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.

Thursday, May 20, 2010

A day is a long time in politics....

....and a week even longer. Before the election, both the Conservatives and Liberal Democrats committed to a targeted cull of badgers to end this crazy one sided polemic of slaughtering sentinel cattle, while ignoring the cause of up 90 percent of their problems.

But on Tuesday 18th May, Caroline Spelman, newly appointed Secretary of State for the Department of Environment, Food and Rural Affairs, in an interview with Farmers Guardian political editor, Alistair Driver, was less than enthusiastic about honouring this manifesto pledge.
She indicated that there was no guarantee the policy would be delivered, despite a pre-election Tory pledge to implement a badger cull if they were elected.
Asked if the Tory pledge on a badger cull still held, Ms Spelman said only that she had ‘not closed down any options’. Mrs Spelman was clear she wanted make up her own mind on the issue and was prepared to take her time in order to develop a ‘science-led policy’.
Mrs. Spelman said she wanted to monitor the effectiveness of the Welsh pilot badger cull, due to start in north Pembrokeshire this month, before deciding whether to pursue the policy in England.

(And how long is that lukewarm prevarication going to take, one may ask? The Honourable Lady's predecessor was going to 'await for the outcome of the Irish 4 County trial'. And when it successfully reported, he ignored it.)
“In all areas, I must take my time and be properly briefed,” she said, adding that the problem had got much worse since she was last involved in the agricultural industry more than a decade ago. “The fact that the disease is now much more widely penetrated over a much wider geographical area makes the decision more difficult and more complex. I believe in evidence-led policy making and I think we should wait to see how the Welsh get on,” she said.
But in curious twist to this comment (made by Mrs. Spelman on Tuesday 18th May) today, 20th May a press release was issued by her office which appeared less reticent. The Guardian has the strapline, "English Badgers set for Targeted culls" and describes how:
The new coalition agreement released by Downing Street today says: "As part of a package of measures, we will introduce a carefully managed and science-led policy of badger control in areas with high and persistent levels of bovine tuberculosis."

While Valerie Elliot of The Times seems to have cut and pasted a different offering from Caroline Spelman's department. Carrying the strapline "Minister blocks cull of badgers in bovine TB hotspots", The Times continues:
Plans for an emergency cull of badgers in hotspots of bovine TB are to be delayed while Caroline Spelman, the Rural Affairs Secretary, reviews the scientific evidence. Ministers will also await the outcome of a pilot cull in West Wales before embarking on such a policy in England.

The decision will disappoint many farmers, especially those in areas with highest incidence of the disease, such as the South West. A further review is surprising because the Conservatives and the Liberal Democrats supported an emergency cull of badgers during the election campaign.
But while readers of The Times were digesting that with their organic muesli, the Minister of State, Jim Paice MP., speaking on the opening day of the Devon County show confirmed his commitment to a targeted cull of badgers in TB hotspots.
A cull of badgers is to be introduced in Devon and Cornwall to combat bovine tuberculosis (TB) in cattle. Farming Minister Jim Paice confirmed the news at the Devon County Show. The government says it is examining how best to roll out the policy, with a pilot vaccination scheme due to start across England this month.

So dear readers, make of that what you will. Wriggle room? More prevarication? More dead cattle - and alpacas, cats, dogs, sheep, pigs, goats and companion mammals?

As manifestos are torn up and our newly self-appointed Siamese Twins bulldoze their ideas through and over their party faithful, the only sure thing about politics is that when a politician's lips are moving - he's lying..

Wednesday, May 19, 2010

Shrinking halos ?

During the RBCT Badger Dispersal Trial's 8 night, very infrequent hit-and-run excursions into TB infected badger populations, the ISG's computer models logged an increase in cattle TB in the areas surrounding the 'clearance' zones. These 'halos' were offered as an argument for doing nothing, as they had appeared to make matters worse for cattle herds surrounding culled areas.

The fact that in previous decades of GB's progressively sanitised badger removals, no such 'halos' appeared around areas (large or small) which were culled out adequately, seems to have escaped the great and the good of the ISG. As did the change in RBCT protocol after the first 4/5 years of chaos, which meant that they did actually achieve some sort of a clearance as we reported here.

This was reflected in the Jenkins paper, published in 2008 which we discussed here. The ISG team requested more government cash work, and they were able to continue to log cattle breakdown data from the RBCT areas for a longer period of time. The team of scientists and statisticians undertaking the follow-up work to the RBCT trial have published again updating data on the impacts of cattle TB incidence of repeated badger culling

This additional data has been further analysed as a comment on a scientific website by one of the team, Prof. Christl Donnelly.

Since publication of the paper “The duration of the effects of repeated widespread badger culling on cattle TB following the cessation of culling”, (see abstract here) an additional six months of cattle testing data have become available. These allowed analyses to be updated.
In the time period from one year after the last proactive cull to 31 January 2010 (the post-trial period), the incidence of confirmed breakdowns in the proactive culling areas was 37.0% lower (95% CI: 25.3% to 46.8% lower) than in survey-only areas and in areas up to 2km outside proactive trial areas was 3.6% lower (95% CI: 29.0% lower to 31.0% higher) than outside survey-only areas.

"Exploratory analyses stratified by 6-month periods (Table 1) suggested, unexpectedly, that the beneficial effects observed within trial areas in the first year post-trial, have reappeared in the last 6-month period analysed (37 to 42 months post-trial)."

"These latest results are consistent with a constant benefit of proactive culling continuing through this latest period. However, the effects observed outside trial areas are consistent with no ongoing effects of proactive culling in these areas."

"There is no clear explanation for the unexpected pattern observed within trial areas based on these latest data. (We examined parish test intervals and they are very similar in and around proactive and survey-only trial areas.) Continued monitoring is necessary to quantify any further temporal changes in the effects."

This updated data shows that in the period starting one year after culling stopped up until 31 January 2010 the incidence of confirmed breakdowns in the proactive culling areas was 37% lower than survey only areas (areas which were surveyed but not culled). Furthermore in the areas adjoining the culled area the incidence was 3.6% lower. This means that any initial perturbation effect has been quickly overturned and there is now a lower than previous incidence in these areas.

So, a begging bowl extended for 'more monitoring' ? - that was to be expected.
But no halos? And the excuse for doing nothing goes where, exactly?

Wednesday, May 12, 2010

Doubling up

We have received the following update from the Alpaca TB Support Group. This small number of owners and breeders (about 28 herds) are in contact with each other for support and advice, when they find they have a TB casualty among their animals. The number of deaths from bTB which they have reported within the group, is a mere snapshot of camelid deaths from TB in the country, but even among this group, casualties have almost doubled from last year.

Through their enquiries, the group have learnt that the 'official' camelid TB figures, produced occasionally by Defra and updated quarterly (although we note that this chart has been the same for six months ) refer only to samples submitted to VLA. So if an animal dies on farm, is postmortemed on farm, but is part of a larger or ongoing TB breakdown, then culture samples are not submitted. And thus it drops off the 'official' statistics radar.

Which would go some way to explaining why the Defra figures are (still) showing 68 confirmed TB casualties for 2009, with 120 samples submitted, while the members of the TB support group have recorded 144 deaths. All positively confirmed by veterinary post mortems.
Up to Dec 31st 2009 those in contact with the TB support group lost 144 alpacas/llamas [with] confirmed TB. This works out roughly 12 a month. From that 144 we had 12 skin test positives 7 of which were from one herd.

In the first 4 months of 2010 From 1st Jan - 30th April 2010 members in contact with the TB support group have lost 94 alpacas.
.... which works out to over 23 animals per month - and almost double the incidence of 2009.

Statistics for cattle are more robust, as BCMS and CTS are involved and individual animals are logged. But we understand that due to financial pressures, (and numbers?) as with camelids, samples consigned to VLA for TB strain cultures or 'spoligotyping' are limited to the first couple of an ongoing breakdown.

For over forty years, the results of cattle casualties and RTAs or badger removals, have been painstakingly logged and mapped by VLA and our posting gives some results of the blocks of GB countryside where an 'environmental' strain of TB is circulating between sentinel tested, slaughtered cattle and free ranging, endemically infected badgers - and available to any other mammal who happens to wander by. Including highly susceptible alpacas.

From a comment on the Alpaca blog, it would appear that although TB can be spread between infected imported herd members, only 6 herds could nail their outbreaks positively to this source. For the others TB had come from a wildlife source, whose name Defra are not keen to mention.

Saturday, May 01, 2010

Welsh pilot area begins

Today, May 1st, the Welsh bTB eradication area pilot begins.
This was kick started with clearance of the pilot badger cull from the Bern Convention which yesterday decided to squash a complaint brought by the Badger Trust.
"The Rural Affairs Minister Elin Jones has welcomed the decision by the Bureau to the Standing Committee of the Convention on the Conservation of European Wildlife and Natural Habitats - also known as the Bern Convention - not to continue with a complaint brought by the Badger Trust with regard to the planned cull of badgers in west Wales."
In a meeting in Strasbourg on 29th March 2010, the Bureau, which takes administrative and organisational decisions between meetings of the Standing Committee, decided to remove the complaint from its complaints list.
Elin Jones said:
“This is confirmation that the Bureau agrees with our view that the provisions of the Bern Convention have been fully respected in considering the proposed badger cull. “

“We will continue with the preparations in the pilot area. Bovine TB is one of the biggest problems facing cattle farmers across Wales, and we have to tackle all sources of the disease. We will face serious consequences if we do not.”

This decision comes hard on the heels of a recent Judicial Review in the High Court, where the Welsh Assembly Government successfully defended its decision to implement a limited badger cull in west Wales.

At the same time, cattle measures in Wales will be tightened up to reflect 'severe interpretation' protocol on all tests. Farmers Guardian gives the following details:

* Herds to be tested every six months.

* All breakdowns, whether or not ‘confirmed’ by post-mortem, will require two clear 60 day tests, to release movement restrictions.

* Breakdowns will also be subject to tracing which will generate additional testing for associated cattle herds. (We assume this means 'all' breakdowns, as confirmed ones generate traces at present? - ed)

* There will also be restrictions on cattle movements within and outside the area.

* All British Cattle Movement Service (BCMS) linkages and Sole Occupancy Authorities (SOAs) between holdings inside and outside the pilot area are being cancelled, requiring farmers to report all movements to BCMS and comply with pre-movement testing requirements.

* Farmers have also received visits from their private vets to discuss bio-security arrangements on their farms to reduce risk of TB getting into and spreading in their herds.
“The bovine TB eradication programme is a long-term project will last for five years and includes a range of measures designed to restrict and ultimately eradicate TB in cattle,” said Chief Veterinary Officer for Wales, Dr. Christianne Glossop “In the pilot area, local vets have been working with farmers since before Christmas to improve bio-security on farms. The additional measures are a vital element of the programme.

“We know that cattle and badgers are the main sources of the disease and that, if we want to achieve our aim of eradicating bovine TB, we have to tackle the disease in both species." said Dr. Glossop.

With that we would agree, and we wish them luck.

But if they get the badger part wrong then as has been tried before, no amount of nailing cattle to the floor, will make the slightest difference to TB incidence, which is already spilling over into other mammals both in the Principality and England.