Bovine
Tuberculosis.WE HAD RESTRICTIONS
LIFTED IN JANUARY 2011!!
Some of our Junior Male Show Team members contracted
Bovine TB in 2009(we believe whilst at a Show but, not necessarily
from other alpacas). We closed the herd from 10/9/2009 when we
had our first suspicious symptom (but were not closed by Animal
Health until November 2009!). Although we were clear at the end
of January 2011, we did not move any stock until May 2011. We
are now resuming sales and matings (however, we will only be having
drive by matings. Mobile matings may be possible subject to circumstances.
We do not wish to go through another TB cession!). Please do contact
us for advice on how to handle TB in the herd, the risks of your
own herd becoming infected and the potential sources of infection,
also, for methods of controlling the infection if you have or,
suspect that you have an alpaca with TB. However, we would advise
that Defra take a rather dim view of treatment with anti-tuberculin
drugs (despite there not being any legislation restricting administration
of these drugs to camelids). We lost a total of 13 alpacas to
TB (14% of the herd). Of these thirteen, ten had been placed in
quarantine from the start in September and October 2009. A number
of other breeders lost/are losing a considerably higher proportion
of their herd, so it is a disease that has to be taken very seriously
and, in our opinion, can be (but not always) transmitted very
readily between alpacas. Early quarantine of any suspect/close
contact alpacas is essential, as is treatment (if you wish to
embark on that course, the cost of the drugs is in the region
of £1,000 to £3000 plus per animal depending on the
length of treatment decided upon (the longer the better)and the
weight of the alpaca). We believe that we successfully cured two
out of five alpacas (however, we can't be sure that those two
had TB in first place). We think that the disease had progressed
too far, before they showed any symptoms, in the other treated
and prophylactically treated close contact animals. The last few
to die/be put down, all in a quarrantine group, were the last
ones to be given any TB drugs. We think that all had been quietly
incubating the infection for a while and although they had high
dose treatment for varying lengths of time, it was not long enough
and was started too late. However, the treatment did work sufficiently
for them to regain weight and be outwardly well for some months
(and almost certainly reduced or illiminated their infectiousness
during that time). One, that we had put down, appeared to indicate
that the treatment was substantially successful. One of the most
recent deaths was the cria of a female that died of TB in November
2009. This male never showed symptoms until a couple of days prior
to death, but should probably have been treated as soon as his
mother died, as from the PM, he had clearly had it for a long
time ( he may have developed some resistance, hence it taking
13 months before symptoms appeared). Most of the others had some
sign of not being 100% fit at a much earlier stage.
The
two alpacas that were treated early on and completed initial treatment
in November and December 2009, are both still alive (July 2011)and
appear to be very well. So it would seem that, on the evidence
so far, one has to start treatment very early if a short high
dose course is going to work (or they didn't have it in the first
place?). Otherwise, a much longer, possibly multi-drug, course
will be needed (assuming you can get the drugs). Unless the alpaca
is very valuable, this is not a viable proposition as the cost
could be in the region of £4,000 to £5,000. However,
Isoniazid alone does appear to be effective but, a longer 6 to
12 months high dose course is probably required. As a precaution
(based on experience gained via the later failures), we gave the
early treated alpacas further 12 + month courses of Isoniazid
and vitamin B6 (this helps to reduce any adverse side effects).
Tb
tests are not infallible and one female passed two tests and yet,
was subsequently put down and confirmed to have Tb. However, she
did have side effects - see below. Be very suspicious of any alpaca
that has any adverse reaction to the test and of any that have
even the slightest thickening of the skin at the bovine injection
site (it is probably best to ignore the required level of thickening
that officially indicates a "reactor". Quarantine all
that show any reaction at all. We had two with a very slight reaction,
both had been in quarantine from the start and both did have TB).
It is essential to adequately quarantine any alpaca showing suspicious
symptoms (these, in our case, were a higher respiration rate than
normal, a high temperature -(above 104 f and up to 107.8 f in
one case, the normal range is 101.5 f to 102.5 f) and a bit later,
symptoms similar to pneumonia and some weight loss and for one,
the only symptom was constipation!). Please note that heat stress
can be the cause of a high respiration rate and raised temperature
- so if the alpaca is in full fleece and the weather is hot/humid,
suspect heat stress before assuming TB and cool the alpaca down.
We
had none with really significant weight loss until two later cases
but, this can be common for other spoligotypes of bovine TB and
none with coughs (except for the last of the two females in June/July
2010 at a late stage)but, again, this is a sign with some spoligotypes
and, if our experience is anything to go by, the symptoms can
vary significantly within the same spoligotype. One appeared to
be in the peak of health until suddenly dropping dead! The problem
for all alpaca owners is that many of the symptoms of TB are similar
to those encountered with many other ailments - so don't immediately
think the worst (in young animals, coccidia can give rise to some
of these symptoms and not all coughs are due to TB) but, do quarantine
until you are sure of what you are dealing with. Our experience
has shown that it can be spread rapidly to those in close and
continuous contact, especially if an alpaca is shedding TB bacteria
(they are not all necessarily infectious). One interesting fact
is that neither of the two females, that had b TB, had lesions
in their mammary glands but, one cria subsequently died, the other
is totally fine and passed four tests. From all accounts that
we are aware of, TB has yet to be found in the genitalia of alpacas
(certainly not those that were otherwise appearing to be well).
So matings would not appear to be a particulary high risk of infection
and any risk that there may be can be reduced further by placing
a clean sock over the nose of each alpaca (they can breath perfectly
well). However, it is not a good idea to do spit offs outside
your own herd - with or without socks! Even within your own herd,
it is often sufficient to just place the females adjacent to a
mating couple and see which ones sit. Not quite as accurate as
a one on one spit off, but nearly as good and reduces the risk
of passing on any infection (not just TB).
TB
should be suspected in any alpaca that has colic following a skin
test. There are now many such reported cases, including our last
female case(we,also,had one with this reaction after a blue tongue
vaccination and he, also, had TB). Do not put too much reliance
on the blood tests either, there are far too many cases of probable/possible
false positives (alpacas that test positive for TB but, don't
visibly have it on PM) and, we still don't know if they are picking
out all of the alpacas that actually do have it. Further research
is required before one can be confident in using these tests (both
of which are still being trialed) - particularly with regard to
possibly losing animals unnecessarily. Given the lack of any currently
proven ante-mortem test, we had hoped to try high definition x-rays
during our breakdown, but unfortunately, the machine was wrecked
by a horse. We understand that others have tried this method and
have found it to be effective in picking out those with lesions/lesion
like damage (remember that liver fluke, lungworm and other parasites
and infections can give a similar picture). Obviously, early stage
infection will not be picked up, but if three lots of x-rays are
taken 60 days apart, it would seem likely that a high proportion
(possibly all) would be detected over that period. Ultra sound
scanning can, also, work, however, given the rather grainy picture
obtained from this method, you need a very experienced vet to
interpret the images.
If
you are located in a TB "hotspot" area, it is worth
considering installing electric badger fencing or, high tensile
steel mesh badger fencing around the perimeter of your farm. Obviously,
this might not be practical for large establishments but, for
those with smaller farms they are effective. The cheapest option
is a four strand electric fence (plus an earth wire on the ground)
with mesh on all access gates (the cost is considerably less than
that of one good female alpaca). We have found the electric fence
has detered all badgers (not that we think our local badgers have
TB but, they could do so in the future or may have already caught
it from our alpacas), however, we have found that it also, unfortunately,
kills hedgehogs as well as frogs and toads heading to our pond
for spawning. So a ramp is needed on their main run so that they
can climb over the bottom wire. Curiously, the frogs and toads
soon learnt not to touch the wires - they are not as stupid as
one might have thought! We installed double fencing between all
paddocks (effectively making all 10 main paddocks capable of being
a quarantine paddock). This was a bit late in the day in our case
(although it certainly enabled us to successfully manage our way
out of the disease)but, it is something that should be considered
on all alpaca farms. Apart from the bio-security benefit, the
gaps will make convenient herding lanes from all directions to
the mating and husbandry task pens. The cost is not insignificant,
especially as we use post and rail, and the number of gates grew
exponentially!
I
had a meeting with the Minister (Jim Paice), on 18th October 2010,
to discuss the whole issue of bovine TB in camelids, including
amongst others, the lack of adequate ante-mortem testing, the
lack of adequate compensation, the restricted qualification for
receiving that compensation and the department's view on vaccinating
camelids against b TB.
The
meeting was not as succesful as hoped for. This was mainly because
it was hijacked by representatives from Defra. Much misinformation
and untruthful statements were made by one representative, in
particular. This, unfortunately, meant that much time was wasted
(probably by design) in challenging and correcting what was said.
However, the minister did agree that immune response tests for
bovine TB were not ideal and they were now revisiting the possibility
of developing a version of the PCR test (which detects actual
infection, rather than an immunity that could be acquired or inherited).
In the meantime, the gamma interferon trials will be going ahead.
(Since the meeting, it seems that the PCR test has been
kicked into touch again (although, a recent Countryfile programme
suggests that something similar to PCR is being tested by the
VLA and that vaccination of livestock could be back on the medium
term agenda, but the DIVA test (a test to differentiate between
vaccinated and infected animals) has to be perfected first, plus
agreement is required from the EU.
The minister agreed that there was a problem with the current
level of compensation and quite understood why owners feel it
to be inadequate and, until recently, had not been aware of the
high values of many alpacas. Opinions, in this respect, could
be submitted under the bovine TB consultation process which, also,
posed questions as to whether non-bovines should come under similar
rules to those applying to bovines etc(the consultation is now
closed to new input). There was insufficient time to discuss why
Defra chooses to disqualify some animals from any form of compensation
(I did say that I believe that many of these cases are incorrectly
excluded and had more to do with cost saving and reducing the
numbers with regard to the TB data submitted to ministers and
to the EU). Defra's appallingly bad recording of data on TB was
raised. (Following the round of spending cuts, I was later
advised that a voluntary increase in compensation is extremely
unlikely).
Vaccination
was only briefly discussed at the time. There does not seem to
be any objection in principle. The current BCG vaccine has an
efficacy of around 65% to 70% (meaning that out of 100 animals
vaccinated only 65 to 70 would be immune - however, that number
does reduce the chances of infection for those not technically
immune). There is a recently developed vaccine for humans (still
under trial) that has shown a close to 100% success rate, in a
number of animal test species for various forms of TB, including
bovine. So there's hope on that front.
The
minister mentioned that a decision with regard to the badger problem
might be brought forward to early next year (was scheduled for
mid May 2011). Does not seem to be a change on this front!
Since
the meeting, I have asked for further clarification of certain
issues. Obviously, the current round of spending cuts will not
help (29% in the case of Defra) but, I hope that the current government
will see that expenditure on prevention and better tests would
save tens of millions of pounds in future compensation expense
and costs to farmers. My MP, Laurence Robertson, has raised a
number questions in the commons relating to bTB and with regard
to camelids in particular. He will continue to push for further
answers and will raise more questions in relation to compensation.
An area where, in our opinion, the Government is not correctly
interpreting the law and should be paying market value in accordance
with the Diseases of Animals ( Ascertainment of Compensation)
Order 1959 (an old order that was not repealed by later Acts of
Parliament and is therefore still in place) and not relying
upon a "voluntary Ex-Gratia" payment of £750.
We
have not had any TB deaths in the main herd since 2nd July 2010
and now feel confident that we are out the other side of it.