Memorandum submitted by D J B Denny, BVET
MED MRCVS (BTB 19)
1. EXECUTIVE
SUMMARY
1.1 Preamble
Historically TB was eradicated from our herds
because there was no reservoir of infection in the wild life.
1.2 Tuberculosis
TB is an infectious disease of all mammals with
a very slow onset of symptoms.
1.3 Badgers
With over 30% in some areas having TB it is
endemic in the badger population. It is beyond all reasonable
doubt that they are the reservoir of infection to cattle.
1.4 Tuberculin test
It is the internationally recognised test that
was used to eradicate TB from our herds 50 years ago.
1.5 The blood test
It is far too sensitive resulting in too many
cattle being culled. It only might have a place where there is
no reservoir of infection in the badgers.
1.6 Herd breakdowns
The pattern of herd breakdowns is such that
there MUST be a reservoir of infection other than cattle.
1.7 Science
Much of the Science appears biased and
is flawed so cannot be taken at face value.
1.8 Krebs trial
The trial under Professor Bourne was doomed
from the onset. It was poorly designed, by those with minimal
knowledge of badgers and badly executed. Insufficient badgers
were culled. In spite of these failings it did demonstrate the
badgers are responsible the transmission of TB to cattle.
The science is seriously flawed.
1.9 Independent Scientific Group chaired by
Professor Bourne
This is certainly not impartial. It is attempting
to defend the flawed "science" in the Kreb's trial,
by rubbishing others' work. They appear to be sacrificing their
integrity to salvage their credibility.
1.10 Cattle to cattle transmission of TB
It is, in my experience, very limited and insignificant
overall.
1.11 Cattle movements
Transmission of TB does result from movement
in a few incidents. Provided there is no badger reservoir, once
the reactors have been culled, herds remain clear.
1.12 Conclusion
Infected badgers are by far the most significant
reservoir of infection responsible for the current crisis. An
efficient cull will benefit not only the cattle population but
the badger one too.
1.13 The cull
Badger culling must be the most humane and cost
effective. The only method is by gassing them in their setts with
Carbon Monoxide gas from exhaust fumes.
2. PREAMBLE
2.1 As a Veterinary Surgeon with 45 years
of clinical experience in the field, there has been a very significant
difference in the outbreaks of TB in cattle herds, over the latter
years.
2.2 In the 1950s and early 1960s using the
tuberculin skin test TB was eradicated from herds; they then remained
free of TB for 30 to 40 years. The deterioration has been gathering
momentum for the last 15 years, and has now become a catastrophe.
2.3 Since the 1970s the badgers were made
a protected species and rround the same time farmers started to
grow maize, which became the badgers' preferred food and being
high in energy resulted in them being more fertile and having
a higher survival rate. Consequently there has been a significant
expansion of the badger population, with, in some regions a very
high incidence of them having TB.
2.4 It is a catastrophe not only for farmers
and their cattle but for the badgers as well.
3. TUBERCULOSIS-BTB
3.1 TB is an infectious disease of all mammals,
including man, caused by bacilli (antigen), with a very long incubation
period-time from first contact (challenge) to development of symptoms,
of months or even years, depending on size of the challenge. Infection
is usually by mouth or inhalation; the bacilli can also enter
the body via open wounds and bites.
3.2 Once in, the bodies' initial defence
mechanism is the lymph glands. There are lymph glands scattered
through out the body protecting all organs. The infected glands
become enlarged-lesions; if the challenge is small then the glands
will eventually return to normal. However with a larger challenge,
then the body will attempt to wall off the infection by forming
an abscess or abscesses. This process in cattle takes at least
four to six weeks.
3.3 At the same time the bodies' immune
system produces antibodies to the bacilli (antigen). In cattle
this process again takes at least four to six weeks.
3.4 With a low challenge the animal will
win the battle and the antibody level will fall. With a high challenge
or a frequent one, the bacilli will via the blood stream and enter
any organ of the body; usually the lungs, liver or kidneys, because
they act as filters. Once there multiple abscesses develop and
the animal will become ill. It is at this stage when it becomes
infectious to other animals (open infection).
4. TB-BADGERS
4.1 Badgers can live for over three years
with TB. For the first two or more years they appear healthy and
are capable of breeding etc It is only in the last six months
of their lives that they actually become ill and suffer before
they eventually die of starvation. For at least two years the
badgers are infectious. They excrete bacilli in their saliva and
over 1,500,000 bacilli in every teaspoonful of urine, which they
are continually dribbling out to contaminate the environment.
4.4 The assumption is then made because
badgers do not become ill, they therefore cannot suffer when they
have TB.
4.5 Ill badgers, unable to carry out their
normal "sett duties" are expelled and go into "sheltered
accommodation" often in or near farm buildings, stacks of
hay or straw, and drink from cattle troughs which they will contaminate.
5. TUBERCULIN
TEST
5.1 The tuberculin test is the internationally
acknowledged test for identifying TB reactor cattle.
5.2 It was the only test that eradicated
TB from our herds in the 1950 and '60s. The test has kept Europe
and Australia clear.
5.3 It is a comparative test which involves
injecting the "cow" at two different sites into the
skin in the neck, with a controlled amount inactivated TB—an
antigen. The animal if it has developed antibodies to TB, reacts
by producing a swelling at the injection site. 72 hours later
the reaction—swelling—if any is measured and the consistency
noted.
5.4 The result of the test is decided by
the difference in size of the swellings.
5.5 The test is claimed to be 98+% accurate—a
positive indicates that the animal has almost certainly been challenged
at least a month previously.
5.6 It is claimed that the test is only
80+% accurate in identifying all those that have been challenged,
even those that have lesions.
6. BLOOD TEST
6.1 This "new" blood test was
on trial as a complimentary test to the established tuberculin
test. It was inevitable that the trial would fail and it has now
been withdrawn.
6.2 The test is expensive both in man power
and lab fees. The test is too sensitive, which results in far
too many being slaughtered as reactors. The intention to remove
those few cattle that the tuberculin test missed was theoretically
a good idea. It however did not make any allowance for re-infection
from the reservoir of infection that exists in the badger population.
All my clients whose cattle underwent the test have since lost
yet more cattle and are still losing them.
6.3 The blood test would only be of use
were there NO external reservoir of infection.
7 HERD BREAKDOWN
7.1 It is not unusual, at the first herd
test when reactors are found there are no visible lesions found
at post mortem. At the subsequent 60 day test the cattle might
go clear only to react again at the six month test, when even
more reactors are found. This process can be repeated for several
years until finally lesions are found. Clients have lost 50 to
60 cattle before lesions are found. They may have a reprieve for
six months before having still more reactors.
7.2 Because there are no visible lesions
at tests farmers claim that their cattle do not have TB and that
the test is wrong. NO—it is an indication that those animals
have had a challenge, and that the testing is ahead of the game
(disease).
8. SCIENCE
8.1 Research scientists accumulate as much
information—data—as they can about their subject;
this data can then "cherry picked" by statisticians
to produce the result suitable for their source of finance or
in the case of controversial subjects to satisfy their supporters.
The result is "science".
8.2 Science itself is self perpetuating.
The more one looks the more one finds and the less one knows.
It appears that for some research scientists who depend upon external
funding it would be in their interests to prolong the process?
8.3 It is a very sad state of affairs but
no "scientific" claim, particularly if controversial
can be taken at face value.
9 THE KREB'S
TRIAL
9.1 The trial was set up to establish the
link, if any of badger involvement in the transmission of TB to
cattle.
9.2 The trial under Professor Bourne was
doomed from the very start.
9.3 At the launch farmers' meeting in Leominster,
in answer to a question Bourne stated that "I will make allowances
for any interference by the `badger groups' to the trial"!
9.4 Why were the dates and sites of trapping
posted on the web site??
9.5 The trial was inevitably sabotaged—traps
being wrecked, badgers relocated and those directly involved were
intimidated. How many arrests were there? What happened to the
badgers in the traps?
9.6 The trial was designed by those with
minimal knowledge of basic badger behaviour and was very poorly
executed. Trapping only took place for a few days at a time.
9.7 There was no way that sufficient numbers
of badgers would be culled. Who could have designed a culling
trial which stopped for the breeding season? Trapping only took
place for a few days at a time and during December when the weather
would be fickle and badger activity minimal.
9.8 The trapping was so inefficient that
only 30 to 60% of the guesstimated badgers were culled.
9.9 No account was taken that the ill badger,
having gone into "sheltered accommodation" would not
be on the trappers' target; they would only be trapping the healthy
badgers.
9.10 I would have expected at least a year
between an efficient cull for there to be any significant improvement
in the cattle TB numbers. This lag will also allow for those in
sheltered accommodation to have died.
9.11 The number of TB reactors in the hot
spot areas, including in the proactive trial area has in the last
few months reduced. This is no doubt to the death of the ill badgers
together with the culling. There is also less evidence of badger
activity in the area.
9.12 The reactive cull was, in some cases
did not start until six+ months after the TB breakdown. This is
intolerable.
9.13 At the Independent Scientific Group
open meeting in November 2004 one of the statisticians referring
to the termination of the reactive cull said "we put in all
different combinations of data and were unable to come up with
a different answer"!!
9.14 The Krebs trial found that both in
the reactive cull and the proactive one there was a decrease in
the number of breakdowns within the two areas, but an increase
in the number of breakdowns around the perimeters. This was put
down to perturbation (disturbance to you and I). At least it demonstrates
beyond all reasonable doubt, that the badgers have a definite
role in the transmission of TB to cattle.
9.15 The science of the Kreb's trial is
so flawed that little value can be put on the findings.
10. THE INDEPENDENT
SCIENTIFIC GROUP
(ISG)
10.1 The ISG, chaired by Professor Bourne
would, I hoped, have been impartial. Not so, in September 2004
Bourne told a Committee of MPs that it was cattle to cattle movements
that were responsible for transmission. He told me the same at
his open meeting November 2004.
10.2 At the January 2006 meeting we were
told by one of the group, that not many badgers die from TB! She
had not found many dead badgers. It is only commonsense, that
a terminally ill badger is not going to die out in the open. Any
one making such a statement deserves minimal credibility.
10.3 At the November 2004 meeting a report
on an experimental research project was given. Professor Bourne
was asked if it had been peer reviewed. Peer review is the scrutiny,
by anonymous, independent specialists on the subject. Bourne just
waived his arm at his group and said "I think they are well
enough qualified to say the report had been peer reviewed".
10.4 Bourne claimed in September 2004 when
discussing movement of cattle with MPs, that there is no such
thing as a closed herd. A closed herd, is usually a pedigree herd
were no cattle have been purchased- they are self contained, for
years. Occasionally every five or more years a bull might be purchased
to introduce fresh blood. There might be fewer closed herds than
there used to be, because they too have been ravaged by TB.
10.5 In the 1950s and '60s a double fence
six foot apart was all that was necessary to protect your cattle
from your neighbours. Now no herd is safe.
Bourne has rubbished the successful Tuberculin
test, rubbished the successful Thornbury cull, and rubbished the
successful Irish culls, yet still defends his own failed trial.
10.6 Professor Bourne stated "that
any action must be taken on the back of good science". If
this was tempered with commonsense then the correct action—a
cull would follow. Unfortunately, the science in the Krebs trial
is so seriously flawed and there was certainly no commonsense
applied, there is minimal sound evidence on which to plan a solution.
10.7 I find it despicable that under pressure
from his critics, Professor Bourne has resorted to writing to
the main stakeholders in the Government's current Consultation
exercise informing them that cattle movements are the cause of
the current crisis.
10.8 Bourne has graciously acknowledged
that "there is no doubt that badgers are implicated in the
transmission of TB to cattle. Because of the effect of perturbation,
any cull to be effective, would have to be over a very large area".
(So much for the Krebs trial.) "Since such a large cull would
not either be socially or politically acceptable, financially
affordable or sustainable, then a cull is not an option".
10.9 Bourne having failed the Krebs trial,
deliberately diverts attention away from the badgers and blames
cattle to cattle infection and cattle movements, for the TB.
11. CATTLE TO
CATTLE TRANSMISSION
11.1 Bourne claims that all cattle that
have been challenged with the bacilli are potentially infectious
and has stated that "there are a lot of cattle with undetected
TB out there".
11.2 This transmission, unless infection
in the herd is long standing, just does not occur in the field.
If it did then how did we eradicate TB from our herds in the '50s
and '60s?
12. CATTLE MOVEMENTS
12.1 There are incidents where cattle movements
have been directly responsible for outbreaks of TB. When farmers
were restocking, post Foot and Mouth TB was taken North to herds
in Cumbria. At their 60 day herd re-establishment test these cattle
were identified and culled. A few herds had reactors at the subsequent
60 day test, others went clear. I understand that virtually all
these herds were clear within a year and have remained clear since
because there is no external reservoir of infection in the wild
life.
12.2 On farms where there were reactor cattle
prior to foot and mouth, on restocking six months later with "TB
free" cattle, some of these cattle subsequently became reactors.
12.3 Analysis of the outbreaks locally indicate
that 70% are beyond all reasonable doubt due to badgers. The majority
of the others the cattle have come from herds with a previous
history of badger related outbreaks.
13. CONCLUSION
13.1 It is beyond all reasonable doubt that
TB infected badgers are by far the most significant reservoir
of infection for our cattle.
13.2 Professors do NOT have a monopoly of
knowledge; statisticians in their ivory towers should not be able
to influence those in the field.
13.3 The solution must be a clinical one
and not be one of consensus. The only solution is a cull of the
reservoir host.
13.4 An efficient cull will not only benefit
the cattle population but the badger population too.
14. THE CULL
14.1 Any cull must be humane and cost effective.
14.2 The handling and disposal of the badger
carcases and the financial cost involved must be taken into account.
14.3 Trapping has a high initial capital
cost, together with high manpower requirements. The badgers have
to be culled and disposed of. It is not a very efficient method,
as demonstrated in the Krebs trial.
14.4 Snaring—Completely indiscriminate
any other animal can be snared. Snares have to be inspected frequently—the
badger will suffer severely. Snares have to be anchored to a secure
object; not available in the open or when there is little or no
soil-stony/rocky ground.
14.5 Shooting—Shooting involves specialist
man power, and has a high risk of injury to the badger; never
mind the safety of those in the vicinity. Shooting would only
be efficient at night when the nocturnal badgers are active.
14.6 Frequent shooting would also be an
obnoxious stimulus to the badgers causing a behaviour change.
14.7 Poisoning is again indiscriminate having
multiple species as target.
14.8 Gassing the badgers in their setts
with carbon monoxide is by far the best option. Carbon monoxide
acts like an anaesthetic in that the animal just quietly becomes
unconscious and dies. There is no suffering. All the occupants
of the sett will die. There is no problem with disposal of carcases.
Exhaust fumes from any vehicle are suitable.
14.9 Culling must be left to the farmers,
who have the incentive, unlike official cullers, to do undertake
the work.
14.10 I am concerned that if licences are
required, who is going to issue them, and who is going to "vet"
them. If there is any publicity then the farmers will be liable
to intimidation by the "badger groups".
February 2006
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