A most interesting contribution forwarded by Betty in Holland:
Date: 31-8-2001 1:03:50
For those interested in FMD in deer I am attaching a copy of the paper that
Paul Gibbs and I will pressent at the meeting of the Unites States Animal
Health Association, the first week of November in Hershey, PA, USA.
Somebody else may give you an answer on the ELISA test using deer serum,
but I would use a virus neutralization test in this case, that is the test
used in the experimental work at Plum Island and Pirbright.
------ Einde van doorgestuurd bericht -----
FOOT-AND-MOUTH DISEASE IN DEER: IMPLICATIONS FOR THE POLICY OF CONTROL AND
ERADICATION OF THE DISEASE
Paul Sutmoller* and Paul Gibbs**
*Animal Health Consultant, 1502 Largo Rd., Virginia 23233, USA,
** College of Veterinary Medicine, University of Florida, Gainesville,
Florida 32611, USA, e-mail: firstname.lastname@example.org
The continuing epidemic of foot-and-mouth disease (FMD) in the United
Kingdom (UK) has led to veterinarians and others questioning whether
wildlife species (particularly deer) are perhaps playing a more significant
role in the maintenance of the epidemic than is currently acknowledged.
Similar concerns concerning deer are being expressed in the Netherlands,
which has also had a FMD epidemic in 2001 (5).
Many wildlife species are known to be susceptible to FMD virus, but it has
been very difficult to assess their role in transmission of disease to
domestic livestock (6). The general opinion is that wildlife species are
not a significant factor in maintaining a FMD epidemic. While the African
Cape Buffalo is believed to maintain FMD virus in the absence of infection
in domestic livestock in Southern Africa, no comparable situation has been
discovered in any other wildlife species elsewhere in the world.
Descriptions of FMD in deer were already made during the 1924-1926 extensive
outbreak of the disease in California, USA. This outbreak not only affected
livestock, but spread to the deer population in the Stanislaus National
Forest. In those years some 22,000 deer were killed, of which 10% showed
typical FMD lesions (4).
In the years 1973-74, FMD in deer was studied by a group of investigators of
the Animal Virus Research Institute in the UK (1,2,3), presently the World
Reference Laboratory for FMD and by a group of researchers of the Plum
Island Animal Disease Laboratory (4). The publications of both groups
present a very complete picture of FMD in deer.
McVicar et al. (4) reported as follows: ".. white-tailed deer were clearly
susceptible to infection with this strain of FMD virus both by intranasal
inoculation and by contact exposure. The clinical syndrome in deer was
somewhat variable but, in general, severity of the disease was intermediate
between that seen in cattle and in sheep and goats exposed and housed under
The lack of knowledge about the susceptibility of deer during the extensive
1967-68 FMD outbreak in the UK prompted the UK group to first investigate
this aspect of the disease for three of the in the UK existing deer species
(1). The conclusions from that work were: "All three species were
susceptible to infection with FMD virus. Clinical disease was mild or
inapparent in the red and fallow deer but was more severe in the roe deer.
The appearance and distribution of the lesions were similar to those in
This research was followed by a more detailed investigation on the behavior
of FMD virus in infected deer. The results showed that, in general, FMD
virus acts very similar in deer, cattle and sheep with regard to the amount
of virus in the blood as in excretion of virus and the carrier status (2).
Finally, Gibbs et al. (3) carried out a large experiment that studied the
full infectious cycle. It was shown that cattle can infect deer, that these
deer in turn can infect cattle and sheep, and that these species can
transmit FMD back to deer. These investigation also confirmed all earlier
observations: "This study and earlier observations .. have established that
the five species of deer seen in the British countryside are susceptible to
FMD. .. the smaller species .. both develop severe disease and death is not
uncommon during the acute stage of the disease.(underlining added) ".
The authors speculated that deer were unlikely to play an important role in
the survival and transmission of the virus during a FMD epidemic, because of
the natural behavior of free-living deer in the UK: ". none of the five
species are in general likely to come in close contact with domestic
livestock except in some areas of common grazing such as the New Forest,
Hampshire. However, it must be remembered that the larger deer often
intergraze with cattle and sheep in parks and in these conditions
transmission of FMD between the species could occur" (3).
In the intervening period between the above mentioned studies in the 1970's
and 2001, the deer populations of the UK and countries, such as the
Netherlands, have risen significantly. In this paper we will therefore
examine the validity of the earlier conclusions on the role of deer in the
epidemiology of FMD in Western Europe.
Implications of FMD infection of deer for FMD control
Two countries in Western Europe with recent FMD outbreaks and with a
substantial deer population are the Netherlands and the United Kingdom.
In the Netherlands FMD was confirmed in February of this year. Control of
the outbreak was originally by the "stamping-out" policy, that is the
killing and destruction of all susceptible livestock on the infected farms
and their immediate contacts. When it seemed that the outbreak was running
out of control, vaccination of all susceptible species was applied in a zone
with about 250,000 of such animals. They were mostly cattle and sheep, some
goats and pigs. The vaccination stopped the outbreak within a few days, but
for fear of "carriers" among the livestock population all vaccinated animals
were killed and destroyed in the course of about a month. The mass killing
of these vaccinated healthy animals caused tremendous hardship for the
communities that were stricken.
Livestock, roe deer and farmers live in close contact in the infected zone
in the Netherlands. According to the official opinion, vaccinated livestock
could become easily infected and thus become carriers of FMD virus. This was
the reason for the killing of large numbers of healthy vaccinated cattle and
vaccinated sheep. However, deer roaming between farm premises in areas that
experience FMD outbreaks should at least have to be considered as being
In any case, there are two possible scenarios with regard to FMD in roe
(a) either deer in the infected zone in the Netherlands are not infected;
(b) deer in the infected zone in the Netherlands are infected.
Scenario 1: Deer not infected
a) FMD vaccination of livestock in it self does not produce FMD virus
carriers. Vaccinated livestock must be exposed to FMD virus - before or
after vaccination - in order to become a carrier. Exposure may be by contact
with infectious secretions, or inhalation of infectious aerosols, from
animals with FMD.
b) Roe deer range in the vaccinated area, cross fields between farms, visit
premises and yards with animal feed and slurry, etc. Thus, susceptible deer
act as sentinels for FMD virus.
c) If FMD virus is present in the environment the chance that free roaming
roe deer become infected is many magnitudes greater than the chance of
exposure to infection of livestock in pens or stables. The risk that stabled
vaccinated livestock becomes infected is close to zero. In the absence of a
FMD virus source there cannot be any carrier among the vaccinated livestock.
Scenario 2: Deer infected
a) If FMD has infected the deer population the Veterinary Authority will
have a difficult task to control the disease in those species.
b) FMD in deer will run its natural course, and after several months the
outbreak is likely to burn out, similarly to what happened in the early days
with FMD in cattle, before the introduction of the mass vaccination, or,
lately, with FMD in wildlife in sub-Sahara Africa.
c) After the outbreak peters out the virus will probably still be present in
the area for some length of time. Re-population of the area with susceptible
livestock would be risky. Therefore, all livestock in the area should be
vaccinated or re-vaccinated, preferably within three months to obtain an
optimum population immunity. Re-population of the area with vaccinated
livestock does not need to wait for the infection to peter out in deer.
d) The official opinion that FMD infected roe deer constitute a low risk,
because sick animals hide and probably die, is not valid. Like cattle or
sheep, susceptible deer are very infectious prior to the development of
lesions while they still actively move and graze. Also deer with
sub-clinical or minor lesions will still roam around.
Conclusions: In both scenarios the killing of healthy vaccinated livestock
is senseless for the control of FMD. In this case of scenario 2 (deer in the
area infected), a vaccination zone with solidly immune livestock is the only
way to control FMD.
The FMD outbreak in the UK is dealt with by the slaughter and destruction of
all susceptible livestock on infected and suspected premises and the culling
of all susceptible sheep and pigs on contiguous premises within a 3-km
radius. This policy has lead to the destruction of more than 3,500,000
cattle, sheep, goats and pigs. Here again one can question the wisdom of
such actions. If deer are roaming and grazing in the infected area there is
a good probability that the deer population becomes infected. In that case,
the destruction of livestock on contiguous farms does not make much sense.
If the deer population is not infected, one can ligitimately ask: "Has
destruction of livestock at this large scale become an overkill?".
Ecological conditions in several counties have changed since the 1960s, in
particular wild deer densities have increased significantly in Europe and in
the USA. Thus previous assessments of Gibbs et al. (3) of the role of
wildlife may no longer be relevant.
There is anecdotal evidence of infection in wild deer, but there is a lack
of scientific data to confirm or refute the presence of wildlife infection.
Like has been done for wildlife in many parts of Africa, a thorough field
and laboratory investigation can proof beyond doubt the presence or absence
of FMD in deer populations. In the absence of a scientifically sound
epidemiological survey of deer and other ungulate populations in the FMD
recent infected areas, this uncertainty must be a cause of great concern for
all stakeholders such as decision makers, farmer and agricultural
industries, wildlife managers and trading partners. If indeed FMD were
present in wildlife in some of Western Europe that would be of potential
consequences for other countries around the world.
The above arguments underline the urgent need for a reappraisal of the role
of wildlife in the epidemiology, prevention, control and eradication of FMD.
This revision must be based on risk analysis using scientific facts, not
1. Forman, A.J.& Gibbs, E.P.J. - Studies with Foot and Mouth Disease virus
in British deer (Red, Fallow and Roe) I. Clinical Disease. J. Comp. Path.
Vol 84, 215- 220, 1974.
2. Forman, A.J., Gibbs, E.P.J., Baber, D.J., Herniman, K.A.J. & Barnett,
I.T. - Studies with Foot and Mouth Disease virus in British deer (Red,
Fallow and Roe) II Recovery of virus and serological response. J. Comp.
Path. Vol 84, 221- 228, 1974.
3. Gibbs, E.P.J., Herniman, K.A.J., Lawman, M.J.P. & Sellers, R.F.- Foot and
Mouth Disease in British deer: Transmission of virus to cattle, sheep and
deer. Veterinary Record June 28th ,1974, 558-563.
4. McVicar, J.W., Sutmoller, P. Ferris, D.H., & Campbell, C.H. - Foot and
Mouth Disease in white-tailed deer: clinical signs and transmission in the
laboratory. Proceedings of the 78th Annual Mgt USAnimal Health Association
5. Sutmoller, P. - Verdenking van MKZ onder Nederlands wild. Tijdschr.
Diergeneesk. 126, 12, 2001, 434-435.
6. Thompson, G.R., Bengis, R.G. & Brown, C. Picornavirus infections in
Infectious Diseases of Wild Mammals 3rd Ed. Edited by E.S. Williams and
I.K. Baker. Iowa State Univ. Press 2001.
And still on the subject of deer, Michaela sends this informed contribution
on the ELISA test that we have been discussing recently:
I got a friend to comment, I would simply have said that the elisa test is
not specific to deer. That the plates need to be sensitised/prepared with
deer blood/Ab and that the test has not been validated. As we also know its
uncertain that elisa for sheep has been validated.
What they test for is not the virus
itself, because that is present in very low quantities in blood, even at the
height of an infection. There are tests for virus in blood (the PCR based
test being exquisitely sensitive) but these take a minimum of five days, are
tricky and expensive. It needs a skilled technician with quite some
What the ELISA tests for is antibodies against the virus, which in an
infected or recently recovered animal will be present in reasonable to large
quantities. ELISAs are also sensitive, but easy to carry out and are, in
fact, done by an automated machine.
The way an ELISA (Enzyme Linked Immunosorbent Assay) works is to start with
viral protein made in the lab, which is bound to a dish so it cannot wash
away. Antibodies, if present in the sample, will bind to this - the antigen
- and so they too won't be washed away. It is the next bit that is species
specific. To detect the bound antibody (from the blood sample) a previous
anti-antibody is added, like the starting antigen, previously made in the
lab (or, rather, in a lab animal - usually a rabbit).
This second, anti-antibody antibody (the terminology gets clumsy here) is
specific for the constant region of the antibody from the blood. These
constant regions differ between species (although for closely related
species, such as goats and sheep, there is some cross-reactivity). The
constant regions of sheep (which is, in the end what determines the
sensitivity of the test) are different from those of cattle, and both are
different from those of deer.
Consequently, to test cattle samples one has to use anti-antibody made which
binds to cattle antibody constant regions. To test sheep, one has to use
anti-sheep antibody, and so on.
Just for completion (I know you know, but you might like to send this on)
the Enzyme bit comes from how one detects the bound anti-antibody. What one
does is tag onto this second antibody an enzyme that creates a colour that
can be measured when a reagent is added. Ultimately, it is this colour that
North's point is that there is no deer test. Developing the test for each
species is not difficult, but is time consuming and expensive. The
anti-cattle and anti-sheep kits are mass produced by pharmaceutical
companies and sold as kits, which is what they are using at Pirbright.
There are no anti-deer kits on the market.
North has a valid point. I tried to point this out in April and May, but
got no serious response. All that MAFF would say was that deer were not a
problem because in 1968 there were no recurrences from any wild pool of
virus. However, the deer population is now around ten times that of 1968
and in Cumbria perhaps many more.
Foot and mouth is probably not serious in red and fallow deer, but in our
smaller deer it definitely is - often fatal. In the north this means roe
deer - there are loads of roe deer right across here. I walk eight miles
into Durham cross country most days. In the winter when they are easier to
spot I would see roe deer most days.
Because they do not test positive when tested with a sheep based ELISA, any
dead deer that have been found with FMD like symptoms have been dismissed by
MAFF/DEFRA as misdiagnosed parapoxvirus infection.
Perhaps I am being too simplistic/optimistic, but I still contend that deer
are not a serious infectious risk. Time will tell.
Our comment: There is plenty here to contradict the categorical denial by
DEFRA that deer have any role in spreading disease during the current UK
outbreak of FMD. But our own (unscientific) feeling is this - that although
deer clearly can, and do, become infected with FMD, it is not a serious
issue either for them or the domestic livestock with which they mingle.
Rather like sheep? This is precisely why DEFRA cannot admit any infection
in deer, because to do so also acknowledges the fact that a mildly
susceptible species has no role in onward transmission of the disease, thus
demolishing their "case" for the slaughter of sheep with antibodies . . . .
. . .
Final comment from Richard North:
Re deer -
Is this DEFRA the successor to the same MAFF which said there was no risk
BSE and which denied that there was a problem with OP sheep dips? I think
should be told.
Better late than never:
Foot and mouth culls divide rural society
Friday August 31, 2001
Foot and mouth disease is not disappearing as fast as ministers predicted.
months on from an election in which the public was assured we were in the
straight", fresh outbreaks are still recurring. During four days in the past
new cases broke out in one Northumberland valley, Allendale, close to the
where the first case was identified in February. By yesterday, the total had
just 11 short of 2,000. Autumn approaches, a period of many animal
with sheep having to be brought down from the high ground, where the grass
stops growing, if they are to survive. The colder - and wetter - weather
conditions in which the disease thrives. Worse still, the countryside
government's advisory group on rural affairs, warned ministers this week
long-term social effects of the epidemic will last for years.
In the face of this gloomy news - with even the farmers admitting they had
guard drop in recent weeks - the cabinet's emergency committee agreed to a
relaxation of the rules restricting animal movements. It might seem absurd,
Lord Whitty, the food and farming minister, set out a persuasive case why
should be done for both commercial and animal welfare reasons. He
acknowledged there was a risk, but pointed to the rules which would remain:
licensing of movements between farms; individual identification of animals;
tests for some sheep; and in high risk areas, movements only after animal
inspections by vets.
The minister was right to assert that a stricter observance of biosecurity
procedures would reduce the risk. But another crucial decision awaits him,
further outbreaks like Allendale develop: the need to try a control
than massive culls. The countryside agency is in no doubt what it should
chairman, Ewen Cameron, called on Wednesday for a pilot vaccination scheme
deal with any new outbreak. He was right.
Government scientific advisers remain divided over vaccination, but farmers
longer totally opposed. Government officials described the vaccination
"still open", but it must be more than just open. There needs to be a
which could be put quickly into effect, in the event of a further serious
Allendale. Lord Whitty himself warned farmers that the government was
"anticipating more cases".
Vaccination should be tried for multiple reasons. It was tried in the
and worked. They have even been allowed to restart their meat exports to
the obstacle which prompted opposition from farmers here. But there are
reasons, beyond farming, why vaccination needs to be tried. It is less
community life than mass culling, which shuts off roads, footpaths and open
countryside. Other rural industries have been hit even harder than farming.
Tourism alone has suffered at least twice as much. And beyond tourism a raft
other services - traders, decorators, car hire - have been hit. Indeed, the
countryside agency estimates one in four businesses has been hurt. Where
rural communities were united in their support for farmers, divisions have
appeared. Many tourist operators and hotels will not survive if there are
restrictions. They, understandably, want other options tried. There is a
ministers could help these other rural businesses: speedy introduction of
initiatives in the rural white paper - better marketing, more help to market
better transport - rather than require even further delay.
Lawrence Alderson of the RBST has sent us his report entitled
"Foot-and-Mouth Disease in the United Kingdom 2001;
its cause, course, control and consequences" which we have attached to
tonight's message as a Word document.
(warmwell note: I think this paper by Lawrence Alderson is dynamite...I have turned it into a webpage that can be viewed here)
This contribution comes from Sara:
I was given to understand that the foot and mouth virus can't be passed on
to humans, now I may be being completely dumb here (and being a townie, not
completely understanding what does go on
in the countryside) but instead of killing (culling doesn't sound as bad,
and lets face it, it is killing isn't it?) and burning (air born infection)
or burying (possible water pollution) animals. Wouldn't it have been better
to have mobile slaughter houses and process
the meat for the food chain or am I being totally unrealistic (and stupid?)
Our comment: No one with any common sense has been able to understand why
the majority of animals slaughtered could not enter the human food chain in
the normal way. Most were never infected anyway so presented no possible
risk. Even infected stock could still be processed and eaten with complete
safety, as there are no human health implications. The only risk (as we
understand it) of disease transmission lies in the bone marrow and the outer
skin/hair/wool covering of the animal, while pH changes in the body tissues
destroy the virus in all other parts of the carcase - so if the former parts
are removed and sensibly disposed of, there is no problem and no risk, which
is the rationale behind the continuing importation of deboned meat from
countries with endemic FMD. If we can eat this imported stuff, why can't we
eat our own?
Seems to us that only the authorities have been "totally unrealistic and
Richard North sent this comment on Amy's joke yesterday:
Is your wingless fly any relation of Kirsty Walk of Newsnight fame?
Vaccination package drawn up in secret
By John Harvey, Geoffrey Lean, and Robert Mendick
02 September 2001
The Government's top advisers on foot and mouth have been drawing up secret
plans to vaccinate animals to combat the disease, The Independent on Sunday
The special interdepartmental scientific committee chaired by Professor
David King, the Government's Chief Scientific Adviser, has commissioned the
plan to try to stop a fresh epidemic breaking out while sheep are moved off
the hills and down to lowland farms for winter grazing. Five million animals
are expected to be moved during the autumn.
The news comes as the Army yesterday moved into Northumberland to organise
the slaughter and disposal of thousands of sheep and cattle following the
latest outbreak in the Allendale area of the county. The number of confirmed
cases since the epidemic began last February is expected to exceed 2,000
early this week.
Gareth Davies - a member of the scientific committee and the former head of
the epidemiology unit at the official Central Veterinary Laboratory - was
asked to start drawing up the plans in July. The committee has set itself
until the end of this month to finalise them.
The move - which would propose a separate vaccination package for each of
the English regions to address differences in the way sheep are moved in
different areas - is the latest sign that pressure is building up for a
U-turn in the Government's foot and mouth strategy.
Ministers are reported to be prepared to authorise a limited programme of
vaccination in six weeks, if the disease has not then been eradicated. Lord
Haskins, the Prime Minister's top rural adviser, has long been in favour of
it, and last week Ewen Cameron, chairman of the Countryside Agency, called
for it to be tried out.
Sources say that the entire scientific committee now supports vaccination
after formerly sceptical members changed their minds. They say that it is
now only being blocked by Dr Jim Scudamore, the Government's Chief Vet, and
the farming unions. Ben Gill, the President of the National Farmers' Union,
recently described the case for vaccination as "bilge".
Mr Davies - who dealt with the last European outbreak of the disease in
Greece in 1996 - said recently: "If we had vaccinated during late March, we
would have been spared the loss of thousands of animals and the public
revulsion at the carcasses strewn across the countryside.
"However, I had underestimated the almost mystical belief in the superiority
of slaughter as a method of control. This has allowed all sorts of false
statements to flourish."
In a further blow to the case against vaccination, the Government has now
admitted that the British are eating thousands of tons of vaccinated meat.
The National Farmers' Union's insistence that people would never consume it
was one of the factors that persuaded the Government to abandon tentative
plans to vaccinate this spring, even though experts pointed out that they
already ate meat inoculated against many other diseases.
Now, in a letter to the Soil Association, the Department of the Environment,
Food and Rural Affairs (Defra) has disclosed that 18,718 tons of beef were
imported from Brazil - which vaccinates against foot and mouth - in the year
up to last May.
It says it has "no reason" to trace it and so has "no detailed information
about when or where meat imported from vaccinating countries is on sale".
How annoying that farm virus will not obey rules
THE foot and mouth epidemic is over, as we all know, because Mr Blair told
us so. So when 16 new cases appeared in Northumberland last week, several
outside the Government's new "blue box" restriction zone, it was appropriate
for the local National Farmer's Union to say that these had "breached the
boundaries set by the Government". How tiresome of the disease to ignore
regulations in this way.
In reality, as independent scientists suggest, this constant reappearance of
foot and mouth, in south Wales, north Yorkshire, Somerset, Cheshire, Cumbria
and now Northumberland, means that it is now in effect endemic. This puts
paid to any notion that the European Commission will let Britain revert to
its "disease-free export status", possibly even for years to come.
Had Britain gone for mass vaccination last spring, stopping the epidemic in
its tracks in weeks, the UK could, under international rules, have had
export status back by next April.
One condition informally laid down by the Commission for recovery of export
status is that the disease must not be in Britain's wild deer population.
Although anecdotal evidence suggests that it has been in deer for months,
the official line of the Department of the Environment, Food and Rural
Affairs (Defra), as they were suspiciously quick to point out when I asked
them last week, is that they "do not consider deer to be a risk". There has
therefore been no need for them to test the deer population. Thus, hardly
surprisingly, there is "no evidence" that deer have been infected. As one
might say, knowing how sensitive the Commission is on this point, deer have
not "breached the boundaries set by the Government"; unlike, alas, those 16
new outbreaks in Northumberland, where there are even more deer than there
are Defra officials. Sept 2
from Alan & Rosie