Saturday, April 28, 2007

Cattle 28 : Badgers 0?

A row between a member of the new TB Advisory Group, dairy farmer Bill Madders and the Badger Trust has erupted over the source of Mr.Madder's ongoing TB breakdown.

The Badger Trust, no doubt with irrefutable evidence to support their claim, assert that Mr. Madders’ 28 very dead dairy cows, were exposed to infection from the movement of “untested, TB infected cattle, into south Staffordshire, following FMD”.

Mr. Madders refuted the Trusts’ claims and said that his local SVS office were 99 – 100 percent certain that his cattle had been subject to infection from the local badger population. He also pointed out that his farm was surrounded by roads or arable land, and that his cattle had no contact with any neighbouring herds.

The fact that south Staffordshire had not been a major FMD area and was not subject to significant ‘re stocking’, seems to escaped our Trevor. As has the six years which have elapsed since any FMD restocks, time in which Mr. Madders’ cattle have presumably tested clear - several times. That neither he nor SVS have claimed any purchased cattle is also noteworthy, but let that pass.

Trevor Lawson of the Badger Trust said that local veterinary officers could not claim with any certainty to know the cause, as “they did not have enough familiarity with what goes on at farm level”.

They’re going to love that little gem aren’t they? Access to CTS records, printed off and produced for every TB test – individual cattle identification for Mr. Madder’s herd, which will now be approaching four 60 day short interval whole herd tests since the beginning of his breakdown at a routine test last autumn. So what is our Trevor saying? That CTS is wrong, and cattle moved onto this farm quietly and in the night, anonymously and with no one knowing? Wow, that’s a big statement. Libellous too I suspect. But clutching at straws non the less.

Of course SVS are sure by now of the cause. If no bought in cattle can be targetted, which in this case appears to be the case, and no cattle to cattle contact is possible, then it’s down to a 'non-bovine' source. And in Defra speak, that means badgers. The spoligotype from any lesions found in Mr. Madder’s dead cattle, will confirm the geographic origin of the strain responsible – and if SVS are saying they are 99 – 100 per cent sure it is badgers, then they know for certain cattle restocks, it ain’t.

We have heard since posting this story that the spoligotype isolated from lesions taken from reactor cattle on Mr. Madder's farm is Type 25. And according to the ferrets at VLA who know about these things, outbreaks in cattle mirror the spoligotype which is indigenous to the little furry stripey thing, co-habiting in a certain area. We listed the main types in our november posting:

And where do we find Type 25 mycobacterium bovis? Staffs / Derbys. Just where Mr. Madder's (now very dead) cattle lived - and where 79 percent of the cattle outbreaks feature this strain - which was originally isolated and mapped over the last 30 years - in badgers.

Ed's note: Most of this cattle / cattle clackety clack is coming from the recently published Warwick Uni.paper on incidence of Tb following FMD restocks. A small cohort study using skin testing data (skewed by FMD delays, and which Defra warned was not to relied on for statistical purposes)was added to cattle movement data - (and not much else) and shredded through a series of mathematical models to come up with - not a lot. We will post this one when we've number crunched it a bit more. But as usual, our Trevor has assumed that "Only 16 - 28 per cent of cattle are ever tested for TB". That is not what this lightweight piece said at all. In the study, that percentage were found to be dead before they could undertake a skin test. These were most likely 2 year beef animals, and as Andrew Proud said, it must be realised that MHS postmortem inspection is as much a part of TB surveillance as the skin test.

We find it very strange that dear old Defra refuse to consider PCR as its use has not been 'validated'; but has the use of mathematical / computer modelling to track infectious disease ever been 'validated'? And more important, is it an accurate reflection of its input data? Remember BSE / CJD?
The word 'validation' seems to us to be an excuse for doing nothing, any time soon.


Anonymous said...

From Trevor Lawson, Badger Trust

Ho ho. Good luck with the number crunching using the data gathered by the University of Warwick. When you've finished, make sure that you - as they did - get the papers presented at the Society for Veterinary Epidemiology and Preventive Medicine, followed by publication in a peer reviewed journal. As for your claim that the cattle in the study were two year beef cattle, er, where's the beef (evidence)? The data involve three randomly selected cohorts covering different periods.

Meanwhile, given the rather partial presentation of our press release, here it is in full:

Cattle movements blamed for Government advisor's TB outbreak

For immediate release 25 April 2007

The Badger Trust today publishes evidence that a TB outbreak on the farm of Defra TB Advisory Group member[1] and dairy farmer, Bill Madders, was triggered by the movement of untested, TB-infected cattle to South Staffordshire. Badgers cannot be blamed and there is no evidence to support the accusation.

In February 2007, Mr Madders advised Farmers Guardian that officers of the State Veterinary Service (now Animal Health) had blamed badgers for an outbreak of bovine TB on his farm in the parish of Coppenhall, Staffordshire [2]. The pyramid-shaped parish is bounded to the east and to the west by Castlechurch and Bradley respectively, and by the parish of Dunston to the south. Bradley and Dunston hold the majority of herds. Mr Madders reported that his herd is 'self- contained' and that 'the only way in is through wildlife'.

Using the Freedom of Information Act, the Badger Trust has secured details of herds and bovine TB outbreaks in all four parishes, from
1995 to 2006. The total number of herds registered on VetNet in all four parishes declined from 67 to 49 over that time. The bulk of the decline occurred in the wake of foot and mouth disease (FMD). The Stafford disease control centre dealt with 72 FMD incidents during the outbreak and for some farmers it prompted retirement from the industry.

The data obtained by the Badger Trust reveal that TB was virtually unknown in the four parishes between 1995 and 2002. Only a single herd, in the parish of Bradley, went under TB restriction, and then only from 1998 to 1999. Thereafter, there was no evidence of bovine TB until 2003.

In 2003, in the wake of FMD, three herds went under restriction, one in each of the three parishes surrounding Coppenhall, followed by a fourth in 2004 in Bradley. The number under restriction dropped to three again in 2005 and the outbreak on Mr Madders' farm took the number back up to four in 2006.

This sudden upsurge in 2003 mirrors that which occurred all over the country in the wake of FMD. This followed Defra's stupendously foolish decision to allow the movement of untested livestock for restocking, which the NFU claimed as a "victory". The buying-in of TB infected cattle led to a huge rise in the distribution of TB infection right across Britain and an explosion of new cases. For thousands of farmers, it proved to be a pyrrhic victory.

"The unavoidable fact is that Mr Madders' TB outbreak would never have occurred were it not for the movement of untested, TB-infected cattle to South Staffordshire," commented Trevor Lawson. "The disease was virtually unknown in the four parishes for at least eight years. There is no evidence explaining the final route of the disease to Mr Madders' farm. Officers of Animal Health cannot claim, with any shred of certainty, to know the cause.

"If free-roaming badgers were the TB vector for Mr Madders' farm, it does not explain why the three other herds in his parish have escaped the disease. Indeed, 92 per cent of the herds in the four parishes are currently TB-free. Infected badgers, surely, would cause a "clumping" of infection and cannot explain this scattered distribution. Officers of Animal Health cannot possibly claim that badgers are the index source of this infection. Clearly, cattle are the index source of this disease. Animal Health should publicly apologise to Mr Madders for misleading him in this way."


1. Bill Madders was appointed to Defra's TB Advisory Group by the chief vet, Debby Reynolds, in 2006.
2. Levitt, T. (2007) TB outbreak at farm of Defra adviser, Farmers Guardian, 16 February 2007. Mr Madders was reported as saying: "The local SVS view is that it is almost certainly badger contamination of the pasture last spring ... The consistent view coming out of the State Veterinary Service is that until we do something about the disease in the wildlife it will get worse. It is the politicians that we're up against."

Matthew said...

Thank you for your good wishes, Trevor.

You comment: "... that the cattle in the study were two year beef cattle, er, where's the beef (evidence)? The data involve three randomly selected cohorts covering different periods."

"The data indicate that the majority (>70%) of cattle are nver in a herd when it is tested, and therefore are untested during their lifetime.[ ] ..on a 4 year cycle, meaning that many animals can be born and slaughtered in between scheduled tests."

BORN and SLAUGHTERED in between scheduled tests? Only animals for the beef market fit this description, with MHS slaughterhouse sutveillance kicking in post mortem.

The cohort studies in this work were not random. They were specifically targetted at herds restocked after FMD, and compared with herds within the reactive and proactive areas of the RBCT. 33 of the 148 study farms had no adult breeding cattle, indicating they were store buyers / beef finishers. (see above)

The testing regime post FMD was highly skewed, indeed Defra warned that it not be used for statistical purposes, as it was targeted at 'high risk herds' and not 'typical'. It caught up early 2004. This study used first test data from 30th Sept. 2001 - 17th August 2005. Data which Defra had warned was a-typical due to testing delays post FMD.

What we do not see factored into the computer models is the effect of both FMD and Bourne's badger dispersal trial on the badgers. A point we have repeatedly made is that in the former, when huge swathes of countryside were depopluated, the badgers moved. They are dependent on cattle 'habitat, they moved, found other groups already there, fought and regrouped. And in the 'trial' much the same problems were caused, particularly in the Reactive areas, by the shattering of the social groups and then abandonment of the area sometimes for several years.

More later when we've really read this.
Bill Madders' outbreak. Spoligotypes? No mention of the type source in the Warwick paper. And no comment from you re. Bill's No bought in Cattle, and an indigenous Tb strain (Type 25) to that part of Staffs.

Anonymous said...

From Trevor Lawson, Badger Trust

Ho ho. Wrong again Matt. You say: "The cohort studies in this work were not random." Wrong. Again. The cohorts are actually detailed in a separate paper (An analysis of single intradermal comparative cervical test (SICCT) coverage in the GB cattle population, Mitchell et al, SEPVM, March 2006). They consist of three cohorts drawn at random from the CTS. The authors consider issues such as cattle age, sex and whether the samples are representative of the population as a whole in detail. They also examine the implications of FMD. The paper clearly illustrates that testing is highly skewed towards a minority of cattle which are tested many times.

I can't comment to any great extent on your claim that the Type 25 strain of bovine TB is indigenous to Staffs, since you don't offer any evidence for that. Let's see a detailed map illustrating the distribution of Type 25 in GB. Presumably, you do have one?

However, the presence of a given strain in cattle and badgers is not, as several papers have pointed out, evidence of the direction or force of transmission. As the work published in PNAS illustrated, cattle rapidly transmit TB to badgers, so it is just as likely that cattle are the source for the infection in badgers.

For understandable reasons, you (and Animal Health) tend to focus on the individual farm in seeking to understand the dynamics of bovine TB and in trying to find a solution to it. But the evidence shows that this disease operates over long periods of time and wide spaces that are, at the very least, regional. As we showed, what happened to Bill Madders' herd was part of a wider pattern triggered by cattle movements. The pattern is repeated all over the country and is independent of badgers.

The Badger Trust is in regular contact with TB experts in a wide variety of countries and I can assure you that other nations are utterly amazed at the decision to allow untested livestock movements in the wake of FMD. The NFU drove that profoundly stupid decision and state vets failed to stop it. But you keep on blaming badgers: nothing's ever the fault of farmers, is it?

Matthew said...

You sound like Father Christmas Trevor. "ho ho"

Now , Methodology.
1."A cohort study of 148 herds in the south West of England" ...using "data both prospective (??!) and retrospective and incorporated the RBCT groupings into the results"

2."A retrospective cohort study of restocked herds across Great Britain". using data from the FMD, Vetnet and BCMS.

Seems fairly clear to us.

We covered spoligotypes in our posting of that title. See archive November 2006. A map is easy. Outline of GB, counties outlined and 12 coloured pencils. Very effective it is too. Been the same for 30 years, VLA say. So although your point of who gives what to whom is valid, what it does show is that cattle don't traipse different strains all over the country.

And you are correct in saying that our focus comes from 'our individual farms', rather than a wide picture. When those farms have had no bought in cattle and no cattle contact, then good grief man, where the blazes did this bacteria come from? Sometimes the trees of that 'bigger picture' obscure the wood under one's nose.