Saturday, November 03, 2007

Manx mischief

We are used to the politics of 'spin' from government. But we are becoming increasingly weary of the same misinformation spin, churned out via press releases from various prominent animal charities and unquestioningly regurgitated by lazy media hacks.

In our posting Spot-the-difference we showed a master in action. Our Trevor, Mr. Lawson, media advisor to the Badger Trust, carefully snipped a vital piece of English grammar - the subject no less - from a sentence and turned scientific fact into Badger Trust fiction.

That was after both he and the ISG spent more than a few years chasing postcards, in the mistaken belief that the 14 million animal movements logged by the British Cattle Movement Service (BCMS) were individual bovine hoofprints. They were not. They were data, often quadrupled, generated by just 2.2 million cattle movements and 400,000 calf hops.

And now they have turned their attention to the Isle of Man. An island enjoying similar climate and geographic features to both Ireland and West Wales, it has cattle herds (large, small, organic and conventional, beef and dairy) - but no badgers. And the clarion call has gone up that TB is 'rife' on the island and as badgers are in no way implicated - well it's gotta be cattle.

First of all Tb is not 'rife'. The Isle of Man logged just five cases from 2001 - 2003 as described in the Department of Agriculture's newsletter of 2003:
Bovine tuberculosis was discovered on the Island in October 2001, the first outbreak since 1971. The affected milking herd on the initial farm had to be destroyed because of clear evidence of rapid spread of the disease within the adult cattle. Four other locations had only one affected animal each. No evidence of spread from any of the five locations has been found. Laboratory tests conclusively demonstrated that at least four, if not all five, of these outbreaks were unrelated to each other.

The last confirmed case was in April 2002. All herds that had confirmed cases have been subjected to further testing with negative results.

Government and private practice vets, have worked together to deliver the increased level of testing required. The 2003/4 programme has been completed with no herd under restriction for failing a tuberculosis test.
The Manx government take bovine Tb very seriously. Cattle imported on to the island are subject to strict veterinary controls, which the Department describes thus:

All imported cattle are subject to -
* testing prior to importation;
* movement restriction following importation; and
* post-import testing.
We are grateful for information direct from the Manx veterinary authorities for the following up-to-date quote:

...Other advances in genetic testing have permitted the Animal Health Division to specifically identify the bacteria isolated from each of the Island’s outbreaks (12 since 2000) and determine whether they may be related. These investigations, together with movement analyses, have shown that many of the outbreaks are unrelated and are likely to have been the result of importation. ...
There is two year testing on most herds on the island, but much more important, as described above, they post movement test imported cattle at 60 days plus.

If a cow is carrying Tb when she jumps into a lorry, it his highly unlikely that the journey to the Isle of Man will produce a miracle cure. And it is this vital post movement skin test, we are told, that is finding the occasional reactor,(12 in 7 years) described as "unrelated" and "likely to be the result of importation".

And this is the crucial 'snip' that escaped the press releases.

The Isle of Man is also looking at its own particular 'wildlife' in case a reservoir is building. They are mindful of problems not a million miles away from their shores. They may not have badgers - they do have feral ferrets, wallabies and polecats. If an outbreak cannot be traced to imports the IOM authorities comment:
We can clear up our outbreaks without further breakdown because we don’t have a large reservoir of infected badgers.
We think it may be circulating to a minor extent outside cattle and are looking for a wildlife reservoir – suspects at the moment are feral wallabies, feral cats, polecats and rats.
If and when we find proof of an infected wildlife reservoir, we will take action to control/eradicate.
If any badgers were to be imported and released illegally, we would take immediate steps to eradicate on the grounds that they are non-indigenous species and a threat to our national herd.
All of which sounds extremely sensible. The Department of Agriculture is aware that the threat of Tb is always present. Particularly as TB incidence in the nearest exporting country (that's us) has risen from under 100 herds affected in the mid 1980s to 5,787 (in 2006)and thus the odds that the IOM will import problems have increased considerably. The authorities, by using a post movement test are determined that Tb will not be imported and they add that although TB is present on the island, it is definitely not 'rife'.

GammaIFN has been used in one herd, as was described here and the Isle of Man's Animal Health Division co-ordinates the periodic testing for Tuberculosis of all the Island's cattle. All herds are currently tested within a two-year cycle. The period of testing will be reduced to an annual basis if the herd is deemed a high-risk herd, if the herd has imported any cattle or if the herd sells retail milk. Link to that information.

So is TB 'rife' on the Isle of Man? Official Manx documents from the Department of Agriculture (at least they still have a Department which even mentions 'Agriculture') describe 5 cases 2001 - 2003 and a total 12 cases from 2000 - 2007 - all of which proved to be 'unrelated' after culture spoligotypes were received, and most were 'likely to be the result of importation'. Result: less than two cases annually over the last seven years and all found by post-movement skin tests?

The Isles of Scilly off SW Cornwall enjoys similar status - or its cattle do.

We should be so lucky.


Anonymous said...

So are you thinking that badgers are somehow infiltrating the Isle of Man, or perhaps it's because "once the disease is established in a herd some animals can continue to spread disease without testing positive"?

Certainly the new gamma interferon test allows both the earlier detection of infected animals and detection of some infected animals that do not react to the usual skin test".

The Isle of Man clearly illustrates cattle to cattle transmission despite the precautions that they're taking does it not?

Matthew said...

Anon: 8.48

If imported cattle escape the testing net, and Tb develops -particularly lung lesions - to infectious status, then cattle to cattle spread is a possibility. That was possibly the cause of the 2001 herd breakdown.

Rigourous post movement testing of all imports at 60 days after arrival should mop this up, as it overcomes the latency (30 - 50 days) of the skin test from exposure to immune response. It is a very sensible disease measure, and we should be doing it on cattle moving to extended testing areas too.

We are not suggesting that badgers have been introduced to the IOM, indeed we hope that they have not.

Some cattle in the advanced stage of TB will neither react to the skin test, nor flag up on gamma IFN, it has been found. IOM's strategy aims to sort out problems well before that stage. And very successful they have been.

We have received this comment from the IOM which we print in full:

" We have had contact from the NFU in England about this issue recently, due to misleading press reports. To put the record straight yes there is bovine TB on the Isle of Man but it is a recent arrival and is carefully controlled.

To say it is 'rife' is inaccurate.

As your blog correctly states between 1971 and 2001 there were no recorded cases and only a handful have been found since.

It is true to say that the Isle of Man has no badgers. We have no foxes, deer, squirrels or moles either. But, we do have other wildlife that could potentially spread TB including ferrets, polecats and bizarrely enough a feral wallaby population.

To jump to the conclusion that as there are no badgers on the Isle of Man and there is TB therefore badgers are not responsible for spreading bovine TB in the UK is flawed logic.

The [] position is that bovine TB came to the Isle of Man via imported cattle, despite our very strict livestock import controls. It could be argued that one reason that it is not rife, other than our careful monitoring and control of the disease on the island, is that we do not have badgers.

The Isle of Man can not we believe safely be used as a case study which supports a ban of a badger cull in the UK.

The views expressed on your blog in relation to the Isle of Man and the quotes from our Department of Agriculture Fisheries and Forestry are accurate.

I hope that this clarifies the situation."

So no, we would not agree that the very few recent IOM cases support cattle to cattle transmission - and neither would the IOM authorities.. Quite the opposite.

Tb infection can occur anywhere: from onwards transmission from infected humans, or possibly cattle from the 2001 outbreak? - and I'm kite flying here, not having pathology reports on the slaughtered cattle in that outbreak - so it is possible that Tb has entered a section of the island's wildlife.

Particularly those feral wallabies. Shared airspace / feeding has to occur and the transmission bacteria to be be in big enough cfu's (70cfu to infect a cow) to flag up infection at the cattle skin test.

For the IOM's sake we hope that this has not happened.

Anonymous said...

No one has yet shown that badgers give TB to cattle, despite years of "research" by the powers that be.

One simple reason for the spread of TB in cattle is that farmers have ripped out hedgerows by the mile and replaced them with fences. Hedgerows prevent cattle from having contact across boundaries, fences do not.

Once again, our government is pandering to an ignorant and outdated part of our community - the farmers - who mostly still live in the 19th Century

Matthew said...

Anon 10.33.
An individual infectious with TB can pass it on. But there are degrees of infectivity both with the disease progression and within different species. Cattle may have lesions but in the main, the lymphatic system has done its job and postmortems show that these are in the lymph nodes either behind the lungs or lower. Sometimes in the head. Culture is difficult as numbers of bacteria are very small.

Badgers with very small lesions have proved at pm to be highly infectious, both within their groups and to anything else. They are such a successful host, because TB doesn't kill them straight away.

Camelids have become a 'spillover' reservoir of TB in the UK now. And unfortunately, the disease appears to progress very rapidly, they become highly infectious, interherd spread is common - and TB kills them quickly.

In humans, so called 'bovine' TB may infect many contacts, and has done so quite recently in a Birmingham nightclub.

In several parts of the country where TB has been allowed to become endemic, (Devon, Cornwall, Derbyshire and the Cotswolds) 'hedges' or field / farm boundaries are based on local materials which may or may not involve shrub growth. Stone and earth bank walls, sometimes topped with scrub must be back fenced with wire to protect them. This gives them a base width of several metres.

Hedgerows have been 'protected' for several years now, and farmers cannot just rip them up. Many of us have planted new shelter belts. Our own field boundaries are at least 4 m wide, and many years ago this farm was registered as 'bio secure' by animal health for the voluntary cattle EBL (Enzootic Bovine leucosis) scheme. No cattle contact across farm boundaries is possible.

Badgers have carried TB to our cattle for 9 years now, and if we have been able to prevent their entry to cattle buildings and feed stores during winter housing, they are ranging across ours and our neighbour's fields waiting turnout.

Your assumptions on both counts are quite wrong.

Ashley said...

"Badgers have carried TB to our cattle for 9 years now".

Have you got any proof that it was badgers and not imported cattle that are infected but showed up as negative for the disease from the SICCT (skin test)?

The SICCT is only around 70% accurate. Meaning that in every 100 infected cattle 30 are missed.

The Randomised Badger Culling Trial also showed that whilst culling reduced bTB by 23% in areas where badgers were proactivly culled it actually increased incidence rates by 25% in neighbouring areas.

The problem is that the skin test is not effective enough, movement restrictions are not strict enough, farmers are not doing enough to protect their herds.

During the 2001 foot and mouth outbreak routine TB testing was suspended. As a result positive cattle were neither detected or destroyed. During this period the number of badgers who contracted TB increased.

How about if we reverse the arguement... cattle give badgers TB (it is the ony place they could have caught bovine TB from) therefore all cattle should be destroyed to save the species native to the country.
This obviously is never going to happen, because it is a ridiculous notion. Just as ridiculous as is the notion of a mass slaughter of badgers.

Matthew said...

Hi Ashley. This is very old posting, so we hope you get this reply.

Yes, we do have 'proof'.
A confirmation from BCMS of 'No bought in cattle' on the holding, which is ring fenced and no cattle neighbours. No showing, or exhibition visits either and no rented off land. When lesions were found, two years (and 40 dead cattle) into the main breakdown, the spoligotype matched those of three seriously manky badgers caught by the RBCT in their just two visits to this farm.

You are misquoting the RBDT with this statement;
"The SICCT is only around 70% accurate. Meaning that in every 100 infected cattle 30 are missed."

What the Final Report actually said was:

"Thus for example IF the true sensitivety of the test is 75%, infection will remain undetected in one in four herds..." 7.4 [p140]

The problem with that is the sensitivety is much higher than that when the SICCT is used on a herd, and even more so the more regularly it is used. (PQs. )

Badgers with TB will spread the disease to other badgers, and also any other mammal. Compulsory testing of cattle is showing up the problem. And it is a bigger problem than it needed to have been due to decades of prevarication.