Wednesday, 28 April 2010

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.


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.

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