bTB Test Volunteers Needed Urgently

You do not have to be a BAS member to take part in this trial.




bTB Test Volunteers Needed

As you know, we have some areas of the country where bTB is endemic in the wildlife and cattle populations. It is in these areas where the majority of infected alpaca herds reside at present. Those areas are defined by the red 12 month, and yellow 24 month cattle testing areas on the map that you can find here:

http://www.defra.gov.uk/animalhealth/managing-disease/bTb/pti/images/Map-large-2010.jpg If you live outside the 12 and 24 month areas, we need your help.

The VLA have developed a new blood test for bTB which has been used on several infected herds already. It shows great promise, and they have proposed that once validated it could become available to be used as a screening test (along side the skin test) to identify bTB infected alpacas. That would mean that we could test alpacas going to a show, or a stud male with reasonable accuracy - something we cannot do at present.

I will give you a representative example. Recently an infected herd had 62 alpacas tested. The skin test found 2 positives. The currently available rapid test found 1 more. The new gamma interferon test found 16 more - all of which had visible lesions on PM. With just the skin test 60 bTB infected alpacas would have tested clear.

To validate the test, the VLA require BLOOD SAMPLES from 300 alpacas from supposed 'clean' herds that live in 36 or 48 month areas. The blood will be taken on farm by a VLA vet, and sent to be tested at the VLA laboratory at Weybridge. As all currently available blood tests will be validated at this point, there is a chance that a false positive could occur. In that event, the alpaca in question would be culled and post mortemed. Unless bTB was cultured (in which case you would surely want to know) your herd would NOT be put under restrictions. This is the same procedure by which the VLA have validated other tests.

Whatever we as owners think about how important alpacas are, in the scheme of things it is remarkable that the VLA are giving us so much of their time and resources. This opportunity won't last for long though, and we are under pressure to let them have details of the alpacas for testing. So far we have had only a handful of volunteers and we need more. Please don't rely on someone else to come forward on your behalf - this is vital and it's probably now or never.

My own herd is in a 48 month area, and we are putting 15 alpacas forward. Please consider doing the same.

Best wishes

Mike Birch
BAS Chairman

Case History 4

Again this is published with the kind permission of Dianne Summers.

Dianne runs a Tb support group for those unfortunate enough to contract it in to their herd. This is a completely confidential group. She also runs a Tb update group for those that want to kept in touch with the latest news. Dianne was awarded the National Felipe Benevides Trophy at the BAS AGM for her work on Tb in Alpacas. This is awarded to people for extraordinary work to benefit welfare of camelids for no financial gain. A link to her Yahoo Alpaca and Llama Welfare Discussion Group is included in the links at the side of this blog.

Dianne has put a video on YouTube of the cough that one of her Tb infected animals had click here


Dianne makes it clear that if you see your animal cough like this it does not mean it definitely has Tb but recommends that you act on it right away. If she had seen this video 12 months previously she would have isolated her animal along with a companion and could possibly have saved more of her alpacas. This cough is different to the usual cough that may occur when they have eaten too quickly or a piece of hay has tickled their throat.

Raphael was actually stressed when this video was being made as Dianne was being taught how to use a stethoscope on him and he got into a bit of a strop, hence the high breathing rate.

This video was sent to the owners of Tb infected herds and those that had coughing as a symptom all confirmed that this was the exact same cough that their animals displayed.

They do not cough continually so if you do not live close to your animals you could quite easily miss it. Raphael and his companions only used to cough like this 3 or 4 times a day.

It is better to err on the side of caution because if it is Tb then they are passing it on to other alpacas they come into contact with, and possibly onto you and your family.

Case History 3

Trachea

This is a PM film of an alapaca that was given up as a dangerous contact in a herd with a Tb breakdown.

When Dianne had an alpaca develop a cough it was isolated, and then had to make the horrendous decision on which other animal to put with him as a companion. None of us envy that position.

When the animal with the cough did not get better after treatment Dianne made the decision to euthanise and Animal Health allowed the companion to be given up as a dangerous contact. He couldn't be put back with the rest, it is remarkable that this film is of the companion and NOT the alpaca with the cough. These lesions in his throat were highly infectious and he must have been spreading Tb with every breath. He weighed 97kg on PM and was showing no symptoms whatsoever.

If he had not been chosen as a companion he may well have been in the field infecting the rest of the herd and may never have developed symptoms.

This alpaca could have been in the next pen to you at a show or in with your agisted alpacas for mating.

Case History 2

This is a brief history of the devastation caused by BTb in one herd given with the kind permission of the owner.

Sept 17th 2009 Had female euthenized and Post Mortem examination revealed BTb.

Sept 18th - Oct 4th 2009 Lost 2 more females, one a 7 week old cria, both confirmed BTb, even the cria had lesions on its lungs.

Oct 5th 2009 Entire herd of 47 alpacas skin tested for BTb.

Oct 8th 2009 Skin test results showed only one alpaca positive for BTb but showing no clinical signs.

Oct 13th Positive female alpaca culled and confirmed riddled with BTb on PM.

Oct 13th - Nov 18th She lost 5 more animals to BTb yet all had passed the skin test.

Nov 18th DEFRA blood tested remaining herd they used Rapid Stat Pak and Gamma Interferon IG test. Both these tests are under trial.

Nov 24th Results received - 12 of the animals failed BOTH blood tests and were therefore classed as positives.

15 failed only one of the tests and fell into what they class as a grey area.

The remaining alpacas tested negative to both.

Nov 25th All 12 that failed BOTH blood tests were culled on her farm along with one that fell into the grey area but was displaying symptoms of illness. All were removed and PM'd
That same evening DEFRA contacted the owner and confirmed that all 13 were riddled with BTb.

Conclusions:

Alpacas can be infected and display no outward symptoms.

This case has shown a 94% false negative result using the skin test, also in this case using BOTH blood tests showed 100% accuracy.

Using the skin test to confirm that alpacas are free from BTb for sales, showing, matings etc could possibly be said to be deceitful, or possibly even malicious, especially in the light of the information that has been made available to all BAS members.

BTb seems to be particularly virulent in alpacas as shown by a 7 week old cria showing lesions on its lungs.

Case History 1

Lung

Liver

Sorry to start with these shocking images but it is important to see the damage Tb does, as you read on you will see these pictures are of an animal that tested negative to the skin test TWICE. The cheese-like substance is BTb.

This case history has been reproduced with the kind permission of the owner.

The above animal displayed no outward symptoms of Tb, he weighed 83kg on PM, but luckily the owner knew that the skin test is unreliable. She had the animal X-rayed which showed up lesions, this animal was therefore highly infectious so she agreed to it being culled.

This is a common finding - no outward signs but highly infectious. This disease can easily be passed on via shows, on-farm matings etc. and yet to date there is no reliable test.