Thursday, 29 April 2010

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: 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

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