Memorandum submitted by C Thomas-Everard
(BTB 34)
COMMENT ON
BOVINE TB CONTROL
TO EFRA SELECT
COMMITTEE
1. I write having heard, at 5.45 am yesterday,
a report of some of the statements made to the Select Committee
by members of the ISG—as I feel our experience and conclusions
may assist the Committee. I hope very much that this comment is
not yet too late for you to pass to members of the Select Committee.
2. We farm on Exmoor and have much experience
of bovine TB. It is also apposite that I write when the results
of TB incidences for the whole of 2005 have just been released
showing that bovine TB has worsened in this one year—27%
more cows have been compulsorily slaughtered as reactors (25,373)
and that 27% of all herds in Gloucestershire, 21% of all herds
in Devon and 20% of all herds in Hereford & Worcestershire
have been under movement restrictions during the year (3,667 herds
in the SW (and 5,242 herds nationally).
3. Several vets tell me that the rate of
spread within the badger population, and from them to cattle,
may increase much more in the coming years than the average of
18% in past years. Therefore, the quoted cost of £2 billion
for the next ten years to continue dealing with, but not controlling
bovine TB, may be an under-estimate.
4. I also believe that politicians and the
public should treat the controlling of the spread of TB from infected
social groups of badgers to the rest of the badger population
as a matter of controlling a wildlife disease, as important as
stopping the spread further into the cattle population. The photograph
below shows the reason.
A badger badly affected by TB, after a bite from
an infected badger. The huge neck abscesses have turned to puss.
This badger would have suffered for a long time before dying.
EXECUTIVE SUMMARY
My family are engaged in hill-farming and beef
production on Exmoor.
A. We have been affected by bovine TB in
our herd of over 800 cattle on seven occasions since 1993 each
time coming clear after repeated testing and removal of infected
cattle.
B. There is strong evidence that our problems
have been derived from an outside wildlife source—which
I believe to be TB-infected badgers.
C. I consider that it is possible to differentiate
between infected setts, less infected setts and uninfected setts
using the PCR Enigma Field Lab within 20 minutes of taking samples.
D. I am sure that using only snaring and
shooting as the only means of killing badgers will be infective
and will spread bovine TB to more herds.
E. I believe that treating TB-infected setts
with petrol exhaust gas (properly adjusted for maximum CO emission)
is easy to administer and humane. Such treatment causes minimal
amount of stress and can be carried out in the daytime at a cost
lower than any of the alternatives while all the members of an
infected social group of badgers are asleep underground.
F. I believe that wherever there is a widespread
area of TB-infection in sentinel cattle most setts in such areas
should be dealt with by engine exhaust gas, with coordination
being administered by DEFRA and the work carried out by farmers,
gamekeepers and DEFRA's wildlife team. Some healthy setts, identified
by PCR analysis as being un-infected could be left if the PCR
machine, referred to above, is as effective as the MOD developers
at Porton Down state.
G. If this work (F above) is done thoroughly,
I believe the immediate results of having far fewer herds with
TB breakdowns will mean that the cost to DEFRA of administering
a cull of infected badger social groups will be less than the
cost of dealing with more and more herd breakdowns, even in the
first year.
H. I believe that if such exhaust gas treatment
of infected setts is carried out effectively, bovine TB could
be eradicated within 4 years to the same low level of only 0.1%
of herds being under TB restriction that existed in 1980.
I. In order to achieve that speedy improvement,
and a rapid reduction in the cost to DEFRA of over £100 million
in 2006 of dealing with bovine TB, it is essential to retain the
skills and knowledge of the 2 DEFRA wild life teams; 52 at Polwhele,
Truro and 48 trappers at Aston Down near Stroud.
A. Background to our knowledge
1. A few of our herd of 350 suckler cows
and their calves were first infected by bovine TB in 1993, after
being clear of TB for 34 years. At first 3 out of 657 were found
and slaughtered as TB reactors. At the two next tests in June
and August a further 6 cattle had picked up infection.
2. I believe that this infection originated
from TB-infected badgers introduced into the Exe Valley after
being "rescued" from MAFF traps at Chagford on the edge
of Dartmoor. I understand that the spoligotype of the TB in our
cattle and the infected badgers in this valley was the same as
that found at Chagford.
3. Shortly after that first outbreak in
1993, MAFF trapped and removed all badgers here and up the valley
towards Mr Rawle's farm which first had a TB breakdown (a closed
pedigree Devon herd). Of the first 47 badgers, 40 were found to
be infected with TB (85%), 7 with open infectious lesions. When
a further 100 badgers in setts on the edge of our property where
trapped, killed, examined and samples cultured, all 100 were found
to be free of TB. Unfortunately the data was then generalised
so that it appeared that the 40 were infected out of 147, indicating
that only 27% were infected. I suspect some of the Krebs trial
results may be similarly over-generalised.
4. After that initial outbreak, we were
clear of TB infection for over 3 years and I believe this to be
because those infected badgers had been removed.
5. Only in 1997 did we have further TB infection
in the herd. 10 invasive badgers were then trapped of which 4
were found to be suffering from TB. Each year since then we have
found TB in the herd when tested in the early winter, a month
or more after housing.
6. Although we are not totally self-contained,
the only cattle brought onto the farm are about 30 bulling heifers
a year and the occasional bull. We have never had a TB reaction
in a bought-in animal within the first two years of arrival—which
would happen if the infection came from bought-in animals.
7. With the exception of two years we have
gone clear at repeated TB testing during each on the 9 winters
since 1997. In all cases the incidence of infection has reduced
during winter testing. If there had been any cow-to-cow transmission
of infection the TB problem would have got worse instead of improving
during the winter. I am advised that cow-to-cow transmission is
potentially possible during winter housing but is very unlikely
during extensive summer grazing.
8. We know from discussion with neighbours
and others that this sequence of going clear during the winter
and finding infection after summer and autumn grazing is a common
situation.
9. Because we record where each animal has
grazed each month and in which group, we can identify which part
of the farm gives rise to TB infection during the summer. Often
the infection is picked up by and identified in young stock which
tend to be more curious graziers, reaching under gates and into
hedges where badgers patrol and mark their territory by urination.
10. Last week our herd of 808 cattle tested
clear of TB. Even on severe interpretation (a 3 mm lump in the
skin instead 5 mm) there were no reactors and one animal only
showed as an IR (inconclusive). Last week's result was the best
(fewest IRs) we have ever had. We believe this to be because we
are in the Krebs proactive area in which the DEFRA wildlife team
have removed most badgers. If at the next test in 60 days time
we remain clear we will again be allowed to sell live cattle.
11. To ensure we are protected from infection
from bought-in replacement breeding heifers and the occasional
bull, we always put such bought-in animals on another farm, farmed
by this family, which has consistently remained clear of TB. Only
after a post-movement test do we transfer such heifers onto Broford
Farm where the main herd reside.
12. For all of the above reasons we conclude
that we have not had any infection from bought-in cattle and that
the source of our infection has been from the TB-infected badgers
found on the farm or travelling up the heavily wooded Exe Valley.
B. Other Outside Information
1. The current standard, EU enforced, intradermal
herd test for TB is very reliable, particularly when two tests
are carried out 60 days apart. Infection picked up within 8 weeks
before a test is less likely to be identified, because the bovine
animal has to have time to develop hypersensitivity to any TB
bacteria encountered. (For this reason the proposed pre-movement
test may give a dangerous false sense of security). It seems very
strange that so little notice is taken of the remarkably low annual
record of TB found in slaughterhouses where every bovine animal
is purposely inspected for TB. This for 2005 was only 288 animals
with TB lesions found in over 3.23 million adult cattle slaughtered
at the 33 UK abattoirs (with another 1/2 million slaughtered as
calves). The figures for 2004 was 201, for 2003: 161, and for
2002: 163. For 2005 the figure was equivalent to 1 in every 11,215
cattle (0.009%). This figure of only 288 cattle included animals
from areas on a 2, 3 or 4 yearly TB-testing regime, and therefore
many such cattle would never have been TB-tested in their lives.
What this minimal number of TB cases found at slaughter also surely
demonstrates is that there can be very little cow-to-cow transmission.
2. In addition to seeing that the standard
skin herd test is very effective at not missing TB infection (as
shown above), if anything it is hyper-sensitive. It should be
noted that for 2004 (the latest results published) only 6,413
cattle were confirmed to have TB out of the 19,972 compulsorily
slaughtered in the UK as TB reactors to the skin test, i.e. 68%
of the 19,972 reactors did not appear to have TB and may have
been "false positives". This bears out our own results
when, in the one year we tested right through the summer, we had
25 reactors over 4 tests, none of which on post-mortem were found
to have TB, either by visible lesions or by culture testing. We
(and the SVS vets) suspect that there was a small amount of badger-originated
TB infection at pasture which sensitised the 25 cattle to TB without
incurring the disease.
C. Potential huge advantage of using the
MOD's Enigma Field Lab PCR machine
1. This Field Lab will give a reliable result
as to whether a particular social group of badgers have TB within
20 minutes of samples of badger faeces (or urine or saliva) being
put in it by any un-skilled person by matching the DNA of bovine
TB. Thus the Field Lab can be used to identify where the edge
of any proposed badger culling area should be to avoid the culling
causing dispersal of infected badgers. Thus the 29% increase in
herd TB breakdowns, identified as a problem during the Krebs trial,
can by avoided or mitigated.
2. There may be also a role in identifying
some social groups within a cull area which are not infected with
TB so that these can be left to repopulate culled areas. This
is a hypothesis which as yet is unproven, but work on using PCR
machines to identify healthy social groups of badgers on the edge
of culling areas will quickly indicate the approximate proportion
of healthy setts to infected ones within a cull area. Thus if
a number of healthy setts can be left alive, farmers and politicians
can live with an easier conscience that they are not causing local
disappearance of all badgers; there will be less chance of a ruling
by the EU that Articles 7 and 8 of the Bern Convention have been
breached and the culling is "not detrimental to the survival
of the populations concerned" in such areas; and lastly the
political task of reassuring the public that the culling of infected
setts is necessary to save the health of the badger population
will be more easily achievable.
3. I attach with this comment details of
this Enigma Diagnostics machine.
4. This device requires no laboratory skill
in preparing samples, all the preparation to draw out the DNA
of the sample is automated in a series of treatments in the top
half of the machine (the field lab), and gives a clear positive
or negative answer within 20 minutes as to whether the DNA in
the sample matches the bacteria being sought.
5. This Enigma Field Lab has been designed
at Porton Down by the MOD to give a certain and definite answer
to soldiers suffering a biological agent attack as to whether
anthrax or other live organism is present, and what protection
to don or utilise. It is therefore designed to be soldier-proof
and to be sufficiently reliable because lives depend on its accuracy.
[40]
6. I am assured by the Porton Down personnel
who designed the Field Lab that there will be a reasonable degree
of accuracy if a number of samples from a badger latrine are mixed
and analysed as to whether the setts adjoining the latrine are
infected by TB. If a more accurate result is required then samples
of badger urine or saliva will give better results also with 20
minutes. Other live tests on badgers have been very unreliable
and take about a minimum of three days for an answer. If mixed
samples from badger latrines proves to be effective at identifying
clean setts, then farmers could send such samples to a central
point by post for immediate confirmation that their sett is healthy
or infected.
7. Enigma Diagnostics is owned by the MOD
and the Treasury so any payment by DEFRA to the MOD will make
no difference to the tax payer, merely causing interdepartmental
accounting. Enigma Diagnostics are willing to enter into a financing
arrangement once DEFRA are satisfied as to the effectiveness of
this machine.
8. Enigma Diagnostics have already drawn
down an assay of BVD (Bovine Viral Diahorrea) from University
work being carried out for DEFRA and used this in the Field Lab.
In the same way much time can be saved by DEFRA asking Dr Mike
Taylor of the Department Of Infectious Diseases and Micro-Biology,
Imperial College, London, to make his bovine TB assay available
to the Enigma team. Dr Taylor has been carrying out bovine TB
work for DEFRA—principally on testing cows.
D. Reasons why snaring and shooting alone
should not be adopted
1. I personally have a horror of snares
having had a favourite terrier killed in someone else's snare.
Whatever the intention, one size of "stop snare" cannot
fit all size of badgers or dogs without causing very serious injury
or death to larger animals.
2. I understand the law on snaring is that
snares have to be inspected every 3 hours. In the case of badgers,
which as a specie, are very wary, this requirement, although necessary
for welfare reasons, is likely to reduce the number of badgers
snared and will have a very high man-hour requirement. Once the
method of culling badgers in the 1980's was changed DEFRA found
that there was a fivefold increase in the number of personnel
required to trap badgers compared to the previous regime. The
earlier method of culling, when eradicating TB from the whole
Thornbury area near Bristol and the Isle of Purbeck in Dorset,
was by gassing with Cymag (made illegal under EU law from January
2005).
3. In reality if farmers have to do the
snaring themselves, the pressure of other farming tasks is likely
to mean that many snares will be set in the evening and only inspected
in the morning. There is therefore a likelihood that dogs, cats
and deer may be caught and die in extreme pain in such snares.
4. Having listened to many farmers about
this subject I find that few want to take part in a campaign of
snaring alone.
5. I understand that when badgers are caught
but not killed in a "stop snare" they will demolish
a bank, or undermine a small tree to try to free themselves. They
also try every possibly way to get free including twisting the
wire into a tight spiral or excessively tightly around and around
themselves.
6. Setting snares on visible badger runs
will merely weaken the social structure of a group of badgers
by killing the healthy dominant males, which regularly patrol
the boundaries of their territory, leaving sick TB-infected older
badgers either in the sett or ejected to travel randomly. Removing
the settled dominant male will cause fighting for territory.
7. Bites from infected badgers fighting
hither-to uninfected badgers will cause the type of disease symptoms
and wounds shown in the photograph at the beginning of this comment.
8. I believe that Appendix IV and Article
8 of the Bern Convention ban the use of indiscriminate means of
killing badgers and prohibit the use of snares on badgers (unless
exempted under Article 9 if "there is no other satisfactory
solution").
9. If badgers are only to be snared or shot,
then the current rule that a close season should be observed while
badger cubs are reliant of a lactating sow is likely to apply.
For the past 8 years of the Krebs trial, the DEFRA wildlife team
has observed a close season from February to April in each year.
However, it is now realised that, with milder weather, many badgers
have far better winter feed and often make intensive use of crops
of fodder maize. This has resulted in badger cubs being born outside
of the normal late January / February season. If it is proper
to avoid killing badgers when lactating sows may still be feeding
their young then, by extension if sows are having two litters
in a year or in eighteen months, the close season should match
the period when neonatal cubs are suckling and there may therefore
be almost no season when badgers should be snared or shot.
10. Relying on shooting badgers at night
by rifle from a cross country vehicle in motor-able fields within
100 metres will be very piecemeal, and will cause dispersal of
TB-infected badgers as the remaining ones fight for territory
(so-called "perturbation"). I understand that badgers
are much more shy at night than foxes and disappear when they
see a light moving in a field.
11. I believe that only a minority of farmers
own and have firearm certificates for rifles of sufficient size
(.223) to kill badgers properly (ie a .22 rifle is too small).
However well practised and competent the rifle user may be, the
high rate of wounding in any mass attempt to cull sufficient badgers
at night would cause far more suffering than treating badger setts
with car engine exhaust in the daytime while the occupants sleep.
12. Snaring and shooting should only be
used as a last resort where car exhaust cannot be used, such as
dealing with a very sick badger which seeks shelter in farm buildings
and has been thrown out of his old sett by his family. The fullest
possible toolbox should be available to ensure a really complete
cull of infected setts. For this reason cage trapping by the DEFRA
Wildlife Teams may also be necessary (see page 10).
13. Very sadly, in the last 18 months, one
teenager was accidentally shot by his stepfather while lamping
foxes, and another person suffered a punctured lung (and nearly
died) from a rifle shot while watching a badger sett at night
in similar circumstances. Such accidents may be even more probable
if large parts of the SW and West Midlands are peopled at night
by farmers desperate to go clear of TB reinfection, or to prevent
TB affecting their herd.
E. Petrol Engine Exhaust Gas
1. In contrast to snaring and shooting,
petrol engine exhaust will kill an entire TB-infected social group
at once. These means that any suckling cubs will be culled as
they sleep beside their dam, so that there is no need for a close
season. This means that setts can be culled concurrently across
a whole infected area on the same day, minimising movement or
dispersal of lone badgers and avoiding territorial fighting. If
a number of the healthy setts are left entire, the social groups
in them will not be weakened.
2. The sickest badgers tend to be ejected
out of the main sett as soon as overcrowding occurs. These TB
sufferers will be ejected by their progeny in the normal way,
but because there will then be many empty badger setts to which
such sick badgers can retire, they will move to such empty setts
and drag out old carcases.
3. Twigs should be placed across the entrances
of previously gassed setts after gassing and inspected regularly.
As soon as fresh nomadic badgers are seen to have entered the
sett it should be gassed again. This should thereby catch any
TB-infected badgers which have been ejected from the healthy setts.
4. The DEFRA desk study records that normal
petrol engine exhaust contains about 2% Carbon Monoxide (CO) when
idling with adjustment to the carburettor to limit the air. American
studies shown on the internet quote CO from an American petrol
engine as being 12% and 24% if "detuned".
5. The DEFRA report states that petrol engines
produce about 6% carbon Dioxide (CO2) and that CO2 increases the
breathing rate and speeds absorption of CO. It concludes that
1 % CO in 1 hour is a lethal concentration.
6. Carbon Monoxide is odourless and colourless.
If done quietly, a sett-full of badgers, which sleep by day, can
be treated while they stay asleep. CO induces a deeper sleep followed
by a painless death. I understand the main side effect, if any
survive, is normally only a headache and nausea.
7. I understand from reading the DEFRA paper
that, by computer modelling only, the authors concluded there
would be a slower dispersal of exhaust gas into blind tunnels.
In practise however exhaust gas can be seen on a cold day to mix
rapidly with air. My very limited understanding of physics is
that, by diffusion, gases and vapours mix and reach an equilibrium.
Avogado's law, "that equal volumes of gases, at the same
temperature and pressure, contain the same number of molecules"
indicates this, unless the gas is particularly heavy, or very
light e.g. hydrogen.
8. Because there are plenty of gas concentration
measuring devices available commercially as gas alarms for domestic
and marine use, the dispersal rate of exhaust gas in blind tunnels
can rapidly be determined.
9. Most large badger setts have extensive
links to a number of outlets and have, in addition, ventilation
holes in the main accommodation. Treating a large and complex
sett can therefore be done by watching for the exhaust gas to
emerge and after sufficient time blocking each exit and ventilation
hole. Any hole where exhaust gas does not emerge can then be treated
separately. Adding an odourless colouring agent to the petrol
to make it easier to see where exhaust gas emerges would be beneficial.
I understand that most recent experience of engine exhaust gassing
has been that of dealing with heavy infestations of rats or rabbits
in banks.
10. The DEFRA report confirms that diesel
exhaust contains at most 0.2% CO and should not be used.
F. Selecting a widespread area of culling
infected setts
Where TB infection in the sentinel cattle indicate
that TB is in some of the badgers within an area, the setts in
that area should be dealt with by the most humane and effective
manner. If possible PCR analysis should be used to identify uninfected
social groups. It seems essential that coordination of such culling
should be administered by DEFRA and the work carried out by farmers,
gamekeepers and DEFRA's wildlife team. Such a cull should be carried
out within a short time scale preferably, on the first occasion
in an area, on the same day.
G. Cost to DEFRA could be less than the cost
of continuing to test increasing numbers of cattle and the other
component costs in failing to control TB
1. If this work (F above) is done thoroughly,
I believe the immediate results of having far fewer herds with
TB breakdowns will mean that the cost to DEFRA of administering
a cull of infected badger social groups will be less than the
cost of dealing with more and more herd breakdowns, even in the
first year. Our own experience has usually been that once the
source of the TB infection, infected badgers, was removed, the
following TB test of the cattle proved them to be free of TB.
Where TB-infected badgers (85% with infection) lived, the cattle
TB test at the end of the grazing season (when cow to cow transmission
is highly unlikely) proved a few cattle in the herd were positive
to fresh TB infection (less than half of one percent). However
even those very few infected (usually young) cattle caused a period
of further testing (testing being the main element, £36 million,
in the costs to DEFRA of dealing with TB).
2. Thus the reduction to be brought about
in the spread of TB to fresh healthy badgers and from them to
healthy herds will give an immediate reduction in the biggest
item in DEFRA's TB costs.
H. Eradication of bovine TB within 4 years
1. To stop the suffering of badgers, the
distress to farmers, the loss of productive animals and the escalating
cost of over £100 million a year which has failed to control
TB, the target surely must be to use all practical measures possible
to eradicate (or at least to reduce bovine TB incidence back down
to 0.1%. In only 20 years of procrastination bovine TB has worsened
from less than a 100 herds affected to 5,634 herds in 2005 and
from 686 cattle killed as reactors to 20,119 cattle. I believe
that if all practicable steps are taken bovine TB can be brought
down to a minimal level within 4 years.
2. The very removal of infected setts will
cause a substantial reduction in the overcrowding and competition
for territory that currently causes TB to spread from one badger
social group to another and to cattle. Where older badgers are
sick with TB they will be ejected by their progeny in the normal
way, but, because there will then be many empty badger setts to
which such sick badgers can move, they will move to such empty
setts and drag out old carcases. Thus old TB sick badgers are
much less likely to go into farm buildings looking for any form
of shelter.
I. Retain the DEFRA wildlife team
1. In order to achieve a speedy improvement,
and a rapid reduction in the cost to DEFRA of £ 90.5 million
in 2005 (forecast to rise to over £120 million in 2006) of
dealing with bovine TB, it is essential to retain the skills and
knowledge of the 2 DEFRA wild life teams; 52 at Polwhele, Truro,
and the 48 trappers at Aston Down, near Stroud.
2. This is not as great an immediate cost
as may be supposed because only 20 of the skilled wildlife trappers
have contracts which terminate shortly. The cost of the retention
of these 100 highly skilled people should be borne by DEFRA until
TB is brought under control.
3. The fact that bovine TB is out of control
is essentially because successive Ministers have abrogated their
governmental responsibilities by refusing to make a decision to
control the infection in badgers before it got out of hand. Ministers
have tolerated TB-infected badgers spreading infection to other
healthy badgers, and to cattle, almost wholly for political reasons.
4. Until Ministers confirm their decision
to control TB in infected badger setts, the skilled trappers should
continue to be employed. They should use the time to identify
healthy badger social groups at the edge of infected areas, while
the ground is soft enough for tracking, and before the growth
of leaves, shrubs and grass in the Spring obscure the badger setts.
5. A great advantage of retaining the 100
trappers is that they can, legally and with their specialist skills,
trap badgers where it is desirable to do so. This will include
live trapping within infected areas on the boundaries of properties
where the owner will not allow anyone access, and in situations
where it is helpful to take saliva or blood samples directly from
live badgers to confirm that the spoligotype of the TB in the
badgers matches that of TB in the adjoining cattle.
J. Information source
At present much veterinary advice is that cattle
are acting as sentinel animals revealing a wildlife problem. I
can only end by saying that coalminers would not have survived
long if the mine-owners had merely killed all sentinel canaries
and taken no other action to prevent fire-damp explosions.
Much of the knowledge about the behaviour of
families and social groups of badgers in this paper comes from
Mr Bryan Hill. Mr Hill has made a very through study of the behaviour
of many different social groups of badgers. I recommend very strongly
that anyone who is in a position of responsibility as to the choice
of methods of controlling bovine TB should talk to Mr Hill.
February 2006
40 You can also go to the Porton Capital website at
the web address http://www.portoncapital.com/web/index.php. To
enter the demonstration part of website, type in the username
as porton and the password as down. There is a video entitled
"Out of the lab" which you can view. For further
information contact Dr Ian George, Business Development Director,
Enigma Diagnostics Ltd, Building 224, Tetricus Science Park, DSTL,
Porton Down, Salisbury, Wiltshire SP4 0JQ. Back
| 
