary sources of infection across the sheep dense

areas of England, Wales and southern Scotland. These were

equivalent in effect to multiple primary cases of FMD that

propagated the epidemic locally for days before the first case was

diagnosed in GB.

19. One important factor was the initial delay in reporting

suspicion of FMD on the inde x farm. Awareness of FMD as a possible

differential diagnosis for the cause of lameness or oral lesions in

pigs and sheep is low in countries such as Great Britain that have

been free of the disease for many years. There had been little

propaganda since the last outbreak to make farmers aware of the

clinical signs or to encourage reporting of suspect disease. In

most FMD epidemics, as in this one, the first case has been

detected and reported by a veterinary surgeon (Donaldson and

others, 1982; Hugh-Jones, 1976) . In both the1967/68 and 2001

epidemics, FMD was detected when pigs were observed to be lame and

when the morbidity had reached 25%.

20. This in itself might not have been so important if windborne

spread of infection from the index case had not infected sheep on a

nearby farm or that the introduction of disease had occurred at

another time of the year when large numbers of sheep were not being

traded through markets and dealers as part of the seasonal sheep

management cycle. Setting aside the problems of diagnosing FMD in

sheep, prolongation of the epidemic could in part be attributed to

changes in the structure of the sheep industry over the years

leading to a greater reliance on shared or contract labour creating

greater opportunities for the spread of disease despite a national

ban on livestock movements.

ANNEX 2

THE ESSEX CLUSTER OF FMD CASES

Summary

1. On 20 February FMD was confirmed in 3 groups of pigs which had

arrived at Cheales abattoir in Essex on 16-18 February. There was

no evidence of FMD on the farms from which these pigs originated.

The source farms for the three groups were not infected with FMD.

2. FMD virus was probably introduced into the abattoir by pigs

delivered from Burnside farm (outbreak FMD/04) on the nights of 8/9

February and 15/16 February. Mechanical and personnel spread from

the abattoir was the probable cause of infection at farms in

Upminster (outbreak FMD/02), Brentwood (outbtreak FMD/03) and

Canewdon (outbreak FMD/05) in Essex.

3. The pigs in which suspect FMD was reported on 19 February showed

early acute clinical signs with obvious lameness which could be

easily detected on ante mortem inspection. Pigs usually recover

quickly especially once the blisters on the feet have ruptured and

provided the horn of the hoof does not separate and there is no

secondary infection. Affected but recovered pigs would not be

expected to show clinical evidence of disease at post mortem

examination. This may account for the failure to detect evidence of

disease in pigs arriving from Burnside Farm on 8/9 February.

4. No other possible source of infection for outbreak FMD/01 was

found in spite of intensive tracing to identify and visit all

holdings that might have introduced FMD infection into the

abattoir.

Investigations

5. On 19th February 2001 the Official Veterinary Surgeon at Cheales

abattoir in Essex noticed lameness with vesicles on the feet in

sows at ante-mortem veterinary inspection. He reported suspicion of

a vesicular disease to MAFF and all slaughtering ceased. A MAFF

Veterinary Officer (VO) examined the 109 pigs remaining alive at

the abattoir and found disease suspicious of FMD in 28 of them. FMD

was confirmed the following day after the receipt of positive

laboratory test results from the National and World Reference

Laboratory for FMD, the Institute for Animal Health, Pirbright,

Surrey.

6. An expert from the Pirbright Laboratory visited the abattoir on

20 February. The oldest lesions were seen in two groups of pigs

from the Isle of Wight and Buckinghamshire that had entered the

abattoir on the 16th February. More recent lesions were seen in the

third group of pigs that had arrived from Yorkshire on the 1 8th

February and in a group of pigs that arrived from Suffolk on 19

February, suggesting a very short incubation period.

7. FMD virus Type O, Pan-Asia strain (Knowles and others, 2001) was

recovered from epithelial tissue samples from pigs from all three

sources.

8. Urgent tracings were instigated and the farms of origin for the

3 groups of pigs were subjected to clinical inspection by the MAFF

State Veterinary Service (SVS). No evidence of FMD was found on

these farms. This fact, together with the estimated age of the

lesions suggested that all the pigs had become infected after

leaving their farms.

9. Pigs (cull adults and finishers) were sent to Cheales Essex

abattoir from all over the country. Pigs were not normally

slaughtered at the weekends. If they arrived late in the week they

sometimes remained in the lairage to be slaughtered on the

following Monday. This practice appears to have allowed FMD to

develop and manifest itself in the pigs that remained in the

lairage over the weekend of 16/17 February.

10. MAFF VOs visited all premises that had supplied livestock to

the abattoir during the previous two weeks. Tracings were

prioritised and visits to premises feeding waste food to pigs were

undertaken first. In addition the tracing of dangerous contacts

with potential links to the abattoir were initiated.

11. On 22 February, a MAFF VO reported suspect FMD at Burnside

Farm(outbreak FMD/04) a pig finishing unit in Northumberland.

Disease was confirmed following laboratory confirmation on 23

February. This farm had sent sows to Cheales abattoir that arrived

on the nights of 8/9 and 15/16 February and which were slaughtered

on the mornings of 9 and 16 February.

Spread of FMD from Burnside Farm (Outbreak FMD/04)

12. Burnside Farm regularly supplied pigs to Cheales abattoir every

Thursday. These were either pigs purchased by the owners from ot her

premises and markets or from their own premises. Burnside Farm had

not sent pigs to the abattoir for a period of 4 weeks from 12

January until 8 February.

13. Pigs from Burnside Farm arrived at Cheales abattoir during the

night of 8/9 February. 10 sows and 1 boar in the batch were

slaughtered on Friday 9 February, possibly quite early in the

morning. A further 160 pigs from other sources arrived on 9

February and were put into the lairage over the weekend of 10/11

February. Although they overlapped with pigs from Burnside Farm, no

clinical signs of disease were seen in pigs slaughtered on Monday

12 February. These pigs were held in a separate pen and did not

move around the lairage.

14. On 15/16 February two batches of pigs arrived at the abattoir.

One batch comprised 29 pigs from the owners of Burnside Farm which

possibly originated from the farm, the second batch comprised 34

pigs from Burnside Farm and 34 pigs bought by the owners via

Darlington market.

15. The relatively small number of pigs sent by Burnside Farm on

8/9th and the relative position of the lairage pens is critical.

Some of them may have been incubating disease in which case virus

excretion may have been low depending on the stage of incubation.

On 9 February the pigs that overlapped with those from Burnside

Farm remained solely in pen 23 at one end of the lairage until they

moved for slaughter. As a consequence they did not have close

contact with the pigs from Burnside farm. On 15/16 February,

Burnside Farm supplied many more pigs to Cheale's Abattoir and it

appears there was much more movement within the pens in the lairage

over the subsequent weekend which could have facilitated

transmission, and with possibly a much greater virus load lead to

shorter incubation in the contact pigs.

FMD infections on other, related farms in Essex

Old England Farm, Brentwwod (FMD/02)

16. Old England Farm (outbreak FMD/02) is adjacent to Cheale's

Essex abattoir and was sometimes used as an extension to its

lairage. On Wednesday 14 February a bull from Oswestry entered the

abattoir but was too dirty to slaughter and was removed to Old

England Farm for cleaning. Old England Farm was visited on 20

February as a dangerous contact to the abattoir. The bull was

identified as an index case on the farm with early clinical disease

and lesions approximately 1 day old. Pigs on the premises were

stated not to be affected.

17. The period is far too short for the bull to have been infected

by airborne spread from the abattoir and two other routes of

infection are possible:

- the bull became infected in the lairage on 14 February and

following a 5 day incubation developed clinical disease on 20

February;

- mechanical transmission of the virus by personnel movement from the

abattoir on 16 or 17 February. This would fit in with an incubation

period of 2-3 days resulting in the one day old lesions seen in the

bull on 20 February.

Great Warley Hall, Basildon (FMD/03)

18. The outbreak at Great Warley Hall (outbreak FMD/03) was

reported on 22 February and 3 cattle were identified with 2-3 day

old lesions. Two other cattle nearby had signs of FMD when

slaughtered on 21 February. This was a beef farm and was 1 km from

Cheale's abattoir. There were personnel contacts with the abattoir

but the premises were also very close to a minor road down which

pigs from Burnside Farm would have been transported to enter the

abattoir.

Greenacres Farm, Canewdon (FMD/05)

19. This was a licensed waste food feeding premises situated

approximately 30 km from the Cheale's abattoir. Waste food was

processed on site and pipeline fed to the pigs.

20. The pigs belonged to the owner of Cheale's abattoir and a

tracing visit took place on 22 February. Around 40 sows we re

affected by FMD. The pigs in two pens had the oldest lesions and in

one other pen in the same shed, pigs with early lesions were

observed. The pigs in all other pens were unaffected. Early lesions

were seen in some pigs in a second shed. Lesions thought to be 7-8

days old were visible when the pigs were slaughtered on 23

February. A stockman had reported they were becoming concerned

about the pigs and increasing lameness.

21. By the ageing the lesions on this farms it was apparent that

infection had been present from 15 or 16 February.

22. The outbreak at Greenacres Farm raises the question of whether

the pigs were infected before the pigs from Burnside Farm arrived

at the abattoir on 15/16 February. There are a number of possible

options:

- First, infection entered the abattoir at some earlier date from

Burnside Farm and infection at Greenacres Farm was due to

mechanical or personnel transmission from the abattoir.

- Second, infection at Greenacres Farm predated the infection at the

abattoir and was transmitted there and to Old England Farm and

Great Warley Hall by mechanical means before the Burnside Farm pigs

arrived at the abattoir on 15/16 February. There is no evidence

that there was any direct contact with pigs from Burnside Farm.

Equally the disease picture at these premises, the timelines and

the lack of significant fallout in the immediate area where there

were cattle indicators does not support the view that disease at

Greenacres farm predated the infection at the abattoir

- Third, infection entered both the abattoir and Greenacres Farm at

the same time from another common source. The available

epidemiological evidence does not support the existence of disease

on any premises in GB predating that at Burnside Farm

23. Option 1 is the most likely scenario based on the available

evidence and suggests that Burnside Farm was the most likely common

source for these outbreaks.

ANNEX 3

OUTBREAK FMD/04 -

'BURNSIDE FARM', HEDDON ON THE WALL, NORTHUMBERLAND

Summary

1. After exhaustive inquiries into the origin of FMD the conclusion

has been reached that the likeliest source of infection at Burnside

Farm was meat or meat products containing or contaminated with FMD

virus consumed by the pigs on this premises sometime between in

mid-January and early February 2001.

2. There is strong circumstantial evidence that inadequately

processed waste food was the vehicle for the introduction of virus

to the pigs especially when considered in conjunction with the

procedures for the collection, processing, storage and feeding of

waste food to the pigs on this premises.

3. There was no evidence of FMD predating the outbreak at Burnside

Farm in the vicinity of the farm or on the premises that supplied

it with pigs, or for that matter, anywhere in the UK. No disease

was detected during the serological testing and clinical

surveillance of farms within the 3km or 10km Protection and

Surveillance Zones established around the outbreak. No evidence

exists for a possible source of FMD virus from the tracing

exercises conducted as part of the epidemiological inquiry carried

out in connection with this outbreak.

4. Based on the timescales for infection, the age of the disease in

the pigs at Burnside Farm, the movement of pigs to the Essex

abattoir where the first FMD outbreak was detected and the airborne

spread to Prestwick Hall Farm (outbreak FMD/06), the outbreak at

Burnside Farm remains the index case for the GB epidemic of 2001.

5. Airborne spread from this outbreak was probably responsible for

the outbreak at Prestwick Hall Farm and also for a further 9

outbreaks in the area under the plumes of virus excreted by

affected pigs.

Investigation

6. FMD was confirmed at Burnside Farm on 23 February following the

laboratory examination of samples collected from affected pigs on

22 February. Samples were examined at IAH Pirbright and included

epithelium samples from 2 pigs and 20 blood samples taken from

other pigs on the premises. The farm was visited on the afternoon

of 22 February as a result of the epidemiological inquiry carried

out to identify the source of infection for the abattoir outbreak

(outbreak FMD/01) in Essex.

7. The pigs were accommodated in 4/5 sheds on the premises and the

owners were licensed to feed them processed waste food obtained

from a neighbouring premises. They were not licensed to process

waste food for feeding to livestock.

8. At the clinical inspection on 22 February, there was little

obvious sign of vesiculation in pigs in Shed 1 but the presence of

'freckles' lesions on the snouts, indicative of long standing FMD

infection, was recorded. None of these pigs appeared notably

unwell, distressed or lame. Several, however, showed a growth check

line on the hoof, often well down the hoof.

9. Shed 3, contained 70% of all the pigs on the premises. All the

pigs in pens 14 & 16 were clearly unwell. They appeared miserable,

were huddled together and reluctant to rise. FMD lesions of varying

ages were found in the pigs, ranging from 9 to10 days old to

one-day-old.

10. On 24 February 200, the premises was visited by FMD experts

from IAH Pirbright. His examinations revealed widespread lameness

in the pigs and it was estimated that approximately 90% of the 527

pigs on the farm had lesions suggestive of FMD. Many pigs exhibited

lameness, with the feet showing separation of old horn from the

underlying tissue. Vesicles were found on the snouts of some pigs

and it was from these that FMD virus of an identical strain to that

found at the Essex abattoir was recovered (N. Knowle s, personal

communication). The oldest lesions on this farm were estimated to

be 12 days old.

11. The pigs with the oldest lesions were found in Shed 2, where a

high proportion exhibited lesions estimated at 10 and 12 days old.

In contrast, some of the pigs exhibited lesions only one to two

days suggesting that disease was still active and spreading within

the herd.

12. The pigs in Shed 1 showed lesions that were 1-4 days old with a

few aged 8-10 days old.

13. This pattern of lesions suggested that the disease may have

been spreading within the herd helped by the continuous

introduction of purchased, susceptible pigs and that there may

originally have been a point source introduction of FMD infection

to one or a small number of pigs

14. Assuming an incubation period of 2-14 days and that those

undertaking the epidemiological investigation had been presented

with the pig with the oldest lesion, virus could have infected pigs

between 26 January and 7 February 2001. However, Burnside Farm had

moved up to 85 pigs of the premises on two occasions between 8 and

22 February. With an ever-changing pig population and advancing

disease, it is possible that pigs that had recovered from the

initial, acute phase of the disease had already been sent to the

abattoir. The significance of this is that the pigs that had been

sent to slaughter might have had older disease than those evident

on the farm and that the introduction of virus onto the holding

could have taken place earlier in January.

15. 88% of the 241 pigs blood sampled were seropositive for FMD

Type O antibodies. This included pigs that showed no discernible

FMD lesions. Given that the pipeline system used to deliver the

processed waste food to the pigs was blocked and pigs were

therefore being fed using a barrow and bucket, it would have been

possible for inadequately processed waste food to have rea ched only

one or two pens of pigs initially. The first phase of disease could

then have been succeeded by second and third waves until all the

pigs on the premises were infected. The disease could spread to

other pens in the same house, and then adjoining houses. This could

support an earlier introduction date.

Origin of the outbreak

16. A full investigation has been made into the origin of the

outbreak and all possible routes by which FMD could have been

introduced onto the farm between 1 January and 22 February 2001

have been considered.

- Movements of live animals:- The statutory animal movement records

for Burnside Farm showed that all pig movements off the premises

were sent to Cheale's Abattoir in Essex: The animal movements onto

Burnside Farm involved the direct purchase of 110 pigs from 11

producers between 3 January and 19 February 2001. All these

producers were visited and none showed evidence of FMD on their

premises

- Purchase of pigs from markets:- Burnside Farm purchased pigs at

Darlington, Thirsk, and Stokesley Markets.

- Darlington between 11 January 2001 and 15 February 2001. Burnside

Farm purchased 83 pigs from 23 vendors. No evidence of disease was

found on these premises when they were visited and no outbreaks of

disease were associated with the movement of pigs from these

premises

- Thirsk between 4 January 2001 and 15 February 2001. Burnside Farm

purchased 116 pigs from 46 vendors. Again, no evidence of disease

was found on these premises when they were visited and no outbreaks

of disease were associated with the movement of pigs from these

premises

- Stokesley between 2 January 2001 and 13 February 2001 Burnside Farm

bought 90 pigs from 16 vendors. No evidence of disease was found on

these premises when they were visited and no outbreaks of disease

were associated with the movement of pigs from these premises.

- These visits to market vendors premises and the lack of evidence

that disease was present in Darlington, Thirsk or Stokesley Markets

indicates that the markets and the vendors were unlikely to have

been the source of FMD infection for Burnside Farm.

- Movements of people:- The tenants of Burnside Farm lived off site

and visited the premises daily. Their landlord was not a farmer and

did not enter the site. They had contact with the owner of Heddon

View Farm East Heddon, where the waste food used by Burnside Farm

was processed. There was one employee, who also had contact with

Heddon View Farm.. There were no other visitors. Burnside Farm

visited Thirsk, Stoksley and Darlington Markets during the period.

No disease was associated with market source tracings. There were

no migrant workers employed and none were noted in the area.

- Feed:- Burnside Farm was licensed under the Animal Byproducts Order

1999 to feed processed waste food to its pigs: it was not licensed

to process waste food for feeding to livestock. The waste food for

Burnside Farm's pigs was collected from a number of restaurants,

hotels, schools, bakeries and an armed forces establishment in the

north-east of England by the tenants and two other collectors using

their own vehicles. The records maintained by Burnside Farm did not

allow these sources to be identified reliably. Unprocessed waste

food was deposited on a hardstanding outside the curtiledge of

Burnside Farm before being sent for processing at a neighbouring

establishment, Heddon View Farm, after which it was returned to

Burnside for feeding to the pigs, Burnside Farm had a pipeline

feeding system for delivering the processed waste food to the pigs

but this had not been in operation since late 2000 and the

processed waste food was being fed by means of a barrow and bucket.

Bins of unprocessed waste food were present on Burnside Farm at the

time of the MAFF VO visit on 23 February, some of which was in bins

supposedly reserved exclusively for processed waste. There was also

evidence of cutlery in the pig troughs and pens at Burnside Farm.

Catering waste normally contains some cutlery butit would be

unusual for this cutlery to survive the processing operation and

end up in the processed waste fed to livestock.

- Vehicles and equipment:- Slurry tanker traced with negative

results. No visits by the knackerman.

- Public:- No public footpaths or rights of way crossed the premises

which were locked. The gates giving access to the premises were

chained and locked. There was a well maintained perimeter fence. No

hunts, hare coursing or whippet racing crossed the premises. No new

age travellers seen in the area

- Vehicles and Equipment: No evidence of disease was found on all the

premises linked by vehicle movements with Burnside Farm. The

tenants of Burnside Farm used their own vehicles for private

movements. A contractor was used to move pigs from markets and to

abattoir. They entered the site and reversed to a loading bank.

Only Burnside Farm vehicles are thought to have entered the farm.

Equipment moved between Burnside Farm and the waste food processing

premises at Heddon View Farm.

- Discharges onto site; - Human sewage sludge was not used on the

premises. Slaughterhouse effluent had not been used on the

premises. There was no evidence of discharge or overflowing from

septic tanks from houses adjoining the premises.

- Materials used on the farm: - Bedding was only used in hospital

accommodation. No bedding had been purchased during the risk

period.

- Wildlife: - There were 2 dogs on the premises. No cats. No feral

pigs, goats or sheep were in the area. Foxes seen occasionally in

the area, no den on farm, not seen in or near farm buildings.

Badgers were not reported on the farm. Rabbit s and hares were

present in the area. Roe deer were seen in the area but had not

been seen in or near the pig sheds. Rats were present. No control

other than the presence of 2 dogs on the premises.

- Birds: - No migrating flocks were noted passing or alighting on the

site during winter of 2000/2001. Birds noted include crows,

sparrows, pigeons and starlings. None were recorded in unusual

numbers. Small birds fly into farm buildings.

- Waste Disposal site: - There was a municipal waste disposal site

within 10 km run by Seta. No flocking of seagulls from this site

had been seen. No movement of waste from the site had been seen or

recorded.

- Newcastle airport: - The airport is 5 km from the farm. There was a

chain link, 2 metre high, perimeter fence around the airport. The

airport buildings and main car park were 5 km from the farm; an

overflow car park was half km further away.

- Neighbouring farms: - Clinical examination of cattle and sheep and

serological surveillance of sheep within the 3 km protection zone

and 10 km surveillance zone was completed with negative results. No

disease, which predates infection at Burnside Farm was found during

the epidemic.

- Windborne: - The prevailing wind was from the southwest and there

was not evidence that windborne spread could have caused disease on

these premises. Viral plumes from the premises infected ten farms

to the north and east.

- Illegal rubbish dumping: - There was unprocessed waste food on the

premises

ANNEX 4

PRESTWICK HALL FARM, PONTELAND, NORTHUMBERLAND (OUTBREAK FMD/06)

Summary

1. Having investigated and eliminated all other possible sources of

infection the likeliest source of infection for the animals on

Prestwick Hall Farm (outbreak FMD/06), was airborne spread of virus

from infected pigs belonging to Burnside Farm (outbreak FMD/04)

2. The FMD virus could have infected cattle as early as 2 February

but if sheep were the species first infected, then this could have

occurred earlier in January especially if the sheep treated for

lameness on 6,10 and 12 February were affected by FMD and

experienced the maximum incubation period. However, tracing

evidence suggests that when a sheep scanner was there on 3

February, the sheep were not excreting virus.

3. The sale of 19 sheep, some of which were incubating disease,

from Prestwick Hall Farm to Hexham market on 13 February represents

the initial stage of the widespread dissemination of FMD virus.

4. Ten of these sheep were subsequently sent for re-sale to

Longtown Market on 15 February and the movement of sheep through

this market and those held on later dates, resulted in the

introduction of infection to the sheep dense areas of England and

Wales and the southern borders of Scotland.

Investigation

5. FMD was confirmed on Prestwick Hall Farm, Ponteland

Northumberland (outbreak FMD/06), a mixed beef and cattle sheep

farm, on 23 February 2001 as a result of the ownerreporting suspect

FMD in his cattle. The farm enterprise comprised three farms, two

in Ponteland and one near Morpeth.

6. On 25 February, experts from IAH Pirbright carried out a

detailed investigation on the premises. Four groups of cattle

housed in a single shed showed evidence of FMD but young stock

housed separately did not have evidence of disease. Of the four

affected groups, 38 heifers in two groups in the southwest corner

of the shed all had lesions but only 13/37 bulls housed in two

groups on the other side of the shed were showing lesions

7. Epidemiological investigations revealed that until 12 February a

group of 26 ewes were grazed during the day and housed at night in

an outside bull pen close to the affected heifers which had the

oldest lesions (estimated as 9 days old on the 25th February). The

group of 26 was reduced to 11 when 15 of the ewes, together with a

ram from a separate field and 3 sheep from the owner's other

premises, were sent to Hexham market in Northumberland on 13

February.

8. The ewes had been kept together since early February. The owner

reported that the group of 26 had experienced two episodes of

lameness which he thought to be due to 'foot scald' necessitating

footbath treatment on 6, 10, 12 and 20 February. Examination ofthe

11 remaining ewes from this group when they were slaughtered on 25

February, revealed healing foot lesions consistent with FMD in five

animals; all 11 were seropositive for FMD.

9. As far as the cattle were concerned, the oldest lesion (9 days)

was observed in a heifer when the livestock were slaughtered on 25

February. The other animals in the group had lesions aged 3 days

whilst the majority of affected bulls had lesions aged 1-3 days. If

the cattle were the first to be infected, this would suggest that

the index case on the farm developed clinical signs of disease on

about 16 February. With an incubation period of between 2 and 14

days infection could have been introduced on 2 February.

10. However if the sheep had been infected first, the foot

treatments on 6, 10 and 12 February could be significant especially

if the lameness diagnosed as 'foot scald' was due to unrecognised

FMD. This was the group that were all positive for antibodies on 25

February. If the initial lameness had been due to FMD, then taking

an incubation period into account, the virus could have been

introduced onto the farm at an earlier date than if the cattle had

been first affected and as early as 23 January.

11. In summary, it is considered likely that the affected sheep

were infected concurrently with, and possibly earlier than, the

affected cattle. None of the other 339 sheep on the premises showed

clinical or post mortem evi dence of disease.

Origin of the outbreak

12. A full Investigation has been made into the origin of FMD and

all possible means whereby FMD could have been introduced onto this

farm have been considered in the period 23 January to 19 February

2001.

- Movements of animals: - Although cattle and sheep had been moved

onto Prestwick Hall Farm, they only originated from the owner's

other farms High Callerton, Ponteland, Northumberland, where no

disease was recorded prior to slaughter as a 'dangerous contact'

premises, and Shaftoe Moor Farm, Morpeth, Northumberland where no

disease has been diagnosed

- Movements of people: - The farmer and his sons moved between the

farms but The second son farmed 15km away at Shaftoe Moor Farm,

Morpeth, Northumberland and visited the Ponteland farms in the risk

period; his stock remained alive and were examined clinically and

serologically with negative results. There had been no contact with

other farms and they had not taken foreign holidays in the past 12

months There had been no other significant visits apart form one by

a sheep scanner who visited on 3 February to scan ewes. No disease

had been found on any premises visited by him either before or

after the visit. There were no migrant workers employed and none

were noted in the area.

- Feed: - Bulk feed was delivered on 28 January 2001, first delivery

of the day vehicle and the driver did not enter livestock yards as

the feed store was beside the farm entrance. Oats and barley were

rolled at Home Farm, and delivered daily to Prestwick Hall using

the same bags.

- Public: - A footpath passed outside the farmyard and was used by

local people. No disease was found on surrounding farms. The right

of way did not enter the handling pens or yards, only fields. No

picnics were held. No hunts, hare coursing or whippet racing took

place.

- Vehicles and Equipment: - The owner used his own vehicles. Only own

farm vehicles were known to have entered the farm. No evidence of

cyclists having using the footpath, none had been seen. No

equipment was shared or used by farms out with the same ownership.

- Discharges onto site: - Sewage sludge had not been used on the

premises. Slaughterhouse effluent had not been used on the

premises. There was no evidence of discharge or overflowing from

septic tanks from houses adjoining the fields. There was no

evidence of fly tipping on or near the farm. There was no evidence

of picnic site litter or food wrappings.

- Materials used on the farm: - Home-produced straw was used for

bedding. No bedding had been purchased. Straw was stored on the

site adjacent to the cattle sheds.

- Wildlife: - The owner had a collie dog, which he took between the

two farms (Prestwick Hall and Home Farm). No feral pigs, goats or

sheep were in the area. Foxes were occasionally seen in the area,

no den on farm, not seen in or near farm buildings. Badgers were

not reported on the farm. Roe deer were seen in the area but had

not been seen in or near the cattle sheds.

- Birds: - No migrating flocks were noted passing or alighting on the

site during winter 2000/2001.Birds noted include crows, sparrows,

magpies, pigeons, starlings, robin. None were recorded in unusual

numbers. No shooting parties had entered the site.

- Waste Disposal Site: - There was a municipal waste disposal site

within 5km run by Seta. No flocking of seagulls from this site had

been seen. No movement of waste from the site had been recorded.

- Newcastle Airport was across a road from the farm. There was a

chain link, 2 metre high, perimeter fence around the airport The

airport buildings and main car park were 1 km from the farm, an

overflow car park was .5 km away. There was no access from the

airport or car parks to the farm.

- Ne ighbouring Farms: - No disease was found on farms with livestock

that were contiguous with the farm boundaries. Clinical examination

of cattle and sheep and serological testing of sheep within the

3-km protection zone was completed with negative results. No

disease, which predates this IP, had been found in the area except

at Burnside Farm.

- Windborne: - The potential windborne spread of FMD virus from

Burnside Farm was later modelled using the Epiman (Sanson and

others, 1999), NAME (Gloster and others, 2001) and 'Rimpuff'

(Sorenson and others, 2000) models. IP 2001/06 is 8 5km north-east

of IP 2001/04 and lies under the predicted plume. Suitable weather

conditions existed for airborne spread from Heddon to Ponteland in

mid January. During early February there were suitable weather

conditions not only for spread of virus to Ponteland but also to

other farms in the area. The significance of airborne spread in

causing FMD at PrestwicK Hall Farm would be dependent on the timing

of virus excretion from the infected pigs at Heddon.

ANNEX 5

THE ORIGIN OF THE FOOT-AND-MOUTH DISEASE VIRUS CAUSING THE UK

2001 EPIDEMIC

The PanAsia strain was identified in India during 1990 and spread

westward into Saudi Arabia during 1994 and then throughout the Middle

East becoming essentially endemic. Major outbreaks were caused in

many countries in the Middle East during the following two years and

this particular strain progressively replaced the other Type O

strains circulating in the countries. It was responsible for

outbreaks in Saudi Arabia on large dairy farms during 1999 in spite

of regular vaccination. It reached Turkey from where it then spread

into Greece and Bulgaria in1996.

This strain has spread northwards from India into Nepal where it was

identified in 1993 and 1994, Bangladesh in 1996 and Bhutan in1998,

infecting mainland China by 1999. In 1999 the virus was identified in

Taiwan and in 2000 in South Korea, Mongolia, eastern Russia and Japan

In September 2000 it caused the first outbreak of FMD type 0 in the

Republic of South Africa where the origin was attributed to the

feeding to pigs of untreated shipping waste. The primary case was in

pigs but later the disease spread to cattle on the neighbouring

premises. Intensive investigations indicated that the disease had

been contained in the 10km control zone.

The nucleotide sequences of the VP1-coding regions (639 nucleotides)

of a large number of foot-and-mouth disease virus (FMDV) type O

isolates belonging to the PanAsia strain have been examined at

Pirbright over the last few years. These genes differ by no more than

5% despite being isolated over a period of 11 years.

Virus isolates from recent outbreaks of FMD in South America have

been sequenced (VP1 gene) in Pirbright, Brazil (PANAFTOSA) and

Argentina (INTA). None of these viruses are related to the PanAsia

strain. Similarly, FMD type O viruses from various African regions

with the exception of the isolate from Kwazulu-Natal in South Africa

are unrelated to the PanAsia strain.

Phylogenetic analyses of the VP1 gene showed an extremely close

relationship between the UK and South African outbreaks (99.7%

nucleotide identity) leading to the conclusion that they must be

connected, either directly or via a third country (i.e. the two

outbreaks had a common origin. All of the viruses most closely

related to the UK and South African isolates come from the Far East

(including south-east Asia), with the Japanese isolate being the

closest. Many viruses isolated between 1999 and 2001 in the Middle

East (including Turkey) also belong to the PanAsia strain, but are

more distantly related.

Confirmation that the UK virus is most closely related to the South

African isolate (99.7% nucleotide identity) comes from using other

techniqu es involving complete genome sequencing. Further analysis of

these complete genome sequences is in progress.

This note reviews the latest information on the likely origin of the

UK outbreak based on nucleotide sequence comparisons. There is no

absolute certainty as to the extent of the spread of the PanAsia

strain similar to the UK isolates.

Conclusion

Thus it is most likely that the origin of the UK and South African

outbreaks lies in the Far East and that both outbreaks were caused by

the feeding of untreated infected meat or meat products to pigs.

ANNEX 6

POSSIBLE ROUTES BY WHICH FMD TYPE O PANASIA STRAIN OF VIRUS

COULD HAVE ENTERED GREAT BRITAIN IN 2000/2001

Summary

1. In order to infect animals, the virus must be introduced into

the country in a minimum infective dose and come into contact with

susceptible species in order to establish the infection. There may

be a single entry or multiple entries, which in turn may or may not

initiate disease.

2. A detailed analysis of potential routes of entry into GB (See

the analysis at Appendix 1) suggests that the source of the virus

for the 2001 epidemic was most probably infected meat or meat

products. The probability of other sources is very low, especially

with this strain of virus.

3. To present a risk, virus must enter the country in a viable

state and a minimum infectious dose must reach a susceptible

animal. (See details at Appendix 2). There are essentially four

possible routes by which disease could have entered the country:

- legal imports into the EU from countries with FMD, in which case

they must come from defined FMD-free regions approved by the EU

Commission

- personal imports in baggage, by mail or by courier;

- illegal commercial consignments

- ships' or airline waste which has not been disposed of in

accordance with national (UK) legislation.

4. Whilst legal imports are theoretical possible as an origin of

disease, the complex of risk management measures makes the

practical reality of this occurring extremely unlikely. Legal

imports have not taken place from any country where the PanAsia

strain occurs, apart from South Africa. Information available on

imports suggests it is highly improbable that disease was imported

from South Africa in this way.

5. It will never be possible to determine the exact route by which

the virus entered the country. Personal imports could pose a

problem if they were infected and were then discarded in such a way

that animals could gain access to them. Experience has shown that

only on flights from the African continent are quantities found

sufficiently large to be sold into the restaurant trade. But it is

more likely that most will go forpersonal consumption or be

discarded as domestic waste and not as catering waste that could

have been fed to livestock. Even then, such waste would only have

presented a risk to livestock if it had not been properly cooked to

destroy FMD virus, a legal requirement that has operated in the UK

since 1973 The feeding of catering waste containing meat or meat

products was banned early in the 2001 epidemic..

6. Illegal, commercial size, shipments where the meat is likely to

be dried, cured or salted are more likely intended for wholesale

outlets or for sale direct to restaurants or canteens. This

increases the chance of the virus getting into catering waste and

if not properly processed find its way into susceptible pigs in

sufficient quantities to cause disease.

Possible Routes of Introduction of Infection via meat or meat

products into Great Britain.

7. The following are regarded as presenting a negligible risk

i. Meat products heated in hermetically sealed container (con) to a

Fo value of 3 or more.

ii. Meat deboned and heated to a core temperature of at least 70oC.

iii. Meat deboned and matured for 9 months (hams)

iv. Deboned meat subject to pH of less than 6 throughout its

substance.

8. The above present negligible risk whether legally or illegally

imported. Products, which have not satisfied the full requirements

of ii, iii or iv above, present a risk if fed directly to pigs. The

level of risk depends on the origin of the meat, the quantity fed

and process used to prepare the product. Virus will survive in

partially cured products such as bacon and air or sun dried meat

for up to 6 months.

9. The risk from meat varies greatly depending on country or region

of origin, livestock species and cut of meat. FMD virus is

inactivated within 48 hours in muscle held at 4oC where the pH

falls below 6. The pH changes in pork are less than for beef or

sheepmeat. However virus will live for at least 5 months at 4oC

(chilled) in bone marrow and lymph nodes. If the carcass is frozen

the virus could survive for at least 6 months and possible for

several years.

10. Legally imported meat will be certified as coming from FMD free

countries or regions. If from an FMD vaccinating country or region

only deboned matured beef permitted. There are strict conditions

applied to legal imports.

11. The highest risk is illegally imported consignments of meat or

meat products from countries with endemic FMD and from meat,

especially pork, that is still on the bone and with lymph glands

attached. Deboned frozen meat especially pork also presents a risk

but the likelihood of a significant quantity of frozen meat evading

checks is low as it will tend to be in refrigerated containers and

easier to target.

12. The high-risk areas for the current strain of FMD virus are

Eastern Mediterranean, Middle East, India and Far East where the

virus has spread since 1990. Other strains of FMD virus are present

in Sout h America, Africa, Middle East and Far East. These illegal

imports could be in personal baggage or commercial consignments.

Personal Imports

13. We have evidence that illegal importations of meat, meat

products and fish occur on a regular basis in personal baggage from

a number of countries. Searches in the past year have revealed

significant quantities of meat from Ghana and Nigeria. Smaller

quantities of higher value meat and products have been found on

flights from China and Malaysia.

14. Only on flights from the African continent have sufficient

quantities been found that give rise to the suspicion that some may

be destined for sale to the restaurant trade. But it is more likely

that this material is destined for personal consumption or sale for

private consumption from market stalls and that unused material

would go into domestic waste and not into the waste food chain and

hence into livestock. Of course casual discard of these products in

such a way that livestock could consume them is a risk e.g. CSF ham

sandwich theory.

Commercial Imports

15. All legal shipments are notified in advance and arrive at

Border Inspection Posts where they are checked to ensure they are

correctly certified and identified.

16. Illegal shipments are likely to be imported by container or

hidden as part of a container load, the contents of which are not

disclosed to the Border Inspection Post or HM Customs as animal

products and subject to inspection. The meat is likely to be dried,

salted or partly cured. It will be intended for wholesale outlets

or direct to restaurants or canteens.

This increases the chance of virus getting into catering waste and

if not properly processed into susceptible pigs in sufficient

quantity to cause disease. During 2001 we had knowledge of 2

containers containing illegal meat products entering the country

and 3 being intercepted at t he port of entry.

17. HM Customs X-ray significant numbers of containers entering the

UK as part of its measures against duty evasion and drug

trafficking. For example, 7,348 containers were scanned in November

2001 including certain intra-Community traffic. Whilst these checks

are not specifically looking for meat, examination following

unexplained images would have been likely to identify large scale

meat smuggling.

18. Also an exercise to establish the accuracy of Customs

declarations was undertaken between 1 November 2000 and 9 April

2001. During this period, 132 Customs declarations were selected as

a control sample to test overall compliance with Customs

requirements. All consignments selected were to physically

examined. Within this sample no instances were found of failure to

declare meat products.

Examples of illegal imports

19. On 5 April 2001 and investigation officer and staff from DEFRA

visited a warehouse in Northumberland. The warehouse was owned by a

company that provided a storage facility forcustomers. During the

investigation a large quantity of foodstuffs originating from China

or Hong Kong were identified. Amongst it were 24 baskets

containing dried legs. The anatomical structure of the preserved

legs and the presence of cloven hoof structure indicated that they

were the legs and feet of pigs. The Chinese characters, which were

legible on the hams, suggested that the place or district of origin

was in the province of Zhejiang in China, which is famous for

Chinese style ham production. The legs were submitted to IAH

Pirbright for virus testing but no OIE list A viruses were

isolated. The range of test included feeding material to pigs under

experimental conditions.

20. Southampton Port handles some 35 million tons of cargo

annually. incorporating 55 thousand commercial shipping movements.

The container terminal currently hand les 1.2 million containers

each year with over 1.300 containers of food arriving monthly. The

principal trade links are with the North America, South America,

Indian Subcontinent, Middle and Far East.

21. The Port Health Authority had identified a recent problem with

the importation of animal products contained within personal

effects that were either undeclared or mis-described on the ships

manifest and on 21 February 2001 it intercepted a consignment of

personal effects which contained cured meat sourced from Saudi

Arabia. The total of ten cartons were opened and found to contain

various undeclared products of animal origins. These illegal

products were subject to a Regulation 25(1) Rejection Notice and

were destroyed under the supervision of the Authority.

Waste food from ships and aircraft

22. EU and UK law prohibits the feeding of this type of higher risk

waste food to animals. All such food from ports and airports is

collected under MAFF/DEFRA licence and destroyed by incineration or

exceptionally supervised landfill. This material presents a high

risk if fed to animals and was thought to be responsible for the

outbreak of FMD Type O in South Africa.

23. The FMD outbreak in South Africa was probably due to waste from

a ship in Durban Harbour being fed to pigs in the nearby locality.

The ship was allegedly of Asian origin. The genetic fingerprint of

the virus suggests it had originated in the Far East. It is well

established that international waste poses a major risk and

evidence is available for the spread of FMD, Classical Swine Fever,

and African Swine Fever by this route.

Appendix 1

Analysis of possible route for the entry of

FMD PanAsia strain into GB

Airborne - Unlikely: no outbreaks of disease in nearby countries.

Live animals - Low risk: no live susceptible species legally imported

from countries whi ch have had FMD in last 2 years or which have

vaccinated animals in past 12 months. Illegal importation from third

country unlikely. All Member States have same import policy for farm

livestock and exotic species on FMD

Semen - Low risk: country freedom from FMD required plus semen held

in quarantine for 28 days after collection to check status of donor.

Illegal importation easier but again unlikely. No desirable genetics

in affected countries.

Embryos - Very low risk for same reasons as semen plus embryos are

washed after collection. This would remove FMD virus. Pig embryo

transfer not common for technical reasons.

Vehicles - Low risk that contaminated vehicles would come to UK

directly from a third country affected with the relevant strain of

virus and that an infective dose would reach susceptible animals.

Footwear - Low risk from normal footwear but heavy contamination with

organic material e.g. in the grooves of wellington boots where virus

could survive for up to 14 weeks in organic material increases the

risk. Again contact with susceptible livestock would be necessary.

Virus could survive for up to 14 wks in winter.

People and Clothing - Low risk. Would require direct contact with

infected animals within 72 hours prior to entering UK and having

close contact with livestock. Virus could be carried for up to 14 wks

on clothing that was not cleaned or washed. Virus would be cleared

from nose and throat 28 hours after exposure.

Hides, skins, blood products - Treatment required for legal

importation would safeguard against introduction of FMD virus. Low

risk that illegally imported or improperly treated skins would come

in contact with susceptible animals.

Milk and Milk Powder - The dilution factor involved in producing bulk

milk and subsequent pasteurisation (72oC for 15 secs) reduces the

infective dose such that a pig would have to ingest between 125 and

1250 litres of milk at one session to become infected. At maximum

intake the pig would take in between 20 and 200 times less than the

infective dose. The risk is low.

In unpasteurised milk virus can survive for up to 15 days if

refrigerated but would be inactivated as soon as the milk turns sour.

The chance of illegally imported untreated milk reaching susceptible

animals in sufficient quantity is low.

The combination of the time/temperature treatment and drying process

involved in producing milk powder will decrease infectivity by up to

1 million infective doses. Risk is low for milk powder.

Milk Products - The risk of a dairy product produced by a process

involving a higher temperature treatment (UHT) or followed by further

heat treatment or acid treatment (cheese) is very low. Virus could

not be detected in cheddar cheese 2 weeks after processing or

camembert 14 days after processing. Survival time depends on the

process used.

Risk of an infective dose reaching a susceptible animal is very low.

Meat products - The following are regarded as presenting negligible

risk

1. Meat products heated in hermetically sealed container (con) to a

Fo value of 3 or more.

2. Meat deboned and heated to centre temperature of at least 70oC.

3. Meat deboned and matured for 9 months (hams)

4. Meat subject to pH of less than 6 throughout substance.

The above present negligible risk whether legally or illegally

imported. Products, which have not satisfied the full requirements of

2, 3 or 4 above, present a risk if fed directly to pigs. The level of

risk depends on the origin of the meat, quantity fed and process used

to prepare the product. Virus will survive in partially cured

products such as bacon and air or sun dried meat for up to 6 months.

Meat - The risk from meat varies greatly depending on country or

region of origin, species and cut of meat.

FMD virus is inactivated within 48 hours in muscle held at 4oC where

the pH falls below 6. The pH changes in pork are less than for beef

or sheepmeat. However virus will live for at least 5 months at 4oC

(chilled) in bone marrow and lymph nodes. If the carcass is frozen

the virus could survive for at least 6 months and possible for

several years.

Legally imported meat will be certified as coming from FMD free

countries or regions. If from an FMD vaccinating country or region

only deboned matured beef permitted.

Illegal meat - Highest risk is from countries with endemic FMD and

from meat especially pork still on the bone or with lymph glands

attached. Deboned frozen meat especially pork also presents a risk

but the likelihood of a significant quantity of frozen meat evading

checks is low as it will tend to be in refrigerated containers and

easier to target.

The high-risk areas for the current strain of FMD virus are Eastern

Mediterranean, Middle East, India and Far East where the virus has

spread since 1990. Other strains of FMD virus are present in South

America, Africa, Middle East and Far East. These illegal imports

could be in personal baggage or commercial consignments.

Appendix 2

Basic principles

1. Before assessing the route of entry in this case consideration

must be given to the following factors:-

- Routes of infection

- Minimum dose of virus to cause infection

- Relative susceptibility of different species

- Strain of virus and infectivity

Routes of infection

2. Two principle routes of infection are

(a) aerosol with virus entering respiratory tract

(b) ingestion by eating food infected or contaminated with the virus.

Minimum dose of virus required to cause infection

3. Theoretically it takes only one infectious particle to establish

infection in a susceptible animal but in practice a greater dose is

required due to in activation and clearance of virus by the host.

Relative susceptibilit y of species - minimum dose to indicate

infection

Respiratory route Oral route

Cattle 12 TCID50 (infectious unit) 1,000,000 TCID50

Pigs >800 ' 8,000 '

Sheep 10 '

4. Adult cattle because they inhale a greater volume of air are

more likely to be infected by the airborne route than pigs or

sheep.

Effect of strain of virus type on infectivity

5. The minimum infectious dose does vary with virus type, as does

the amount of virus excreted by infected animals. The current UK

strain produces about 300 times less virus by aerosol from the

respiratory tract of pigs than the strain which was used to do many

of the infectivity studies. This can also influence the incubation

period of the disease

ANNEX 7

ALTERNATIVE THEORIES

There have been a number of allegations that FMD existed in the

country before the index case at Burnside Farm (outbreak FMD/04).

After detailed investigations into the allegations no evidence has

been found to indicate that FMD was present in the country before the

index case at Burnside Farm.

For convenience these are dealt with in two separate groups

- Alternative theories for the origin

- Alternative theories for the time that disease was present in the

country

- Alternative theories on the origin

- Army caused outbreak by importing food from FMD areas.

All food that is imported for use by the Army complies with all

relevant UK and EU regulations. This means only importing from areas

that are certified free from FMD.

The Type O, Panasia strain of the virus present has not been isolated

from outbreaks of FMD in S America that is where the Army sources its

imports of meat. The strains of Type O virus in S America are

completely different to the {an Asia strain.

The army receives expert a dvice from the State Veterinary Service for

troops, vehicles and armoury returning from countries which are

likely to be infected with FMD.

Outbreak caused by escape of virus stolen from Porton Down

No Foot and Mouth viruses have been stolen from either the Centre for

Applied Microbiology and Research (CAMR) or the Chemical and

Biological Defence Sector (CBD) of DERA at Porton Down. In fact, no

samples of Foot and Mouth virus have been held at CAMR or CBD Porton

Down.

Virus was deliberately released from Porton Down research

establishment.

The laboratories licensed to hold and manipulated FMD virus in the UK

are the Institute of Animal Health, Pirbright Laboratory and the

Merial Biological Laboratory (FMD vaccine production), on the same

site. No other laboratories are licensed for this purpose in the UK,

including Porton Down.

Alternative theories for the time that disease was present in the

country

FMD found in UK sheep exported to France before 1 February - casting

doubt on Heddon-on-the-Wall being the earliest point of infection.

The French authorities responded to a UK letter seeking an

explanation for the appearance of FMD antibodies in sheep at a French

farmers premises when they were sampled prior to slaughter. The

French initially indicated that 7 of the 31 samples had tested

positively initially but that subsequent tests had showed that all

the samples were FMD negative. The French concluded that these

findings invalidated the hypothesis that FMD positive sheep were sent

from the UK to France prior to 1 February 2001.

MAFF knew about FMD before the outbreak was officially discovered

MAFF's Staffordshire animal health office carried out a routine foot

and mouth disease contingency planning exercise in January during

which supplies of a range of items we might need to procure are

checked. As part of that annual exercise staff contacted suppliers of

railway sleepers for inc ineration. The reason more than one supplier

was contacted was that staff were checking prices to find out the

competitive rate.

Similarly, officials spoke to the Antec disinfectant company in

November last year as part of a normal contractual discussion. Not

surprisingly, routine enquiries were made about disinfectant supplies

A veterinary surgeon working for DEFRA is alleged to have indicated

that he had seen disease that pre-dated that seen at Burnside Farm

The veterinary surgeon in question was identified and confirmed that

this allegation was incorrect.

A claim was made in the Sunday Express that the disease had been

present in the UK in 2000

Claims were made in the Sunday Express that Canada knew of the

presence of FMD in the UK prior to February 2000. In a letter to the

UK CVO, Canadian CVO refuted any such claim.

the first premises to be infected with FMD (outbreak FMD/04)

the premises on which FMD was first confirmed (outbreak FMD/01)

outbreaks which acted as the principle source of infection for others

or as local 'index' cases

Gibbens JC et al Descriptive epidemiology of the 2001 epidemic in

Great Britain: the first five months

Veterinary Record 2001 149 729-743

Donaldson AI et al (1982) Use of prediction Models to forecast and

analyse airborne spread during the foot-and-mouth disease outbreaks

in Brittany, Jersey and the Isle of Wight in 1981.

Vet. Rec. 110 53-57.

Lorenz (1989) Economic evaluation of the foot-and-mouth disease

vaccination control programme in the Federal Republic of Germany,

Part1.Tierarztliche 44 275-279

Hugh-Jones (1976) Epidemiological studies on the 1967-68 foot and

mouth disease epidemic; the reporting of suspect disease.

Journal of Hygiene, Cambridge, 77 299-306.

Knowles et al (2001) Outbreak of foot-and-mouth diseasevirus serotype

O in the UK caused by a pandemic strain.

Vet Rec 148 258-259

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