Sunday, May 30, 2010

'Side effects' after the skin test - a request

The intradermal skin test, universally used to screen cattle for exposure to bTB, is also used when a breakdown has occurred on goats, sheep and camelids.

We are hearing of increasing numbers of whole body 'reactions' to skin test jabs in alpacas.

In another life, we were taught that the mantra of "clinical disease + an introduced top up dose" - in the form of vaccination, or possibly a screening jab? - meant death. In almost 40 years of first hand experience of the test used on cattle, we have never seen a reaction such as this. But talking to cattle farmers who were around during the eradication years of the early 1960's, and who remembered the effect of the skin test on some clinically infected cattle, it could happen.

We have received the following request for further information on these 'reactions' from the Cornwall Alpaca Group's welfare liaison officer, and organiser of the Alpaca TB Support Group, Dianne Summers, which we are happy to post:

Members of the Alpaca TB support group who have kindly forwarded details of their tests, losses and post mortem results to me for filing, have also mentioned some extreme reactions in their animals, following the skin test jabs.

One of my own animals, (Cloud) also had this reaction. In Cloud’s case, it appeared within an hour of the test, (after my AHO had left) and left him gasping for breath, with legs extended, distressed and with an increased heartbeat. Although his ‘reaction’ had gone within a couple of days, Cloud was subsequently found to have generalised TB at postmortem.

Within our small support group of 28 alpaca owners, 22 animals have suffered a similar reaction. In three cases, the animals have died before the reading of the test. Others have been euthanased on welfare grounds. Some appeared to recover, but a positive skin test and/or blood test has meant they have been culled and found to have clinical TB at postmortem, some in several organs of their bodies.

A retired veterinary scientist, who attended an Alpaca TB Awareness Roadshow and is on my mailing list for updates of our support group, has expressed interest in this 'side effects' data which the group have provided. Although he has been worked for almost 40 years with bTB in cattle (and badgers), the extreme reaction to the skin test which some of our alpacas have had, is something he has not experienced before.

He is keen to document it and offer his findings to the veterinary / scientific press. To do this he needs to speak directly to the owners (or their vets) of animals in which this reaction has been seen. In papers of this sort, owner's anonymity is completely protected, with the animal in question given a label 'a' or 'b', or numbered.

It is not lumps or bumps he is looking for. It is this violent (and sometimes fatal) whole body type reaction to the skin test, which is of interest. This may happen within the first minutes (or hours) of the jab and in my case (Cloud) could not have been passed off as ‘stress’. The interest of the veterinary professionals who have requested information from owners, is driven by concern for the welfare of our alpacas. As this reaction is not routinely seen in cattle, it is possible that it is a violently ‘positive’ reaction of alpacas who may have clinical TB (as the majority of this 'side effect' group have proved to have) when given the screening test of a bTB ppd antigen jab.

If any alpaca owner has experienced this ‘side effect’ of the skin test on any of their animals, and would be prepared to contribute this experience to the author of the proposed veterinary paper, could they please contact me on the numbers below.

Dianne Summers
Camelid TB Support Group
01209 822422

Amongst the members of the TB support group, 28 alpaca owners have reported that 22 of their animals suffered this type of reaction a short time after receiving the intradermal TB skin test. In some animals, the reaction eventually proved fatal. Others were euthanased ahead of an elective cull, after a positive reaction to the test, on welfare grounds.

For the welfare of alpacas, we think it is very important to investigate the scale of this 'reaction', when the intradermal TB screening test is offered to animals which may be already clinically infected.


Anonymous said...

You state:

"We are hearing of increasing numbers of whole body 'reactions' to skin test jabs in alpacas.

In another life, we were taught that the mantra of "clinical disease + an introduced top up dose" - in the form of vaccination, or possibly a screening jab? - meant death."

What's the scientific view of vaccinating infected badgers then?

Will bTB in cattle 'improve' because we've vaccinated badgers or because - as a by-product of vaccination - we have killed the badger?

Looks like the only good reason to vaccinate badgers!

Is this what the DEFRA scientists really want?

Matthew said...

Anon 10.00

We couldn't possibly comment on what Defra 'scientists' want - other than more gravy on their already laden plates.

The VLA chap in charge of the Vaccine Deployment Project is on record as saying that they 'hope it doesn't make things worse'. Well hallelujah for that.

The welfare issue of these huge anaphylactic type reactions should not be underestimated. Alpaca owners can witness the distress, and sometimes death. But if this did happen to badgers vaccinated with BCG, when they already had clinical disease, then it is pretty dire.

The whole Badger vax thing is as big a scam as the RBCT. Prevarication on a huge scale. What is the use of a 2 night, (3 hours daylight per trapping night), session, which may catch only one or two of the group. And has to be repeated annually. And is targetted at a population already highly infected.
(That was rhetorical, by the way)

Go and play where the cattle tests are telling Defra that the badgers are relatively uninfected. While we still have some healthy badgers left.

Anonymous said...

"Go and play where the cattle tests are telling Defra that the badgers are relatively uninfected."

Is that because there's less chance of them (badgers) getting infected by cattle perhaps?

So here is some breakthrough science - you can tell if one species has a disease by testing some other species.

Never mind, what I really can't stomach is how you guys bang on about killing diseased badgers that are suffering horribly (according to you), and then suggest 'welfare issues' as an argument against vaccination on the offchance badgers may be 'shocked to death'

Matthew said...

Anon 10.43

Please put your brain into gear before posting.
That anyone should doubt the suffering of badgers in the latter stages of TB, is naive.

To vaccinate such animals, (and the VDP is centred on areas where badgers are endemically infected) is not only recklessly naive, it could have serious welfare consequences for infected badgers - similar to those described by alpaca owners on this thread.

And that is VLA and experienced veterinary scientists speaking. Not 'banging on' but using decades of epidemiological experience, and expressing their professional opinion that they "hope not to make matters worse".

That is why we are in favour of vaccinating badgers in areas where sentinel tested cattle are telling us that there are few problems.

Anonymous said...

Anonymous 10.43.
Please look up the word "sentinel"

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Matthew said...

Last comment deleted- %££** Spam. (Even with check digits, some still gets through)