Tuesday, October 23, 2007

Cutting to the chase

The media has led a hysterical chorus, aided and abetted by the Badger Trust and fuelled by John Bourne's final report - now neatly chewed up by Sir David King - that cattle-to-cattle transmission of bTb is the primary author of its spread.

Keep focussed readers.. The existing model used worldwide for eradication of Tb from cattle herds is the well proven intradermal skin test. In countries with an environment uncontaminated by other mycobacteria, it is used alone. In the UK and some other countries it has evolved as a comparison test between m. avium and M. bovis. Nevertheless, this primary OIE / EU approved test has managed in the majority of countries worldwide, to clear bTb from the cattle herds with a programme of test and slaughter.

If the chattering voices citing cattle-to-cattle transmission are correct, this would have been unachievable. The only countries having problems are those where bTb has been allowed to establish in a wildlfe reservoir, which has proved a secondary but a maintenance source of disease. And in areas where regular testing and cattle culling have exceeded predictions and failed to stem the increase in disease, by default such reservoirs have become the primary source of spread.

We explored this on several occasions with Parliamentary questions to 'Baby' Ben Bradshaw, in his days manning the Animal Health desk for his boss. And most grateful we were for his patient replies:

Parliamentary Questions. 30th January 2004 Column 540W [150492]

Mr. Bradshaw: All countries have either eradicated or have a programme to control bovine tuberculosis use one or more forms of the skin test. The government have close links with a number of countries in various stages of eradication and exchanges information and experience on the use of the tests in the context of these programmes.

The government is not aware of any country that has replaced the skin test as the primary test for bovine tuberculosis.
And on vaccination v. wildlife interface and the skin test:

Parliamentary Questions 25. March 2004 col 989W. [159061]

Mr. Bradshaw. Evidence from other countries shows that, in the absence of a significant wildlife reservoir, (of Tb ) cattle controls based on regular testing, and slaughter (of reactors), inspection at slaughterhouses, and movement restrictions (including tracing and contiguous testing), can be effective at controlling bovine Tb without vaccination."
A case of tripping over the obvious?


Mat said...

Bovine TB: Farmers to Blame


Government chief scientist Sir David Kings call for a badger cull to curb bovine Tuberculosis (bTB) in cattle is an attempt to appease a powerful and irresponsible farming lobby, which refuses to accept responsibility for the disease outbreaks that are a direct consequence of modern industrial farming methods.

Bovine TB is caused and spread by the often filthy, crowded and poorly ventilated conditions in which cows are kept, and by the increasingly intensive regimes to which the animals are subjected. A recently published Animal Aid report and supporting undercover footage (http://www.animalaid.org.uk/h/n/NEWS/news_factory/ALL/1660//)revealed that many dairy cows are now virtually permanently confined in crowded sheds under a system known as zero grazing. The evidence demonstrates that these battery cows are prone to increasing levels of a range of infectious diseases.

The government-appointed Independent Scientific Group (ISG) announced in June after a decade of research that killing badgers will not reduce bovine TB and could make matters worse. Thirty thousand badgers have been destroyed since 1975 in a failed attempt to curb the disease. And despite virtually exterminating badgers from four counties in Ireland, a massive bTB problem remains in each of those areas. Animal Aid agrees with the author of the ISG report, Prof John Bourne, that Kings statement was more in line with the political need to do something.

Director of Animal Aid, Andrew Tyler, says:

Once again, a reckless and greedy farming industry is holding the government hostage. It blames everyone except itself for a range of devastating disease outbreaks now afflicting farmed animals. They include bird flu, salmonella, campylobacter, BSE, Foot & Mouth, swine fever and bovine TB itself. The government should force farmers to recognise that, when animals are treated as reproducible and disposable objects, large-scale disease will follow. Instead, the government succumbs to the industrys demands for publicly-financed compensation packages.

The recent public consultation on the merits of a badger cull produced a decisive verdict: the public overwhelmingly opposed such a slaughter. Now, the government has been taken aback by the negative early response to David Kings statement and has indicated that no imminent decision on a cull will be taken.

Animal Aid urges the public to continue to voice its clear opposition to the proposed bloodletting that would be devoid of any moral or scientific rationale.

Matthew said...

Thanks for that Mat.
As we said, hysterical and predictable. We stand by the skin test and its universal success. We also stand by our own experiences - not as 'factory farmers' but as small to medium sized farms, where cattle are valued and cared for.
All of us have has long and persistent breakdowns - even our 'organic' Matthew, with just a handful of cattle on 80 acres.

I wonder how Animal Aid will view the chorus which will erupt from angry cat owners, when they realise the source of their favourite moggy's demise?
Will they accuse the owners of keeping their pets in filthy, poorly ventilated and over crowded conditions? And there was Shambo....

Jim said...

Under the present regime of regular testing of cattle and removal of reactors, it seems to me that the extent of cattle-to-cattle transmission of TB is likely to be very much overstated. Perhaps the most glaring example of this is the ISG's grandly assumed "roughly equal" contribution of local infection (e.g. across farm boundaries), infection from cattle bought in, and infection from wildlife (para. 7.24 of the ISG report).

The difficulty which cattle have in giving TB to each other is borne out by the recent Defra funded studies SE3013 and 3015, but the ISG do not seem to have paid a great deal of attention to these.

Given this, as well as the Chief Scientist's demolition of the ISG's main conclusion, the question which the Badger Trust now have to ask themselves is: can they make a morally coherent case for saying that cattle must continue to be slaughtered in preference to, and to the exclusion of, badgers?

The answer should be clear enough to anyone who is willing to face up to the facts.

It's interesting that the Chief Scientist is now being accused by the Badger Trust of being nobbled by the politicians. If he's saying what they want to hear, why did they not trumpet his report from the rooftops when it was given to ministers three months ago? I've been assuming the unexplained delay in publication was because the report said precisely what the politicians did not want to hear.

Anonymous said...

Jim said: "I've been assuming the unexplained delay in publication was because the report said precisely what the politicians did not want to hear."
Seems much more likely that it was delayed until two days before the Select Committee meeting to prevent the ISG from responding formally.
It also seems quite apparent that the govt would rather cull otherwise they would have made a decision based on the ISGs report rather than commissioning yet another report, presumably in the hope that it would say something other than 'don't cull'. It seems that the govt have managed to get themselves into a position where they can do what they like and claim it's back by the "science" - the ISGs report wasn't leaving them with too many options so they did what they could to get more.

Jim said...

Thanks Anonymous. Guess I need to learn to think more like a politician... But it's interesting that Bourne made such a thing in previous evidence to the EFRA Committee that he had been given a strong political steer.

Came across another couple of gems today on a comment type website. First that cattle spread TB "by spitting on the ground". Second, even more amazing, that TB is being spread by foreign agricultural workers coming here from East European and other countries where TB [the human form] is prevalent.

Anonymous said...

I agree that there are far too many ignorant comments being circulated at present although the one regarding foreign workers suffering from TB may contain a grain of truth. In countries where there are no adequate veterinary services or TB eradication schemes humans may become infected with bovine TB, Mycobacterium bovis, through contact with infected animals, drinking raw milk etc. It is clinically impossible to distinguish between Mycobacterium tuberculosis (human TB) and M.bovis in an infected human without lengthy laboratory tests.As I understand the situation not all TB sufferers in the UK are subjected to lab. tests but are treated only for the clinical signs of TB. Unfortunately the drugs required for the treatment of M.tuberculosis are different to those required for M.bovis and a patient suffering from the latter may initially be given the wrong drugs. The delay in correct diagnosis may result in the spread of the disease to other people and may also result in the build up of drug resistant strains. It is quite possible for an immigrant to this country to be suffering from M.bovis and it is possible for such a person to spread the disease to farm animals if working in close proximity, although I suspect that such an occurance would be unlikely. It is however worrying that there appears to be no routine testing of immigrants where there appears to be a higher level of TB infection than in the general UK population.
Details of confirmed M.bovis cases in humans are not available from the Health Protection Agency other than bare numbers and the occasional comment that older people must be suffering a recurrence of an infection caught in their youth. It makes one wonder what trouble we are storing up for the future especially for those heavily involved in the present bovine TB epidemic.
After three years of battling with TB in our herd I have no confidence in the government actually solving this problem. Their complacency in the face of this deadly disease is quite shocking.Perhaps they will only take action when there are a few well publicised cases of bTB in humans.

Matthew said...

Anon. 12.31
Some far thinking scientists (in US) are already predicting a growth in human Tb for future populations to contend with, after contact with 'environmental' sources.

Children and young adults exposed now, may not show symptoms for decades. Although very young children may, and of this government are aware. It has happened.

You said;
"Perhaps they will only take action when there are a few well publicised cases of bTB in humans."

Forget people. Domestic pets and 'companion' cattle, may flag this spillover up first.
Never underestimate the British public's love affair with (most) things small and furry. Whether that will still include tuberculous badgers, when it affects their 'family', I doubt.

Jim said...

I take your point, Anonymous. I was just trying to show that the person making the original comment did not seem to understand (a) that there is a difference between bovine TB and human TB, or (b) that the epidemic of bovine TB has been around in this country a lot longer than foreign workers have. Where we are in East Cornwall the foreign workers seem to be involved in horticulture or working in the abattoirs.

An aunt of mine, now 91, who was a nurse back in the 1930's well remembers nursing children who had caught bovine TB from unpasteurised milk. It was not pleasant and particularly affected the bones, apparently.

GilesW said...

I cannot find any info about what percentage of the badger population is infected with btb, and the rate of spread of bTB across the land by badger-badger transmission. Is this known?

On the basis that "a stitch in time saves nine", how much has the delay in culling of infected setts increased the number of infected badgers, requiring more badgers to be culled to control the disease?

Matthew said...

In PQ's the minister described bTb in badgers as 'endemic'.

The problem becomes an 'epidemic' (Minister's description - not ours) in regularly tested cattle when stress / overcrowding / changes to badger habitat or weather (or the fractured attempts of the RBCT) bring about the inevitable shake out in population known as 'peturbation'. The territorial scrapping which follows, kick starts latent disease from 'infected' status, to 'infectious' with inevitable consequences to cattle and other mammals who contact the bacteria - including and especially other badgers.

PQ's showed that bite wounding and within-group transmission in the confines of the sett were the primary means of bTb spreading throughout the badger population.

The tight social grouping of badgers means that the spoligotypes of bTb found in the populations, hasn't moved a great deal (except where they have been translocated) in all the many years VLA have been logging this information, and these strains are tightly mirrored by reactor cattle slaughtered.

It is our experience as cattle farmers, that infectious disease will ripple through a badger population (as shown by the sentinel cattle tests ) at about 6 miles / year. Thus the original 7/8hotspots shown red on MAFF /Defra maps in 1996 - 97 have now practically joined to give an area from the tip of Cornwall to the north Midlands and Wales are coloured red - indicating that the parish has had at least one confirmed case of bTb. As with our own contributers, herds now affected had been clear for 40 - 50 years.

The cost of this can be measured in the cattle test results.
After the countrywide sweep of cattle herds in the 1950's and 60's, these small but stubborn pockets of infection remained, and were linked to wildlife (badger)interface in the early 1970's.

During the 70's and early 80's, any outbreak of Tb in cattle which was not traced back to a cattle movement, was followed by gassing of badgers in a 'clean ring' around the outbreak. This stopped at about 7km or when badgers tested clear on pm.

In the mid 1980's GB had less than 100 herds under restriction, and culled 686 cattle in the year.

Gassing was replaced by cage trapping and land available for that limited to 1 km from the outbreak farm, and to land 'grazed' by cattle only. Not arable, woodland or neighbouring farms or orchards. The inevitable rise was seen as slowly the hotspots became bigger, until in 1997 all badger culling stopped - except in the areas of the RBCT, where it was attempted for 8 nights only on main setts using traps. The figures from badger pms. undertaken in the 90's quoted in the ISG 4th report show up to 84 per cent were infected (Broadway, Worcs.)

The Tb cattle stats. for 2007, after twenty years of hand wringing and prevarication following shrill shrieks from 'activists', is 6,532 herds affected during the year - almost 8 per cent., and 28,175 cattle slaughtered.

So you are quite right in suggesting that 'a stitch in time' would have saved taxpayers' money and also much suffering on behalf of the badger population. Prof. Steve Harris offered an alternatiive to the RBCT in 1996, to the then minister where he wanted to clear out the seven hotspots - a sensible solution.

The solution now is more complicated, as while 'wipe out' works (Thornbury etc.) it is unachievable on the scale necessary. The alternative is to let the badgers do the work, and use their selection of infectious inmates to cull only infected satellite sets, leaving a main sett intact. And well spaced out so territorial scrapping does not occur.

A book we read several years ago "Badgers without Bias" published by the Avon Wildlife Trust, commented that with ultimate protection and endemic disease, without a management strategy, badgers would suffer more rather than less from the misplaced total protection afforded to them.

At the time we don't think even the authors of that statement foresaw the carnage that would cut through the cattle herds from such inaction and imaginative prevariaction.

Neighbouring Glos. now has over 27 percent of its herds affected by a Tb restriction, Hereford/Worcs 26 per cent and the smaller Avon itself, 14 percent.