Tuesday, June 22, 2010

The silent killer

These videos (click left hand arrow to view) were kindly sent by one of the members of the Camelid TB Support Group. We have permission to use them. Their purpose is not to break your heart (and it will) but to show you how perfectly healthy a young alpaca can look (this cria was under a year old) - and yet be riddled with TB having PASSED a skin test.

The first clip was taken an hour before he was put down. He was in his pen - alone, waiting to be culled. He wasn't showing ANY signs of ANY illness let alone TB. He had passed the skin test twice, but failed the blood test. He is eating, inquisitive, bright and has no weight loss. No outward signs at all.

This alpaca was culled one hour after the footage was taken. He had TB lesions throughout his entire organs. This is the silent killer known as TB. Alpaca owners cannot rely on the skin test alone to detect TB infected animals. They cannot trade with any confidence when out of restriction having only used the skin test.

Advice from alpaca vet, Gina Bromage is to not consider selling, showing or moving alpacas around for a minimum of one year (possibly longer) - on the back of a negative skin test. As the video clip clearly shows , a negative skin test in alpacas does not mean a lot and stresses the importance of the blood tests and the current research into the gamma interferon validation project and the hope of a reliable ante-mortem TB test.

(This posting from Dianne Summers, who runs the Camelid TB Support Group)


Anonymous said...

What is happening with the validation test? Is the testing of negative alpacas going ahead? BAS members do not get any updates from the BAS board on the subject of BTB.

Thank goodness for the TB Support Group! Thank you to the owner of the alpaca in the video - this is information we should all know about.

Anonymous said...

This is my alpaca in the video and I asked Di who runs the TB Support group to send it out. I came down to TB in November last year and have lost 19 of my wonderful alpacas and it has broke my heart.
No help from BAS and no info on the website. Di keeps us all informed of what is going on.
I also sent Di the video of my 7 ladies I had to put down all on the same day -all full of Tb - no outward signs. I will remain anonymous because I don't want to have to go through abuse that Di gets from the big commercial alpaca breeders who treat her in a cruel and awful way just because she tries to educate us all on TB.

Matthew said...

Anon 9.37.
As far we are aware, the GammaIFN validation pilot study, funded by BAS and with animals volunteered by their members is going ahead.

Anon 12.53
We are grateful to you for allowing us to share the story.

It may be worth you contacting VLA with your numbers of TB casualty alpacas, if only to support and confirm our information that only culture samples appear on the Defra stats. And due to cost pressure, these are limited to the first couple of any TB breakdown. Thus within Defra's alpaca stats, only 2 or 3 of your 19 may have been counted.

Anonymous said...

When I looked at the videos I sobbed. I am going through the same and have lost 40 of my herd of 52. I came down to TB in September 09.
I have lost everything.
I had one skin test positive the rest either died or were found on blood tests.
Some people have come out of restriction and refused blood tests and I don't know why. Do they not want to know which of there herd have TB. Do they not care about who they are selling to.
I also would like to thank the kind person who sent in the video -I too have to remain anonymous - I have seen what some of the alpaca breeders have done to Di.
I wouldn't have got through this without her.

Anonymous said...

Ditto to the last post - I have lost 19 since Feb this year - all passed the skin test - 14 failed the blood tests all 14 full of TB.
The video is exactly what we have to go through. I had to hold a 6 month cria whilst she was put down.
I called Di and she listened to me shout rant and rave for hours. i am angry - the badgers have killed my herd. I am finished.
I could have refused the blood tests - I would have gone clear and out of restriction and could have sold. It was Di who told me not to rely on a negative skin test - she was right.
Isn't it time we were classed as livestock. Sorry if I sound angry but I am.

Matthew said...

To the authors of all the above comments - do you realise that bewteen you - just three alpaca owners,- your losses from TB in just a few months are 80 animals?
This is more than Defra were showing for the whole of 2009, and their figures have yet to be updated for any alpaca which has died of TB in 2010.

No wonder the Scottish minister, and many others when they view these stats, are saying 'problem, what problem?'

Anonymous said...

Seems like the problems for alpacas are the same as cattle in that "owners cannot rely on the skin test alone to detect TB infected animals. They cannot trade with any confidence when out of restriction having only used the skin test."

But trade must go on.

Matthew said...

Anon 9. 22
We refer you to Hansard written PQ ansers, Jan - March 2004:

"The tuberculin skin test for CATTLE has been compulsory in Great Britain since 1950. It is prescribed by the OIE for international trade as well as under EU directive 64/432/EEC."

".. the comparative skin test, at standard interpretation provides sensitivety in the range 68 - 95 per cent and specificity in the range 96 - 99 percent."

"Any single test with imperfect sensitivety, when applied more than once to an infected animal, will cause the overall sensitivety of the procedure to rapidly approach 100 per cent.."

"All countries that have either eradicated, or have a programme to control tuberculosis (in cattle) use one or more forms of the skin test."

".. in the absence of a significant wildlife reservoir, cattle controls based on regular testing and slaughter, inspection at slaughterhouses and movement restrictions (including tracing and contiguous testing) can be effective at controlling TB (without vaccination) [159061]

And in the 'absence of a significant wildlife reservoir', some EU member States, and some other international trading countries no longer skin test at all, relying on slaughterhouse surveillance.

In cattle, the skin test works.

Unfortunately for alpaca owners, in their species, the 'bovine' intradermal comparative skin test does not.

Anonymous said...

Well said Matthew. A perfect response.

The latest BAS mag has a Tb update
feature and from over 144 alpacas lost last year ony 12 had skin test positives and from 94 lost this year only 9 were skin test positive.

Dianne Summers said...

In response to Matthews very useful reply - I would just like to make one important correction and that is if we get a positive skin test reactor in camelids then it is positive. Those in touch with the TB Support group have never had a false positive on the skin test but sadly we get many false negatives.
Hence the importance of blood tests. Hence the importance of the gamma validation project.
Dianne Summers
Camelid TB Support Group

Matthew said...

Just to add to this debate, the intradermal skin test does not indicate disease. It is primed to flag an immune response to an animal that has exposure to the bacteria which cause tuberculosis.
It it similar to the Mantoux test in humans, where a multi needle jab, usually on the inner forearm, will indicate whether the candidate has come into contact with TB. If the result in humans is a postive reaction, then further investigations are carried out.
Cattle are shot.
And AHO reports show that about half slaughtered cattle reactors have NVL, (No Visible Lesions) that is, disease hasn't progressed to a stage where it can either be seen at pm, or cultured.

As Dianne says, in the experience of alpaca owners whose animals have undergone these tests, if there is the slightest rise on the alpcaca bovine jab site, is likely to indicate full blown infection, rather than 'exposure'.

In cattle, if (and with regular testing, this is very rare) the disease has completely taken over, then there will be no immune response to the skin test. This is known as an 'anergic' reaction.

Matthew said...

We have received the following comment re bTB in alapcas, from a prominent member of the veterinary professsion.

"Those owners who are in denial that their Alpacas could have bTB are not only being totally irresponsible, but are endangering their own and other's health.

Such is the level of infection in those alpacas with bTB that it is inevitable that sooner than later someone will become infected from them.

The bTB disease process in humans (and cattle) is both slow and insidious, whilst in alpacas it is rapid up to the point of being highly infectious.

In spite of being warned by MAFF a decade plus ago that bTB was rife in the Countryside, the medical profession is still oblivious to the fact that your chronic and vague symptoms could be bTB. Even when bTB is suspected, it is not routine to use the special media essential to culture samples for bTB. The diagnosis is an 'atypical Mycobacterium species'.Thus the statistics are consequently (deliberately?) skewed, resulting in under reporting of bTB in the human population."

We have heard this reporting process described by VLA staff as 'a one way street' in that when animals (particularly cattle) are diagnosed with confirmed TB, health professionals must be informed. But the opposite does not happen very often. VLA are rarely involved in tracing to source a case of TB in humans. In fact it it not unknown for cases to be misdiagnosed or treated with blanket antibiotics, making sampling ineffective.
Medical textbooks are still hooked into the 1950s 'drinking unpasteurised milk' as a cause of bTB, and as our comment points out, have not caught up with the gross environmental contamination now around.