Thursday, September 27, 2012

Save the Badger... ??

A stunning piece of artwork behind Dr. Brian May, backed by the RSPCA and fellow travellers, this picture is an amazing piece of PR. It may stir the hearts of his followers, but is it accurate?
Dr. May says he wants to 'Save' badgers. But obviously not from tuberculosis.

Cattle farmers  regularly see badgers in the later stages of tuberculosis, crawling around their fields and buildings in an emaciated and distressed state, coincidentally, often just before losing a shed load of cattle. But they don't look anything like the sleek, iconic beast behind Dr. May.

They look like this.

So in the interests of accuracy rather than spin, we invite Dr. May to pick up a badger with tuberculosis to advertise his aims . This one is rather messy, his tuberculous neck abscesses having burst... 

But it may look something like this. Now obviously this badger would not attract nearly so much attention ..... or funding. It may however attract sympathy for its plight and the manner of its death.

A victim of its protector's success.

Sunday, September 23, 2012

How much is enough?

When people (who should know better)  talk about vaccinating badgers, because this over time 'reduces transmission opportunities', what exactly do they mean, and in the case transmission to cattle, by how much?

As we pointed out in many previous posts about this subject, including the posting below, the amount of bacteria left behind is crucial to a sentinel tested cow. And although we are not in the habit of making assumptions, presumably to many other species too.

Secretary of State, Owen Paterson's Parliamentary Questions queried this and received the following answer on January 29th 2004:
Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs pursuant to the answer of 8 December 2003, Official Report, column 210W, what the presumptive infective dose range of M. bovis is in respect of cattle; and whether some badgers suffering from bovine TB are capable of excreting sufficient numbers of M. bovis bacilli to constitute such an infective dose. [150526]

Mr. Bradshaw: Determination of the minimum infectious dose of Mycobacterium bovis in cattle is part of the TB pathogenesis research programme. Early indications are that the minimum infectious dose for cattle via the respiratory tract is relatively small; the lowest infectious dose recorded so far is 70 colony forming units (CPU) when introduced by the intracheal route or 9,600 CPU by the intranasal route.

Relatively high levels of M. bovis in the urine of badgers with renal TB have been identified. Bacterial loads of up to 300,000 CPU per millilitre of urine have been measured. This suggests that inhalation of as little as 0.03 ml of the urine could result in infection.
 Thus up to now, 70 CPU has been the figure which we have quoted. But coming in under our radar, and once again published in the USA is a paper   prepared by our own VLA which has downgraded that figure to just 1 CPU for calves. The paper explains that four groups of calves were infected with 1,000, 100, 10 or just 1 CPU of M.bovis.  These animals were skin tested twice and blood tested, then subjected to rigorous post mortem. The results were described thus:
 One-half of the animals infected with 1 CFU of M. bovis developed pulmonary pathology typical of bovine tuberculosis. No differences in the severity of pathology were observed for the different M. bovis doses. All animals that developed pathology were skin test positive and produced specific IFN-γ and IL-4 responses. No differences in the sizes of the skin test reactions, the times taken to achieve a positive IFN-γ result, or the levels of the IFN-γ and IL-4 responses were observed for the different M. bovis doses, suggesting that diagnostic assays (tuberculin skin test and IFN-γ test) can detect cattle soon after M. bovis infection regardless of the dose.

So 1 CPU of M.bovis is all it takes to infect a calf. Is this one 'safe'? Does anyone care?

As it is established that badgers can excrete up to 300,000 CPU (colony forming units) of bacteria in each 1 ml of urine, we would respectfully point out, that the amount of  'bacterial reduction' achieved by vaccinating an unscreened population of tuberculous badgers, has to go down a very long way for it not to affect our tested sentinels.

This paper was primarily about the minimum infectious dose needed to infect cattle, but not from any particular source. So we share the author's 'comfort' that the skin test found all the infected cattle.The summary is as follows:
In summary, we found that 1 CFU of M. bovis is sufficient to cause established tuberculous pathology in cattle. This pathology is identical to that resulting from significantly higher experimental doses (up to 1,000 CFU in this study) and reflects the pathology seen in naturally infected field reactor cattle. Cattle infected with 1 CFU that developed pathology exhibited strong positive responses to the diagnostic tuberculin skin test. Furthermore, the infectious dose of M. bovis had no bearing on the time taken to obtain a positive IFN-γ response in the animals that went on to develop pathology.
Our data are in accord with very low numbers of bacilli transmitted aerogenously between cattle, potentially by nasal shedding. Comfortingly, the animals that do go on to develop pathology and therefore become a likely source of contamination within a herd can be detected at an early stage with the IFN-γ test and also provide a positive tuberculin skin test response.

Quite. We kill all our positive skin test reactor sentinels, and leave their herd mates free to be infected by just 1 CFU of M.bovis. Very sensible.

Edit: The term CFU or CPU is a pathological term meaning a cluster of single bacteria, capable of establishing disease. Although Owen Paterson's  PQ referred to CPUs and the second paper CFUs, essentially they mean the same. A colony forming or producing clump of single m. bovis bacteria. 

Tuesday, September 18, 2012

Vaccination myths

We are hearing the 'V' word from numerous sources at every photo opportunity at the moment. Vaccination is the holy grail for bTB it seems. But does it work? We covered the debacle surrounding badger vaccines in several postings as the Myth unfolded in 2010. As that 74 per cent efficacy lie bounced round the world, courtesy of the BBC and FERA, very belatedly Defra told its advisory group that 'the data should not be used to support this claim', and Jim Paice found the headline was 'misleading and unhelpful'.

Nevertheless, on the basis that it did no harm to badgers, BCG was licensed as a Limited Market Product by the Veterinary Medicine Directorate (VMD) and is now being administered to un-screened populations of badgers in several parts of England and Wales. And the reason?

 In 2011 Defra published this little gem:
a): Bovine tuberculosis Animal species: Badger vaccination: Description of the used vaccination, therapeutic or other scheme Badger BCG licensed in March 2010 has been used as part of the Badger Vaccine Deployment Project to build farmer confidence in vaccines as a key tool in an eradication programme.
To build farmer confidence? What an extraordinary reason for promoting a vaccine which doesn't work.

 So what about cattle vaccination?
 Many people, some of whom really should know better, slip this into their conversations at every opportunity. If we vaccinate the cattle (who are telling us the true level of badgerTB in our increasingly polluted environment) then all will be well? No it will not. It's far to late for that, even if it were effective or affordable. Despite Defra's contorted gymnastics to dumb down its own statistics for over spill into other mammals, it is happening on a wide and increasing level.

But back to BCG for cattle. Weybridge VLA have published a report where sentinel vaccinated yearling cattle were kept with reactor cattle in 10 pairings for twelve months. Post mortem results from this study published in Vet.Record found that the pen level transmission rate was 50 per cent but crucially:
"There was no difference in the number of infected sentinels in the non-vaccinated or vaccinated groups."
This should come as no surprise, as Defra put its collective thoughts into this paper in 2007 which gave efficacy of cattle BCG little encouragement:
Annex 3. 6:3. A BCG vaccine is likely to confer full protection against M. bovis infection to 50% of vaccinated animals. For both the epidemiological model and economic assessment it is assumed that the protection conferred will last a lifetime. Of the remaining 50% that remain susceptible to infection, it is estimated that over half will be partially protected and have a much reduced capability of transmitting M. bovis should they become infected. The benefits of vaccination are likely to last for at least 12 months.
The cost is assessed at £8.25 per dose. The skin test is still mandatory and thus the DIVA test which differentiates between vaccinates and infection, must be used. So how accurate is that?
2.5.2: The DIVA test would be used when a vaccinated animal gives a positive reaction to the skin test (i.e. will be used as an ancillary test to the skin test). In such cases the DIVA test will confirm whether the animal is indeed infected or whether the positive response to the skin test is due to vaccination with BCG. 62. However, the nature of the test makes it impossible to guarantee the disease status of an animal. As with existing antemortem diagnostic tests for TB, there will be a number of false positive and false negative test results since neither the specificity nor the sensitivity respectively is likely to be 100%. The diagnostic accuracy of the new test will have to be assessed in field trials of herds of known TB status, which has already been done for some prototype DIVA reagents. In order to get the test accepted in EU legislation it will need to be at least as good as the current skin test in terms of sensitivity. However, data is available to suggest that the prototype DIVA reagent will satisfy this criteria, although as noted above this will need to coincide with the recommended age of vaccination.
So giving variable sensitivity / specificity, the DIVA test will cost around £26.00.

 Trade implications are huge, in that a number of both International and EU directives would need to accommodate this country's love affair with wildlife infected with tuberculosis. Withdrawal periods for vaccines and bans on all exports out of vaccinated 'zones' are mentioned.

So in summary, Defra say they are 'pump priming' farmers to accept vaccination, however futile its efficacy - and they will have to pay for it. All of it. As explained in this posting which invites farmers to have a 'conversation' with them.

Sunday, September 16, 2012

Defra invite a 'conversation'.

Our cash strapped Department of Environment, Food and Rural Affairs cordially invite all interested parties to 'engage' with them, on how they can screw cattle farmers even more save money from their TB budget.

Some of the ideas being bandied about are on this link.

It would be churlish to point out that if they'd kept a handle on infected wildlife two decades ago, they wouldn't be in this position, but we'll do it anyway as the patronising language phrasing this proposed cash grab is - irritating in the extreme. A 'conversation' implies a two way dialogue, but bitter past experience has proved this not to be case with Government. And successive 'consultations' have only served to show that Defra will do what they like, having 'consulted', regardless of replies.

We note that these reductions  proposed changes seem only to apply to farmers under restriction and their reactor cattle. So vets are not being asked to jab one, jab one free? Rhetorical question, as the EU's latest broadside has doubled testing requirements for many - hence doubled the cost to Defra.

Your views can be emailed to
Or you can write to: AHWBE (Bovine TB Call for Views), Nobel House, 17 Smith Square, London SW1P 3JR.

The AHWBE is also planning four open events in Exeter (September 18), Pulborough in West Sussex (September 25), Telford (October 2) and York (October 11).

Wednesday, September 12, 2012

"UK politicians must accept their responsibilty... their own farmers and taxpayers as well as to the rest of the EU and commit to a long-term strategy that is not dependent on elections."

 This is the conclusion of the latest European Union report on Defra's efforts (sic) to comply with their assigned international obligation to eradicate bovine TB.

We touched on the most recent tranche of cattle measures, in this posting as our masters in the EU deftly unravelled almost all the measures put in over the last decade in order to allow farmers to trade while under TB restriction. These measures all had the effect of pushing further into the long grass, the question of what to do about the main cause of their problems.

In 2006, DG SANCO, the department responsible for Health and Consumer Affairs in Europe had this to say  about Defra's prevarications. They visited again this spring and their full report can be viewed on on this link.

Its conclusion is unequivocal.
"It is however of utmost importance that there is a political consensus and commitment to long-term strategies to combat TB in badgers as well as in cattle.

The Welsh eradication plan will lose some impetus as badger culling will now be replaced with badger vaccination. This was not part of the original strategy that consisted of a comprehensive plan that has now been disrupted.
There is no scientific evidence to demonstrate that badger vaccination will reduce the incidence of TB in cattle. However there is considerable evidence to support the removal of badgers in order to improve the TB status of both badgers and cattle.
UK politicians must accept their responsibility to their own farmers and taxpayers as well as to the rest of the EU and commit to a long-term strategy that is not dependent on elections.

The TB eradication programme needs continuity and it must be recognised that success will be slow and perhaps hard to distinguish at first. There is a lot of skill and knowledge among the veterinary authorities and they must be allowed time to use it."

There is nothing we could add to that.

Tuesday, September 04, 2012

Welcome Back!

A resounding welcome back to Owen Paterson, MP whose new appointment is Secretary of State for Environment, Food and Rural Affairs (Defra)

It was Owen Paterson's Parliamentary Questions on bTB and more importantly, their answers, which form the basis of this site. When he was Shadow Minister, the number of cattle herds having TB problems in Great Britain was 5.6 per cent, a figure which shocked him. Last year that total had almost doubled to10.07 percent. The number of cattle slaughtered in GB during 2004, (the year Owen asked the PQs ) was 23,000. Last year Defra sent  34,617 to their  premature deaths. The spillover into other species, especially camelids, had just started in 2004 and Defra recorded 6 herds with at least 1 infected animal 1999-2004.  We will post again on their contortionist gymnastics to avoid the question,' how many alpacas have you killed today?' But infected herds of camelids, (not individual deaths) we are told, now stands at 60.

A full biography of Owen Paterson is  here from Alistair Driver at Farmers Guardian.